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1xEV-DO rev A 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. 2G/2.5G Second and two-point-five generation cellular wireless technologies. These include TDMA, GSM, GPRS, and CDMA. 3G 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. 3GPP 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. 3GPP2- 3G Partnership Project 2 The Third Generation Partnership Project 2 is a collaborative third generation (3G) telecommunications specifications-setting project that comprises of North American and Asian interests developing global wireless specifications. 3GPP LTE 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. AAA Authentication, Authorization and Accounting AAS - Advanced Antenna System 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. ACK - Acknowledge A signal passed between wireless base stations and MSs, Ues or SSs used to acknowledge the receipt or response, as part of a communication protocol. ACP - Automatic Cell Planning An ACP tool can be used by network engineers to help plan and optimize networks. Adaptive Beamforming 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. [Audio for flash: Note that beamforming helps avoid interference and concentrate the signal in areas of interest.] Adjacent Channel Interference 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. AES - Advanced Encryption System AES stands for Advanced Encryption System and is one of the most popular algorithms used in symmetric key cryptography. AFP - Automatic Frequency Planning An AFP tool can be used by network engineers to create a frequency plan. AGPS Assisted Global Positioning System Assisted GPS is an advanced GPS system used in cell phones and other portable devices. An Assisted GPS system allows the UE to calculate an accurate position in dense urban areas as well as inside buildings. The UE relies on an external resource such as a cellular system to calculate the position when there isnt sufficient signal from typical GPS satellites. AGPS is an integral component of E911 and Location Based Services. ALI Automatic Location Identification 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. AMC - Adapted Modulation and Coding 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. [Audio for flash: The downlink user throughput is maximized given the instantaneous channel conditions.] AMPS Advanced Mobile Phone Service AMPS, an analog cellular technology, was developed by Bell Labs in the 1980s. AMPS uses FDMA. AN Access Node A connecting point for data transport or data packet networks. The Access Node usually resides in a central office. AP Access Point A device that connects wired or wireless (WAP) communication devices together to form a wired or wireless network. AOA Angle of Arrival 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 determined exact angle the UE is 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 from different cellsites meet is the location of the UE. APC - Automatic Power Control 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. API Application Programming Interface A source code interface that a computer system or program library provides to support requests for services originating from another computer program. ARPU Average Revenue Per User The Average Revenue Per User is the average revenue generated per user per month. ASCA Adjacent Subcarrier Allocation While DSCAs can gain frequency diversity in frequency selective slow fading channels, ASCAs can gain multiuser diversity in frequency non-selective fading channels. ASN - Access Services Network ATM - Asynchronous Transfer Mode 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. ATTD - Adaptive Time Division Duplexing A version of TDD where the timeslots in the uplink and downlink can be dynamically adjusted based on traffic conditions. With ATTD split in 802.16, uplink/downlink timeslots can be changed to support asymmetric data flows such as IP traffic. AUC - Authentication Center 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. BA - BCCH Allocation List 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. Backhaul 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. [Audio for flash: Three examples of backhaul include servicing cellular customers, Wi-Fi hotspots and WiMAX users] Bandwidth The range of frequencies occupied by a modulated carrier wave. BCCH - Broadcast Control Channel 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). BE Best Effort Mobile WiMAX service class intended to provide efficient service for BE traffic. Typical BE service is Web surfing. BER Bit Error Ratio 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. Bluetooth 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. BPSK - Binary Phase Shift Keying 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 Binary Runtime Environment for Windows 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. Broadband The broadband designator can be used when the average connection speed per user exceeds 2 Mbps. BS - Base Station An earth-based transmitting and receiving station for wireless technologies such as cellular, paging, WiMAX and other wireless transmission services. BSC - Base Station Controller 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). BSIC - Base Station Identity Code 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. BSS - Base Station System All GSM radio-related functions are performed in the BSS, which consists of base station controllers (BSCs) and the base transceiver stations (BTSs). BTA Basic Trading Area 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. BTS - Base Transceiver Station The BTS manages the wireless communication between the UE and the network. BWA - Broadband Wireless Access Provides high-speed wireless access to the Internet over a wide area over licensed or unlicensed spectrum. CAMEL Customized Application for Mobile Network Enhanced Logic 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. CC Convolutional Code 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 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. CDG CDMA Development Group 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. CDMA -Code Division Multiple Access 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). Chase Combining 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 [Audio for flash: Chase Combining increases the probability of successful decoding by combining retransmitted data blocks with the original transmission.] C/I - Carrier to Interference Ratio The ratio in dB of the carrier power to the power of interfering signals at the same frequency. When carrier power is too high for one user, it may create interference for other traffic and reduce the overall capacity of the radio subsystem. Wireless network operators place a high priority on managing C/I in the network. CINR - Carrier to Interference + Noise Ratio The ratio in dB of the carrier power to the total received noise plus interference power. CIR - Committed Information Rate 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. C/N - Carrier to Noise Ratio 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. Co-Channel Interference Interference from two different radio transmitters on the same frequency. Causes can be from poor frequency planning or overly crowded radio spectrum. CP - Cyclic Prefix 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. CPE - Customer Premise Equipment Terminal or associated equipment and inside wiring located at a subscribers premises and connected with a carriers telecommunication network (wired or wireless). The structure demarcates the customers equipment from the network operators equipment. CPICH - Common Pilot Channel 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. CQI - Channel Quality Indicator 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. CQICH - Channel Quality Information Channel Utilized to provide channel-state information from the user terminal to the base station scheduler for UMTS and WiMAX networks. CRC Cyclic Redundancy Code 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. CSN - Core Services Network CTIA Cellular Telecommunications & Internet Association "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. " CTC Convolutional Turbo Code 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. dB - Decibel 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). dBm Abbreviation for the power ratio in decibels of the measured power referenced to one milliwatt (mW). dBm is referenced to the watt and is an absolute unit. Graphs can be helpful when converting dBm to microvolts for instance. DCD Downlink Channel Descriptor BS periodically broadcasts DCD to indicate burst profiles in terms of modulation and FEC schemes. DCS Digital Communications Service Any communications system that transfers data using a digital signal. Delay Spread The same signal can be received mutliple times due to multipath propagation. Delay spread is the difference between the first time and the last time the signal was received. DFS - Dynamic Frequency Selection The ability of a system to switch to different physical RF channels based on channel measurement criteria to conform to particular regulatory requirements. DHCP - Dynamic Host Configuration Protocol 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. Digital Multimedia Broadcasting (DMB) A digital radio transmission system for sending multimedia to mobile devices such as mobile phones and subscriber stations. DBM 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. Dipole Antenna 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. DIUC Downlink Interval Usage Code 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. Diversity 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. DL - Downlink The radio path from the Base Station to the mobile station or subscriber station. DLFP - Downlink Frame Prefix DL-MAP - Downlink Mobile Application Part Protocol which provides an application layer to communicate with the MS to support mobility services such as location management, authentication and service subscriptions. 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. DPC - Dynamic Power Control 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. DSCA Distributed Subcarrier Allocation Distributed subcarrier allocations work well in mobile WiMAX applications. DSL Digital Subscriber Line 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. DSSS - Direct Sequence Spread Spectrum 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. D-TDD Dynamic TDD 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. Duplexing A method where a signal can flow in both directions between connected parties. [Audio for flash: Half duplex refers to a system that provides two-way communication, but each party takes turns communicating. Full duplex allows simultaneous communication in both directions.] DVB-H - Digital Video Broadcasting-Handheld 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. Dynamic Range The ratio of a specified maximum level of a parameter, such as power, to the mimimum detectable value of that parameter. EAP - Extensible Authentication Protocol EDGE - Enhanced Data rates for GSM Evolution 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. EIR - Equipment Identity Register 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. ertPS extended real-time Polling Service 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. ETSI European Telecommunications Standards Institute 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 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. FA - Foreign Agent Fading Refers to the time variation of the received signal power caused by changes in the transmission path. The most common types of fading are slow fading caused by larger movements of the receiver or obstructions; and fast fading (multipath fading) caused by small movements of the receiver or obstruction. Fast Link Adaptation 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. FBSS Fast Base Station Switching Mobile WiMAX (802.16e) 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. FCC - Federal Communications 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. FCC Part 15 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. FCH Frame Control Header 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. FDD - Frequency Division Duplexing A duplex methodology where the uplink and downlink paths are separated by a frequency offset. Examples of FDD systems are most cellular systems (TDMA, GSM, WCDMA). FDM - Frequency Division Multiplexing Signal multiplexing where multiple baseband signals are modulated on different frequency carrier waves and added together to create a composite signal. FDMA - Frequency Division Multiple Access Access technology that is used by radio systems to share radio spectrum by allocating individual frequencies for each communications signal within the band. FEC Forward Error Correction 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. FHSS - Frequency Hopping Spread Spectrum 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. Flash OFDM - Fast Low-latency Access with Seamless Handoff OFDM An OFDM based system that includes higher protocol layers to enhance functionality. Developed to compete with GSM and 3G networks. Fractional Frequency Reuse 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] Frequency 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 Selective Scheduling 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. FSL - Free Space Loss 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. FRF Frequency Reuse Factor 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. FUSC Fully Used Sub-Carrier Uses all subchannels and minimizes the performance degradation of fading channels by frequency diversity. GGSN - Gateway GPRS Support Node 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). GMSC - Gateway Mobile Switching Center The GMSC is the MSC that determines the current location of the UE for all incoming calls. All incoming calls must go through the GMSC. GPRS - General Packet Radio Service 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. GPS - Global Positioning System GPS 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. GSM - Global Systems Mobile 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. HA - Home Agent HARQ - Hybrid Automatic Repeat-Request 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. H-FDD Half-Duplex FDD H-FDD systems use two different frequency bands for DL and UL, and the DL and UL subframes do not overlap in the time domain. HHO - Hard Handoff The process of transferring an ongoing call or data session from one channel connected to the core network to another. [Audio for flash: 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 High Performance Metropolitan Area Network 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. HLR - Home Location Register 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. HSUPA - High Speed Uplink Packet Access As defined by the 3GPP, "the technical purpose of the enhanced uplink feature is to improve the performance fo uplink dedicated transport channels, i.e. to increase capacity and throughput and reduce delay." This will be enabled through the use of HARQ to make retransmissions more efficient and by shorter Transmission Time Intervals (TTI) that enable faster link adaptation. HSDPA - High Speed Downlink Packet Access 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 Integrated Digital Enhanced Network 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. IEEE - Institute of Electrical and Electronics Engineers The IEEE is a non profit organization that is a leading authority on areas ranging from aerospace systems, to computers, to telecommunications. IEEE 802.11 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. IEEE 802.16 IEEE 802.16, commonly known as WiMAX, is a specification for fixed broadband wireless access systems employing a Point-to-Multi Point (PMP) or Point-to-Point (PTP) architecture. 802.16 can operate in licensed and unlicensed bands from 2 GHz to 60 GHz. WiMAX supports true broadband data rates of up to 40 Mbps for fixed and portable applications and up to 15 Mbps for mobile applications. IEEE 802.16e-2005 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. IETF IF Intermediate Frequency A frequency to which a carreir frequency is shifted as an intermediate step in transmission or reception. IMEI - International Mobile Equipment Identity The IMEI is a unique number programmed into every GSM mobile phone and UMTS UE. IMS IP Multimedia Subsystem A network architecture created to standardize and simplify deployment of next-generation multimedia communications, such as instant messaging, video conferencing and mobile TV. IMS Forum 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. IP Internet Protocol, the method by which data is sent from one computer to another on the Internet. IR - Incremental Redundancy 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. ISI - Intersymbol Interference 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 - International Telecommunications Union 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 Java 2 Micro Edition J2ME provides a robust, flexible environment for applications running on mobile and other embedded devicesmobile phones, personal digital assistants (PDAs), TV set-top boxes, and printers. LAC - Location Area Code A location area is the area associated with one Visitor Location Register (VLR). LAI - Location Area Identity 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). LAN - Local Area Network 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). Latency 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. LBS - Location Based Services 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. [Audio for flash: The location information can be provided by embedded GPS receivers in the phone or via network trilateration techniques.] LDPC Low Density Parity Check 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. Link Budget 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). [Audio for flash: A sample calculation might look like this: Received Power (dBm) = Transmitted Power (dBm) + Gains (dB) Losses (dB).] LOS - Line of Sight A clear line from one antenna to another in a long-range wireless network. MAC - 802.16 Media Access Control 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. MAC CPS MAC Common Part Sublayer Sublayer in WiMAX MAC, which classifies each service data unit (SDU). MAC CS MAC Convergence Sublayer Sublayer in WiMAX MAC, which makes it possible to map data coming from external networks such as ATM and IP to MAC-type service data units (SDUs). MAC PS MAC Privacy Sublayer A separate MAC security layer for authentication and exchange of keys and ciphering. MAN - Metropolitan Area Network A network covering a large geographical area ranging from several city blocks to an entire city. The network will support moderate to high data rates and may be privately owned or owned and operated by public utilities. MAP Medium Access Protocol Provide sub-channel allocation and other control information for the downlink and uplink sub-frames. MBS - Multicast and Broadband Service Refers to the networks ability to provide flexible and efficient mechanisms for sending common content to multiple users using the same shared radio resources. Mesh Network A network topology in which every device can communicate with any other device that's within range. Mesh networking is another option for bringing wireless network access to an entire neighborhood. MCC - Mobile Country Code This parameter is unique to each country as defined by the ITU. It is used in GSM and UMTS networks and helps form the MNC (Mobile Network Code). MCS - Modulation and Coding Scheme Modulation and Coding Schemes are defined to address varying levels of robustness in wireless networks such as EDGE. EDGE uses nine MCSs, where MCS-1 has the greatest amount of coding and error correction and the slowest data rate, while MCS-9 doesnt use as much error correction and has the fasted data rate. Algorithms are defined based on Call Quality Indicators to increase the robustness (slow data rate) for weaker RF signal connections and to increase the data rate (reduce robustness) in stronger areas. MDHO Macro Diversity Hand Over Mobile WiMAX (802.16e) handoff method in which the Base Station (BS) and Mobile Station (MS) maintain an active set of BSs. An Anchor BS is defined and a MDHO begins when the MS decides to transmit or receive unicast messages and traffic from multiple BSs in the same time interval, thus providing diversity. MIMO - Multiple Input Multiple Output 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. [Audio for flash: MIMO offers the possibility for two additional modes in WiMAX networks to improve downlink performance Space Time Coding (STC) and Spatial Multiplexing (SM).] Missing Neighbor A channel with strong enough signal strength to be a valid neighbor however is not in the neighbor list. MM Mobility Management Includes functions that allow GSM and UMTS networks to locate and track Mobile Stations (MS) to provide service. Functions of mobility management include location updates, assigning temporary mobile subscriber identities in each geographical area, and managing roaming across location and routing areas. MMS Multimedia Message Service 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. MNC - Mobile Network Code The MNC is used in combination with a Mobile country code (MCC) to uniquely identify a mobile phone operator using the GSM and UMTS mobile networks. Mobile Network A mobile voice and data network must provide ubiquitous coverage and must support high velocity mobility. Mobile WiMAX 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 Channel Coding Mobile WiMAX has four channel coding steps: randomization, forward error correction (FEC), interleaving, and modulation. Mobile WiMAX Service Classes 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. MOU Minutes of Use The number of minutes of use. MPLS Multi-Protocol Label Switching MS - Mobile Station 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. MSC - Mobile Switching Center 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. MSS - Mobile Subscriber Station End user Mobile WiMAX devices that interface to the base station. These may also be referred to as handsets or mobile terminals. Multipath 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. [Audio for flash: Multipath can cause errors and reduce quality in wireless networks such as GSM due to intersymbol interference. CDMA and WiMAX technologies use multipath to their advantage by incorporating rake receivers and OFDM techniques.] MVNO Mobile Virtual Network Operator A cellular company that provides wireless services to customers without having a network or any licensed spectrum. These companies purchase bulk usage from a MNO (Mobile Network Operator), and then resell the usage at retail to its customers. NAP Network Access Provider Neighbor List 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. Network Optimized Hard Handoff (HHO) Minimizes overhead and achieves a handoff delay of less than 50 milliseconds. NLOS - Non or Near Line of Sight Term used to describe radio transmission across a path that is partially obstructed, usually by a physical object buildings, trees, mountains, etc. The signal is subjected to reflection, refraction, absorption and multipath, which may limit the usefulness of the signal. Some more advanced technologies such as WCDMA and WiMAX use the multipath signals to their benefit to compensate for NLOS conditions. NMT Nordic Mobile Telephone 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. Node-B In a UMTS system the Node-B refers to the Base Station. nrtPS non real-time Polling Service Mobile WiMAX service class that offers regular unicast polls, which ensures that the service flow receives request opportunities even during network congestion. NSP - Network Service Provider NSS - Network Switching System 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). OFUSC Optional Full Usage of Subchannels 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). OFDM 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. OFDMA 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. [Audio for flash: OFDMA operates efficiently and is well suited to multipath environments to provide high data rates.] OFDMA TDD Frame This figure shows an example of the OFDMA frame structure in TDD mode. OPUSC Optional Partial Usage of Subchannels 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 Over the Air 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/firmware inside of a cell phone. Providers will use this technique to make sure all the phones in their system are running the same software. FLASH: OTA programming is used to send information from one tower to multiple devices. PAN Personal Area Network 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. Panel Antenna 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." Parabolic Antenna 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. Pathloss 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 Personal Communications Industry Association 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 Personal Communications Service 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. PCU - Packet Control Unit 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. PDU Protocol Data Unit PDU is the data that are passed between communicating entities of the same protocol layer. In 802.16, the MAC PDU consists fo a fixed length header, a variable size payload field and an optional CRC field. PER Packet Error Rate The number of erroneous packets received divided by the total number of packets transmitted. PHY - Physical Layer 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. Pilot Channel 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. Pilot Pollution The condition of having an excessive amount of pilots in a specific area. [flash: There are two major problems with pilot pollution. The first arises when there are more pilot signals received than the receiver is capable of receiving. The second occurs when none of the pilot signals are dominant.] PKMv2 - Privacy and Key Management Protocol Version 2 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. PLMN - Public Land Mobile Network A PLMN is a network established and operated for the purpose of providing land mobile telecommunications services to the public. PMP - Point-to-Multipoint 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. [Audio for flash: 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.] POTS Plain Old Telephone Service 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 word with almost 99.999% uptime. POTS is also known as PSTN (Public Switched Telephone Network). PSAP Public Safety Answering Point 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. PTP - Point-to-Point 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. [Audio for flash: Network operators may use point-to-point wireless networks for backhaul applications.] [Could use same animation from backhaul term] PTT Push To Talk 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. Preamble In OFDM, the preamble is the first OFDM symbol of the frame and it is used for synchronization. This is followed by frame control header (FCH) in the second symbol. PSTN Public Switched Telephone Network The network of the world's public circuit-switched telephone networks. PUSC Partially Used Sub-Carrier 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. QAM - Quadrature Amplitude Modulation 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. QPSK - Quadrature Phase Shift Keying 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. QoS - Quality of Service 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). RAC - Routing Area Code The LA (Location Area) is made up of several routing areas. The RAC identifies a routing area within a Location Area. RAN Radio Access Network 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. Ranging Used in mobile WiMAX for the purpose of OFDMA network entry, connection maintenance, bandwidth request and efficient HO. Rake Receiver 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. Rake Search Window The maximum length of time the RAKE Receiver searches for each unique signal. [flash: 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. RBOC Regional Bell Operating Company 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. Request IE - Request Information Element The Request IE's are part of the UL-MAP in WiMAX and specify uplink intervals for the SSs to make bandwidth requests. RF - Radio Frequency Radio signal in the portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current. RF Noise 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. RF Power 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: RF Propagation 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. RNC - Radio Network Controller 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. RS - Repeater Station RSCP - Received Signal Code Power 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. RTG Receive Transition Gap 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. rtPS real-time Polling Service 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 Spatial Diversity Multiple Access 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. SDU Service Data Unit 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. Sector Antenna An antenna type that radiates in only a specific direction. Multiple sector antennas are commonly used in point-to-multipoint situations. SF Spreading Factor [pull from engage] SGSN Serving GPRS Support Node 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. SHO - Soft Handover Overhead 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. [flash: 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. SIM - Subscriber Identity Module 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 - Single Input Multiple Output 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 ratio combining techniques. SIP - Session Initiation Protocol The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more participants. These sessions include Internet telephone calls, multimedia distribution, and multimedia conferences. SISO - Single Input Single Output SISO is an antenna system that utilizes one transmit antenna and one receive antenna. SLA - Service Level Agreement A formal agreement between customers and service providers. It may include performance (minimum throughput, uptime, etc.), responsibilities, priorities or other attributes. SM - Spatial Multiplexing 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. [Audio for flash: SM improves peak throughput, but the coverage area may be limited when channel conditions are poor] SMS Short Message Service A service that allows cellular users to send short text based messages from one UE to another. SMS is also referred to as a Text Message. Soft Handoff 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. Spread Spectrum Modulation 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 signals 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. SS - Subscriber Station 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. SS7 - Signaling System #7 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. SSID - Service Set Identifier In a IEEE 802.11 wireless LAN, SSID is a code attached to all packets on a wireless network to identify each packet as part of that network. STC - Space Time Coding 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. [Audio for flash: STC provides large coverage regardless of channel condition, but does not improve the peak data rate.] Subcarrier 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). Subchannel In OFDMA, multiple data subcarriers are grouped into a subchannel. 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. TD-CDMA - Time Division Code Division Multiple Access 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. TDD - Time Division Duplexing 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.] TDM - Time Division Multiplexing 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. TDMA - Time Division Multiple Access 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 Time Difference of Arrival 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. FLASH: 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. TD-SCDMA - Time Division Synchronous Code Division Multiple Access 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. TE - Terminal Equipment TSA Time Slot Allocation TTG Transmit Transition Gap 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. TTI Transmission Time Interval 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. TUSC Tile Usage of Subchannels For use in the adaptive antenna system (AAS) zone; similar in structure to UL-PUSC. UCD Uplink Channel Descriptor MS periodically broadcasts UCD to indicate burst profiles in terms of modulation and FEC schemes. UE User Equipment The 3GPP designation for the mobile phone, PDA or smart-phone used in UMTS networks. UGS Unsolicited Grant Service 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. UIUC Uplink Interval Usage Code Labeled WiMAX burst profile periodically broadcasted by the base station based on known environmental conditions, equipment limitations, etc. BS may send the UIUC to terminals to configure their uplink burst profiles. UL - Uplink The radio path from the Mobile Station (MS) or Subscriber Station (SS) to the Base Station (BS). UL ACK Sub-channel in an OFDM frame that is allocated for the mobile station to provide acknowledgements for DL HARQ. UL-MAP Uplink Mobile Application Part Protocol which provides an application layer to communicate with the BS to support mobility services such as location management, authentication and service subscriptions. 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. UL Ranging 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. UL CQICH Channel allocated for the mobile station to provide feedback channel state information. UMA Unlicensed Mobile Access 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. UMTS - Universal Mobile Telephone System A 3G mobile phone technology utilizing WCMDA and standardized by 3GPP. UMTS supports 14.0 Mbps downlink data transfer rates in theory, although current implementations support 7.2 Mbps using HSDPA. UTRAN - UMTS Terrestrial Radio Access Network The UTRAN contains the base stations (Node-Bs) and the Radio Network Controllers (RNC). The RNC typically serves multiple Node Bs. UWB Ultra Wide Band 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. VoIP - Voice over IP 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 to VoIP. WAN - Wide Area Network Wide Area Network 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. Watt Derived unit of power equal to one joule per second. WEP - Wired Equivalent Privacy An encryption system for preventing eavesdropping on wireless network traffic. WEP stands for Wired Equivalent Privacy. WEP is easily broken, and has been replaced by WPA on newer Wi-Fi products. WiBro 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. Wi-Fi 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. Wi-Fi Alliance 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. 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. WiMAX MAC Scheduler 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. WiMAX Forum 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. WiMAX Security Sublayer Provides subscribers with privacy, authentication or confidentiality across the broadband wireless network. In addition, it provides operators with strong protection from theft of service. WISP - Wireless Internet Service Provider A WiMAX or Wi-Fi hotspot network predominantly for rural environments where cable and DSL are not available. WLAN - Wireless Local Access Network Linking of two or more computers using spread spectrum 802.11 modulation technology within a limited area, also known as the basic service set. WPA - Wi-Fi Protected Access 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. Yagi Antenna An antenna type that radiates in only a specific direction. Yagi antennas are used only in point-to-point situations.