- General information
- Basic technologies
- Radio access technologies
- Cellular network
- Signal processing
- Video communications
- Customer identifications
- Signal encryption
- Terminal position detecting
- Network design
- Software in cellular phones
- Electronics in cellular phones and portable communication devices
- Personal Digital Assistants technologies
- Mobile applications
- Mobile data
- Cellular phone safety
- Cellular phone jamming and detecting
- 1G Introduction
- 1G Introduction
- 2G Introduction
- Enhanced GSM data
- Short messsage service (SMS)
- Multimedia Messaging Service (MMS)
- Other 2G systems than GSM
- CDMA Based cellular phone systems information
- Third generation mobile phone systems
- Other cellular phone systems
- 4G Mobile communications
- Cellular phone design articles
- Mobile phone hacking
- Cellular phone modifications
- Controlling cellular phone
- Build cellular phone accessories
- Cellular phone internals and connectors
- Cellular phone codes
- Cellular phone software, logos and related information
- Ultra Wide Band (UWB)
- Satellite telephones
- Unsorted mobile communication links
Mobile communications page
- 1G (first generation): This described the early analogue cellular phone technologies. For example NMT and AMPS cellular technologies belong to this category.
- 2G (second generation): This described the generation of first digital fidely used cellular phone systems. GSM technology is the most widely used 2G technology. This gives you digital speech and some limited data capabilities (circuit switched 9.6 kbit/s). Other 2G technologies are IS-95 CDMA, IS-136 TDMA, and PDC.
- 2.5G (two and half generation): This is an enhanced version of 2G technologies. This gives higher data rate and packet data services. GSM system enhancements like GPRS and EDGE are considered to be 2.5G technologies. The so-called "2.5G" systems represent an intermediate upgrade in data rates available to mobile users.
- 3G (third generation): Third generation mobile communciation systems often called with names 3G, UMTS and W-CDMA promise to boost the mobile communications to new speed limits. The promises of third generation mobile phones are fast Internet surfing, advanced value-added services and video telephony. Third-generation wireless systems will handle services up to 384 kbps in wide area applications and up to 2 Mbps for indoor applications.
- 4G (fouth generation): It has not been widely defined what this is. 4G is intended to provide high speed, high capacity, low cost per bit, IP based services. The goal is to have data rates up to 20 Mbps. Most propable the 4G network would be a network which is a combination of different technologies (current celluart networks, 3G celluar network, wireless LAN, etc.) working together usign suitable interoperability protocols (for example Mobile IP). There are also views that 4G could be some entirely new radio access technology.
- 5G (fifth generation): There is no clear definition what this is. This wil be somethign more advnaced than 4G.
- 3G (third generation): Third generation mobile communciation systems often called with names Rate this link
- 4G (fouth generation): It has not been widely defined what this is. 4G is intended to provide high speed, high capacity, low cost per bit, IP based services. The goal is to have data rates up to 20 Mbps. Most propable the 4G network would be a network which is a combination of different technologies (current celluart networks, 3G celluar network, wireless LAN, etc.) working together usign suitable interoperability protocols (for example Rate this link
Introduction to modern mobile communications
The most modern telephone is the cellular telephone, or commonly called a cell phone. A cellular telephone is designed to give the user maximum freedom of movement while using a telephone.Mobile communications is a hot topic. The number of mobile communicationdevices users is growing very fast. The number of mobiles (cellular phones)is now exceeding the number of fixed lines in many countries(Finland, Japan etc.).Cellular/mobile phones are everywhere and their utility is growing. A cell phone is a radio telephone, that may be used wherever "cell" coverage is provided. The role of cellular phones has risen with improvement in services, reduction in service costs and the ever increasing services available through cell phones.Mobile Internet access is a global phenomenon with even great implications.Leading phone manufacturers such as Ericsson, Matsushita (Panasonic), Motorola, and Nokia have put a great deal of marketing effort behind the mobile Internet phenomenon, recognizing that adoption is a complex business proposition. In Europe, WAP is has generated widespread interest because of lots of marketing and expectations put to it. In Japan NTTDoCoMo's mobile Internet service is based on a service called iMode that uses Compact HTML (CHTML) microbrowsers in the phone.There are also products on the market which combine a PDA, a real web-browser and some communication interface (cellular phone, WLAN etc.) into one smart communication device. A the generic phone may soon acquire a browser. And mobile phones will morph into PDAs or organizers. The markets will show what customers will buy and use. The handsets sold over the next few years are likely to operate much differently than those of today. Mobile terminals are complex embedded systems, with stringent real-time requirements for signaling and voice processing. Now Web browsing, multimedia, and connectivity requirements are added to the list.There are many technical challenges to be solved to make all this to work.Ubiquity is a pinnacle that the cellular communication sector has hoped to reach for the past five years. To reach this goal, a series of networks must be built that allow consumers to use their phone anytime, anywhere.The truth is ubiquity is far from becoming a reality. Across the world cellular carriers can't seem to agree on a single air interface for wireless operation.But, despite battles on the standards front, the wireless community has pushed forward in its efforts to build mobile networks and phones that deliver worldwide coverage. To make this happen, they have focused their attention on developing multimode systems that can support CDMA, TDMA, GSM, GPRS, wideband CDMA (W-CDMA), and a host of other air interfaces in the same box. Nowadays the mobile communication technology seems to be divided to differente generations of technologies. A short description thosegenerations are the following:
- allNetDevices - on-line publication for network devices Rate this link
- A Wireless World - As demands on both my time and my physical presence begin to increase, it's all too apparent that mobility is key. However, there are several issues, including getting the darn devices to work, that must be attended to. Rate this link
- Cell Phone Carriers - one stop source for cell phone information, tips, advice, features, history, deals and specials Rate this link
- Cellular Communications Tutorial - A cellular mobile communications system uses a large number of low-power wireless transmitters to create cells?the basic geographic service area of a wireless communications system. Rate this link
- Cellular Telephones Health Issues Rate this link
- Development of mobile communications in Finland - text in Finnish Rate this link
- EDN hands-on project: All-in-one cell phones - not a one-for-all panacea - If you take a sufficiently powerful and feature-equipped digital cellular phone when you hit the road, can you leave your PDA and notebook PC behind? In some cases, the answer is a resounding "no way." But if your needs are more moderate, cellular-centric slimming may be in your future. Rate this link
- EDN Special Supplement: The Wonders of Wireless - articles on technology and standards on 3G, WLAN, Bluetooth, GPS and related wireless technologies, document is in pdf format Rate this link
- Emerging Technologies Promote "Post-PC" Era - there are lots of emerging technologies for wireless applications Rate this link
- Enhanced Services Messaging Tutorial Rate this link
- Generation Wireless - Vendors and carriers are working to develop and deploy the next generation of wireless systems, often referred to as 2.5G, which is packet-based and increases data communication speeds to as high as 384 Kbps. This document describes what is coming in near future. Rate this link
- How a Cell Phone Works Rate this link
- Mobile World - general mobile telephone topics portal Rate this link
- Peering through the peer-to-peer fog - In spite of all the hype about peer-to-peer computing, some useful applications have emerged from this not-so-new computing model. Rate this link
- Pervasive computing: a computer in every pot - The success of the Web, wireless connectivity, and the commoditization of computing are creating a world in which you can buy a movie ticket at a soft-drink machine or your house can remind you where you left your keys. Rate this link
- Speeding Up Wireless Standards Development - Quality assurances and time-to-market concerns are always on the minds of wireless systems designers. Fortunately, there is the specification and description language (SDL) to help speed up the development process. Rate this link
- The Next Big Thing...The Cell Phone - The real wireless revolution is being driven by the cell phone -- and is already creating rich opportunities for huge players and small startups alike. Rate this link
- Ultrawideband: an electronic free lunch? - We may soon be sharing our cell-phone, television, satellite, networking, and emergency-radio frequencies with a radically different wireless technology that spreads tiny portions of its signal under the noise floor of existing communications bands. Rate this link
- Where has wireless been? - Exactly 100 years since Marconi demonstrated that radio waves defy the curvature of the Earth, "wireless" is again all the rage. So where has it been, asks Ryan Dilley. Rate this link
- Why can't I use my cell phone on airplanes or in hospitals? - Why are these prohibitions in place? Rate this link
- Wireless.national.com - web community for wireless design research, news and product information from National Semiconductor Rate this link
- Wireless Planet - page about AVL system, GSM modem, GSM module, GSM / GPS antenna Rate this link
- Wireless Resources tutorial - from nuts and Volts magazine at January 1998 Rate this link
- Worldwide Wireless Telecommunication Standards - comparision table Rate this link
- 1864 James Clerk Maxwell presented the Maxwell Equations for electromagnetic radiation
- 1876 Alexander Graham Bell invented the telephone.
- 1887 Heinrich Hertz discovered "hertzian waves" which are now called as radio waves.
- 1896 Guglielmo Marconi carried out the world?s first radio transmission.
- 1st generation: analogue transmission: AMPS (Advanced Mobile Phone System) in USA, TACS (Total Access Communication Service) in Europe, NMT (Nordic Mobile Telephone), and others
- 2nd generation: digital transmission: GSM (Global System for Mobile Communications), ERMES (European Radio Messaging System) - paging, CT2, CT3 (Cordless Telephone Standards), DCS 1800 (Digital Communication Service), DECT (Digital European Cordless Telephone)
- 3rd generation: unification of different technologies: FPLMTS (Future Public Land Mobile Telecommunication System), UMTS (Universal Mobile Telecommunication System), IMT-2000 (International Mobile Telecommunication)
The origins of radio communications are in the 19th century.
- The absorption of radio signal power (air and surrounds absorb signal)
- Signal refelctions caused by the ground and obstacles (signal detected in the receiver is a sum of direct and reflected waves which can cause an effect known as fading)
- Co-channel interference (distant radio transmitters on the same frequency will disturb the reception)
- Intermodulation distortion (transmitters on different frequencies can disturb each other)
- Background noise in receiver (thermal noise generated by the receiver electronics itself)
- Atmospheric noise (bursty noises from thunder storms and similar)
- Industrial noise (RF noise from electronics, sparks)
- Advanced wireless technology revamps spectrum analysis - Spectrum analyzers may not be changing overnight, but, by borrowing technology from the systems whose signals they analyze, today's RF analyzers bear little resemblance to your father's instruments. Rate this link
- Efficient GMSK Modulator Targets GSM Designs - New modulator takes advantage of the inherent symmetry of the Gaussian filter to generate a baseband-modulated signal using a look-up table. This article details the proposed GMSK modulator and discusses how it compares to traditional GSM modulator architectures. Rate this link
- Evaluating BER in wireless systems: confidence in waterfall curves - To effectively test the performance of wireless systems, you need to understand their underlying error probability and the trade-offs between confidence, accuracy, and test time. Rate this link
- Gaining Control of CDMA Power - Through the use of system-level design techniques, wireless systems developers can more efficiently design, optimize, and test power control algorithms in IS-95A CDMA handset and base station products. Rate this link
- Maintaining cellular connectivity indoors demands sophisticated design - Providing users with seamless cellular connections inside structures requires a different type of engineering thinking. Rate this link
- Paving Paths to Software Radio Design - The lines between ASICs, FPGAs, and DSPs are blurring. With that in mind, designers must rethink product selection in their software radio architectures. Rate this link
- Paving the Way for Software Definable Radios - Handsets that support multi-operational modes and frequency bands will rely on "breakthrough technology" to achieve advanced functionality. Rate this link
- Piecing Together the Bluetooth/Mobile Phone Puzzle - Mobile phones are seen as the biggest growth sector for Bluetooth radios. Embedding this radio in a mobile architecture, however, causes big RF and software integration challenges. Rate this link
- Polarizing RF Transmitters for Multimode Operation - With standards still in flux, base station and handset developers must build multimode systems that support CDMA, W-CDMA, GSM, and more. By using polar modulation, designers can make these systems a reality. Rate this link
- RF transistors meet wireless challenges - Discrete RF transistors, using a variety of processing techniques, are proving their mettle in the demanding world of wireless communications. Rate this link
- Spread-spectrum communication rises from military roots to star in wireless world - From high data security to effective spectrum use to improved noise immunity, spread spectrum offers it all. But these virtues, though inherent in the technology, don't come automatically or easily to real systems. Rate this link
- Time Division Multiple Access (TDMA) Tutorial - digital transmission technology that allows a number of users to access a single radio-frequency (RF) channel without interference by allocating unique time slots to each user within each channel Rate this link
- The Effect of CDMA-Receiver Minimum Standards on RF Systems - A Guide to the Derivation of Essential Specifications (Block Level and RF-Front-End Level) for the Receiver Section of a CDMA Mobile Station Rate this link
- Web Exclusives: Fundamentals of TDMA-receiver testing - article in pdf format Rate this link
- Antenna Considerations in the Deployment of Wireless Broadband Networks - Antenna selection for wireless broadband networks is critical, due to the technology's inherent line-of-sight limitations. Rate this link
- Antennas: critical links in the wireless signal chain - right antennas can strengthen the chain by yielding better signal coverage, increased S/N ratio, reduced bit error rate, and lower power consumption all at very low cost Rate this link
- Basics of Dual-Polarized Antennas Tutorial - information on special antennas used in celluar networks Rate this link
- Cellular Phone Antennas and Human Health FAQ - Nokia and Ericsson: The sexy hipster vs. the button-down engineer Rate this link
- Designing dual-band internal antennas - You can fit most cellular phones with an internal antenna if you gain a thorough understanding of the physics of the problem and if your performance expectations remain consistent within some fundamental limits. Rate this link
- GSM1800 Moxon Square Antenna - If you are looking for an easy-to-build, ultra-cheap and good performance antenna to extend the range of your GSM1800 band cellular telephone, you've come to the right place. This little antenna claims works much better than the small tip found in most cell-phones. Rate this link
- Guidelines Geared Toward Antenna Design - Learn what the experts know about designing antenna systems that really work, from mobile devices to base stations. Rate this link
- Operation of conformal handset antennas in the presence of human body - The objective of this thesis is to compare a planar inverted-F antenna, which resonant at 1800MHz, with a conformal PIFA antenna and investigate their performances in the presence of human body. With the results, the feasibility of the adoption of conformal PIFA in modern handset will be determined. Rate this link
- Smart Antenna Design: Antenna Diversity Rate this link
- Smart Antenna Systems Tutorial - A smart antenna system combines multiple antenna elements with a signal-processing capability to optimize its radiation and/or reception pattern automatically in response to the signal environment Rate this link
- Reduction of mobile terminal and base station transmitting power compared to many other radio systems
- The dynamic allocation of frequencies during the call
- The reuse of frequencies in cells separated far enough apart
- Increased number of subscribers
- DSPs for next-generation cell phones balance performance and power - DSP vendors are fighting the battle on several fronts for high-performance, low-power operation and offering scalable architectures and optimized instruction sets. Rate this link
- Mastering Turbo Coding for Wireless Apps - Turbo coding has become a key ingredient in the 3G system design process. Here's a look at the key elements of a turbo coder as well as some implementation issues. Rate this link
- Simplifying Direct-Conversion Tx Paths in Wireless Designs - Much attention has been given to reducing BOM costs through direct-conversion receiver schemes. These same benefits can also be attained through the implementation of direct-conversion transmit paths in wireless designs. Rate this link
- System-Level Design Tackles Tough Soft Radio Framework Challenges - Recent design trends tends to add layers and virtualization even to high-rate and hard real-time systems such as wireless receivers. System-level design tools and high-level frameworks, such as the software communication architecture (SCA) developed within the Software Defined Radio (SDR) Forum, are serious threats to the "good old days" of "classical" C and VHDL programming approaches for DSP and/or FPGA/ASIC wireless systems. Rate this link
- Array Processors Enable Flexibility in FFT Designs - Reconfigurable processors allow designers to implement FFT architectures in OFDM-based comm systems that can adapt to changing standards. Rate this link
- Gearing Up For Wireless Video with Compression - Sophisticated video compression standards, like MPEG-4 and H263, make realtime video streaming on wireless handsets a reality - but not without some complexity. Rate this link
- Wireless Video--Get The Picture? - Today, wireless video is in the transitional phase between the "advanced prototype" and "functional solution with practical application"--what Geoffrey Moore might call, "crossing the chasm." All of the enabling technologies currently exist and are either in the market, beginning to be deployed, or will become available over the next 18 months. There is little doubt that these technologies will make widespread, global wireless video a reality. Rate this link
- Wireless Videophones and Windows CE - The increase in wireless bandwidths over the next few years puts us on the verge of making wireless video as common as the cell phone in your pocket. Rate this link
- Smart Cards in Wireless Services Tutorial - presents a business case for the use of smart cards or subscriber identity modules (SIMs) in the marketing and network operations of wireless communications operators Rate this link
- Secure Your Wireless Future - The recent trend toward Internet-enabled wireless devices has prompted rapid growth of the mobile-commerce (m-commerce) marketplace. For this market to really take off, users must feel comfortable transferring personal and financial information via their wireless Internet connection. As a result, the issue of security takes on renewed interest. Public-key-cryptography systems (PKCS), in particular, will play a central role in providing users with the required level of comfort they desire. Rate this link
- Smart Antenna Schemes For E-911 - With 2001 quickly approaching, designers of wireless systems are faced with meeting an FCC mandate for E-911 functionality. By combining smart antenna technology with direction-of-arrival (DOA) algorithms, engineers can develop systems that provide accurate location information Rate this link
- Introducing circuit and packet switching - There's much talk about the coming mobile internet, about how people will have a wireless, always on connection to the web. How will that come about? In two words, packet switching, a fundamental, elemental change between how wireless was delivered in the past and how it will be presented in the future. Rate this link
- Modeling Maximizes Wireless Telephone Network's Effectiveness - congestion in wireless telephone networks can be greatly reduced through accurate up-front modeling Rate this link
- Wireless Intelligent Network (WIN) Tutorial - a concept being developed to drive intelligent network (IN) capabilities into wireless networks Rate this link
- Wireless Internet Network Communications Architecture Tutorial Rate this link
- Software Bugs Mobile Phones - Until recently, software for cellular telephones has been developed entirely in-house, but the growing demand for more complex software is making the task more difficult. As a consequence, the industry is now frequently outsourcing software components, and introducing techniques to improve the development process. Rate this link
- Advanced Displays Bring Mobiles to Life - While advances in LCDs will continue to extend their viability well into the future, research into alternative display technologies is starting to bear fruit. Efficient, high-contrast organic and polymer LEDs, along with flexible plastic displays, are readying a coup that could spell the demise of the humble LCD. Rate this link
- Dynamic voltage scaling conserves portable power - With portable applications on the rise, designers are turning to dynamic power-conservation techniques to delay the inevitable dead battery. Rate this link
- EDGE Handsets: Baseband Processing Methodologies - The EDGE protocol has quickly gained acceptance in the wireless market. As designers begin to rollout EDGE-based systems, they must re-architect the baseband portion of their mobile phone designs so that they can support voice and data functionality. Rate this link
- Energy Management for Small Portable Systems - Numerous diverse and conflicting constraints burden the designer of small hand-held products Rate this link
- Low-power operation is a state of mind - Achieving low power requires a certain mindset. The straightforward way to turn the heat down is to re-evaluate clock sources or to reduce the power-supply voltages. Another equally effective approach is to operate with a partial or a complete controller/processor-shutdown mode. But if you combine these techniques with execution time and a little intelligence, you can easily tackle your most challenging power-conservation problems. Rate this link
- Mobile phones put the squeeze on battery power - powering mobile phones from fewer cells focuses attention on every aspect of battery discharge Rate this link
- Thin, flat, and low power: The ideal display is (still) just around the corner - New display-technology options are opening up, led by the long-awaited introduction of OLED products. Rate this link
- Reducing audio "buzz" in GSM cell phones - The pulse rate for GSM is within the audio band, and the dc current and RF energy readily convert into an objectionable audio "buzz" within the phone's circuitry. You can minimize the buzz if you take precautions early in the design stage. Rate this link
- EDN hands-on project: building pocket power - Astonishing portable computing and growing popularity and power has lured legions of system developers to the Pocket PC platform. This hands-on project examines the software tools that you can use to build your own pocket applications. Rate this link
- Gaming as serious business - Snicker about playing games at work, but the low cost, appropriate features, and availability of Gameboy resources might change your mind about using it as a nongaming, handheld terminal. Rate this link
- handhelds.org - site to encourage and facilitate the creation of open source software for use on handheld and wearable computers Rate this link
- Microdisplays Play Larger Role In Emerging Internet Appliance Designs Rate this link
- PDABuzz - PDA tips, news and discussion Rate this link
- Power down for portables - A big battery can mean small market share. Reducing power consumption in your portable digital device is the "green" thing to do, as in money. Rate this link
- Tucows PDA section - PDA information and software Rate this link
- Wireless application protocol stimulates 3G mobile telephony - Fast-moving developments affect products at all levels. Designers must be nimble to meet the market and reality. Rate this link
- Secrets of the wireless elite: Mobile applications need scripting too! - Mobile game developer Tom Park believes that scripting for wireless devices is important for proficiency sake. And with the need to scale mobile applications across so many different platforms, proficiency is everything. Rate this link
- Effects of radio frequency fields: Electromagnetic field and public health - Radiofrequency (RF) fields are part of the electromagnetic spectrum. For the purpose of the International EMF Project, such fields are defined as those within the frequency range 300 Hz (or 0.3 kHz) and 300 GHz. Natural and human-made sources generate RF fields of different frequency. Rate this link
- Electromagnetic fields page by The World Health Organization (WHO) - This page provides links to descriptions of activities, reports, news and events, as well as contacts and cooperating partners in the various WHO programmes and offices working on this topic. Rate this link
- Mobile Telephones and Their Base Stations Safety Fact Sheet Rate this link
- Interception Technology May 'Capture' Your Cell Phone - The device works by duping a cell phone into thinking it's the "cell tower" of choice. Once the unit has "captured" the phone, the system instructs the phone to move to a channel that is not active in that cellular system, prohibiting the phone from receiving communication from its normal base station. Rate this link
The vast majority of today's voice-only (2G) wireless communications devices were originally based on a dual-processor architecture. A digital signal processor (DSP) handled many of the communications tasks, such as modulating and demodulating the bit stream, coding and decoding to maintain the robustness of the communications link despite transmission bit errors.In addition DSP part usually handles encrypting and decrypting for security, and compressing and decompressing the signal. The second processor was a general-purpose processor, which processed the user interface and the upper layers of the communication protocol stack. The basic dual-processor architecture of 2G will migrate to data-centric 2.5 and 3G devices, but needs to be enhanced.New 2.5 and 3G applications, such as streaming video and others, will change the nature of wireless communication devices. Designers of wireless platforms should be concerned about maintaining a high degree of flexibility.
Radio access technologies
Cellular phone systems use radio access technologies to make the wireless connection between your cellular phone and the base station servicing you at the moment. Modern cellular systems use genrally duplex radio links. They use two different frequencies to communicate. The base station transmits at one frequency, and the cellular phone listens to this. The phone transmit at another frequency, and base station listens to this. Two different radio frequecies are use to be able to make the cellular phone and phase station to transmit and receive signal at the same time without those signals interfering with each other. This how majority of the analogue and digital cellular system work. There is a limited set of frequencies use for transmission and reception and those are called radio channels. In analogue system when phone makes a call, it takes into use one transmitting frequecy and one reception frequency (what the phone uses is controlled by the cellular network). In digital systems the idea is the same, but the modern system allow many phones to share the same frequency using time dividion multiplexing (each phone has a defined timeslow when it can receive and transmit it's data packets, thus many phone can use the same frequency, each at different times). There are limit to the maximum distance from phone to base station communications. The signal power generated by transmitter, receiver sensitivity, antenna performance, distance, attenuation caused by environment and noise in then used frequency band define how long the signal can travel until it becomes unusable. Depending on the environment the signal coverage from the base station to phone can be from few hundred meters up to tens of kilometers. The impairments in radio transmission are difficult to model dynamically because of their unpredictable nature. Typical impairments are:
Antennas are critical links in the wireless signal chain.Right antenna for the application yields a good signal coverage, increased S/N ratio, reduced bit error rate, and lower power consumption all at very low cost.As cellular telephones have evolved over the years, so have their components, particularly the antennas. Cellular phone used to have large external antennas, but nowadays most cellular phones use an internal antenna. Consumers do not (and should not have to) understand antenna theory, but design engineers needs to understand it. . An antenna is fundamentally a transmission line that transforms information from electrical energy (current and voltage) into electromagnetic energy (RF waves). The length of this line is inversely proportional to the frequency of transmission. Therefore, as new wireless applications in the past moved up in the frequency spectrum (Commercial Radio, Broadcast Television, Analog Cellular, Digital PCS, Wireless Data), their antennas correspondingly decreased in size. As an example, a 1/4-wave 4-inch analog cellular "whip" antenna at 800 MHz becomes a 1.5-inch digital PCS "stubby" antenna at 1900 MHz. Old cellular used monopole used retractable antennas (stubby antennas).This kind of monopole antennas are implemented using lambda/4 length. They are the antennas of choice for wireless device designers implementing an external antenna. Typical antennas you will see in more modern cellular is a helix radiator using 1/4-wave or 1/2-wave resonances. The cellular phone antenna radiator is mounted on a plastic carrier, the antenna is a solid and compact unit. On dual band antennas usually 1/4-wave is used for GSM and 1/2-wave for DCS/PCS. Those antennas are generally matched for 50 ohm impedance. A rapid growing market for wireless communication has create a remarkable trend towards the development of integrated antennas for mobile phones. Many modern small cellular do not use external antennas anymore. Those cellular phones use a tiny planar or otherwise miniature special antenna which can be embedded into the phone plastic case. Antennas are slowly becoming more integral as new antenna technology becomes available. Today there are four leading antenna architectures that are commonly used in embedded applications: microstrip, patch, Planar Inverted 'F' Antenna (PIFA) and Meander Line Antenna (MLA).Microstrip lines are an extension of the monopole. They can be easily fabricated by etching a copper strip of 1/2- or 1/4-wavelength onto the radio circuit board. While very inexpensive to make, its performance is limited by surrounding electronics on the circuit board. Microstrip is also only a single-frequency solution.Patch antennas are a good choice for a system that requires a beam pattern focused in a certain direction. Patches are fabricated out of square or round copper clad on the top surface of a circuit board. Their radiation beam is normal to the surface of the board.One antenna type becoming increasingly popular is PIFA (planar inverted-F antenna). The PIFA antenna literally looks like the letter 'F' lying on its side with the two shorter sections providing feed and ground points and the 'tail' providing the radiating surface. PIFAs make good embedded antennas in that they exhibit a somewhat omnidirectional pattern and can be made to radiate in more than one frequency band. PIFA has a low profile, and it can easily be incorporated into wireless handsets.PIFA antennas are generally used with a ground plane, which is generally the cellular phone circuit board ground plane. The MLA (Meander Line Antenna) is a new type of radiating element, made from a combination of a loop antenna and frequency tuning meander lines. The electrical length of the MLA is made up mostly by the delay characteristic of the meanderline rather than the length of the radiating structure itself. MLAs can be designed to exhibit broadband capabilities that allow operation on several frequency bands. For the base stations classical dipoles are very common. The common dipole has long been recognized as an efficient radiator when cut to the appropriate frequency length. It is made from bending the end of an open circuit two-wire transmission line into a 'T' shape, where the top of the 'T' is the radiating section of the antenna. The length of the top is lambda, the wavelength of the signal. In some applications also monopole antennas with lambda/2 or lanbda/4 length mounted over ground plane are used. There are also special antenna constructions for special applications. When you need to flood a wide but defined area with RF energy, such as for perimeter security systems, tunnels, and cellular- or 802.11-system interior zones, one approach is to use an RF-leaky feeder cable to provide controlled radiation.
The idea behind cellular networks is the sub-division of a geographical area covered by a network into a number of smaller areas called cells. The frequencies allocated to one cell can be reused in other cells that are far enough not to disturb. A fixed radio station called as a base station within each cell acts as a transmitter/receiver serving all the mobile stations inside the cell area.A base station controls a group of transmitting/receiving frequencies allocated by the network to that cell. The base station has also the control over subscribers that are currently in the cell area. When a subscriber wants to make a call, the base station allocates a transmitting frequency which is then used between the subscriber and the base station. When the subscriber moves into another cell, a handover takes place, and a new base station takes over the control of the call and assigns a new frequency that is different from the first. The original frequency used in the first cell is released. The cellular concept enables the following features:
Modern mobile communications used lots of very heavy signal processing. Signal processing is generally done in speed coding and for doing complex data signal modulation/demodulation. Signal processing is generally done with DSPs, FPGAs and special ICs.
The digital cellular phones allow voice communications using quite low bit rates. The voice codec system used on digital cellular phone systems allow efficient compression of voice data. The GSM codec, indeed most voice codecs used nowadays, compress the signal by modeling the human voice tract as a tube of varying cross-section excited by a series of pulse trains. The encoder tries to figure out the pulse information and from there derive the transfer function. For unvoiced signals such as fricatives it uses a simpler model excited by noise. The decoder then uses this information to regenerate the guessed-at signal. Lots of research has made to make these sound pretty good for reduced bit rates (typical bit rates 8-14 kbit/s). Most codecs can prioritize your bit allocations, so critical bits absolutely needed for intelligibility are encoded with robust error correction, the next most have CRC checksums and allowed to have errors (for example few lost or broken data packets does not make phone to crash or voice totally unuseable). In any case, voice codecs are not the best way of encoding a music signal. Feeding a music signal through for example GSM codes causes significant amounts of distortion. When thinking of how the codecs work and how much the data is compressed indeed it's quite surprising that music comes through as well as it does.
The Holy Grail of wireless communications is ubiquitous wireless video. Hype has quickly been building around wireless video for the past few years. With 2.5G and 3G systems on the way, many have started to view the delivery of video content to mobile phones as one of the killer apps. The challenge, however, is making this work. Streaming video to a mobile phone places huge strains on the processing engine within these systems. The processing involved in streaming video applications can be divided into roughly two types of functions: control and transport (CT) and media decode (MD).The CT and MD functions have different processing requirements. CT is not computationally intense and mainly involves string parsing, data packet manipulation, and finite state machine implementation (suitable for normal microprocessors). The CTR functionality usually used protocols like real-time streaming protocol (RTSP) session control and real-time transport protocol (RTP) media transport. The MD functionality is much more computationally intense because of the sophisticated signal processing required by audio and video coding algorithms (suitable for DSPs or microprocessor with special multimedia instructions). In the next three years we will see wireless communication speeds go from the existing and rather pathetic 9600 bps to an impressive 384 kbps. This will come about with the implementation of Third Generation mobile networks or UMTS (Universal Mobile Telephony Services).
Terminal position detecting
Software in cellular phones
Electronics in cellular phones and portable communication devices
Running a powerful, potentially power hungry, electronics device from small batteries for long time is a challenge. Paractically all cellular phone devices must incorporate sophisticated power management chips in order to maximize the time that batteries can operate between recharges, minimize charging times and improve the lifetime of the battery itself. Most cellular phones are built in such way that the battery and the charging electronics for battery charging is mostly built into the cellular phone. The cellular phone mains adapers are typically just simple mains adapters that give usually somewhat current limited unrgulated DC to the cellular phone. The votlage from mains adapter to cellular phone is typically in 5-10V range and the current rating us typically in 300-500 mA range. Using wrong type of adapter can damage some cellular phones.
It is also a great EMC challenge to built a cellular phone, because this device includes a quite powerful ratio transmitter, radio receiver, digital electronics and senstive audio electronics all in the same tight package. Mobile-phone designers who build to the GSM standard must sufficiently reduce audio "buzz" so that it is inaudible to users. GSM cell phones use a TDMA (time-division multiple-access) time-slot sharing technique that results in high-power RF in the 800/900- or 1800/1900-MHz bands. The transmitter operating current when it operates is quite high (easily hundreds of milliamps to one amp) and it is taken in the pulses. Those pulses occur during a phone call at a repetition rate of 217 Hz and pulse width of about 0.5 msec. If current pulses couple to the audio circuitry, the harmonic-rich, 217-Hz signal results in an audible buzz. Users rarely encounter an audible buzz with most quality mobile phones on the market today. However, when a wired headset's signal lead gets too close to the phone's antenna element, the problem emerges even in quality phones. There can be a considerable amount of RF energu near a phone. At the highest power level setting (cell phone long distance away from base station), thre cen be up to 32 dBm (more than 1W) of RF power in a typical phone. And received signal levels as low as -40 dBm (less than 1 microwatt) impinging upon semiconductor junctions can create a strong buzz.
Good layout must prevent RF energy from coupling into the audio and power traces. Prevention methods include shielding, ground design, and careful overall layout practice. Despite your best effort, some RF will couple onto audio traces. To prevent this energy from conducting into the audio amplifiers' semiconductor junctions many designs employ filtering methods, for example small bypass capacitors that bypass RF without affecting audio. Because cell-phone RF occupies bands in the vicinity of 900 and 1800 MHz, the best choices are those capacitors that are self-resonant at those frequencies. Typical values for this application?10 and 39 pF?have negligible effect on audio signals. Usually there are LC or RC filters at the headset, charger, and data ports to prevent connecting cables from acting as antennas and conducting coupled transmitted power into those points. It is common to use a single integrated passive component that includes an RF filter and often ESD protection.
Personal Digital Assistants technologies
In 1993, Apple Computers vowed to reinvent portable computing. The company promised an "all-being, all-knowing, all-doing" electronic device. It would serve as an address book, day planner, notepad, fax machine, pager. It was designed to be an easy to use electronic device in the palm of a human hand. Apple even devised a catchy, hi-tech name for this miracle machine- the Personal Digital Assistant, or PDA for short. After long waiting Apple released the world's first PDA, the Newton. The Apple Newton grabbed people's imaginations, but did not capture their wallets. Since then hordes of other companies attempted to take advantage of Apple's failure. Each one of them released their own version of what they think is the perfect PDA. Nowadays there are still many different PDA product from different companies available. Simplest are only like electroni calendars and notebooks, while most powerful ones have lots of processing power (like Compaq iPaq) and possibly communication functions in them (like Nokia Communicator).
Generally you can't use normal modem communicationsthrough celluar networks, but generally they havesome way to offer a similar service.Normal telephone line modems do not work in mostcellular teleohone systems in any acceptable way.Generally the radio noise in unaccpetable onanalogue cellular systems. And digital cellularphones use speech codecs which compress speech tosomewhat working soundgin speecs, but causequite weird thigns to some non-speech signals.For transferring data on digital cellular systems(like GSM) the designers of networks havedesigned special data service modes tocarry data on the cellular network.For example GSM network can carry data normallyup to 9600 bps (there are aalso higher speed high speedmodes available with some operators and equipments).The data interfaces on many cellular phones makethe phone appear to applications like it werea normal 9600 bps modem.
Cellular phone safety
Cellular phones are electronic devices that commununicate with the ceullar system base station usign radio communications. This means that they contain both radio receiver and transmitter. The transmitter cause RF field around the cellular phone. RF fields are non-ionizing radiations (NIR). ). Unlike X-rays and gamma rays, they are much too weak to break the bonds that hold molecules in cells together and, therefore, produce ionization. RF fields may, however, produce different effects on biological systems such as cells, plants, animals, or human beings. These effects depend on frequency and intensity of the RF field. By no means, will all of these effects result in adverse health effects. RF fields between 1 MHz and 10 GHz penetrate exposed tissues and produce heating due to energy absorption in these tissues. The depth of penetration of the RF field into the tissue depends on the frequency of the field and is greater for lower frequencies. Energy absorption from RF fields in tissues is measured as a specific absorption rate (SAR) within a given tissue mass. The unit of SAR is watts per kilogram (W/kg). An SAR of at least 4 W/kg is needed to produce adverse health effects in people exposed to RF fields in this frequency range. Most adverse health effects that could occur from exposure to RF fields between 1 MHz and 10 GHz are consistent with responses to induced heating, resulting in rises in tissue or body temperatures higher than 1C. Current mobile phone systems operate at frequencies between 800 and 1800 MHz. RF fields penetrate exposed tissues to depths that depend on the frequency - up to a centimetre at the frequencies used by mobile phones. RF energy is absorbed in the body and produces heat, but the body's normal thermoregulatory processes carry this heat away. All established health effects of RF exposure are clearly related to heating. While RF energy can interact with body tissues at levels too low to cause any significant heating, no study has shown adverse health effects at exposure levels below international guideline limitsCurrent scientific evidence indicates that exposure to RF fields is unlikely to induce or promote cancers. Exposure to low-levels of RF fields, too low to produce heating, has been reported to alter the electrical activity of the brain in cats and rabbits by changing calcium ion mobility. However, these effects are not well established, nor are their implications for human health sufficiently well understood to provide a basis for restricting human exposure. Scientists have reported other effects of using mobile phones including changes in brain activity, reaction times, and sleep patterns. These effects are small and have no apparent health significance. More studies are in progress to try to confirm these findings. The human exposure limits for mobile phones set by national organizations usually within international guidelines developed by the International Commission on Non-Ionizing Radiation Protection. These are based on a careful analysis of all scientific literature (both thermal and non-thermal effects) and offer protection against all identified hazards of radiofrequency energy with large safety margins.Rather than emission limits, the standard specifies exposure limits to radiofrequency EMR that regulate the rate at which the mobile phone user absorbs energy from the handset. This is known as the specific absorption rate (SAR). The SAR limit for all mobile, cordless and satellite phone handsets for sale in Australia is 1.6 watts per kilogram of tissue (averaged over 1 gram). There are differences in SAR levels between different mobile phone models. The SAR rating published by the manufacturer is the result of tests conducted at worst case scenario. The energy you absorb from your phone cannot exceed that level. In practice, the energy you absorb in daily use of your phone will vary and in many instances will be much less that the published SAR. This is because the phone only uses as much energy as is needed to communicate with a base station. If the base station is nearby, the phone will only use as much energy as is efficient to communicate with the base station. Mobile phone handsets and base stations present quite different exposure situations. RF exposure to a user of a mobile phone is far higher than to a person living near a cellular base station. However, apart from infrequent signals used to maintain links with nearby base stations, the handset transmits RF energy only while a call is being made, whereas base stations are continuously transmitting signals.Handsets: Mobile phone handsets are low-powered RF transmitters, emitting maximum powers in the range of 0.2 to 0.6 watts. The RF field strength (and hence RF exposure to a user) falls off rapidly with distance from the handset. Therefore, the RF exposure to a user of a mobile phone located 10s of centimetres from the head (using a "hands free" appliance) is far lower than to a user who places the headset against the head. RF exposures to nearby people are very low. RF exposure levels to a user from mobile handsets are below international guidelines. If you are concerned about radiofrequency electromagnetic radiadion (EMR) while using your mobile phone you may choose to use a portable hands-free device. These are sold as an accessory to your mobile phone.Base stations: Base stations transmit power levels from a few watts to 100 watts or more, depending on the size of the region or "cell" that they are designed to service. Base station antennae are typically about 20-30 cm in width and a metre in length, mounted on buildings or towers at a height of from 15 to 50 metres above ground. These antennae emit RF beams that are typically very narrow in the vertical direction but quite broad in the horizontal direction. Because of the narrow vertical spread of the beam, the RF field intensity at the ground directly below the antenna is low. The RF field intensity increases slightly as one moves away from the base station and then decreases at greater distances from the antenna.Both measurements and calculations show that RF signal levels in areas of public access from base stations are far below international guidelines, typically by a factor of 100 or more. Electromagnetic interference and other effects: Mobile telephones, as well as many other electronic devices in common use, can cause electromagnetic interference in other electrical equipment. Therefore, caution should be exercised when using mobile telephones around sensitive electromedical equipment used in hospital intensive care units. Mobile telephones can, in rare instances, also cause interference in certain other medical devices, such as cardiac pacemakers and hearing aids. Individuals using such devices should contact their doctor to determine the susceptibility of their products to these effects. Other risks of using cellular phone: Research has clearly shown an increased risk of traffic accidents when mobile phones (either handheld or with a "hands-free" kit) are used while driving. Technical electronics safety: Cellular phones operate at low voltage (typically at 3-6V voltage) so the voltages in them are not dangerous. Cellular phones contain rechargeable batteries, which include several potential electrical risks. The batteries in cellular phones are lov voltsge devices, but are capble of generating high current if short circuited. Such high currents can cause lots of heat to the batteyr set itself and to electronics device conneced to it if the short circuit happens there. The energy in cellular phone battery is enough to cause fire on severe short circuit situation. For this reason most barries include internal protection circuitry to avoid this. Nowadays Lithium Ion (Li-ion) is the fastest growing battery system, because it has high energy density and is lightweigh. Li-ion technology is fragile (the contents of battery is flammable) and a protection circuit is required to assure safety. There has been some reports that damaged Li-ion batteries have cought in some case fire and even cause small "explosions". The number of this kind of accidents has been very low compared to the number of batteries in use. So there is a risk, but is low. To be safe be careful when handling the battery pack and do not use damaged battery packs.
Cellular phone jamming and detecting
Movie theaters today just ask you to silence your cell phone. Cell phones are asked to be turned off in the aeroplanes and hospitals for safety reasons (they can interfere with plane or medical electronics).
- AMPS stands for Advanced Mobile Phone Service. It is an analog cellular phone system used in North and South America. AMPS uses FDMA and operates at 800 MHz band. AMPS was introduced in USA at 1983.
- NMT stands for Nordic Mobile Telephone. It is an analog cellular phone system deployed in more than 40 countries in Europe. NMT was the first analog cellular phone system (launched in the Scandinavian countries 1979). The system used originally 450 MHz band (NMT 450), but later when more capacity was needed, it was also adopted for 900 MHz band (NMT 900).
- TACS stands for Total Access Communications System. It is a modified version of AMPS. TACS is used in UK, Japan and China.
- 1970?s Microprocessors were used in the implementation of cellular networks
- 1971 The first public radio telephone network ARP in Finland was opened (no automatic switching)
- 1981 NMT 450 (Nordic Mobile Telephone) network started operation in Scandinavia
- 1983 AMPS (Advanced Mobile Phone Service) in the US
- 1985 TACS network in the UK
First generation wide area wireless communication systems are characterized as analog radio systems and designed for voice transfer. 1G Techologies used frequency dividision multiple access (FDMA) to communicate, meaning simply that every call in one are uses their own channels for voice communication.This kind of systems were resiged and used in 1970s and 1980s. Examples of this kind of systems include AMPS, TACS, and NMT. Here is some more information on those systems.
- NMT Nordic Mobile Telephone - This article tells abount NMT-450 and NMT-900 systems. The language of this text is Finnish. Rate this link
- ARP - ARP is an old VHF frequency radio system that was used in Finland. The laguage of this article is Finnish. Rate this link
- Cellular Telephony - This article describes the cellular phone development in USA. The story starts from old "Domestic Public Land Mobile Radio Service" (DPLMRS), then "Improved Mobile Telephone Service" (IMTS) is described and finally "Advanced Mobile Phone Service" (AMPS). Rate this link
- Understanding Cellular Telephone Security and Privacy Rate this link
1G cellular systems refer to the early analogue cellular phone technologies. The early 1980.s marked the first use of wireless cellular systems. It was typical for this kind of systems that the systems were quite limited in performance, no fancy features and mostly country specific standards. 1G systems differed from the earlier radio networks in a couple of ways. The first generation (1G) cellular systems had increased capacity and greater mobility support than the early wireless radio networks. The 1G systems employed the concept of cellular coverage, where the coverage area is divided into small cells. This greatly increased the overall capacity of the entire network due to the ability to reuse frequencies.
The first generation of wireless consisted mostly of voice traffic handled with analog techniques.For example NMT and AMPS cellular technologies belong to this category.
NMT was the first widely used international cellular phone system. It was used widely in Northern Europe. The project started in late 1970's in a co-operation with Finland, Sweden and Norway. The first version of the network started at 1982. This operated at 450 Mhz frequency band and was named first NMT, later NMT-450. The use of this system has then speared to also other countries in Norhern Europe and some areas in Russia. There is also version NMT-900 that operated at 900 MHz frequency band. The use of NMT has pretty much stopped in the countries that started it originally (for example ended in Finland).
The Bell Telephone company (US) introduced the first cellular public network AMPS (Advanced Mobile Phone Service) in 1978. It became a single standard for North America in 1982. Developed in the 1970s and deployed in the 1980s and still used today. These phones transmit voice as an analog signal without any encryption of scrambling. As a result, they can be eavesdropped upon using handheld scanners sold at places like Radio Shack. Analog systems are widely deployed throughout the US, especially in rural areas. Although analog cell phones are still sold but not a good deal, as analog providers generally charge a lot of money, the phones do not have good battery life, and the sound quality is generally poor. The big advantage of analog cell phones is that they have the best nation-wide coverage, but that?s changing fast. If you have an analog cell phone, you probably want to get a new one. Nowadays there are ?dual-mode? digital phones that also support analog AMPS system for roaming in remote areas.
- GSM stands for Global System for Mobile Communication. It was originally designed for operation at 900 Mhz band, bu has been later adopted for other frequency bands also. GSM variations are used in Europe, Asia and North America. Nowadays GSM products are operating at 900, 1800 and 1900 MHz (some people have also though of 800 and 450 MHz versions sometimes). GSM supports voice and data communications. Typical maximum data rate is 14.4 kbps. GSM system uses TDMA access with 200 kHz channels divided into eight time slots, with two slots (in different channels) used to send and receive signals.
- D-AMPS stands for Digital-Advanced Mobile Phone Service. It is a digital version of AMPS. D-AMPS is also known as TDMA/IS-136. D-AMPS is mostly used in USA. D-AMPS cellular phones transmit in the 824-849 MHz range and receive in the 869-894 MHz range using 30 kHz channels (FDMA). In addition to this TDMA is used to create time slots within each channel.
- TDMA (Time Division Multiple Access) is the digital telephone standard that was deployed by AT&T in the 1990s. AT&T?s telephones have a ?voice privacy? or ?voice security? setting which enables encryption, but the network did not seem to support this.
- CDMA-95-A is a cellular phone system that uses CDMA radio communication to be able to dend multiple signals in the same channel (a form of multiplexing). This system used spead spectrum (DS/SS) tecnology to vaty the transmit frequency according the code pattern. CDMA-95-A supports data speeds up to 14.4 kbps. An updated version of it, know as CDMA-95-B supports speed up to 64 kbps.
Second generation (2G) cellular phone system use digital communication methods. They are capable of providing voice, data and other services. Digital technology combined with harmonized standardization has made it possible to make calls at any time, anywhere, and both speech and data can be transmitted and received.The second generation (2G) wireless systems are characterized by the use of digital radio transmission. The increase in system capacity was due to the use of hierarchical cell structures and the ability to use a single frequency channel for multiple users (code and/or time division).Examples of this series of systems include GSM, D-AMPS (TDMA/IS-136) and CDMA IS-95-A. Here is some more informatiom on those system.
- Maximum data rate: 9600 bit/s (there are some extension that allow now faster speeds)
- Maximum mobile terminal output power: 8 W
- Maximum hand-held mobile terminal output power: 2W
- Maximum cell radius: 30 km
- Minimum cell radius: 350 m
- Access method: TDMA/FDMA
- Number of radio channels in each direction: 124
- Number of speech channels per radio channel: 8
- Modulation: Minimum Shift Keying (GSMK)
- 1978 Frequency allocation by CEPT
- 1982 Group Special Mobile within CEPT
- 1987 GSM group described the main technical options for the mobile radio telephony standards
- 1987 GSM MoU (Memorandum of Understanding)
- 1990 Phase 1 specifications were frozen
- 1992 First GSM networks in commercial use
- 1992 Phase 2 specifications
- The first public GSM call in the world took place on the 1st of July, 1991 (Finland)
- A Brief Overview of GSM, by John Scourias, U of Waterloo Rate this link
- A brief Overview of the GSM Radio Interface - This technical memorandum contains a compilation of several papers, reports and books relative to the GSM-900 radio interface. Rate this link
- An overview of the GSM system Rate this link
- GSM 06.10 lossy speech compression - speech coding system used in GSM Rate this link
- GSM Channel Coding Rate this link
- GSM FAQ - written in Finnish Rate this link
- GSM Overview Page Rate this link
- GSM Technical Data - lots of GSM documents Rate this link
- GSM World - information web page by GSM Association Rate this link
- Data Over Cellular: A Look at GPRS - GPRS is an extension of the GSM system, and uses the same channels, the same modulation, and the same network backbone as the existing GSM network Rate this link
- GPRS High Speed 115kbps GSM data - GSM's new GPRS (General Packet Radio Services) data transmission technology is optimized for "bursty" datacom services such as wireless Internet/intranet and multimedia services. It is also known as GSM-IP (Internet Protocol) because it will connect users directly to Internet Service Providers. Rate this link
- GPRS White paper by Cisco - in pdf format Rate this link
- EDGE 384 kbps data over GSM Rate this link
- EDGE in Wireless Data - EDGE is a new modulation scheme that is more bandwidth efficient than the Gaussian prefiltered minimum shift keying (GMSK) modulation scheme used in the GSM standard Rate this link
- Improving Accuracy in EDGE-Based Designs - To make 2.5G wireless systems a reality, system developers need access to more sophisticated design and test techniques. Rate this link
- High Speed Circuit Switched Data (HSCSD) - High Speed Circuit Switched Data (HSCSD) is a new high speed implementation of GSM data techniques. HSCSD allows wireless data to be transmitted at 38.4 kilobits per second or even faster over GSM networks by allocating up to eight time slots to a single user. Rate this link
- Mobile World - all kinds of information about GSM phones Rate this link
- Nokia 6100 series FAQ Rate this link
- GSM Handset Vulnerabilities: RF Performance - article from Rate this link
- GSM Handset Vulnerabilities: Physical Layer Protocol - article from Rate this link
- A headset for Nokia 6110 with answer/end call button - Add an answering & call ending button to your Nokia 5110 or Nokia 6110 headset if you are missing it. Rate this link
- FBUS & M2BUS adapters - adpators for connecting your Nokia mobile phone to PC Rate this link
- Mobile phone - standard audio amplifier adapter - circuit to take your hi-fi microphone and amplifier and make your calls through them with Nokia 5110/6110 series GSM phone Rate this link
- NuukiaWorld - The legendary Nokia mobile phone site. This site has circuit building instructions and downloads for Nokia GSM phones. Rate this link
- mtnsms.com - free gsm sms service Rate this link
- Quios - gives free SMS sending service Rate this link
- Rogers SMS-information site - lot SMS technical information, free SMS gateways, SMS forum Rate this link
- Short Message Service Description Rate this link
- Wireless Short Message Service (SMS) Tutorial Rate this link
- Quios - gives free SMS sending service Rate this link
- Sending Short Messages to GSM phones services list Rate this link
- Extended ETSI Hayes AT command parameters for SMS - commands to make cellular phone to send and receive SMS messages Rate this link
- Kannel: Open Source WAP and SMS gateway Rate this link
- SMS Character Set - described in the middle of this document Rate this link
- Mobile Network Services with Linux - The skinny on building your own SMS gateway Rate this link
- Remote Control Module BieneRemote01 (OEM) - Home Automation control via SMS message. You can receive text messages with the occurrence of an event automatically to GSM mobile (cell) phones. You can transmit command messages and switches the output - switch on/off remote equipment. This is introduction to one product for this and reading this article is also a good introduction what can be done in this field with this or other similar products. Rate this link
- Gnokii Project - software project developing tools and drivers for Nokia mobile phones for Linux, BSD and other operating systems Rate this link
- gsmlib - a library to access GSM mobile phones through GSM modems, works under Linux and Win32 (Win95, NT 4.0), supports several Nokia, Siemens and Ericsson cellular phone + several GSM cards Rate this link
- Kannel: Open Source WAP and SMS gateway Rate this link
- Nokia Logo Editor for Linux Rate this link
- MobileMMS.com - This site is about Multimedia Messaging System. Here you can find for example news on MMS. Rate this link
- Nokia Multimedia Messaging White Paper - The Nokia Multimedia Messaging Solution facilitates new styles of communication in Mobile World. Nokia's approach is based upon a series of evolutionary steps:SMS (text), Picture Messaging (text and graphics), MMS - Multimedia Messaging Service (digital image input)and Mobile Multimedia (new content types). MMS is the most versatile messaging service, and among the different types of messaging, Multimedia Messaging Service (MMS)will emerge as a key technology. Rate this link
- GSM Link Heaven - a world of links on GSM! Rate this link
- Extended ETSI Hayes AT command parameters for SMS - commands to make cellular phone to send and receive SMS messages Rate this link
- MobileKUB - ring tones, standards, protocols, message board Rate this link
The Europeans realized rapid growth of cellular communications early on, and in 1982 the Conference of European Posts and Telegraphs (CEPT) formed a study group called the Groupe Sp?cial Mobile (GSM) to study and develop a pan?European public land mobile system. In 1989, GSM responsibility was transferred to the European Telecommunication Standards Institute (ETSI), and phase I of the GSM specifications were published in 1990. Commercial service was started in mid?1991, and by 1993 there were 36 GSM networks in 22 countries.The most basic teleservice supported by GSM is telephony. From the beginning, the planners of GSM wanted ISDN compatibility in services offered and control signalling used. The digital nature of GSM allows data, both synchronous and asynchronous, to be transported as a bearer service to or from an ISDN terminal. The data rates supported by GSM are 300 bps, 600 bps, 1200 bps, 2400 bps, and 9600 bps (14400 bps was added later). Group 3 fax, an analog method described in ITU?T recommendation T.30 is also supported by use of an appropriate fax adaptor.GSM features:
Network operators in most of the world use the original GSM spectrum allocation at 900 MHz. The frequency range allocated for ceullar telephy purposes (used now by GSM) in the 1978 World Administrative Radio Conference (WARC) was 890-915 MHz for transmissions from mobile stations and 935-960 MHz for transmissions from fixed stations. Additional spectrum at 1,800 MHz is used for the GSM derivative called DCS-1800, and this band is used in many countries. Some countries with cellular allocations at 450 MHz may begin deploying GSM in that band as well to replace old analog networks. In many areas of the United States, there are GSM systems operating in the 1,900- MHz PCS frequency band. There are also plans to make GSM standards for operation at 400 MHz and 800 MHz bands. The practical use of different frequencies is nowadays the following: In Europe the GSM networks generally use 900 MHz frequency band throughout Europe. Quite many countries also use 1800 MHz frequency on places like large cities where the capacity available at 900 Mhz frequency band is not enough to cover the needs of the users. Many modern European GSM phones are built as "dual-band" phones, that can use both of those frequency bands, and automatically transparently to the user switch between those frequency bands as needed (controlled by the operator).In USA GSM networks use 1900 MHz frequency band. This frequency band was selected to be used there, because the 900 MHz and 1800 MHz frequency bands were already used for other purposes. Considering the many options available, dual-band GSM phones are quite commonplace now. A few tri-band (900/1800/1900 MHz) phones are also available, allowing a GSM subscriber to use the same phone almost anywhere in the world.
Circuit-switched voice calls are still the most commonly used services in GSM networks. Users use also data services. Current datacom services over GSM generally allows transferring files or data and sending faxes at 9.6 kbps. This current data communication in GSM network is circuit switched.
GSM phones are designed to work at ground level or quite near to earth with users moving at reasonable speed (maximum speed 500 km/h or so). The GSM system is not designed to work in aeroplanes and trying to use cellular phone in aeroplane is not a good idea (it is generally not allowed). The problem is that at very high altitudes, the phone "sees" tens or hundreds of cell base stations at once, and the system isn't really designed to deal with this. Even if one cell can decide it will take the initial call, cell switching will be occurring every few seconds as the signal strength fluctuates. The problem multiplies if you are crossing those cells at 500mph. Trying to in-flight GSM phone calls is a bad idea. The system is designed on the assumption that calls will be made on the ground, therefore range-limited, and thus can only possibly be routed by one or two base stations, not hundreds. Other peoblem for in flight calls is that the GSM phone can potentially interfere with the electronics on board in the plane, which is not a good idea.
There are many GSM operators operating at different countries, and even in many locations there are several different operators that compete against each other on the same are. In GSM system there is a feature called "roaming" available. It allows you to use the network of some other operator to make calls instead of your own operator that muight not be reacable (for example when youre abroad). If you roam into an area not covered by your home network your handset looks for networks that your network operator has made a "roaming agreement." If the network(s) that are found allow you to register you can use them (because your home carrier has made a roaming agreement with the carrier that you are visiting.) If no roaming agreement is present you cannot use that network and only can make emergency (911/112) calls.
General GSM information
Enhanced GSM data
There are two basic modes of data access over a wireless network: circuit switched and packet switched. In circuit switched system connection is a dedicated connection, and the user is billed, using the same method as that used for a voice call, by the minutes of usage. Current datacom services over GSM generally allows transferring files or data and sending faxes at 9.6 kbps. This current data communication in GSM network is circuit switched. The existing GSM network provides data access at speeds up to 14.4 kbps. This was considered a reasonable speed when the system was developed. In packet switching data streams are broken up into packets, each packet is then quickly routed to its destination over a shared medium. Billing is done on a cents-per-packet basis, independent of the time spent online. Enhanced GSM data technologies promise more transfer speed and also packet mode transmission.
GPRS is an extension of the GSM system, and uses the same channels, the same modulation, and the same network backbone as the existing GSM network.
High Speed Circuit Switched Data (HSCSD)
High Speed Circuit Switched Data (HSCSD) is a new high speed implementation of GSM data techniques. HSCSD allows wireless data to be transmitted at 38.4 kilobits per second or even faster over GSM networks by allocating up to eight time slots to a single user.
Information on GSM products
GSM product design information
GSM phone electronics projects
Short messsage service (SMS)
SMS is a bidirectional service for sending short alphanumeric (up to 160 bytes) messages in a store?and?forward fashion. For point?to?point SMS, a message can be sent to another subscriber to the service, and an acknowledgement of receipt is provided to the sender. SMS can also be used in a cell?broadcast mode, for sending messages such as traffic updates or news updates. Short messsage service (SMS) is a messaging method included in GSM system which allows sensing short messages from one cellular phone to another. GSM Short Messages have a maximum length of 160 characters (from the SMS character set), or 140 octets. However, Short Messages can be concatenated to form longer messages. Besides normal text based user to user messaging SMS system has been used to impement interfaces to on-line services and for carrying other kind of data (like alarm tones and logos to certain GSM phones). Short message service (SMS) is a globally accepted wireless service that enables the transmission of alphanumeric messages between mobile subscribers and external systems such as electronic mail, paging, and voice mail systems. SMS has also been used for tranporting data like cellular phone ring tones and screen logos (for example in Nokia Smart Messaging system). SMS messages can be sent in several ways. The most typical way the users send them is that they type those messages with their cellular phones and then send them from it. There are also other ways to do this. The automated SMS based services need a computerized way to do the same thing. There are several ways how a SMS can be sent from a computer. One of the simplest method for small volume SMS traffic sending is to use a GSM modem or GSM phone connected to a PC serial port. With a suitable software you can send SMS through them from computer. For higher volume SMS sending quite many operators also provide a computer interface that allows sending messages directly from computer to SMSC (Short Message Service Center). There are several protocols that are designed for this. Examples of such protocols that can be used are SMPP (Short Message Peer to Peer), CIMD, UCP/EMI (Universal Computer Protocol / External Machine Interface) and HTTP (Hyper Text Transport Protocol).
On-line SMS messaging services
On-line sites which provideo free SMS messaging services.
SMS related technical specifications
Building systems for hadling SMS messages
Software related to GSM phones
Multimedia Messaging Service (MMS)
Multimedia Messaging is just around the corner. Multimedia Messaging Service (MMS) is a new prominent wireless standard for multimedia. The idea behind MMS is to enhance SMS type messagging to carry larger messages which can contain more text, images, sound and possibly animation. MMS is expected to become a very popular messaging service in the future in both today's GSM networks and 3G networks in the future. In GSM networks the MMS service is generally implemented with the aid of GPRS service with is used to transport the actual messages to GSM phone. To be able to used the new MMS services, the consumers need net MMS capable cellular phones and GSM operator need to update their networks with new features to suport this service. Operators need for example Multimedia Messaging Service Centers (MMSC) to handle the delivery of the Multimedia Messages (the operation of MMSC is roughtly equivalent to what SMS center does to SMS messages).The key factors to make the MMS a success story is theinteroperability, interworking and the availability of the types of handheld devices necessary to make widespread consumer and enterprise mobile multimedia messaging a reality. The MMS messgae itself consists of the message header and the contents of the message (message body). The message body can consist of one or more part (like files). The message body is coded as MIME type application/vnd.wap.mms.Basically the information contained in the message can be in any format supported by the devices. The standard information presentation formats are SMIL and WAP, but the device manufacturers have agreed that the supported standard presentation language is SMIL. The typical size of MMS messages is expeced to be around 6-30 kilobyes. When messages are transported form application to the Multimedia Messaging System, they are generally transporte dusing HTTP or SMTP protocols.3gpp Release 5 defines a SOAP based interface to MMS.
Other 2G systems than GSM
There are also other 2G systems than GSM, Those systems are generally used in more limited areas (usually country or area specific systems).
- CDMA Devellopment Group - to promote CDMA technology for future mobile phones Rate this link
- What is CDMA? Rate this link
CDMA Based cellular phone systems information
Code Division Multiple Access (CDMA) is a digital wireless technology that was pioneered and commercially developed by QUALCOMM. CDMA works by converting speech into digital information, which is then transmitted as a radio signal over a wireless network. Using a unique code to distinguish each different call, CDMA enables many more people to share the airwaves at the same time - without static, cross-talk or interference.CDMA was adopted by the Telecommunications Industry Association (TIA) in 1993. CDMA wireless was commercially introduced in 1995. CDMA is very fas growing wireless technology. Code Division Multiple Access, a cellular technology orginally known as IS-95, competes with GSM technology for dominance in the cellular world. There are now different variations, but the original CDMA is now known as cdmaOne. A newer version of this with more speed is now known as cdma20000. In 1999, the International Telecommunications Union selected CDMA as the industry standard for new "third-generation" (3G) wireless systems. The selected technology variation are called W-CDMA (wideband CDMA) and TD-SCDMA.wideband CDMA forms the basis of UMTS 3G networks. Many leading wireless carriers are now building or upgrading to 3G CDMA networks. May 2001 there were 35 million subscribers on cdmaOne systems worldwide. At year 2003 over 100 million consumers worldwide rely on CDMA communications.
- Bit rates reaching up to 2 Mbps
- Variable bit rate to offer bandwidth on demand
- Multiplexing of services with different quality requirements on a single connection, e.g. speech, video, and packet data
- Delay requirements from delay-sensitive real-time traffic to flexible best-effort packet data
- Quality requirements from 10% frame error rate to 10-6 bit error rate
- Coexistence of second and third generation systems and inter-system handovers for coverage enhancements and load balancing
- Support of asymmetric uplink and downlink traffic, e.g. web browsing causes more loading to downlink and uplink
- High spectrum efficiency
- Coexistence of FDD and TDD modes
- High-speed access, supporting broadband services such as fast Internet access or multimedia-type applications.
- Flexibility, supporting new kinds of services such as universal personal numbering and satellite telephony.
- Affordable to uses (expected to be eventually at same price range or cheaper than current cellular systems)
- Compatibility with existing cellular infrastructure, thus offering an effective evolutionary path for existing wireless networks
- Are 3G Technologies Here Today? - A basic understanding of the 3G movement will go a long way in preparing you to the changes in the future. Rate this link
- CDMA Devellopment Group - to promote CDMA technology for future mobile phones Rate this link
- How filters separate users in 3G - 3G radio techniques require the channel filter to have a much higher sampling rate and a larger resolution than those of a single-channel filter for a GSM signal. Rate this link
- IMT-2000-online - WEB portal site on the IMT-2000 / UMTS / 3G Rate this link
- ITU IMT-2000 - will provide wireless access to the global telecommunication infrastructure through both satellite and terrestrial systems Rate this link
- Powering up 3G Handsets for MPEG-4 Video - MPEG-4 video is on the horizon, but an imbalance between processing demands and processor capabilities presents a challenge for de-signers. Adaptive computing may hold the key to good performance and low power consumption. Rate this link
- Solving FDD Compliance Issues with 3GPP Libraries - The complexity of the 3GPP FDD signal format imposes new linearity and dynamic range requirements on designers, making compliance a nightmare. Fortunately, new design libraries are arriving to help. Rate this link
- Speeding the Development of Wideband CDMA-based Personal Communications Products - A slide set presentation from Cadence Design Systems Rate this link
- Suppressing Errors in W-CDMA Mobile Devices - As the final specs for W-CDMA near completion, handset designs offering wireless Internet access with voice and data capabilities are close behind. But to make these products a reality, designers must first get a grip on minimizing BER in the RF front end. Rate this link
- UMTS Forum - information on UMTS system Rate this link
- Wireless for the rest of us - What happens to 3G dreams of universal connectivity in a year as wretched as 2001? If you're the type of wireless carrier that has leveraged all available resources to acquire licenses, you're probably already trapped in a spiral of debt and despair, ready to follow the DSL service providers into oblivion. On the other hand, if you're a service provider with deep pockets and an existing networks, you're no doubt trying to decipher how to add mediation switch capabilities to metropolitan switching centers, in order to transition to voice-over-IP (VoIP) networks. Rate this link
Third generation mobile phone systems
Third generation mobile communciation systems often called with names3G, UMTS and W-CDMA promise to boost the mobile communications tonew speed limits. The promises of third generation mobile phones arefast Internet surfing, advanced value-added services and video telephony.What will be the reality we will start to see in few years. Mobile communication is promised to move from simple voice to rich media, where we use more of our senses to intensify our experiences.3G technology improves upon 2G systems in two main ways. First, is a move towards packet switching from circuit switching. Packet switching uses the communication system more effectively, therefore boosting the capacity of the system. Packet switching also enables users to always be online. This will eliminate the need for users to "dial up". Via judicious use of the frequency spectrum and inventive coding methods, 3G technology is poised to achieve bit rates up to 2 Mbps. Essential qualities and characteristics of a 3G wireless system:
- Personal Communications Service (PCS) Tutorial Rate this link
- TETRA MoU Web - information on Terestrial Trunked Radio (TETRA) standard by ETSI Rate this link
- Wireless Local Loop (WLL) Tutorial - technique to replace telephone wire using radio Rate this link
Other cellular phone systems
- Making the Leap to 4G Wireless - information on possible RF technologies for 4G cellular networks Rate this link
- Mobile IP - Connecting a personal device to the Internet using Bluetooth or 802.11 wireless Ethernet is that simple. Fortunately, mobile IP was designed to addressed sticky routing issues involved in this type of communication system. Rate this link
- Mobile IP Explained Rate this link
4G Mobile communications
Cellular service providers are slowly beginning to deploy third-generation (3G) cellular services. As access technology increases, voice, video, multimedia, and broadband dataservices are becoming integrated into the same network. The hope once envisioned for 3G as a true broadband service has all but dwindled away.While 3G hasn't quite arrived, designers are already thinking about 4G technology. To achieve the goals of true broadband cellular service, the systems have to make the leap to a fourth-generation (4G) network. 4G is intended to provide high speed, high capacity, low cost per bit,IP based services. The goal is to have data rates up to 20 Mbps.Most propable the 4G network would be a network which isa combination of different technologies (current celluart networks,3G celluar network, wireless LAN, etc.) working togetherusign suitable interoperability protocols (for example Mobile IP).There is standardization work on 4G already on the way. For example IEEE is standardizing 4G celular networks. The aim is to support up to 4 Mbit/s speeds. The networks is expected to support communications to moving vehicle up to speeds of 250 km/h. This 4G system is going to be based on OFDM modulation, CDMA and multiple antenna technology. The aim is to bring together 4G mobile technology, WLAN and satellite communications so that they can all work seamlessly together.
- Designing a DECT telephone tests your receiver knowledge - desiging a DECT telephone is similar to designing a digital FM radio Rate this link
- High-Speed Networks And 3G Wireless Hike Demands On Test Gear - faster rates, higher bandwidth, and changing standards continue to challenge communications designers Rate this link
- Modulation and Demodulation Techniques for FPGAs - presentation slides from a presentation of digital demodulation for FPGAs, includes implementation of an IS-95 North American Cellular Modem in a Xilinx 4013 as an example Rate this link
- RF Design of a TDMA Cellular/PCS Handset - this article describes a typical RF architecture and focuses on key RF design considerations and trade-offs as applied to a typical dual-band TDMA transceiver RF section, read also Rate this link
- Signals and Measurements for Wireless Communications Testing Rate this link
Cellular phone design articles
- NuukiaWorld project: Changing the display and keyboard illumination color - You can make your phone cool looking just by changing the color of the lights. The green color is so common that others easily notice different colors. The procedure is easy for an experienced electronic hobbyist. The illumination of a Nokia 5110 / Nokia 6110 phone is implemented with 12 SMD (surface-mount) LEDs. Rate this link
- Changing LED in Nokia - Blue LED display light solution for Nokia 3210 can be very simple. Rate this link
- Changing the display and keyboard illumination color - you can make your phone cool looking just by changing the color of the lights Rate this link
- How I managed to access the LEDs of my 8210 - Information how to change LEDs on Nokia 8210. Rate this link
- AT Command Set for Nokia GSM Products - This document describes the AT commands that may be used with Nokia GSM products operating in the GSM network. A short description, the syntax, the possible settings and responses of the AT commands are presented. Please note that some AT commands are not supported by all Nokia GSM products. Rate this link
- Gnokii - software project developing tools and drivers for Nokia mobile phones for Linux, BSD, Windows and other operating systems Rate this link
- Car-Battery charger for Nokia 8210 - It's just a simple power supply with a 7805 regulator, the chip must be mounted on a large metal radiator, because the current requested by the regulator is near 0.4 A. You can use it in you car , by connecting it to your lighter plug. The charging time is equal to that of the standard charger. Rate this link
- Integrating a Nokia 6160 Cell Phone - This document is broken into two main sections, the first reviews the concepts and information that was used to develop the approach to making the interface box for handsfree car kits. The second part describes in detail the particular approach the author took in making an interface box to work with the Nokia handfree carkit for the 51xx and 61xx series cell phones. Rate this link
- Nokia Data Cables and Nokia Headsets! - This article describes cheap versions of Nokia n3210 / Nokia 31xx/81xx MBUS data cables for connecting your phone to PC. This article also describes how to build a headset or handheld for Nokia 51xx/61xx/62xx/71xx phone. Rate this link
- NuukiaWorld - circuit building instructions and downloads for Nokia GSM phones Rate this link
- GSM Phone Cables Pinouts - This web page has information on Alcatel, Bosch, Dancall, Ericsson, Motorola, Nokia, Panasonic, Philips, Sagem, Samsung, Siemens, Sony, Mitsubishi and NEC cellular phones. Rate this link
- Nokia 6110 - Nokia 6150 Tech Info - Special control codes, new ring tones trick, connector pinout, some charger information and information on carkit/headset menu and "auto call receive" option. Rate this link
- Nokia Phone Secrets Rate this link
- Nokia Pop-port pinout - Nokia phone connector information Rate this link
- Pinout on the 6110/6150 Rate this link
- Siemens S25/C25 Pinout diagram Rate this link
- Siemens C55 Pinouts Rate this link
- Siemens S-40 Pinouts & Schematic Cable Rate this link
- The connector pinout for Nokia phones series 51xx, 61xx and 71xx - This description is valid for 51xx, 61xx and 71xx phones Rate this link
- Nokia 6110 - Nokia 6150 Tech Info - Special control codes, new ring tones trick, connector pinout, some charger information and information on carkit/headset menu and "auto call receive" option. Rate this link
- Nokia Phone Secrets Rate this link
- Nokia Codes Tips and Tricks - Check Nokia cellular phone IMEI, software revision, service menu and other settings. Trics to add some new menu features to 6110 phone. Rate this link
- NokiaHeaven - Nokia secrets, tips, trics, free SMS, logos, sofware and ringtones. Rate this link
- Secrets, tricks, & Codes for the 5100 series Rate this link
Mobile phone hacking
This section gives you tips how to use yout cellular phone beyond normal speaking and SMS messages.
Cellular phone modifications
Controlling cellular phone
Controlling cellular phone from external electronics (computer orsome other device) is usually manufacturer and cellular mode specific. This means that different manufacturers use different kind of physical and electrical interface to control their cellular phones using the accessory connector on the cellular phone (usually on thebottom of the cellular phone).
Build cellular phone accessories
Cellular phone world has many possibilities for your homebuilt accessories, but you need to have necessary technical information and/or ready building plans for you phone you use to successfully build your accessories. Many people have successfully built accessories like custom chargers, custom headsets and their own data cables.
Remember when building your own accessoried for cellular phones or modifying existing accessories there is also the concern for RF interference, and safety under some conditions. Take care that whatever you are doing, especially with a cell phone, that you are in proper compliance. All attachments for cellar phones must meet proper safety and RF radiation performance specifications. Wrong type, wrongly built or damaged accessory can damage your cellular phone.
Cellular phone internals and connectors
Cellular phone codes
- IXO paging protocol example - HyperTalk functions implement the IXO/TAP protocol sufficiently to handle numeric paging Rate this link
- POCSAG paging format, code and code capacity - featured in Line Noise section of Rate this link
- The Wonderful World of Pagers Rate this link
- Bluetooth - technology for wireless connectivity Rate this link
- Bluetooth interoperability: It's all in the details - Bluetooth faces interoperability issues on several fronts, all of which play a critical role in how quickly Bluetooth will penetrate the consumer market. Rate this link
- Bluetooth Overview / Bluetooth FAQ Rate this link
- Bluetooth SIG Member Web-Site Rate this link
- Bluetooth Technology Integration: Which Path Should You Choose? Rate this link
- Bluetooth White Papers - Many of the companies addressing the Bluetooth space have produced their own educational material on Bluetooth and its capabilities in the areas addressed by their own products. This page provides links to some of these resources. Rate this link
- Can Bluetooth And 802.11b Co-Exist? - Both the WLAN and Bluetooth devices occupy the same 2.4-to-2.483-GHz unlicensed frequency range--the same band, by the way, that is also occupied by a number of other devices such as microwave ovens and cellular phones. Does anyone see a problem here? Rate this link
- Csdmag Special Section on Bluetooth Design Rate this link
- Is Bluetooth All It Is Cracked Up To Be? - Through the hype, Bluetooth emerges to be a simple short-range connectivity technique for mobile devices. Rate this link
- Making the Bluetooth Application Connection - Understanding a system's relationships to complimentary devices is key to developing great Bluetooth applications. Rate this link
- On your marks for testing Bluetooth - The imminent market explosion of Bluetooth wireless interfaces on products signals an RF measurement first for many test engineers Rate this link
- The Wireless Directory - A forum for marketing, engineering and other Bluetooth professionals in the telecommunications, consumer electronics and other application industry businesses to interact and obtain specific information. Rate this link
- Wireless Sensor Architecture Uses Bluetooth Standard - Flexible network enables plug-and-play connection of real-time sensors to the Internet for low-cost data acquisition, measurement, and control Rate this link
- With Devices Ready To Go, Bluetooth Is Poised To Make Its Move Rate this link
- Testing and Qualifying a Bluetooth Design - Adding Bluetooth functionality to an existing design can be challenging, and knowing how to avoid design pitfalls can help engineers prevent time to market delays. Rate this link
- Taking a Walk Inside Bluetooth EDR - New protocol brings a 3X increase in bandwidth to Bluetooth designs without impacting upper-layer (above HCI) protocols. Here's a look inside at how the EDR protocol achieves this feat. Rate this link
Bluetooth is a short-range radio technology that connects portable devices such as cell phones, handheld devices and notebook computers. The technology has a range of up to 10 meters and wirelessly transfers data at rates of up to 720 kilobits per second. The technology was originally developed by Ericsson. Bluetooth is now a global specification for wireless connectivity. The Bluetooth solutions promise to provide a cable replacement technology that simplifies the interaction between people and machines. Bluetooth is, by design, a short-range, low-powered protocol. It is designed to be a small form-factor, low-cost, and low-powerradio communiction technology. Bluetooth technology supports a raw data transfer speed of 1 Mbit per second (Mbps) in the 2.4GHz band (2.400 to 2.483 GHz) and communication at a range of up to 10 meters. Bluetooth, when properly implemented, is great. It's not designed to be the only wireless protocol: It's narrowly designed to do one thing. Replace wires. There has been lot's of hype how Bluetooth could relace many thingsand be everywhere. Bluetooth is quite late in the uptake and will propably be much smaller than first anticipated. Bluetooth does exactly what it's designed to do, replace wires on some applications, but it does not solve all the communication problems. Not even a small fraction of them. Bluetooth is not intended to be a networking technology. Bluetooth is one up from IrDA and one down from Wi-Fi WLAN. Its one up to IrDA because it allows simple devices, close together, to communicate together, simply, and not need to be in line of sight. It is one down from Wi-Fi because, it's data capabilitied (for example communications speed and distance) are much worse than available with Wi-Fi. People who understand Bluetooth are using it for things like wireless keyboards, mice and synching PDAs and mobile phone to PCs. There are also wireless Bluetooth headset sets for cellular phones. Bluetooth provides two types of physical links. The Synchronous Connection Oriented (SCO) and the Asynchronous Connectionless (ACL) link. The SCO is used for voice and the ACL is used for data. Simultaneously up to three synchronous voice channels can be used. The data rate is 432 kbit/sec symmetrically and 721 / 57 kbit/s asymmetrically. 79 channels with 1MHz carrier distance are available. The channels are changed 1600 times per second (channel hopping). This is a pseudo-random sequence of 79 frequencies. In practical Bluetooth applications the transmitting only milliwatts,which gives communication distance up to around 10 meters.The Bluetooth standard defines also a higher power class of devices,which have maximum tranmission power is up to 100 mW and with that transmission distance is up to 100 meters.Bluetooth supports the 'ad-hoc networking' between different mobile wirelessdevices for spontaneous networking and immediate communication. Two supported network types are piconet and scatternet. Piconet is a network consisting of one master and up to seven slaves. This means that generally one Bluetooth device can be at the same time have connection up to seven other Bluetooth devices.Scatternet is a network formed by several piconets. Besides physical networking the Bluetooth standard defines alsothe application layer. All Bluetooth services must be built basedon the predefined Bluetooth profiles. Bluetooth profile canbe viewed as application class. There is currently 13 differentBluetooth profiles defined in Bluetooth 1.1 standard. Examplesof such profiles are wireless hands-free devices, file transferand Internet connection through cellular phone. The compatibilityof Bluetooth devices depends on the supported profiles(if two devices support same profile, they are compatiblewith the services provided with that profile).Bluetooth supports also encryption (64 bit keys).
- Mobile commerce has no future with 27 clicks - Secure mobile commerce transactions can be carried out with existing systems and tools, but its is so complicated that the end users will not take to mobile shopping. This was the result of a pilot study conducted by KPN Mobile and Nokia. Rate this link
- The Great WAP Debate - different views to the future of WAP Rate this link
- The Wireless FAQ - Previously known as "The Independent WAP/WML FAQ" Rate this link
- WAP Complements Internet Technologies - Learn the WAP basics and clarify any confusion over it and other technologies like HTML, Bluetooth, and 3G. Rate this link
- WAPsight - WAP news and information Rate this link
- What is WAP? by WAPsight.com - short description Rate this link
- Wireless Application Protocol (WAP) Tutorial Rate this link
- Wireless application protocol stimulates 3G mobile telephony - Fast-moving developments affect products at all levels. Designers must be nimble to meet the market and reality. Rate this link
- Building WAP Services - examples of using XML and ASP for this Rate this link
- Introducing WML and WMLScript - introductory tutorial in programming WML and WMLScript, beginning with download and setup of the sample environment, the Nokia WAP Toolkit. Rate this link
- Introduction to WML - tutorial where the user operates an onscreen PDA simulator to learn WML concepts and keywords Rate this link
- Nokia WAP discussion board Rate this link
- WAP Wireless Markup Language Specification (WML) Rate this link
- WML and WMLScript programmers discussion board Rate this link
- Kannel: Open Source WAP and SMS gateway Rate this link
- Nokia Mobile Internet Toolkit - offers developers a PC environment for creating, testing, and demonstrating WAP applications, software, documentation, and basic support are free of charge Rate this link
- Nokia WAP Toolkit Rate this link
- Opera - web browser with WAP support Rate this link
- Wapsilon - a free on-line browser for WAP Rate this link
- Phone.com - company which makes WAP minibrowsers for mainly USA markets Rate this link
- Wireless Application Protocol pages by WAP Forum Rate this link
- Wappy - a free service for WAPsite with redirecting and creating wap sites Rate this link
WAP developing information
Information pages from organizations working with WAP
WAP related services
- Compact HTML for Small Information Appliances - HTML version used in iMode system Rate this link
- How does Compact HTML (CHTML) work? Rate this link
- Support for i-mode Grows - Two vendors have announced software products that support both i-mode and the competing Wireless Application Protocol (WAP), confirming that i-mode is gaining momentum outside of its base in Japan. Rate this link
- MobileIPworld.com - site on using the Internet Protocol in Mobile Communications Rate this link
- Mobile IP Explained Rate this link
- Mobile Networking Through Mobile IP Rate this link
- VoiceXML distributes voice to the masses - Tomorrow?s next-generation cell phones promise access to the Internet. But why wait? VoiceXML now enables any phone to browse the Web. VoiceXML promises to standardize various processing components for speech processing. By distributing the processing load of speech processing, even "dumb" nodes, such as rotary phones, can provide access to Internet services. Rate this link
- Wireless Internet Network Communications Architecture Tutorial Rate this link
iMode is a technology used in Japan to add Internet conenctivityand web features to their PDC mobile phone system.iMode is a way of providing information to mobile devices.It uses CHTML (Compact HTML) as a markup language, and uses more traditional internet protocols to deliver it.The content is served using HTTP to a so called iMode center(under the control of the developers of iMode, NTT DoCoMo).The iMode center performs protocol conversions which enable the content to be delivered to the phone.
- Narrowband and Wideband Modulation Schemes Rate this link
- Ultrawidebandplanet.com - UWB news Rate this link
- Ultra Wideband (UWB) : Better Than Bluetooth? - If the FCC loosens up a bit, m-commerce may benefit from this high-speed wireless technology that could leave Bluetooth supporters biting their lips. Rate this link
- Wireless Data Blaster - Radio's oldest technology is providing a new way for portable electronics to transmit large quantities of data rapidly without wires. Rate this link
Ultra Wide Band (UWB)
Ultrawideband wireless technology uses no underlying carrier wave, instead modulating individual pulses in some way. UWB operation relies on razor-thin, precisely timed pulses similar to those used in radar applications. Unlike traditional communications systems, ultrawideband wireless occupies a broad span of frequencies at very low power levels, often below the noise floor of the existing signaling environment. The secret of wide bandwidth is the use of short pulses: the shorter the time interval of a pulse, the broader its bandwidth. Because of extremely short duration of UWB pulses, these ultrawideband pulses function in a continuous band of frequencies that can span several gigahertz. Because the UWB pulses employ the same frequencies as traditional radio services, they can potentially interfere with them. To avoid this UWB devices deliberately operate at power levels so low that they emit less average radio energy than hair dryers, electric drills, laptop computers and other common appliances that radiate electromagnetic energy as a by-product. This low-power output means that UWB's range is sharply restricted--to distances of 100 meters or less and usually as little as 10 meters. For well-chosen modulation schemes, interference from UWB transmitters is generally benign because the energy levels of the pulses are simply too low to cause problems. As with emissions from home appliances, the average radiated power from UWB transceivers is likewise expected to be too low to pose any biological hazard to users, although further laboratory tests are needed to confirm this fully. A typical 200-microwatt UWB transmitter, for example, radiates only one three-thousandth of the average energy emitted by a conventional 600-milliwatt cell phone. Challenging technical problem appears to be finding ways to stop other emitters from interfering with UWB devices. A UWB receiver needs to have a "wide-open" front-end filter that lets through a broad spectrum of frequencies, including signals from potential interferers. The ability of a UWB receiver to overcome this impediment, sometimes called jamming resistance, is a key attribute of good receiver design. UWB technology has been used for some time in Ground Penetrating Radar (GPR) applications and is now being developed for new types of imaging systems that would enable police, fire and rescue personnel to locate persons hidden behind a wall or under debris in crises or rescue situations. UWB devices can be used to measure both distance and position.UWB devices can be used for a variety of communications applications involving the transmission of very high data rates over short distances without suffering the effects of multi-path interference. There are different possible modulation method for UWB. In a bipolar modulation scheme, a digital 1 is represented by a positive (rising) pulse and a 0 by an inverted (falling) pulse. In another approach, full-amplitude pulses stand for 1's, whereas half-amplitude pulses stand for 0's. Pulse-position modulation sends identical pulses but alters the transmission timing. Delayed pulses indicate 0's. At present, it appears that semiconductor-based UWB transceivers will be able to provide very high data transmission speeds--100 to 500 Mbps across distances of five to 10 meters. UWB is superior to other short-range wireless schemes in another way. UWB's precision pulses can also be used to determine the position of emitters indoors: a UWB wireless system can triangulate the location of goods tagged with transmitters using multiple receivers placed in the vicinity. On February 14 2003 the Federal Communications Commission gave qualified approval to UWB usage, following nearly two years of commentary by interested parties. Taking a conservative tack, federal regulators chose to allow UWB communications applications with full "incidental radiation" power limits of between 3.1 and 10.6 GHz. Despite the imposed limitations, UWB developers are confident that the wireless technology will be able to accomplish most of the data-transfer tasks its proponents envision for it. Because of its short range, UWB is seen as the next generation Bluetooth. Capable of speeds between 400 and 500 Mbps. Intel, is taking a close look at adding UWB to its chips. IEEE is working on standardizing UWB system. The aim is to get the 802.15.3a (480 Mbit/s speed UWB) specification ready at year 2004.
- Inmarsat Rate this link
- Internetworking Asynchronous Transfer Mode With The Consultative Committee For Space Data Systems Advanced Orbiting Systems Protocols Rate this link
- IRIDIUM - Motorola's New Cellular Phone System - short introduction to specs Rate this link
- Lloyd's satellite constellations Rate this link
- Satelliittimatkapuhelinj?rjestelm?t - text on satellitephones in Finnish Rate this link
- Satellite Systems Gear Up To Meet The Challenges Of Global Networks - intelligent use of bandwidth, through advanced modulation and coding techniques, allows satellite systems to meet rising and varied demands Rate this link
- Satellite video brings the world home - We can receive high-quality video feeds from almost anywhere in the Western world. So, it's easy to assume that such links are standard and ordinary. For much of the world, however, this situation is not the case. The news-reporting path to your TV from remote lands, such as Afghanistan, which lacks a wideband or cellular infrastructure, requires the careful merger of data-handling geostationary satellites and portable earth-bound terminals. The Talking Head worldwide video system needs only a small earth terminal and the Inmarsat satellite link to bring Afghanistansand the rest of the worldsnews to your TV screen. Rate this link
- TAPR - an international organization dedicated to amateur digital communications Rate this link
Unsorted mobile communication links
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