Rev A is an upgrade to EV-DO Rev.0, which offers fast packet establishment along with air interface enhancements that reduce latency and improve data rates. Burst DL data rates increase from 2.45 Mbps to 3.1 Mbps and UL burst rates increase from 153 kbps to 1.8 Mbps.
Third generation mobile communications technology, as defined by the ITU, provides a global standard for cellular networks capable of handling live video calls and data access at broadband speeds. 3G includes EDGE, CDMA 2000, and UMTS. A handful of carriers are moving from GPRS to EDGE and from CDMA to CDMA 2000 and CDMA EVDO, but the most popular global 3G standard is UMTS.
The 3rd Generation Partnership Project (3GPP) is a collaboration agreement that was established in December 1988 to bring together a number of telecommunications standards bodies to produce globally applicable 3G standards. Current participating standards bodies include ARIB, CCSA, ETSI, ATIS, TTA and TTC.
A project within the 3GPP to improve the UMTS standard in terms of efficiency, cost, services, spectrum usage and standard interoperability. Targets include 100 Mbps download speed, 50 Mbps upload speed, sub 5ms latency, increased spectrum flexibility and coexistence with legacy standards such as GSM, GPRS, EDGE and UMTS.
The Third Generation Partnership Project 2 is a collaborative third generation (3G) telecommunications specifications-setting project. The global wireless specifications address North American and Asian interests.
AAA (Authentication, Authorization and Accounting) services are managed by the CSN for WiMAX networks and by the AUC in GSM and UMTS networks. Authentication schemes using EAP, AES and PKMv2 provide security and confidentiality. Accounting functions track usage for services rendered.
Mobile WiMAX technology supports advanced antenna systems including Adaptive Beamforming, Space Time Coding (STC) and Spatial Multiplexing (SM). These are optional features at the base station, but mandatory for each Mobile Station to ensure interoperability.
Also known as Smart or Adaptive Antenna Systems, this advanced antenna option supported by WiMAX technology can be implemented in a variety of ways, including Switched Beam, Dynamically Phased Array and Adaptive Array to enhance both coverage and throughput.
Interference from two different radio transmitters on adjacent frequency channels. Mobile Stations and Base Stations have filters to remove adjacent channel signal, but if the adjacent channel is stronger than the channel of interest, beyond what can be filtered, it will cause interference. Causes can be from poor frequency planning or overly crowded radio spectrum.
CMAC is a key cryptography hash function that is based on a symmetric key block cipher, such as the Advanced Encryption Standard. AES-CMAC provides stronger assurance of data integrity than a checksum or an error-detecting code. CMAC is designed to detect intentional, unauthorized modifications of the data, where checksums detect only accidental modifications.
An Automatic Location Identification system is required to meet current E911 mandates. The system uses BTS location and signal strength measurements to determine the current location of the UE. ALI can also be used for LBS services.
An Automatic Location Identification system is required to meet current E911 mandates. The system uses BTS location and signal strength measurements to determine the current location of the UE. ALI can also be used for LBS services.
The coding rate and modulation scheme are rapidly adapted to the instantaneous channel conditions. Users experiencing favorable channel conditions (close to the base station) can be assigned higher order modulation and high code rates – thus achieving higher peak throughput. Users with less favorable conditions (close to cell edge or in deep fade) will need to use more robust modulation and low coding rates.
AOA is a system that uses the angle of arrival to determine the GPS position of the UE. Using the antenna array on a cellsite, the phase difference of a cellular signal can be determined. This information can be used to determine the exact angle of the UE from the face of the antenna array. By using the AOA of multiple sites, the location of the UE can be determined. AOA is used in E911 and LBS. FLASH: Each cellsite can use the signals it receives from the UE to determine the AOA. The spot where the AOA signals from different cellsites meet is the location of the UE.
A mechanism to automatically increase or decrease the transmission power to optimize the RF link. The purpose of APC is to overcome noise and interference by outside sources or from within the network.
A small application or utility program, usually written in the Java programming language that is designed to do a very specific and limited task. Applets are most commonly used in hand-held mobile devices.
ASCA allocates subcarriers to subchannels using adjacent subcarriers, which can be adaptively selected by the scheduler. Subcarriers with high CINR are selected and those in deep fades are avoided. This approach is used with beam-forming AAS.
The Access Services Network includes the WiMAX base stations and ASN gateway. Base stations manage the air interface between the ASN and subscriber or mobile stations. The ASN gateway aggregates information from base stations and manages handovers between them.
An audio test signal that accurately represents the full range of sounds and transitions that occur in natural speech. This type of test signal is commonly used as a reference signal for the PESQ testing algorithm.
ATM is a type of circuit switch network that is connection oriented, meaning a logical connection is made between the endpoints before the actual data is sent. This is a cell relay network and data link layer protocol, which encodes data traffic into small fixed-sized cells.
A version of TDD where the time slots in the uplink and downlink can be dynamically adjusted based on traffic conditions. With ATTD in 802.16, uplink/downlink time slots can be changed to support asymmetric data flows such as IP traffic.
The AUC authenticates each SIM card that attempts to connect to the GSM network (this occurs when the UE is turned on). Once authentication is completed, the HLR takes over management of the UE.
The BCCH Allocation List is used by the UE when it is in idle mode. The BA list tells the UE which BCCH channels it should monitor to find the strongest signal.
Connecting Internet access to a location over long or short distances. Traditionally, wired networks have been necessary for backhaul, but with 802.16, also known as WiMAX, backhaul via wireless will become even more common.
The BCCH is used in GSM networks to broadcast the parameters needed to access the network. The BCCH contains the LAC (Location Area Code), RAC (Routing Area Code), MNC (Mobile Network Code) and the BA (BCCH Allocation List).
The number of erroneous bits received divided by the total number of bits transmitted. The ratio could also measure number of elements, characters, or blocks over a specified time interval.
The ratio of the number of negatively acknowledged blocks to the total number of blocks acknowledged by the mobile station. This is a common metric for GPRS testing.
A wireless personal area network (PAN) technology that is an open standard for short-range transmissions of data that support point to point (PTP) and point to multipoint (PMP) applications. Bluetooth provides up to 720 Kbps data transfer within a range of 10 meters using omnidirectional antennas in the unlicensed 2.4 GHz band.
A method of digital communication in which the phase of a transmitted signal alternates between 0 and 180 degrees to convey information. A signal is broken in time to represents bits of information. The state of the bit is determined according to the state of the preceding bit. If the phase of the wave does not change, then the signal stays the same (0 or 1). If the phase of the wave changes by 180 degrees, then the signal state changes (from 0 to 1, or 1 to 0). BPSK is also referred to as biphase modulation.
BREW, developed by QUALCOMM, is a development platform that is used to run applications on the any of the QUALCOMM ASICs regardless of cellular technology. Common applications include games, GPS mapping, sending pictures, texting, etc.
BS (Base Station) — An earth-based transmitting and receiving station for wireless technologies such as cellular, paging, WiMAX and other wireless transmission services.
The BSC controls a group of Base Transceiver Stations (BTS). The BSC handles the allocation of channels and controls handovers between different BTSs. The BSC also reduces the amount of direct connections between the BTSs and the MSC (Mobile Switching Center).
The base 8 BSIC value includes the NCC (network color code) and BCC (Base Station Color Code) and is formed by taking the 8 bit NCC and the 8 bit BCC and combining them in the format NCCBCC.
A geographic area originally defined by Rand McNally. A BTA consists of a county or counties surrounding a city (Basic Trading Area Center). The FCC uses BTAs to define PCS Wireless licenses. The US consists of 493 BTAs.
Packets transversing the MAC interface are associated to a service flow and identified by a 16-bit connection identifier or CID. Resources are assigned for the duration of the connection. Several types of connections may be established between the SS and BS, including management, broadcast, multicast and transport connections.
The ratio in dB of the carrier power to the total received noise power. High C/N ratios provide better quality of reception, increased capacity and generally better voice quality and data throughput.
A set of standards designed to work with GSM or UMTS networks that allow operators to define services above the base GSM or UMTS services. For example, roaming services may be improved by not requiring the country code when traveling.
Convolutional coding is a FEC technique used to improve the performance of digital radio, mobile phones and Bluetooth implementations. Convolutional encoding with Viterbi decoding is a technique suited to channels in which the transmitted signal is corrupted mainly by additive white noise.
CCK (Complementary Code Keying) is a modulation scheme used in IEEE 802.11b wireless networks operating at either 5.5 or 11 Mbps. CCK utilizes approximately the same bandwidth, preamble and header as the pre-existing 1 and 2 Mbps wireless 802.11 networks — thus supporting interoperability.
The CDMA Development Group (CDG), founded in December 1993, is an international consortium of companies who have joined together to lead the adoption and evolution of 3G CDMA wireless systems around the world. The CDG is comprised of CDMA service providers and manufacturers, application developers and content providers. By working together, the members help to ensure interoperability among systems, while expediting the availability of 3G CDMA technology to consumers.
A form of multiplexing the radio channel by using different pseudo-random code sequences for each user, versus dividing the radio channel by time (TDMA) or frequency (FDMA).
A method of error correction where incorrectly received coded data blocks are stored at the receiver and combined with the retransmitted coded data blocks before being fed to the decoder of the error-correction code.
CID (Connection Identifier) — Packets transversing the MAC interface are associated to a service flow and identified by a 16-bit connection identifier or CID. Resources are assigned for the duration of the connection. Several types of connections may be established between the SS and BS, including management, broadcast, multicast and transport connections.
Packets transversing the MAC interface are associated to a service flow and identified by a 16-bit connection identifier or CID. Resources are assigned for the duration of the connection. Several types of connections may be established between the SS and BS, including management, broadcast, multicast and transport connections.
The average bandwidth for a virtual circuit guaranteed by an ISP to work under normal conditions. At any given time the bandwidth should not fall below this committed rate.
Can eliminate Inter-Symbol Interference (ISI) as long as the CP duration is longer than the channel delay spread. The CP prevents inter-block interference and makes the channel appear circular to permit low-complexity frequency domain equalization.
Terminal or associated equipment and inside wiring located at a subscriber’s premises and connected with a carrier’s telecommunication network (wired or wireless). The structure demarcates the customer’s equipment from the network operator’s equipment.
The pilot channel in a WCDMA wireless network is used by the Ues to identify the scrambling code transmitted by the Node-B. There is one primary CPICH (P-CPICH), which is transmitted on spreading code 0, Spreading Factor (SF) 256. There are optional secondary CPICHs (S-CPICH), which are transmitted on arbitrary chosen codes.
Utilized to provide channel-state information from the user terminal to the base station scheduler. Information may include channel quality in terms of C/I or other quality metrics.
An error detection code that takes an input signal and produces a output value of fixed size. A CRC can be use the same way as a checksum to detect common errors caused by noise in wireless transmission channels.
A newer class of interated short convolutional codes that are less complex than the Viterbi algorithm on the long convolutional codes that would be required for the same performance.
CTIA — The Wireless Association®, is an international nonprofit membership organization founded in 1984, representing all sectors of wireless communications — cellular, personal communication services and enhanced specialized mobile radio.
As an organization, CTIA represents service providers, manufacturers, wireless data and Internet companies, as well as other contributors to the wireless universe. CTIA advocates on their behalf before the Executive Branch, the Federal Communications Commission, Congress, and state regulatory and legislative bodies.
Real time adaptation of TDD provides the highest transport efficiency and enables 100% use of available spectrum. Minimal latency variation provides for prioritization of preferred subscribers and critical applications.
DAB describes radio technology that carries information using a digital signal. DAB uses multipath reception to its advantage to optimize receiver sensitivity.
The dB is a logarithmic unit used to describe a ratio and is used commonly in radio for measuring gain. Decibels are abbreviated as dB, and you may also see dBm (decibels relative to a reference level of 1 milliwatt) and dBi (decibels relative to an isotropic radiator, or a single point antenna).
The same signal can be received multiple times due to multipath propagation. Delay spread is the difference between the first time and the last time the signal was received.
The ability of a system to switch to different physical RF channels based on channel measurement criteria to conform to particular regulatory requirements.
A set of rules used by communication devices such as a computer, router or network adapter to allow the device to request and obtain an IP address from a server which has a list of addresses available for assignment.
A digital radio transmission system for sending multimedia to mobile devices such as mobile phones and subscriber stations. DMB was developed in South Korea and has some similarities with the main competitor – DVB-H. DMB is unavailable in the US due to RF band conflicts in the L band reserved for the U.S. military.
An antenna with a center-fed driven element for transmitting or receiving RF energy. This is the simplest practical antenna from a theoretical point of view.
Labeled WiMAX burst profile periodically broadcasted by the base station based on known environmental conditions, equipment limitations, etc. User terminals send a requested DIUC on the basis of the results of testing done during an initial start-up phase. The BS has the option of confirming or rejecting the request.
A method for improving the reliability of a message signal by utilizing two or more communication channels and paths with different characteristics (space, frequency, time or polarization) in order to improve degradation caused by fading or interference.
MAP messages include resource allocation information that allows the MAC scheduler to change the resource allocation on a frame-by-frame basis to adapt to bursty traffic.
FCH contains the Downlink Frame Prefix (DLFP) that specifies the modulation type and number of symbols associated with one or several downlink bursts that follow the FCH.
A method to adjust power of a transmitter in a wireless network to compensate in near real time for fading and signal degradation. Power control algorithms may be open or closed loop.
DSAs are network management messages used to maintain physical link and connections. These MAC management messages include DSA-Request (DSA-REQ), DSA-Acknowledge (DSA-ACK) and DSA-Response (DSA-RSP). These messages are used to create service flows.
DSCA is an approach to allocate subcarriers to subchannels where a subchannel uses a different subcarrier randomly distributed across the channel bandwidth. This is the best approach for mobile environments and is used with PUSC and FUSC.
DSL provides digital data transmission over the wires of a local telephone network. Typical download speeds of consumer DSL range from 256 kbps to 24 Mbps depending on the DSL technology, line conditions and service level implemented.
One of two approaches (with frequency hopping spread spectrum) for sorting overlapping data signals transmitted via radio waves. Direct sequence spread spectrum is commonly abbreviated as DSSS or DS. 802.11b uses direct sequence spread spectrum.
A digital radio transmission system for sending multimedia to mobile devices such as mobile phones and subscriber stations. DVB-H adapts the successful DVB-T system for digital terrestrial television to specific requirements for handheld, battery powered devices in the VHF-III, UHF-IV/V and L bands. DVB-H can coexist with DVB-T.
EAP is an authentication framework often used in wireless networks and point-to-point connections. EAP is a framework, not a specific authentication mechanism. There are about 40 different methods that use the EAP framework.
Enhanced Data rates for GSM Evolution, also known as Enhanced GPRS (EGPRS) is a GSM based wireless technology for packet switched data transmission. Data speeds can reach theoretical speeds of 236.8 kbps using four time slots.
A speech coding standard used in GSM to improve the quality of the then existing full rate codec. EFR works at 12.2 kbits/s and improves the quality of the speech in noise free and in background noise conditions.
EGSM supports both the original 900 MHz spectrum used in Europe and the extended one. The additional 10 MHz (880-890 MHz) provides 50 more communication channels.
The EIR is often part of the HLR. The EIR keeps a list of all Ues which are to be banned from the network or monitored. This is designed to track stolen mobile phones.
The use of wireless technology for new, cutting edge and previously undeveloped services. Today’s enterprise wireless technology and services include two-way trunked and conventional; microwave — MAS and point to point; in-building wireless; RFID; WiMax; real-time location services; VoIP; and unlicensed wireless.
A scheduling mechanism that builds on the efficiency of both UGS and rtPS. TheBS provides unsolicited unicast grants as in UGS, thus saving the latency of a bandwidth request. However, UGS allocations are fixed in size, whereas ertPS allocations are dynamic. VoIP with activity detection is an application.
The European Telecommunications Standards Institute (ETSI) is an independent, non-profit organization, whose mission is to produce telecommunications standards within Europe. These technologies include telecommunications, broadcasting and related areas such as intelligent transportation and medical electronics.
EV-DO stands for Evolution Data Optimized (but is sometimes referred to as Evolution Data Only). EV-DO is a wireless transmission standard utilizing CDMA techniques as well as FDD to maximize the amount of data transmitted. Rev. A has increased the downlink maximum burst rate to 3.1 Mbps and the uplink burst rate to 1.8 Mbps.
A process where link quality is measured and used to predict instantaneous link performance. The highest Modulation and Coding Scheme is selected based on predicted link performance for the transmission.
Mobile WiMAX (802.16e) optional handoff method in which the mobile station (MS) scans and keeps a list of suitable Base Stations (BS) in an Active Set. An Anchor BS is defined and the MS only communicates with the Anchor BS. The MS continuously monitored the signal strength from BSs in the Active Set and may initiate a handover by notifying the Anchor BS. Data is simultaneously transmitted to all members of the Active Set that are able to serve the MS.
The Federal Communications Commission (FCC) is a United States government agency, created, directed, and empowered by Congressional statute (see 47 U.S.C. § 151 and 47 U.S.C. § 154), and with the majority of its commissioners appointed by the current president.
The FCC was established by the Communications Act of 1934 as the successor to the Federal Radio Commission and is charged with regulating all non-Federal Government use of the radio spectrum (including radio and television broadcasting), and all interstate telecommunications (wire, satellite and cable) as well as all international communications that originate or terminate in the United States. It is an important factor in US telecommunication policy. The FCC took over wire communication regulation from the Interstate Commerce Commission.
The FCC is an independent US government agency charged with regulating all non-Federal Government use of the radio spectrum and all interstate as well as international communications that originate or terminate in the US.
Part 15 is a section of the FCC rules and regulations regarding unlicensed transmissions, including power and antenna limits. The FCC has allocated spectrum in the 900, 2,400 and 5,600 MHz band to Part 15 devices. FCC Part 15 covers regulations under which an intentional, unintentional, or incidental radiator can be operated without an individual license. Unlicensed users in these bands are subject to uncontrolled interference from any other users in the band. This may limit the usefulness of wireless broadband applications for business.
Follows the Preamble in WiMAX OFDM frames. It provides the frame configuration information such as MAP message length, coding scheme and usable sub-channels. In the downlink the MAP message follows the FCH.
Signal multiplexing where multiple baseband signals are modulated on different frequency carrier waves and added together to create a composite signal.
Access technology that is used by radio systems to share radio spectrum by allocating individual frequencies for each communications signal within the band.
The purpose of forward error correction (FEC) is to improve the capacity of a channel by adding some carefully designed redundant information to the data being transmitted through the channel. The process of adding this redundant information is known as channel coding. Convolutional Coding (CC) is an example of a FEC technique.
The number of erroneous frames received divided by the total number of frames transmitted. Often used as a link quality estimator for CDMA based systems.
Frequency-Hopping Spread Spectrum changes, or hops, frequencies in a pattern known to both sender and receiver. FHSS is little influenced by radio stations, reflections, or other environmental factors, but it is much slower than Direct Sequence Spread Spectrum. Bluetooth uses this technology.
Used in WiMAX to manage sub-channels for base station edge users. A sub-channel reuse pattern can be configured so that users close to the base station operate on the zone with all sub-channels available. Edge users operate on the zone with a fraction of all sub-channels available to improve connection quality and throughput.[Diagram 1]
The measurement of the number of occurrences of a repeated event per unit of time. [Image 1] This image shows various frequencies. Frequency increases as you move from the waves at the top to those at the bottom.
Frequency-Hopping changes, or hops, frequencies and slots in a pattern known to both sender and receiver. Frequency hopping reduces the effect of co-channel interference because there is a low probability that multiple users will be on the same frequency in the same area at the same time.
In broadband wireless channels, propagation conditions can vary over different portions of the spectrum in different ways for different users. Frequency Selective Scheduling enables selection of frequencies within the band to take advantage of multi-user frequency diversity to improve QoS.
The frequency reuse factor is the rate at which the same frequency can be used in the network. It is 1/n where n is the number of cells which cannot use a frequency for transmission. A common value for the frequency reuse factor is 7.
The loss in signal strength of an electromagnetic wave that would result from a line-of-sight path through free space, with no obstacles nearby to cause reflection or diffraction.
A GPRS support node that acts as an interface between the GPRS core network and the external packet data networks such as the Internet. The GGSN performs authentication and is responsible for IP address assignment and is the default router for the connected User Equipment (UE).
General Packet Radio Service is a packet-switched mobile phone data technology used on GSM networks. GPRS can reach theoretical downlink data transfer speeds of 80.0 kbps using four downlink time slots and the fastest (lease robust) coding scheme.
Global Positioning System, which uses a constellation of 24 medium Earth orbit satellites that transmit precise radio signals. This enables a GPS receiver on Earth to determine its location, speed and direction via trilateration calculations.
Global Systems for Mobile communications is the most popular digital mobile phone standard in the world and used by more than 2 billion people in more than 200 countries. GSM is a FDD and FDMA technology.
A home agent in Mobile IP is a router on a mobile's home network which tunnels datagrams for delivery to the mobile node when it is away from home, and maintains current location information for the mobile node.
HARQ self optimizes and adjusts automatically to channel conditions without requiring frequent or highly accurate C/I measurements. The HARQ process adds redundancy only when needed, saves failed transmission attempts to help future decoding as in Chase Combining, and increases the packet success probability with every transmission.
The process of transferring an ongoing call or data session from one channel connected to the core network to another. Hard Handoffs are break before make type handoffs where the connection from one base station ends before the connection from the new base station begins.
HiperMAN stands for High Performance Radio Metropolitan Area Network and is a standard created by ETSI to provide wireless network communication in the 2-11 GHz bands across Europe. This standard has been harmonized with the IEEE 802.16 by the WiMAX Forum to provide one global standard.
The HLR is a centeral database that consists of the details of each subscriber that is authorized to use the network. The HLR consists of every SIM card issued by the operator, and chooses which UEs can gain access to the network and which UEs cannot gain access.
The HSN has a value from 0 to 63. Zero indicates a sequential mode of frequencies while other values represent pseudo-random lists. Generally, all the channels in the same cell use the same hopping sequence number and different Mobile Allocation Index Offsets (identifies starting frequency) This eliminates the interference between channels within a cell.
A 3GPP protocol to improve the performance of the downlink throughput for UMTS systems. Current HSDPA deployments support 1.8, 3.6, 7.2 and 14.4 Mbps in the downlink. These improvements are made possible by the use of AMC, fast packet scheduling and HARQ.
iDEN, developed by Motorola, is a TDMA based communications network. iDEN has the capabilities of several technologies such as a digital cellular telephone, two-way radio, pager and data/fax modem.
The 802.11 standard, known as Wireless Fidelity or Wi-Fi is a wireless Ethernet standard that was designed to simplify office LAN deployment by eliminating wiring requirements. Today, this technology is deployed in areas as small as a coffee shop to as large as a municipality (WISP). 802.11 is a family of wireless networking standards, including 802.11a, 802.11b, and 802.11g. 802.11a provides up to 54 Mbps on the 5GHz band. 802.11b hits 11 Mbps in the 2.4GHz band and is backward-compatible with 802.11, the original specification. 802.11g provides over 20 Mbps on the 2.4GHz band and it is backwards compatible with 802.11b. Both 802.11b and 802.11g have effective ranges of about 300 feet; 802.11a's higher frequency limits its range to about 60 feet. Other standards in this family include 802.11e, 802.11h, and 802.11n.
Amended WiMAX standard to address mobility. Mobile WiMAX is a broadband IP based technology that is based on open standards and can compliment existing wireless mobile technologies or be deployed as an independent mobile wireless data technology.
The IETF is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet. It is open to any interested individual.
A network architecture created to standardize and simplify deployment of next-generation multimedia communications, such as instant messaging, video conferencing and mobile TV.
The IMS Forum is a global, non profit industry association devoted to interoperable IP Multimedia Subsystems services and solutions. IMS Forum's mission is to accelerate the interoperability of IMS applications and services. These will enable enterprise and residential consumers to quickly benefit from the delivery of quadruple play; voice, video, internet and mobile services.
"The IMSI is a unique number allocated to each mobile subscriber in the GSM system that identifies the subscriber and subscription within the GSM network. The IMSI is included in the SIM, and is made up of three parts (1) the mobile country code (MCC) consisting of three digits, (2) the Mobile Network Code (MNC) consisting of two digits, and (3) the Mobile Subscriber Identity Number (MSIN) with up to 10 digits.
An Hybrid Automatic Repeat Request (HARQ) scheme where redundant information is incrementally transmitted if the decoding fails on the previous attempt. This is a more advanced approach over Chase Combining (CC), which sends simple repeats of the entire coded packet.
Distortion of a signal that causes the previously transmitted symbols to have an effect on the currently received symbol. This is usually an unwanted phenomenon as the previous symbols have a similar effect as noise, thus making the communication less reliable.
ITU is the leading United Nations agency for information and communication technologies. As the global focal point for governments and the private sector, ITU's role in helping the world communicate spans three core sectors: radio communications, standardization and development.
J2ME provides a robust, flexible environment for applications running on mobile and other embedded devices—mobile phones, personal digital assistants (PDAs), TV set-top boxes, and printers.
KPIs are metrics used to quantify the performance of a process or network. For example, Throughput could be designated as a KPI, and a high rate would indicate a good service area for the data network.
The LAI is internationally unique and consists of a three decimal digit Country Code (CC), a two digit Mobile Network Code (MNC), and a Location Area Code which can be 5 decimal digits. The LAI is broadcast regularly by Broadcast Control Channels (BCCH).
A computer network covering a small geographical area such as the home, office or group of buildings. LANs may be based on Ethernet (IEEE 802.3) or Wi-Fi (IEEE 802.11) technologies. Multiple LANs may be connected to form a Wide Area Network (WAN).
The length of time between a packet being sent and the response to that packet being returned or the time delay between when the packet was sent to when it was received.
Services that incorporate location information provided by cellular phone or other mobile devices. One application may be to send custom advertising to the mobile device user as they approach a store or service. LBS requires that either the phone or the network have precise location information. The location information can be provided by embedded GPS receivers in the phone or via network trilateration techniques.
An error correcting code to assist transmitting a message over a noisy transmission link. LDPC was the first code to allow data transmission rates close to the theoretical maximum. LDPC codes are positioned to become a standard in the developing market for highly efficient data transmission methods.
The calculation of all the gains and losses from a transmitter, through free space, to the receiver in a wireless communication system. Typical gains include transmitter antenna gain and receiver antenna gain. Losses may include cable/connector loss and free space loss (FSL). A sample calculation might look like this: Received Power (dBm) = Transmitted Power (dBm) + Gains (dB) – Losses (dB).]
The 802.16 MAC was designed specifically for the PMP wireless access environment with very high bit rates (up to 268 Mbps each way). The MAC uses self correcting bandwidth request algorithms, dynamically assigns burst profiles and uses variable length Protocol Data Units (PDU) to greatly increase the efficiency of the standard.
MIMO is an antenna technology that improves range, works well with multipath, and increases bandwidth and spectral efficiency. MIMO works by using multiple parallel data paths from the transmitter to the receiver, which uses multipath to its advantage.
A 3GPP, 3GPP2 and OMA standard for wireless telecommunications systems that allows for sending messages with multimedia objects including images, audio, video and rich text.
Amended WiMAX standard to address mobility. Mobile WiMAX is a broadband IP based technology that is based on open standards and can compliment existing wireless mobile technologies or be deployed as an independent mobile wireless data technology.
Mobile WiMAX service classes include unsolicited grant service (UGS), real-time polling service (rtPS), extended real-time PS (ertPS), non real-time PS (nrtPS), and best effort (BE). The MAC layer manages radio resources efficiently to support QoS for each connection.
Provides a numerical indication of the perceived quality of received media at the receiver. The scale is from 1 to 5 where 1 is the lowest quality and 5 is the highest.
Motorola is a global communications leader, powered by, and driving, seamless mobility. Motorola is revolutionizing broadband, embedded systems and wireless networks – bringing cutting-edge technologies into your everyday life, with style.
Motorola makes huge investments in research and development. Over 22,000 engineers and scientists are on the Motorola team. We have over 21,300 patents, and counting. Motorola manages an R&D portfolio of over $4.1 billion aimed at delivering commercial value and shaping the future with innovative technology and architectures.
MPLS is a data-carrying mechanism which emulates properties of a circuit-switched network over a packet-switched network. It was designed to provide a unified data-carrying service for both circuit-based clients and packet-switching clients which provide a datagram service model.
Comprises all user equipment and software needed for communication with a wireless voice or data network. This may also be referred to as User Equipment (UE) in 3G networks or Subscriber Station (SS) in WiMAX.
The MSC is a telephone exchange which provides circuit-switched calling, mobility management, and GSM services to the mobile phons roaming within the area that it serves. This includes voice, data and fax services, as well as SMS and call divert. The MSC usually consists of several BSCs which can then consist of hundreds or even thousands of BTSs.
Transmit power of the mobile station is controlled in a GSM system to limit interference and to save battery power. Power control is done in 2 dB steps with specified maximums and range based on the mobile station class. (e.g. Class 4 GSM maximum is 33 dBm with a dynamic range of 28dB).
A propagation phenomenon that is caused by radio signals reaching the receiving antenna via two or more paths. Multipath can be caused by reflection, refraction and ducting. The effects of Multipath include constructive and destructive interference, and phase shifting.
A mobile virtual network operator (MVNO) is a company that provides mobile phone service but does not have its own frequency allocation of the radio spectrum, nor does it have all of the infrastructure required to provide mobile telephone service. A company that does have frequency allocation(s) and infrastructure is known simply as a Mobile Network Operator (MNO). MVNOs are roughly equivalent to the “switchless resellers” of the traditional landline telephone market. Switchless resellers buy minutes wholesale from the large long distance companies and retail them to their customers.
An MNO that does not have a frequency spectrum allocation in a particular geographical region may operate as an MVNO in that region. MVNOs can operate using any of the mobile technologies MNOs use, such as Code Division Multiple Access (CDMA), GSM and the Universal Mobile Telecommunications System (UMTS).
The first commercially successful MVNO in the UK was Virgin Mobile UK, launched in the United Kingdom in 1999 and now has over 4 million customers in the UK. Its success was replicated in the US, but ventures in Australia have not been so successful, and failed in Singapore, albeit with a different strategy.
An MVNO’s roles and relationship to the MNO vary by market, country and the individual situations of the MNO and MVNO. In general, an MVNO is an entity or company that works independently of the mobile network operator and can set its own pricing structures, subject to the rates agreed with the MNO. Usually, the MVNO does not own any GSM, CDMA or other core mobile network related infrastructure, such as Mobile Switching Centers (MSCs), or a radio access network. Some may own their own Home Location Register, or HLR, which allows more flexibility and ownership of the subscriber’s mobile phone number (MSISDN) - in this case, the MVNO appears as a roaming partner to other networks abroad, and as a “network” within its own region. Some MVNOs run their own Billing and Customer Care solutions known as BSS (Business Support Systems). Many use an MVNE.
A network access provider is a business entity that concentrates on establishment and operation of network infrastructure. The network access provider does not need to be owned by the Network Service Provider.
A list of channels that are likely candidates for handoffs. The neighbor list is defined by the network and is sent from the BS to the UE. If a channel is not on the neighbor list, the UE cannot handover to it.
Nordic Mobile Telephone was the first mobile phone system. NMT was created in 1981 to combat increasing congestion. Originally, NMT used the 450 MHz band (NMT 450), but in 1986 900 MHz was added (NMT 900) to create more channels.
Mobile WiMAX service class that offers regular unicast polls, which ensures that the service flow receives request opportunities even during network congestion.
A NSP is a business entity that provides IP connectivity and network services to end subscribers. One NSP may have agreements with multiple NAPs. NSPs may also establish roaming agreements with other NSPs.
The NSS is responsible for performing call processing and subscriber related functions. The NSS consists of the Home Location Register (HLR), Visitor Location Register (VLR), Authentication Center (AUC) and Equipment Identity Register (EIR).
Orthogonal Frequency Division Multiplexing uses a large number of closely spaced orthogonal sub-carriers, which are modulated with a conventional modulation scheme (e.g., QAM) at a low symbol rate. OFDM is able to cope with severe channel conditions including fading due to multipath. Low symbol rate makes the use of a guard interval between symbols affordable, making it possible to handle time-spreading and eliminate intersymbol interference.
Orthogonal Frequency Division Multiple Access distributes subcarriers among users so all users can transmit and receive at the same time within a single channel on what are called subchannels.
A burst is an area within a zone which is assigned to one dedicated user. It uses a certain number of subchannels (frequency domain) and a certain number of symbols (time domain). Bursts contain Slots.
A slot is the minimum possible data allocation unit within OFDMA as defined in frequency and time. It always contains one subchannel and can contain one to three symbols. For example, a DL-PUSC is two symbols wide and a UL-PUSC is three symbols wide.
A subchannel is the smallest logical unit in the OFDMA frequency domain. It contains one or more physical carriers, which are normally non-adjacent carriers. The order may change within a burst from symbol to symbol. A subchannel forms a slot with one or more OFDMA symbols. A slot is a channel and MAP allocation unit, which contains 48 data subcarriers.
This figure shows an example of the OFDMA frame structure in TDD mode. DL PUSC - This is the default DL subcarrier allocation method for OFDMA. Depending on how the subchannels are grouped, the cell can be viewed as a frequency reused by a factor of 3 or 1. PUSC is designed to minimize the probability of using the same subcarrier in adjacent sectors or cells. DL FUSC - Uses all subchannels and minimizes the performance degradation of fading channels by frequency diversity. UL FUSC - Uses all subchannels and minimizes the performance degradation of fading channels by frequency diversity. UL PUSC - PUSC is designed to minimize the probability of using the same subcarrier in adjacent sectors or cells. FCH Follows the Preamble in WiMAX OFDM frames. It provides the frame configuration information such as MAP message length, coding scheme, and usable sub-channels. In the downlink the MAP message follows the FCH. Feedback Channel - UL subframe may have fast feedback channels for fast CQI reports or other fast operational requests or responses. Preamble - in OFDM the preamble is the first OFDM symbol of the frame and it issued for synchronization. This is followed by the frame control header (FCH) in the second symbol. DL Map - Protocol which provides an application layer to communicate with the MS to support mobility services such as location management, authentication and service subscriptions. Ranging - Used in mobile WiMAX for the purpose of OFDMA network entry, connection maintenance, bandwidth request and efficient HO. TTG - TTG is the gap between the last sample of the downlink burst and the first sample of the subsequent uplink burst. This gap allows time for the base station (BS) to switch from transmit to receive mode. RTG - RTG is the gap between the last sample of the uplink burst and the first sample of the subsequent downlink burst. This gap allows time for the base station (BS) to switch form receive to transmit mode.
A zone is one complete logical part of a frame. There are downlink zones and uplink zones of different types. Some may use all the subchannels of the OFDMA frequency range (FUSC) or only parts of them (PUSC). Zones contain Bursts.
Also designed to fully use frequency diversity. One difference from FUSC is that OFUSC uses a bin structure similar to band adaptive modulating and coding (AMC).
OPTis-WiMAX/XCAL-X is a Windows based real-time software application for WiMAX optimization and network performance monitoring. OPTis-X collects data from up to five WiMAX devices. The OPTis-X platform includes real time mapping with key parameters, comprehensive and customizable graphs, message filtering and voice alarms. These key features facilitate network monitoring and identification of problems in real time while drive testing.
Has a tile structure, with each tile comprising three subcarriers by three symbols. The center subcarrier is used as a pilot, and the remaining eight subcarriers are used as data subcarriers.
OTA is a way to broadcast a single signal to multiple locations. Standard TV and Satellite uses OTA to send the same signal to multiple televisions at the same time. OTA programming can also be used to update the software or firmware inside a cell phone. Providers will use this technique to make sure all the phones in their system are running the same software. OTA programming is used to send information from one tower to multiple devices.
A network used for communicating between devices close to one person, typically within a few meters. Personal area networks may be wired or wireless (WPAN) using IrDA, Bluetooth or UWB.
An antenna type that radiates in only a specific direction. Panel antennas are commonly used for point-to-point situations. They are also known as "patch antennas."
Peak power value relative to the average power received from a OFDM signal made up of multiple subcarriers. Excessive peaks can overdrive a receiver and the receiver will not be able to process the signal. PAPR is managed in several ways including using null carriers, adjusting transmission power and special pre-coding techniques, which generate waves with probabilistically lower PAPR.
An antenna type that radiates a very narrow beam in a specific direction. Parabolic antennas offer the highest gain for long-range point-to-point situations.
The attenuation (reduction in power density) of a RF signal as it propagates through space. Path loss is a major component in the analysis and design of the link budget of a wireless telecommunication system.
PCIA represents companies that develop, own, manage and operate towers, commercial rooftops and other facilities for the provision of all types of wireless, broadcasting and telecommunications services. PCIA is dedicated to advancing an understanding of the benefits of wireless services and required infrastructure to local and federal government officials and communities at large.
PCS refers to a specific band used in cellular communications. In the US and Canada, the PCS band refers to the 1900 MHz band. Any cellular technology including CDMA, GSM, UMTS, TDMA, and D-AMPS can be used in this band.
Performs packet data processin for the BSC. The PCU can be built into the base station, built into the BSC or in some proposed architectures, it can be at the SGSN.
A Personal Digital Assistant (PDA) is a handheld computer, but has become much more versatile over the years. PDAs are also known as small computers or palmtop computers. PDAs have many uses: calculation, use as a clock and calendar, accessing the Internet, sending and receiving email, video recording, typewriting and word processing, use as an address book, making and writing on spreadsheets, scanning bar codes, use as a radio or stereo, playing computer games, recording survey responses, and Global Positioning System (GPS). Newer PDAs also have both color screens and audio capabilities, enabling them to be used as mobile phones (smartphones), web browsers, or portable media players. Many PDAs can access the Internet, intranets or extranets via Wi-Fi, or Wireless Wide-Area Networks (WWANs). Many PDAs employ touch screen technology.
PDU is the data that are passed between communicating entities of the same protocol layer. In 802.16, the MAC PDU consists of a fixed length header, a variable size payload field and an optional CRC field.
The most basic network layer, providing only the means of transmitting raw bits over a physical data link, connecting network nodes. It performs services requested by the data link layer. The physical layer provides the interface to the transmission medium, frequencies to broadcast on, what modulation scheme to use and similar low-level parameters.
An unmodulated channel that transmits at constant power. The UE in CDMA based wireless networks uses this channel to compare the signal strength of nearby Base Stations. These measurements are used to manage hard and soft handovers.
The basis of Mobile WiMAX security as defined in 802.16e. This protocol manages the MAC security, authentication, Traffic Encryption Control, Handover Key Exchanges and Multicast/Broadcast security messages.
A fixed wireless network in which one point (the access point) serves multiple other points around it. Indoor wireless networks are all point-to-multipoint, and long-range wireless networks that serve multiple clients usually employ either a single omnidirectional antenna or multiple sector antennas. When compared to point to point (PTP) networks, point to multi-point (PMP) networks cover a wider area with lower antenna gain and distance. PMP networks share network capacity with lower average capacity per user and have limited ability to reuse the same frequencies.
The standard landline telephone system in use in most parts of the world. While POTS is lacking in features and bandwidth, it is the most reliable phone system in the world with almost 99.999% uptime. POTS is also known as PSTN (Public Switched Telephone Network).
The PSAP is the centralized location responsible for answering 911 calls for emergency assistance. The PSAP is usually controlled by the city or county, and there are around 6500 PSAP locations in the US.
Point-to-point is a fixed wireless network, such as a microwave link, that uses directional antennas and can span distances as short as several hundred feet or as long as 25 or more miles, with capacities from 1 Mbps to almost 1 Gbps. Network operators may use point-to-point wireless networks for backhaul applications.
PTT, a half duplex communications technique, was originally used in two way radios. Nextel was the first cellular company to offer PTT, since then several others have attempted to have PTT with little success.
This is the default DL subcarrier allocation method for OFDMA. Depending on how the subchannels are grouped, the cell can be viewed as a frequency reused by a factor of three or one. PUSC is designed to minimize the probability of using the same subcarrier in adjacent sectors or cells.
Modulation scheme that conveys data by changing (modulating) the amplitude of two carrier waves. These two waves, usually sinusoids, are out of phase with each other by 90° (in quadrature). Phase modulation and phase shift keying can be regarded as special cases of QAM, where the amplitude of the waves is constant and the phase is varying.
A mechanism for measuring and controlling the reliability and usability of a wireless telecommunications network. Metrics to gauge QoS include coverage, accessibility, audio quality (voice) and throughput (data).
Uses four points on the constellation diagram, equally spaced around a circle. With four phases, QPSK can encode two bits per symbol to double the data rate compared to a BPSK system while maintaining the bandwidth of the signal.
A rake receiver is a radio receiver designed to counter the effects of multipath fading. It does this by using several "sub-receivers" each delayed slightly in order to tune to the individual multipath components. Each component is decoded independently, and then combined in order to improve the signal.
The maximum length of time the RAKE Receiver searches for each unique signal. RAKE receivers attempt to lock onto time shifted copies of the transmitted signal generated by multipath propagation. Multipath and timing delay are used to optimize the search window, which is the time the phone takes to look for pilots in a CDMA and WCDMA network. If the search window is too small, the phone will not identify pilots with longer delays.
The Radio Access Network is a wireless network resides between the end user equipment (UE), mobile station (MS) or subscriber station (SS) and the core network. Examples of RAN include the GRAN for GSM radio access network, GERAN for GSM with EDGE and UTRAN for UMTS radio access networks.
The RBOC consists of the companies that were formed during the federal mandated breakup of AT&T in the early 1980s. Originally there were seven Regional Bell Operating Companies, but through mergers and acquisitions, there are now only three: AT&T, Quest, and Verizon.
WiMAX base stations may request channel measurement information from the subscriber using REP-REQ messages, in which the subscriber station responds using REP-RSP messages. Subscriber stations may also send unsolicited REP-RSP messages when user interference crosses a specified threshold.
Radio signals generated by something other than the transmitter. The effect is that it either alters the signal, or adds background noise to the signal.
In free space, all electromagnetic waves (radio, light, X-rays, etc) obey the inverse-square law which states that the power density of an electromagnetic wave is proportional to the inverse of the square of "r" (where "r" is the distance [radius] from the source) or:
Term used to explain how radio waves behave when they are transmitted, or are propagated from one point on the Earth to another. Radio waves may be subject to reflection, refraction and absorption.
Counts up or down depending on the successful reception of the SACCH frames. The network can be configured to drop calls if the link degrades past a threshold.
RNC's in the UTRAN are responsible for controlling the Node-Bs (base stations). The RNC carries out radio resource management and interfaces to the MSC and SGSN in the core network.
A repeater is an automated radio station that extends the range of communications. It consists of a receiver tuned to one frequency and a transmitter tuned to a different frequency, linked together with a controller device.
RSCP is used in both UMTS and CDMA. RSCP is measured by the UE and reported back to the Node-B. RSCP is used in UMTS as handover criteria and in the DL and UL open loop power control.
Within the WiMAX OFDMA frame structure for TDD mode, each frame is divided into DL and UL subframes. RTG is the gap between the last sample of the uplink burst and the first sample of the subsequent downlink burst. This gap allows time for the base station (BS) to switch from receive to transmit mode.
Mobile WiMAX service class designed to support real-time service flows that periodically generate variable-size data packets, such as Moving Picture Experts Group (MPEG) video.
SDMA techniques exploit spatial information of the location of mobile units within the cell. The radiation pattern of the base station, both in transmission and reception, is adapted to each user to obtain the highest gain in the direction of the mobile user. This is often done using phased array antennas.
The SDU is the data that a certain layer will pass to the layer below. It differs from the PDU in that the PDU specifies the data that will be sent to the peer protocol layer at the receiving end.
In WCDMA the spreading process is done by directly combining the baseband information to a high chip rate binary code. The Spreading Factor is the ratio of the chips to the baseband information rate. Spreading factors range from 4 to 512 in FDD UMTS.
A GPRS support node responsible for the delivery of data packets to and from the Mobile Stations (MS) within its geographical service area. Common functions include Mobility Management (MM) and billing of user data as the MS moves between routing areas.
In CDMA, WCDMA and WiMAX networks, a high number of soft handovers results in more connections established in the network. This means more consumption of system resources and diminished capacity. Through analysis, the engineers can identify areas where the probability of having a high number of soft handovers is high. Engineers can then fine tune those areas and perhaps reduce the handover threshold, for example from 7dB to 5dB in a WCDMA system, that will result in a lower soft handover probability. By reducing the soft handover overhead, there are more available resources and capacity.
The SIM card is a removable card that securely stores the key information used to identify a mobile phone. The SIM card can also contain memory that allows for storing phone numbers and other data. SIM cards allow users to seamlessly change phones by simply removing the SIM card and inserting it into another phone.
SIMO is an antenna system that utilizes one transmit antenna and two receive antennas to take advantage of multipath and improve the received signal. The signal is improved through the use of diversity and radio combining techniques.
The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more mobile participants. These sessions include Internet telephone calls, multimedia distribution, and multimedia conferences.
"Signal to interference ratio is measured at the base station in a WCDMA system and is used in adaptive transmission power control. A command is issued to the mobile unit to reduce the transmission power whenever a SIR measurement is larger than the target value. "
A formal agreement between customers and service providers. It may include performance (minimum throughput, uptime, etc.), responsibilities, priorities or other attributes.
Spatial Multiplexing in the base station using a MIMO antenna configuration sends different downlink data on each transmit antenna. This, theoretically, can double the downlink capacity. Adaptive MIMO switching can choose between Space Time Coding and Spatial Multiplexing. SM improves peak throughput, but the coverage area may be limited when channel conditions are poor.
Spatial Multiplexing in the base station using a MIMO antenna configuration sends different downlink data on each transmit antenna. This, theoretically, can double the downlink capacity. Adaptive MIMO switching can choose between Space Time Coding and Spatial Multiplexing. SM improves peak throughput, but the coverage area may be limited when channel conditions are poor.
Type of handoff where the Subscriber Station is simultaneously connected to two or more cells (or cell sectors) during a voice or data session. This may also be referred to as a make-before-break handoff.
Signals distributed over a wide range of frequencies and then collected and reassembled at the receiver. The modulated output signals occupy a much greater bandwidth than the signal’s baseband information bandwidth. The second criteria for spread spectrum is that some function other than the information being transmitted is employed to determine the resultant transmitted data.
Comprises all user equipment and software needed for communication with a wireless voice or data network such as WiMAX. This may also be referred to as User Equipment (UE) in 3G networks or Mobile Station (MS) in cellular networks.
A set of telephony signaling protocols which are used to set up PSTN telephone calls. These were originally developed by AT&T in 1975 and then defined as a standard by ITU-T in 1981.
A set of telephony signaling protocols which are used to set up PSTN telephone calls. These were originally developed by AT&T in 1975 and then defined as a standard by ITU-T in 1981.
Space Time Coding in the base station using a MIMO antenna configuration transmits on each transmit antenna to provide space and time diversity. This enhances the signal to noise ratio and increases capacity and range. Adaptive MIMO switching can choose between Space Time Coding and Spatial Multiplexing. STC provides large coverage regardless of channel condition, but does not improve the peak data rate.
In OFDMA, there are three types of subcarriers: data, pilot and null. Data subcarriers are used for data transmissions, pilot subcarriers are used for channel estimation and various synchronization purposes and null subcarriers are used for the direct current and guard bands transmitting no signals. Subcarrier allocation can be distributed (DSCA) or adjacent (ASCA).
A 3G air interface standard using 5MHz of spectrum divided into 10mS frames containing 15 time slots. The time slots are allocated in fixed percentages for downlink and uplink. CDMA is used in each time slot to multiplex streams.
A 3G air interface developed in China. TD-SCDMA uses TDD with TDMA and CDMA for multiplexing. This reduces the number of users in each timeslot, which reduces the implementation complexity. However, this also reduces coverage and mobility, and complicates radio resource management. The "S" in TD-SCDMA stands for synchronous, which means the signals are synchronized. This reduces interference and increases capacity at the cost of hardware complexity.
TDD uses a single frequency channel with uplink and downlink traffic separated by a guard time. The use of TDD is more efficient than FDD at dynamically providing asymmetric data rates, which are typical for Internet traffic. [Audio for flash: For IP-based services such as WiMAX, the use of a single channel for the uplink and downlink makes it substantially less complex and more cost effective to implement link adaptation, MIMO and beamforming.]
Type of digital multiplexing in which two or more signals or bit streams are transferred apparently simultaneously as sub-channels in one communication channel, but physically are taking turns on the channel. The time domain is divided into several recurrent timeslots of fixed length, one for each sub-channel.
Channel access method for radio communications where several users share the same frequency channel by dividing the signal into different timeslots. This allows multiple mobile stations to share the same frequency channel. TDMA is used in 2G networks such as IS-136, GSM, PDC, iDEN and DECT; as well as in satellite systems.
TDOA is a technique that uses three or more cellsites to determine the GPS location of the UE. By measuring the length of time it takes a cellular signal to travel between the BTS and handset, the system can determine the distance between the handset and the cellsite. When this is done with three or more sites, the exact position can be triangulated. This system can be used for E911 and LBS. Because cell signals travel at a known speed, the speed of light, the distance between the cellsite and UE can be found using the time it takes for a signal to be sent from the BTS to the UE. When the distance from three or more sites is known, the location can be accurately determined.
Communications equipment at either end of a communication link. Used to convert user information into signals for transmission or to convert signal transmissions back into user information.
Wireless security encryption mechanism in Wi-Fi Protected Access. TKIP uses a key hierarchy and key management methodology that removes the predictability that intruders relied upon to exploit the WEP key.
Within the WiMAX OFDMA frame structure for TDD mode, each frame is divided into DL and UL subframes. TTG is the gap between the last sample of the downlink burst and the first sample of the subsequent uplink burst. This gap allows time for the base station (BS) to switch from transmit to receive mode.
A UMTS parameter which measures the length of time of a transmission on the radio link. Radio link data is divided at the transmitter into blocks and the bits within a block are encoded and interleaved to combat errors due to fading and interference. The length of time to transmit one such block determines the TTI.
UDP is a core Internet protocol that provides fast and efficient data transfer for applications that do not need guaranteed delivery. UDP does not guarantee reliability and thus reduces the overhead of checking delivery of every packet.
Mobile WiMAX service class designed to support real-time service flows that periodically generate fixed-size data packets, such as T1/E1 and VoIP without silence suppression.
Labeled WiMAX burst profile periodically broadcasted by the base station based on known environmental conditions, equipment limitations, etc. Base stations may send the UIUC to terminals to configure their uplink burst profiles.
Sub-channel in an OFDM frame that is allocated for mobile stations to perform closed-loop time, frequency and power adjustments as well as bandwidth requests.
UMA is part of the 3GPP standard that allows seamless handovers between cellular service and the broadband IP access network. The subscriber will retain access to their mobile voice, data, and IMS services from any Wi-Fi or other broadband location.
A 3G mobile phone technology utilizing WCDMA and standardized by 3GPP. UMTS supports 14.0 Mbps downlink data transfer rates in theory, although current implementations support 7.2 Mbps using HSDPA.
Personal area network type capable of delivering effective speeds of up to 480 Mbps at distances that are less than or equal to 10 meters. This technology is used for peripheral interconnections that will support multiple high-definition video signals simultaneously.
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The VLR is a database in a GSM network. The VLR stores information of all the mobiles that are currently within the MSC (Mobile Switching Center) it serves. The VLR stores both the BSC (Base Station Controller) and LAI (Location Area Identity). This information is important during paging and call setup.
A way of making telephone calls over a packet-switched network like the Internet. Voice-over-IP requires special telephones and software. Voice-over-IP is commonly abbreviated as VoIP.
A Wide Area Network (WAN) is a collection of local area networks connected by a variety of physical means. The Internet is the largest and most well-known wide area network.
A 3G type of network that uses direct sequence CDMA signaling to improve speed and capacity over 2nd generation and 2.5G networks such as TDMA and GSM.
An encryption system for preventing eavesdropping on wireless network traffic. WEP is easily broken, and has been replaced by WPA on newer Wi-Fi products.
Wireless Fidelity or Wi-Fi is a wireless Ethernet standard that was designed to simplify office LAN deployment by eliminating wiring requirements. Today, this technology is deployed in areas as small as a coffee shop to as large as a municipality (WISP). See IEEE 802.11 for details on the standard.
The Wi-Fi Alliance is a trade group that manages the 802.11 standard and certification marks. Wi-Fi certification encompasses numerous different standards, including 802.11a, 802.11b, 802.11g, WPA, and more. Equipment must pass compatibility testing to receive the Wi-Fi mark.
WiBro requirements released in July 2004 harmonized WiBro under the Mobile WiMAX baseline standard, (i.e. IEEE 802.16e-2005). WiBro is the service name for Mobile WiMAX in Korea and uses the same standards and certification processes as Mobile WiMAX.
WiMAX is defined as Worldwide Interoperability for Microwave Access by the WiMAX Forum. As defined by the WiMAX Forum, “WiMAX is a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL. WiMAX will provide fixed, nomadic, portable and mobile wireless broadband connectivity without the need for direct line-of-sight with a base station. In a typical cell radius deployment of three to 10 kilometers, WiMAX Forum Certified™ systems can be expected to deliver capacity of up to 40 Mbps per channel, for fixed and portable access applications.
The WiMAX Forum® is an industry-led, nonprofit organization. The forum certifies and promotes the compatibility and interoperability of broadband wireless products based upon the IEEE and ETSI standards.
Designed to efficiently deliver broadband data services including voice, data and video over time varying broadband wireless channels. The scheduler is located at each base station to enable rapid response to traffic requirements and channel conditions.
Provides subscribers with privacy, authentication or confidentiality across the broadband wireless network. In addition, it provides operators with strong protection from theft of service.
A group of features for wireless networks that improve the user experience for audio, video and voice applications. WMM is based on a subset of the IEEE 802.11e WLAN QoS draft standard.
Class of systems to secure Wi-Fi networks and replace a previous system, WEP, that had several serious weaknesses. WPA implements the majority of the IEEE 802.11i standard.
Provides stronger data protection and network access control then WPA. Based on the ratified IEEE 802.11i standard, WPA2 provides government grade security encryption and authentication.
A Wireless Wide Area Network (WWAN) differs from a WLAN (wireless LAN) because it uses cellular network technologies such as WiMAX (though it’s better applicated into WMAN Networks), UMTS, GPRS, CDMA2000, GSM, CDPD, Mobitex, HSDPA or 3G to transfer data. It can use also LMDS and Wi-Fi to connect to the Internet. These cellular technologies are offered regionally, nationwide, or even globally and are provided by a wireless service provider for a monthly usage fee. Various computers now have integrated WWAN capabilities (Such as HSDPA in Centrino). This means that the system has a cellular radio (GSM/CDMA) built in, which allows the user to send and receive data. There are two basic means that a mobile network may use to transfer data:
* Packet-switched Data Networks (GPRS/CDPD) * Circuit-switched dial-up connections
Since radio communications systems do not provide a physically secure connection path, WWANs typically incorporate sophisticated encryption and authentication methods to make them more secure.
Examples of providers for WWAN include: Sprint, Verizon, or AT&T.
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