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Wireless Glossary and Dictionary [N-R]

NACN: North American Cellular Network
North American Cellular Network (NACN) is an organization of cellular providers that facilitates cellular calls across the country to be linked for seamless roaming.

NADS: North American Digital Standards
North American Digital Standards (NADS) refers to the North America cellular standards: the first generation is TDMA and has been in service since 1992. The second generation is CDMA which was accepted by the TIA2.48 as a standard in 1992. The third generation is CDMA2000 and more.

NAM: Number Assignment Module
Number Assignment Module (NAM) is the programmable module in an AMPS analog phone used to contain the MIN, ESN, home system ID and other information.

NAMPS: Narrowband Advanced Mobile Phone Service
Narrowband Advanced Mobile Phone Service (NAMPS) is an improved version of AMPS systems. NAMPS is a cellular call-handling system that uses digital signalling techniques to split the existing 30 kHz wideband voice channels into three 10 kHz narrowband voice channels. The result is three times more voice channel capacity than the traditional AMPS system provides. NAMPS cellular phones are manufactured for dual mode operation, and they are compatible with traditional AMPS systems.

NASS: Network Attachment Subsystem
The Network Attachment Subsystem (NASS), a component in the IP Multimedia Susbsystem (IMS), provides the following functionalities: (1) Dynamic provision of IP address and other user equipment configuration parameters (e.g. using DHCP). (2) User authentication, prior or during the IP address allocation procedure. (3) Authorisation of network access, based on user profile. (4) Access network configuration, based on user profile. (5) Location management.

Nationwide Paging
Nationwide Paging is a method of national or regional paging in which a single frequency is used throughout the nation (region) for sending messages to a paging system subscriber.

Nested codes
Nested codes is a type of concatenated block code where the layers (inner and outer) are amalgamated in such a way that burst errors -- not able to be corrected by the inner code -- are sufficiently spread over enough blocks as to be corrected by the outer layer.

NetStumbler
NetStumbler is a freely available Windows utility for wireless LAN discovery. It is useful for site surveys, detecting rogue access points, and finding and mapping WLAN installations.

NFC: Near Field Communication
Near Field Communication (NFC) is a short-range wireless connectivity standard jointly developed by Philips and Sony that uses magnetic field induction to enable communications between devices when they're touched together, or brought within a few centimeters of each other. The standard specifies a way for the devices to establish a peer-to-peer (P2P) network to exchange data.

NLOS: Non Line of Sight
Non Line of Sight (NLOS), also known as near-line-of-sight or obstructed path/pathway, is a term used to describe radio transmission across a path that is partially obstructed, usually by a physical object in the Fresnel zone. Many types of radio transmissions depend, to varying degrees, on line of sight between the transmitter and receiver. Obstacles that commonly cause NLOS conditions include buildings, trees, hills, mountains, and, in some cases, high voltage electric power lines.

NMC: Network Management Center
Network Management Center (NMC) is an operations center used to manage network resources such as the MSC, location registers and base stations.

NMT: Nordic Mobile Telephony
Nordic Mobile Telephony (NMT) is the common Nordic standard for analog mobile telephony as established by the telecommunications administrations in Sweden, Norway, Finland and Denmark in the early 1980s. NMT systems have also been installed in some European countries, including parts of Russia, and in the Middle East and Asia. NMT is operated in 450 MHz and 900 MHz bands.

NMT-450: Nordic Mobile Telephony - 450
Nordic Mobile Telephony - 450 (NMT-450) is an early cellular system developed and operated in northern Europe utilizing the 450 MHz band.

Noise
Noise refers to any undesirable communication channel signals.

Noise figure
Noise figure is a figure of merit for receivers and preamplifiers representing the amount of excess noise added to the signal by the amplifier or receiving system itself. The lower the noise figure, the less excess noise is added to the signal.

NRS: Nomadic Relay Station
Nomadic Relay Station (NRS), a concept in the WiMAX network, is a relay station that is intended to function from a location that is fixed during periods of time comparable to that of a user session. An NRS is not permanently installed. An NRS may rely solely on battery power in some instances.

nrtPS: Non-Real-Time Polling Service
Non-Real-Time Polling Service (nrtPS) is one of the five QOS service types defined in the IEEE 802.16 WiMAX. The 802.16 protocol supports five types of QoS UGS (Unsolicited grant service), rtPS (Real time polling Service), ertPS (Extended Real-time POLLING SERVICE), nrtPS (Non-real-time polling service and BE (Best effort service). The Non-Real-Time Polling Service (nrtPS) is designed to support non real-time service flows that require variable size Data Grant Burst Types on a regular basis, such as high bandwidth FTP. The service offers unicast polls on a regular basis, which assures that the flow receives request opportunities even during network congestion.

NRZ: Non Return to Zero
Non Return to Zero (NRZ) is a type of data stream where successive data pulses "ones" are continuous over several clock cycles without returning to the "zero" state between successive "ones".

NSS: Network Switching Subsystem
Network Switching Subsystem is a portion of a GSM network that manages the connections and communications within the network. The BSS and OSS complete the major components of the network.

Numeric Paging or alphanumeric-paging
Numeric Paging is the most widely used type of paging. The caller simply calls your pager phone number and enters the number where you can reach them. This number appears on the receiver's pager, and the receiver can call the sender. On the other hand, text paging allows callers to send the receiver a short message that you can act on immediately.

Nyquist filter
Nyquist filter is an ideal low pass filter with a cutoff frequency equal to the sampling rate. This technique is used to convert PAM pulses to an analog signal in D/A converters.

Nyquist rate
Nyquist rate is the minimum sampling rate proposed by Nyquist for converting a band limited waveform to digital pulses. The rate must be at least twice the highest frequency of interest in the waveform being sampled.

OBEX: OBject Exchange
OBject EXchange (OBEX or IrOBEX) is a communications protocol that facilitates the exchange of binary objects between devices. It is maintained by the Infrared Data Association but has also been adopted by the Bluetooth Special Interest Group and the SyncML wing of the OMA. One of OBEX's earliest popular applications was in the Palm III personal digital assistant. This PDA and its many successors use OBEX to exchange business cards, data, even applications.

OCQPSK: Orthogonal Complex Quadrature Phase Shift Keying
Orthogonal Complex Quadrature Phase Shift Keying (OCQPSK), also known as HPSK, is a digital modulation scheme that conveys data by changing, or modulating, the phase of a reference signal (the carrier wave).

OFDM: Orthogonal Frequency Division Multiplexing
Orthogonal Frequency Division Multiplexing (OFDM) is an FDM modulation technique for transmitting large amounts of digital data over a radio wave. OFDM works by splitting the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver. 802.11a WLAN, 802.16 (WiMAX) technologies use OFDM as the physical layer communication standard.

OFDMA: Orthogonal Frequency Division Multiple Access
Orthogonal Frequency Division Multiple Access (OFDMA), also referred to as Multiuser-OFDM, is being considered as a modulation and multiple access method for 4th generation wireless networks. OFDMA is an extension of Orthogonal Frequency Division Multiplexing (OFDM), which is currently the modulation of choice for high speed data access systems such as IEEE 802.11a/g wireless LAN (WiFi) and IEEE 802.16a/d/e wireless broadband access systems (WiMAX).

OHG: Operators Harmonization Group
Operators Harmonization Group (OHG) is a group of industry operators established to meet on harmonization issues. The group is working towards a way of harmonisation between CDMA2000 and W-CDMA.

Okamura model
Okamura model is a propagation prediction model for land-mobile communications developed by Yoshi Okamuar et al. in the late 1960s.

OMA: Open Mobile Alliance
Open Mobile Alliance (OMA) is the leading industry forum for developing market-driven, interoperable mobile service enablers. OMA was formed in June, 2002, by nearly 200 companies including the world's leading mobile operators, device and network suppliers, information technology companies and content and service providers. The fact that the whole value chain is represented in OMA marks a change in the way specifications for mobile services are done.

OMC: Operations & Maintenance Center
Operations & Maintenance Center (OMC) is a location used to operate and maintain a wireless network.

OQPSK: Offset Quadrature Phase Shift Keying
Offset Quadrature Phase Shift Keying (OQPSK), sometimes called Staggered QPSK (SQPSK), is a type of QPSK modulation that offsets the bit streams on the I and Q channels by a half bit. This reduces amplitude fluctuations and helps improve spectral efficiency. In other words, using OQPSK increases the temporal efficiency of normal QPSK.

ORFS: Output Radio Frequency Spectrum
Output Radio Frequency Spectrum (ORFS) is a measurement for GSM signals that tests for interference in the adjacent frequency channels (ARFCNs) and results from two effects: modulation within the bursts and the power that ramps up and down, or switching transients. ORFS is a critical GSM transmitter measurement.

OSA: Open System Architecture
Open System Architecture (OSA) is part of the 3rd generation (3G) UMTS mobile telecommunications network. OSA describes how services are architected in a UMTS network. The OSA provides APIs to access the network functions like authentication and authorization of the user. The APIs are guaranteed to be secure, independent of vendor specific solutions and also independent of programming language by use of Object Oriented techniques like CORBA, SOAP etc. Various services like VPN, conferencing and many more unknown services can be implemented with the help of these APIs. The standards for OSA are being developed as part of the 3rd Generation Partnership Project (3GPP).

OVSF: Orthogonal Variable Spreading Function
Orthogonal Variable Spreading Function (OVSF) is a set of spreading codes derived from tree-structured set of orthogonal codes and are used to channelize the IMT-2000/ULTRA system.

PA: Power Amplifier
Power Amplifier (PA) is a device for taking a low or intermediate-level signal and significantly boosting its power level. A power amplifier is usually the final stage of amplification in a transmitter.

Packet Radio
Packet radio is a form of digital data transmission used in amateur radio to construct wireless computer networks. Its name is a reference to the use of packet switching between network nodes, which allows multiple virtual circuits to coexist on a single radio channel. Packet radio networks use the AX.25 data link layer protocol, derived from the X.25 protocol suite and designed for amateur radio use.

PACS: Personal Access Communications System
Personal Access Communications System (PACS) is a low mobility low power wireless system designed for residential use.

Paging
Paging refers to deliver a message to someone when their location is unknown through a wireless device usually known as a pager.

PAM: Pulse Amplitude Modulation
Pulse Amplitude Modulation (PAM) is a form of signal modulation in which the data is encoded in the amplitude of a series, or train, of regularly recurrent signal pulses. PAM is used less frequently than PCM (Pulse-Code Modulation).

PAN: Personal Area Network
A personal area network (PAN) is a computer network used for communications among computer devices (including telephones and personal digital assistants) close to one person within a few meters. PAN allows devices to work together and share information and services. Using Bluetooth wireless technology, Personal Area Networks can be created in public places, in your home, in your office, and even in your car. This network enables everyday devices to become smart, tetherless devices--working and communicating together. For example, it offers the ability to wirelessly synchronize with your desktop to access your e-mail and Internet/intranet from remote locations.

Panel Antenna
Panel Antenna is an antenna type that radiates in only a specific direction. Panel antennas are commonly used for point-to-point situations. You may also see them called "patch antennas."Parabolic Antenna Parabolic Antenna is 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.

Paring
Paring is the process of engaging two Bluetooth devices to each other so they can communicate.

Parity
Parity is a simple error detection scheme. The method usually involves counting the '1' bits in a codeword and then setting an additional bit to either '1' or '0' depending on whether the original number of '1' bits was even or odd.

Partial Response Signalling
Partial Response Signalling is a signalling technique in which a controlled amount of intersymbol interference is introduced at the transmitter to shape the transmitted spectrum.

Passphrase
Passphrase, also called password, is the words you must enter to authenticate both sides of the connection when pairing Bluetooth devices. More generically, you may see passphrase used in place of "password" to indicate that you can enter more than a single word.

Path loss
Path loss is the amount of loss introduced by the propagation environment between a transmitter and receiver. Power loss that occurs when RF waves are transmitted through the air. This loss occurs because the atmosphere provides a filtering effect to the signal. Certain electromagnetic frequencies (very high and non-commercial) are completely blocked or filtered by the atmosphere.

PCH: Paging Channel
Paging Channel (PCH), used primarily to notify the mobile that it has an incoming call, is a logical channel in GSM, cdma2000, and W-CDMA systems used to send messages to mobile station.

PCIA: Personal Communications Industry Association
Personal Communications Industry Association (PCIA) is a trade group representing PCS, SMR, private radio and other wireless users and carriers.

PCIA: Personal Communications Industry Association
Personal Communications Industry Association (PCIA) is an international trade association representing the personal communications services (PCS), private radio and other wireless users and carriers. Its primary objective is to advance regulatory policies, legislation, and technical standards in this industry.

PCM: Pulse Code Modulation
Pulse Code Modulation (PCM) is the most predominant type of digital modulation in use today. PCM performs an analog to digital conversion of the speech waveform through a sampling process and encodes and transmits the samples in a serial bit stream as 8-bit digital words.

PCMCIA: Personal Computer Memory Card International Association
Personal Computer Memory Card International Association (PCMCIA) has defined a standardized technology used to develop a expansion for portable devices (i.e.. notebooks) In paging these credit card sized devices support wireless connectivity.

PCN: Personal Communications Network
Personal Communications Network (PCN) is a standard for digital mobile phone transmissions operating at a frequency of 1800 MHz (also referred to as GSM 1800). It is used in Europe and Asia Pacific.

PCS: Personal Communication Service
Personal Communication Service (PCS) describes a wide variety of two-way digital wireless service offerings in North America operating at 1900 MHz. PCS services include next generation wireless phone and communication services, wireless local loop, inexpensive walk-around communications service with lightweight, low-powered handsets, in-building cordless voice services for business, in-building wireless LAN service for business, enhanced paging service as well as wireless services integrated with wired networks. A Personal Communications System refers to the hardware and software that provide communications services.

PCU: Packet Control Unit
The Packet Control Unit (PCU) is a late addition to the GSM standard. It performs some of the processing tasks of the Base Station Controller (BSC), but for packet data. The allocation of channels between voice and data is controlled by the base station, but once a channel is allocated to the PCU, the PCU takes full control over that channel. The PCU can be built into the base station, built into the BSC, or even in some proposed architectures, it can be at the SGSN site.

PDA: Personal Digital Assistant
Personal Digital Assistant (PDA) is a small, handheld wireless device for transmitting pages, data messages, faxes and emails. It also acts as an electronic organizer, giving you access to schedules and contact lists. The term is often used interchangeably with PIM (personal information manager). The 3Com PalmPilot is an example of a PDA or PIM.

PDC: Personal Digital Cellular
Personal Digital Cellular (PDC) is a TDMA-based 2G mobile phone standard developed and used exclusively in Japan. PDC uses 25 kHz carrier, 3 time slots, pi/4-DQPSK modulation and low bit-rate 11.2 kbit/s and 5.6 kbit/s (half-rate) voice codecs. PDC is implemented in the 800 MHz (downlink 810-888 MHz, uplink 893-958 MHz), and 1.5 GHz (downlink 1477-1501 MHz, uplink 1429-1453 MHz) bands. The air interface is defined in RCR STD-27 and the core network MAP by JJ-70.10.

PDCP: Packet Data Convergence Protocol
Packet Data Convergence Protocol (PDCP) is used in UMTS 3G network to map higher-level protocol characteristics onto the characteristics of the underlying radio-interface protocols, providing protocol transparency for higher-layer protocols. PDCP also provides protocol control information compression.

PDF: Probability Density Function
In mathematics, a probability density function (pdf) represents a probability distribution in terms of integrals. Informally, a probability density function can be seen as a "smoothed out" version of a histogram: if one empirically measures values of a continuous random variable repeatedly and produces a histogram depicting relative frequencies of output ranges, then this histogram will resemble the random variable's probability density.

PDF: Policy Decision Function
Policy Decision Function (PDF), a component in the IP Multimedia Subsystem (IMS), controls traffic entering the packet-switched network by allocating or denying IP bearer resources.

PDP Context
Packet data protocol (PDP) context is a term used in the mobile wireless network indicating a logical association between an MS (Mobile Station) and PDN (Public Data Network) running across a GPRS network. The context defines aspects such as Routing, QoS (Quality of Service), Security, Billing etc.

Peak power
Peak power is the maximum instantaneous power radiated by a pulsed or bursted transmitter. It is the power radiated while the transmitter is keyed or operated.

PER: Packed Encoding Rules
Packed Encoding Rules (PER) is a set of rules that specifies how ASN.1-defined information is encoded when transmitted, and how it is decoded when received. PER is a successor to the Basic Encoding Rules (BER). It is more efficient in terms of the number of bytes transmitted and the size of the generated encoder and decoder.

PFS: Proportional Fair Scheduling
Proportional Fair Scheduling (PFS) is a scheme for wireless communication for both a single antenna system and multiple transmit and receive antennas. The Proportional Fair algorithm is an algorithm that schedules the channel for the station that has the maximum of the priority function, where T denotes the data rate potentially achievable for the station at the present moment (in the present time slot), R is the average data rate of this station. Parameters α and β tune the fairness of the scheduler, that is, is it fair to all stations giving them equal bandwidth or is the scheduler maximizing the throughput of the channel.

Phase
Generally speaking, phase is the current position in the cycle of something that changes cyclically.

Phase jitter
Phase jitter is the amount of uncertainty introduced in digital demodulation caused by the rapid fluctuation of the frequency of the transmitted signal, typically due to imperfections in the clock recovery timing.

PHP: Personal Handy Phone
Personal Handy Phone (PHP) is the mobile handset used with the Japanese Personal Handy Phone system.

PHS: Personal HandyPhone System
Personal HandyPhone System (PHS) was developed in Japan as a cordless telecommunication system operating within the band 1895MHz to 1918MHz. PHS is a lightweight portable wireless telephone that functions as a cordless phone at home and as a mobile phone elsewhere. The Personal Handyphone also handles voice, fax, and video signals.

Physical channel
Physical channel is the actual radio channel that carries the various logical and traffic channels in a wireless system.

Pico cell
Pico cell is a very small cell in a mobile network for boosting capacity within buildings.

Pilot code
Pilot code is a logical channel in a CDMA system characterized by an unmodulated direct sequence spread-spectrum signal continuously monitored by each base station. It allows the mobile stations to acquire the timing of the forward channel, serves as a phase reference for demodulation, and allows the mobile to search out the best (strongest) base stations for acquisition and hand-off.

Pilot pollution
Pilot pollution is a type of co-channel interference in CDMA systems caused when the pilot code from a distant cell or base station is powerful enough to create an interference problem.

PIN: Personal Identification Number
Personal Identification Number (PIN) is a code used for all GSM-based phones to establish authorization for access to certain functions or information. The PIN code is delivered together with your subscription.

PLL: Phase Locked Loop
Phase Locked Loop (PLL) is a major component in the frequency synthesizer scheme. This device provides a wide, flexible range of internal frequency dividers which allow the designer the ability to create a synthesizer to match design requirements.

PLMN: Public Land-Mobile Network
Public Land-Mobile Network (PLMN) is a European term used to describe all mobile wireless networks that use earth-based stations rather than satellites. PLMN is the mobile equivalent of the PSTN.

Phase Modulation
Phase Modulation (PM) is the scheme of modulation that the phase of the carrier signal is modulated in accordance with the message signalPMP: Paging Message ProcessorPaging Message Processor (PMP) is a Radio Paging Terminal or equivalent message processing system.

PMR: Private Mobile Radio
Private Mobile Radio (PMR) is for use within a defined user group such as the emergency services or by the employees of a mining project.

PN: Pseudo-Noise
Pseudo-Noise (PN), also known as pseudorandom noise (PRN), is a signal similar to noise which satisfies one or more of the standard tests for statistical randomness. Although it seems to lack any definite pattern, pseudorandom noise consists of a deterministic sequence of pulses that will repeat itself after its period.

PNCQPSK: Pseudo-Noise Complex Quadrature Phase Shift Keying
Pseudo-Noise Complex Quadrature Phase Shift Keying (PNCQPSK) is the spreading technique that uses basic complex scrambling and Pseudo-Noise (PN) signals for Is and Qs. PNCQPSK is used in 3G mobile wireless technologies.

POCSAG: Post Office Code Standard Advisory Group
Post Office Code Standard Advisory Group (POCSAG), also known as RPC1 (a CCIR standard taken directly from POCSAG), is a group formed by the British Post Office to design a non-proprietary digital paging code. The code that they designed is now implemented by most pager manufacturers and is the most widely used code to date. The POCSAG code can be operated at three speeds, 512, 1200, and 2400 bits per second. POCSAG is gradually being replaced by FLEX.

PoC: Push to Talk over Cellular
Push To Talk Over Cellular (PoC) is a walkie-talkie type service provided over a cellular phone network. A push to talk over a cellular system typically supports telephony services. There are proprietary implementations, and the Open Mobile Alliance defines standards for PoC. Push to talk calls are half duplex communications -- while one person speaks, the other(s) listen. A push-to-talk connection is typically connected virtually instantaneously. A single press reaches an active talk group. Users no longer need to make several calls to coordinate with a group.

Polarization diversity
Polarization diversity is a diversity technique where antennas of different polarizations, i.e., horizontal and vertical, are used to provide diversity reception. The antennas take advantage of the multipath propagation characteristics to receive separate uncorrelated signals.

Power control
Power control is a technique for managing the transmit power in base stations and mobiles to a minimum level needed for proper performance. Downlink power control applies to base stations and uplink power control to mobiles. Power control is used in nearly all wireless systems to manage interference, and in the case of mobiles, to extend battery life.

PQA: Palm Query Applications
Palm Query Applications (PQA) is an Internet clipping application developed from HTML code and run on Palm PDAs. The application is designed to streamline the flow to the PDA to minimize the number of kilobytes sent and ultimately paid for.

PRBS: Pseudo-Random Binary Sequence
Pseudo-Random Binary Sequence (PRBS), commonly used to performance test PCM systems, is a digital signal having framing information and using pseudo-noise in the individual traffic channels.

PRMA: Packet Reservation Multiple Access
Packet Reservation Multiple Access (PRMA) is a packet-based TDMA concept where the users contend for the time slots. In situations where the system is not near capacity, a user can reserve a time slot for future uses.

Processing gain
Processing gain is the amount of gain, in dB, provided by the spreading code in a CDMA system, usually the ratio of the spreading rate to the information rate.

Propagation
Propagation is the process an electromagnetic wave undergoes as it is radiated from the antenna and spreads out across the physical terrain. See also propagation channel.

Propagation channel
Propagation channel is the physical medium electromagnetic wave propagation between the transmit and receive antennas, and includes everything that influences the propagation between the two antennas.

PSD: Power spectral density
Power spectral density (PSD) refers to the amount of power per unit (density) of frequency (spectral) as a function of the frequency. The power spectral density, PSD, describes how the power (or variance) of a time series is distributed with frequency. By knowing the power spectral density and system bandwidth, the total power can be calculated.

PSK: Phase Shift Keying
Phase Shift Keying (PSK) is a broad classification of modulation techniques where the information to be transmitted is contained in the phase of the carrier wave.

PSTN: Public Switched Telephone Network
Public Switched Telephone Network (PSTN) is the network of the world's public circuit-switched telephone networks, providing commercial telephony services. Originally as a network of fixed-line analog telephone systems, the PSTN is now almost entirely digital and includes mobile as well as fixed telephones.

PTT: Post, Telecommunications&Telegraph
Post, Telecommunications&Telegraph (PTT) is typically the Ministry of Post, Telecommunications and Telegraph. It is also a term to describe the incumbent, dominant operator in a country, many of which are being or have been privatized.

Punctured code
Punctured code is a technique used in convolutional decoders that allows a limited number of coded bits to be deleted to greatly simplify processing in the codec. This is extremely useful with long codes.

PUSC: Partially Used Sub-Carrier
Partially Used Sub-Carrier (PUSC), sometimes called Partially Used Sub-Channel, was first defined in the IEEE802.16d (Fixied WiMAX) for the OFDMA PHY layer. Basically, the IEEE802.16e (Mobile WiMAX) uses the same OFDMA sub-channelization structure and its extension to address mobility has retained the OFDMA concept for FUSC (Fully Used Sub-carrier) and PUSC. Use of FUSC, mainly in the DownLink, and PUSC in both DL and UL as defined in 16d or 16e with Reuse 1 will endow the WRAN system with the needed capability and flexibility to configure the WRAN in different scenarios with manageable interference among the Base Stations where different Service Providers may deploy the system in the same region using the same free TV channel.

QAM: Quadrature Amplitude Modulation
Quadrature Amplitude Modulation (QAM) is a type of modulation where the signalling information is carried in the phase and amplitude of the modulated carrier wave. Specifically for QAM, the amplitude of two waves, 90 degrees out-of-phase with each other (in quadrature) are changed (modulated or keyed) to represent the data signal, in which each combination of phase and amplitude represents one of sixteen four-bit patterns.

Q-Band
Q-Band, also known as V-Band, is a radio bandwidth range between 40 GHz t0 50 GHz.

QCIF: Quarter CIF
Quarter CIF (QCIF) is a video image format which employs 176 horizontal pixels and 144 vertical lines. Although resolution is courser than CIF, QCIF consumes less memory while still achieving an acceptable level of clarity on small displays such as those incorporated in mobile phones.

QPSK: Quadrature Phase Shift Keying
Quadrature Phase Shift Keying (QPSK) is a digital modulation scheme that conveys data by changing, or modulating, the phase of a reference signal (the carrier wave). Sometimes known as quaternary or quadriphase PSK or 4-PSK, QPSK uses four points on the constellation diagram, equispaced around a circle. With four phases, QPSK can encode two bits per symbol, shown in the diagram with Gray coding to minimize the BER.

Quadrature-Phase
The quadrature phase channel in a phase shift keyed system having more that 2 phase states.

Quantizing
Quantizing is the process of assigning values to waveform samples by comparing the samples to discrete steps.

RAB: Reverse-Link Activity Bit
Reverse-Link Activity Bit (RAB) is for determining the data rate of a reverse link communication of a mobile communication system. A processor in the access terminal may determine whether the access terminal is in an idle mode, and passing a non-busy state value of the RAB to the digital filter when the access terminal is in the idle mode. The RAB may be compared to a threshold to determine a mode of reverse link data rate determination. The mode defines a set of criteria for an aggressiveness level of increasing or decreasing the reverse link communication data rate. The processor, therefore, determines the data rate based on the filtered reverse activity bit in accordance with the determined mode.

RACE:Research in Advanced Communications Equipment
Research in Advanced Communications Equipment (RACE) is an ETSI research project that has subsequently been replaced by ACTS.

RACH: Random Access Channel
Random Access Channel (RACH) is the channel used by mobiles in GSM and W-CDMA systems to gain access to the system when first attaching to it.

Radio
Radio is the electromagnetic waves whose frequencies are below 3,000 GHz as defined in Article 2 of the Radio Law in general. However, in practice, radio is generally refered to as electromagnetic waves whose frequencies are between 10 kHz and 300 GHz.

Radio link
Radio link refers to the equipment and transmission path (propagation channel) used to carry on communications. It includes the transmitting system, the propagation channel and receiving system.

Radio port
Radio port is a unit that supports transmission of signals over the air interface.

Radio propagation
Radio propagation refers to the electromagnetic waves at radio frequencies as they radiate from a transmitting antenna.

Rake receiver
Rake receiver is a radio receiver having multiple "fingers" and utilizing off-sets of a common spreading code to receive and combine several multipath (time delayed) signals, in effect using "time diversity" to overcome deep fades.

RAN: Radio Access Network
Radio Access Network (RAN) is the ground-based infrastructure required for delivery of third-generation (3G) wireless communications services, including high-speed mobile access to the Internet. The RAN must be able to manage a wide range of tasks for each 3G user, including access, roaming, transparent connection to the public switched telephone network and the Internet, and Quality of Service (QoS) management for data and Web connections.

RANAP: Radio Access Network Application Part
Radio Access Network Application Part (RANAP) is the Radio Network Layer signaling protocol used in a UMTS system on the Iu interface. It is responsible for functions including the setting up of a RAB (Radio Access Bearer) between the CN (Core Network) and the RNC (Radio Network Controller).

Random access
Random access is a technique for radio access to a network where an access message is not coordinated or administered by the network and can collide with other attempts by others to access the network over the same channel.

Rayleigh channel
Rayleigh channel is a communications channel having a fading envelope in the form of the Rayleigh Probability Density Function.

Rayleigh fading
Rayleigh fading is a type of signal fading caused by independent multipath signals having a Rayleigh PDF.

RBDS: Radio Broadcast Data System
Radio Broadcast Data System (RBDC), an replacement of Emergency Braodcast System, allows radio stations to send text messages, such as emergency warning and traffic alerts to radios installed with special display screens.

RC: Radio Configuration
Radio Configuration (RC) defines the physical channel configuration of cdma2000 (IS-2000) signals. Each RC specifies a set of data rates based on either 9.6 or 14.4 kbps. RC1 is the backwards-compatible mode of cdmaOne for 9.6 kbps voice traffic. It includes 9.6, 4.8, 2.4, 1.2 kbps data rates and operates at Spread Rate 1 (SR1). RC3 is a cdma2000 specific configuration based on 9.6 kbps that also supports 4.8, 2.7, and 1.5 kbps for voice, while supporting data at 19.2, 38.4, 76.8, and 153.6 kbps. RC3 also operates at SR1.

RCC: Radio Common Carrier
Radio Common Carrier (RCC) refers to a service provider for public mobile service.

RDCCH: Reverse Digital Control Channel
Reverse Digital Control CHannel (RDCCH), defined in the IS-136, is for the upstream signaling and control information from user equipment to cell site in a TDMA-based system. RDCCH works together with FDCCH which provides the downstream signaling and control information in such a system.

REAG Region
REAG Region is a geographic area over which a WCS operator is licensed to provide service. REAGs are a group of economic areas (EAs) and were first used to license WCS service in the late 1990s. REAGs are very large, with 6 REAGs covering the entire continental United States.

Receive diversity
Receive diversity is the process of providing two independent receiving systems and spatially separated antennas to overcome fading effects on the radio signal.

Receiver
Receiver is a device on a transmission path which converts the signals as received from the transmission system into the signals required by the destination equipment.

Reed Solomon code
Reed-Solomon codes are block-based error correcting codes with a wide range of applications in digital communications and storage. Reed-Solomon codes are used to correct errors in many systems including: (1) Storage devices (including tape, Compact Disk, DVD, barcodes, etc) (2) Wireless or mobile communications (including cellular telephones, microwave links, etc) (3) Satellite communications. (4) Digital television / DVB. (5) High-speed modems such as ADSL, cDSL, etc.

Reflection
Reflection is a process that occurs when a propagating electromagnetic wave impinges upon a obstruction whose dimensions are very large when compared to the wavelength. Reflections from the surface of the earth and from buildings or walls produce reflected waves which may interfere,constructively or destructively at the receiver.

ReFLEX
ReFLEX is a two-way paging protocols developed by Motorola for enhanced paging services. ReFLEX 25 supports outbound transfer rates of up to 6,400 bits per second in a 25 kHz channel and 12,800 bits per second in a 50 kHz channel.

Registration
Registration, in mobile wireless, is the process by which a mobile station informs the immediate service provider of its presence in the network and its desire to receive service.

Remote Access Point
Remote Access Point, also known as relay access points, is one of a number of secondary access points in a wireless network that uses Wireless Distribution System (WDS) to extend its range. Remote access points connect to a master access point.

Repeater
Repeater, also known as network repeater, is a type of network device that regenerates incoming electrical, wireless or optical signals. With physical media like Ethernet or Wi-Fi, data transmissions can only span a limited distance before the quality of the signal degrades. Repeaters attempt to preserve signal integrity and extend the distance over which data can safely travel. Active hubs are repeaters. In Wi-Fi, access points function as repeaters when operating in so-called "repeater mode." In moble wireless, repeater receives radio signals from the base station and then amplified and retransmitted to areas where radio shadow occurs, and vice versa.

Reuse factor
Reuse factor, also known as frequency reuse factor, is the number of distinct frequency sets used per cluster of cells.

Reverse link
In radio communications, the reverse link, also known as return link, is the link from a mobile user to a fixed base station. If the link includes a communications relay satellite, the reverse link will consist of both an uplink (mobile station to satellite) and a downlink (satellite to base station).

RF: Radio Frequency
Radio Frequency generally refers to wireless communications with frequencies below 300 GHz. Formally, according to the Article 2 of th Radio Law, radio frequency is below 3,000 GHz. Radio frequencies can be used for communications between a mobile telephone and an antenna mast.

RF License: Radio Frequency License
Radio Frequency (RF) License is the purchased right to transmit RF waves over a given BTA for typically periods of 10 years. The license tightly governs the design parameters of an RF system and its use. RF licenses typically are purchased from the government (FCC in the US) on an auction basis. The government (FCC) provides licenses to ensure maximum competition in a free market and spectral efficiency, which is another way of stating efficient use of the RF spectrum.

RFCOMM: Radio Frequency Communication
Radio Frequency Communication (RFCOMM) is a Bluetooth protocol which is a simple set of transport protocols, providing emulated RS232 serial ports (up to sixty simultaneous connections of a bluetooth device at a time). RFCOMM is sometimes called Serial Port Emulation. The Bluetooth Serial Port Profile is based on this protocol.

RFI: Radio Frequency Interference
Radio Frequency Interference (RFI) refers to the noise caused by other Radio Frequency that interferes with information being transmitted across unshielded copper cable.

RFID: Radio frequency identification
Radio frequency identification (RFID) is a system for tagging and identifying mobile objects such as store merchandise, postal packages and sometimes living organisms (like pets). RFID uses low-powered radio transmitters to read data stored in a transponder (tag) at distances ranging from one inch to 100 feet. RFID tags are used to track assets, manage inventory and authorize payments, and they increasingly serve as electronic keys for everything from autos to secure facilities. RFID works using small (sometimes smaller than a fingernail) pieces of hardware called RFID chips. These chips feature an antenna to transmit and receive radio signals. So-called passive RFID chips do not have a power source, but active RFID chips do. RFID chips may be attached to objects, or in the case of some passive RFID systems, injected into objects.

Rician channel
Rician channel is a transmission channel that may have a line-of-sight component and several scattered of multipath components. This fading characteristic exhibits a Rician PDF (Probability Density Function).

Rician fading
Rician fading is a type of signal fading having a characteristic similar to the Rician PDF (Probability Density Function). It is used to model the mobile radio propagation.

Rician PDF
Rician PDF is a type of signal fading caused by independent multipath signals. The Rician PDF reduces to the Rayleigh PDF for the special case when s = 0.

RLC: Radio Link Control
Radio Link Control (RLC) is a link-layer protocol that is responsible for error recovery and flow control in 3G (UMTS) cellular systems. Compared with its counterpart developed for CDMA-2000 systems, i.e., Radio Link Protocol (RLP), RLC is a more advanced protocol and can support different QoS requirements desired by the users.

RLP: Radio Link Protocol
Radio Link Protocol (RLP) is a link layer protocol used for 2G (GSM and cdmaOne) and CDMA-2000 (3G) network-based error corrections to ensure robust data transmission. RLP terminates at the Mobile Station (MS) and the Interworking Function (IMF) generally located at the Mobile Switching Centre (MSC). Cellular networks such as GSM and CDMA use different variations of RLP.

RNC: Radio Network Controller
The Radio Network Controller (RNC) is the governing element in the UMTS radio access network (UTRAN) responsible for control of the Node Base Stations (BS), that is to say, the base stations which are connected to the controller. The RNC carries out radio resource management, some of the mobility management functions and is the point where encryption is done before user data is sent to and from the mobile. The RNC connects to the Circuit Switched Core Network through Media Gateway (MGW) and to the SGSN (Serving GPRS Support Node) in the Packet Switched Core Network. There are three types of RNCs: C-RNC (Controlling RNC), D-RNC (Drift RNC) and S-RNC (Serving RNC).

Roaming
Roaming refers to the movement of a mobile device from one wireless network location to another without interruption in service or loss in connectivity. When a call is made to a roaming mobile, the public telephone network will route the call to your service provider's network since that is where your phone number terminates. Your home network is then responsible for re-routing the call to the host network.

Rogue Access Point
Rogue Access Point is an unauthorized access point installed on a network that may provide an entry point for unauthorized network access.

RPC: Reverse Power Control
Reverse Power Control (RPC) is a method for a Wireless Local Loop (WLL), in which the number of times of power control value transmission is reduced to 1. RPC reduces unnecessary power consumption in the WLL system and improves the reliability of the communication system.

RPE-LTP: Regular Pulse Excited-Long Term Prediction
Regular Pulse Excited Long Term Prediction (RPELTP) is a type of speech coding using regularly spaced pulses in an excitation frame and a long-term predictor to model the fine structure (pitch).

RRS: Round Robin Scheduling
Round Robin Scheduling (RRS) is a scheduling scheme used in wireless network. Since many stations share one channel in a wireless network, this algorithm provides every station to transmit or receive on the shared channel at a regular interval. Round-robin is one of the simplest scheduling algorithms for processes in an operating system, which assigns time slices to each process in equal portions and in order, handling all processes without priority. Round-robin scheduling is both simple and easy to implement, and starvation-free. Round-robin scheduling can also be applied to other scheduling problems, such as network scheduling.

RRC: Radio Resource Control
Radio Resource Control (RRC) is a sublayer of Layer 3 on the UMTS 3G radio interface. RRC exists in the control plane only and provides information transfer service to the NAS (Non Access Stratum). RRC is responsible for controlling the configuration of UMTS radio interface Layers 1 and 2.

RRD: RF Receiving Device
RF Receiving Device (RRD) receives over the air data and forwards it to the mobile computer.

RRI: Reverse Rate Indicator
Reverse Rate Indicator (RRI) is a parameter in a 3G wireless network provided by the reverse link, which aids the Access Point in determining the rate at which the reverse link is sending data. The RRI is included as the preamble for reverse link frames, indicating the rate at which the data was sent.

RS: Relay Station
Relay Station (RS), a concept defined in the IEEE 802.16j for the WiMAX network, is a station with the following functions: (1) to relay user data and possibly control information between other stations, and (2) to execute processes that indirectly support mobile multihop relay. All RSs are managed by an MMR-BS, but they may have some control of relay functions within their neighborhood.

RSA: Rural Service Area
Rural Service Area (RSA) is a geographic area in the US over which a cellular operator is licensed to provide service. RSAs are a group of rural counties having common financial, commercial and economic ties and were used to license cellular services together in the latter 1980s. RSAs cross state lines in some instances and were developed during a public rule making process at the FCC in 1987 and 1988.

RSSI: Relative Signal Strength Indicator
Relative Signal Strength Indicator (RSSI) is a measurement of radia signals at the point in which they are received and measured.

RTG: Receive/transmit Transition Gap
Receive/transmit Transition Gap (RTG), a concept in the mobile wireless network, is a gap between the last sample of the uplink burst and the first sample of the subsequent downlink burst at the antenna port of the BS in a time division duplex (TDD) transceiver. This gap allows time for the base station (BS) to switch from receive to transmit mode. During this gap, the BS is not transmitting modulated data but simply allowing the BS transmitter carrier to ramp up, and the transmit/receive (Tx/Rx) antenna switch to actuate.

rtPS: Real-Time Polling Service
Real-Time Polling Service (rtPS) is one of the five QOS service types defined in the IEEE 802.16 WiMAX. The 802.16 protocol supports five types of QoS: UGS (Unsolicited grant service), rtPS (Real time polling Service), ertPS (Extended Real-time POLLING SERVICE), nrtPS (Non-real-time polling service and BE (Best effort service). The Real-Time Polling Service (rtPS) is designed to support real-time service flows that generate variable size data packets on a periodic basis, such as MPEG video. The service offers real-time, periodic, unicast request opportunities, which meet the flow's real-time needs and allow the SS to specify the size of the desired grant. This service requires more request overhead than UGS, but supports variable grant sizes for optimum data transport efficiency.

R-UIM: Removable User Identity Module
Removable User Identity Module (R-UIM), also known as UIM, is similar to a Subscriber Identity Module (SIM), but is designed for networks other than GSM such as CDMA. R-UIM cards support roaming between CDMA and GSM networks.

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