Radio Access Bearer Assignment Of Contract

ACLR:Adjacent Channel Leakage Ratio. A measure of the power which leaks into certain specific nearby Radio Frequency (RF) channels as a result of transmitting in a given channel. It provides an estimate of how much a neighbouring radio receiver will be affected by the Out Of Band (OOB) emissions from a transmitter. It is defined as the ratio of the filtered mean power in a set bandwidth within the wanted channel to the filtered mean power in an adjacent channel. See 3GPP TS36.101 Section

ACRR: Adjacent Channel Rejection Ratio. Used in the context of repeaters. It is the ratio of the Root Raised Cosine (RRC) weighted gain per carrier of the repeater in the pass band to the RRC weighted gain of the repeater on an adjacent channel. See 3GPP TS 36.106 Section 13.

ACS:Adjacent Channel Selectivity. A measure of a receiver’s ability to receive a wanted signal at its assigned channel frequency in the presence of an adjacent channel interfering signal at a given frequency offset from the centre frequency of the assigned channel, without the interfering signal causing a degradation of the receiver performance beyond a specified limit. ACS is predominantly defined by the ratio of the receive filter attenuation on the assigned channel frequency to the receive filter attenuation on the adjacent channel. See 3GPP TS36.101 Section 7.5.

ADC:Analogue to Digital Converter. A processor which samples and quantizes ananalogue input signal to convert it to a digital output signal.

ADM:Asynchronous Disconnected Mode. A mode of packet data transfer used bythe Logical Link Control (LLC) layer for unacknowledged communication between a mobile station and a Serving GPRS Support Node (SGSN), withoutprior establishment of a logical connection. Error recovery procedures are notprovided, and in-sequence delivery is not guaranteed. See 3GPP TS44.064.

ADSL:Asymmetric Digital Subscriber Line. It is a means of providing high-speed data transmission over conventional twisted-pair copper telephone lines, by frequency-division multiplexing with analogue voice traffic. Higher download speeds are provided than upload speeds. AES Advanced Encryption Standard. See Federal Information Processing Standards Publication 197, available from

AF:Application Function. An element offering applications that require the control of Internet Protocol (IP) bearer resources, such as dynamic policy or charging control. See for example 3GPP TS23.207 Section 5.2.4 and TS23.203 Section 6.2.3.

AKA:Authentication and Key Agreement. The process by which the Authentication Centre (AuC) and UE exchange information by which they can each verify a secret key held by the other, and then calculate keys to be used for ciphering and integrity protection of data transmitted between the UE and the network. See 3GPP TS33.102 Section 6.3 and TS33.401 Section 6.1.

AM:Acknowledged Mode. One of three Radio Link Control (RLC) modes (the other two being Transparent Mode (TM) and Unacknowledged Mode (UM)). It includes Automatic Repeat reQuest (ARQ) for error-free packet delivery. See 3GPP TS36.322.

AMBR:Aggregated Maximum Bit-Rate. The upper limit on the aggregate bit rate that can be expected to be provided across all non-Guaranteed Bit Rate (GBR) bearers. Excess traffic may, for example, be discarded by a rate-shaping function. Each non-GBR bearer could potentially utilize the entire AMBR, for example when the other non-GBR bearers are not carrying any traffic. See 3GPP TS23.401 Section 4.7.3.

AMC:Adaptive Modulation and Coding. A form of link adaptation which adjusts the transmitted information data rate by varying the modulation order and the Forward Error Correction (FEC) code rate. This is typically done to match an estimate of the instantaneous radio channel capacity.

AMD:Acknowledged Mode Data. The type of Protocol Data Unit (PDU) used to carry user plane data in Radio Link Control (RLC) Acknowledged Mode (AM). The PDU header contains special fields to support the RLC Automatic Repeat reQuest (ARQ) mechanism. See 3GPP TS36.322 Section 6.

AMN:Artificial Mains Network. A model of the mains electricity supply to which equipment is connected, used for ElectroMagnetic Compatibility (EMC) emissions testing. See 3GPP TS36.113 Section 8.3.2 and

A-MPR:Additional Maximum Power Reduction. An additional value of maximum allowed uplink power reduction used to meet additional adjacent carrier leakage ratio and spectrum emission requirements which are signalled by the network in a specific deployment scenario. See 3GPP TS36.101 Section 6.2.4.

AMR:Adaptive Multi-Rate. A type of source coding, often used for digital speech transmission, whereby the bit rate of the generated data stream is adapted by varying the encoded quality of the signal. The different output data rates are provided by switching between different source codecs. See 3GPP TS26.071 and TS26.171.

ANR:Automatic Neighbour Relation. A function by which eNodeBs can automati- cally determine which cells are their neighbours. See 3GPP TS36.300 Section 22.3.2.

AoA:Angle-of-Arrival. The angle (usually azimuth) from which a signal arrives relative to a reference angle of an antenna array.

AoD:Angle-of-Departure. The angle (usually azimuth) at which a signal is transmitted relative to a reference angle of an antenna array.

AP:Application Protocol. Many APs are part of the Control-plane of E-UTRAN and operate across the S1 and X2 interfaces (S1-AP and X2-AP respectively), performing functions such as setting up Evolved Packet System (EPS) bearers. See 3GPP TS36.401 Section 11.1.2.

APN:Access Point Name. Identifies a Gateway GPRS Support Node (GGSN) or Packet Data Network GateWay (P-GW). It includes an APN network identifier which defines the Packet Data Network (PDN) to which the UE requests connectivity, and may also include an APN operator identifier which defines in which Public Land Mobile Network (PLMN) the P-GW or GGSN is located. See 3GPP TS23.003 Sections 9 and

ARFCN:Absolute Radio Frequency Channel Number. An ARFCN defines a pair of Radio Frequency (RF) channel frequencies for uplink and downlink use. See 3GPP TS45.005 Section 2 for the ARFCN for GSM, TS25.101 Section 5.4 for the UARFCN for UMTS and TS36.101 Section 5.4 for the EARFCN for LTE. ARFCN and UARFCN are based on a 200 kHz channel raster, while EARFCN is based on a 100 kHz channel raster.

ARIB:Association of Radio Industries and Businesses. One of the Japanese Standards Development Organisations (SDOs) in 3GPP (the other being TTC). See

ARP:Allocation and Retention Priority. A parameter of the Quality of Service (QoS) profile of an Evolved Packet System (EPS) bearer. It is designed to facilitate decisions as to whether a bearer establishment/modification request can be accepted. See 3GPP TS23.401 Section 4.7.3.

ARQ:Automatic Repeat reQuest. A scheme whereby the receiving terminal requests retransmission of packets which are detected to be erroneous. It is used in Radio Link Control (RLC) Acknowledged Mode (AM), as well as being a component of Hybrid ARQ (HARQ).

AS:Access Stratum. Consists of the functions and protocols used to transfer information across a specific Radio Access Technology (RAT).

AS:Angular Spread. A measure of the width of a transmitted (or received) signal beam or set of signal paths, usually in the azimuth plane.

A-SEM:Additional Spectrum Emission Mask. Specifies additional spectral emission constraints for particular deployment scenarios. A UE is instructed when it has to apply an A-SEM by signalling from the network, typically as part of a cell handover/broadcast message. See 3GPP TS36.101 Section

ASME:Access Security Management Entity. The entity which receives the top-level keys in an access network from the Home Subscriber Server (HSS). For E-UTRAN access networks, the role of the ASME is assumed by the Mobility Management Entity (MME). See 3GPP TS33.401.

ASN.1:Abstract Syntax Notation 1. A standardized notation used to describe structures for representing, encoding, transmitting, and decoding data; it is used for some UMTS and LTE protocol specifications (e.g. Radio Resource Control (RRC) signalling definition. See 3GPP TS36.331.

ATIS: Alliance for Telecommunications Industry Solutions. The North American Standards Development Organization (SDO) in 3GPP. See

ATT:Attenuator. Used in conformance testing, to set the desired power of received signals or interference, for example modelling propagation loss. See 3GPP TS36.508 Annex A and TS36.141 Annex I.

AuC:Authentication Centre. Can be considered to be a subset of a Home Subscriber Server (HSS). It stores an identity key for each mobile subscriber registered with a Home Location Register (HLR). This key is used to generate security data. See 3GPP TS23.002.

AWGN:Additive White Gaussian Noise. Noise with a flat power spectrum and Gaussian amplitude distribution. It is generally added to a received signal to simulate the effect of thermal noise and other sources of noise or interference.


BCC:Base station Colour Code. The least-significant 3 bits of a Base Station Identification Code (BSIC). See 3GPP TS23.003.

BCCH:Broadcast Control CHannel. In LTE, it represents the logical channel carrying broadcast system information. See 3GPP TS36.321.

BCH:Broadcast CHannel. In LTE, the transport channel carrying broadcast system information except that which is contained in the Master Information Block (MIB). See 3GPP TS36.321.

BCM:Bearer Control Mode. BCM can indicate ‘mobile station only’ or ‘mobile station / network’. When the BCM is ‘mobile station only’, the mobile station requests any additional Packet Data Protocol (PDP) contexts for the PDP Address / Access Point Name (APN) pair. In the case of ‘mobile station/network’, both the mobile station and the Packet Data Network GateWay (P-GW) or Gateway GPRS Support Node (GGSN) may request additional PDP contexts. See 3GPP TS29.060 Section 7.7.83.

BER:Bit Error Rate. A measure of received signal quality: the proportion of received bits which is decoded erroneously.

BI:Backoff Indicator. Indicates the upper limit for a random backoff period by which a UE has to delay a new random access attempt if a response has not been received to a first random access attempt. The BI may be used for example in network overload situations. See 3GPP TS36.321 Sections 5.1 and 7.2.

BLER:Block Error Rate. A measure of received signal quality: the proportion of received data blocks which is decoded erroneously. Usually this refers to trans- port blocks, and the errors are detected by Cyclic Redundancy Check (CRC) failure.

BM-SC:Broadcast-Multicast Service Centre. The interface between external broad- cast/multicast content providers and the core network. See 3GPP TS23.246 Section 5.1.

BP:Bandwidth Part. A part of the total downlink system bandwidth, which is further subdivided into a number of sub-bands. It is applicable to periodic ‘UE- selected sub-band’ Channel Quality Indicator (CQI) reporting on the Physical Uplink Control CHannel (PUCCH). The UE selects one sub-band from the BP and the corresponding CQI value is reported. See 3GPP TS36.213 Section 7.2.2.

BPSK:Binary Phase Shift Keying modulation. A modulation scheme conveying one bit per symbol, whereby the values of the bit are represented by opposite phases of the carrier.

BS:Base Station. The entity in a radio access network responsible for radio trans- mission and reception in one or more cells to and from the UE. In LTE the BS is known as the eNodeB.

BSIC:Base Station Identification Code. A 6-bit code which allows a mobile station to distinguish between different neighbouring GSM base stations. It is made up of a Network Colour Code (NCC) and a Base station Colour Code (BCC). See 3GPP TS23.003.

BSR:Buffer Status Report. Medium Access Control (MAC)-level messages transmitted by the UE to the serving eNodeB to provide the eNodeB with information about the amount of data in the uplink buffers of the UE. See 3GPP TS36.321 Section 5.4.5.

BSS:Base Station Subsystem. Either a full GSM/EDGE Radio Access Network (GERAN) network, or only the access part of a GERAN, offering the allocation, release and management of specific radio resources to establish means of connection between a mobile station and the GERAN.

BTS:Base Transceiver Station. The base station in a GSM system. BW Bandwidth. A measure of the width of a range of frequencies, measured in Hertz.


C/I:Carrier-to-Interference Ratio. The ratio between the power of the Radio Frequency (RF) carrier bearing the wanted signal and the total power of interfering signals.

CAC:Call Admission Control. The process by which the network decides whether or not to admit a new call.

CAZAC:Constant Amplitude Zero Auto-Correlation. A property exhibited by certain sequences, such as Zadoff-Chu (ZC) sequences, whereby the sequences have constant amplitude and zero circular autocorrelation at all points except zero lag.

CB:Circular Buffer. A buffer in which data is read in and out cyclically, such that when the end of the buffer is reached the process continues at the beginning. See 3GPP TS36.212 Section

CBC:Cell Broadcast Centre. The part of the Core Network (CN) which manages Cell Broadcast Service (CBS) messages. See 3GPP TS23.002 Section 4a.5.1.

CBE:Cell Broadcast Entity. An information source, external to the 3GPP system, which provides the content of a Cell Broadcast Service (CBS). This may include emergency public warnings. See 3GPP TS23.401 Section 5.12 and TS23.041 Section 4.

CBS:Cell Broadcast Service. A service analogous to Teletex, which broadcasts unacknowledged messages to all mobile terminals within a particular region. See 3GPP TS23.041.

CC:Convolutional Code. A type of Forward Error Correction (FEC) code in which k input bits to be encoded are fed into a shift register with a number stages corresponding to the memory of the CC, and n output bits are taken from the shift register as a linear combination of the content of the shift register. The code rate is given by k/n.

CCCH:Common Control CHannel. In LTE, a logical channel used to deliver control information (in both uplink and downlink directions) during connection establishment. See 3GPP TS36.321.

CCE:Control Channel Element. A set of 36 resource elements to which part or all of a Physical Downlink Control CHannel (PDCCH) message can be mapped. See 3GPP TS36.211 Section 6.8.1.

CCO:Cell Change Order. A message from E-UTRAN to a UE in RRC_CONNECTED mode, instructing it to move to a GSM/EDGE Radio Access Network (GERAN), including information facilitating access to and/or connection establishment in the target cell. See 3GPP TS36.331 Section 5.4.3.

CCSA:China Communications Standards Association. The Chinese Standards Development Organization (SDO) in 3GPP. See

CDD:Cyclic Delay Diversity. A form of transmit diversity whereby a different phase shift is applied to each Orthogonal Frequency Division Multiplexing (OFDM) subcarrier on at least one of the multiple transmit antennas from which the subcarrier is transmitted, thereby increasing the frequency selectivity of the radio channel. In the time domain this is equivalent to introducing a delay which is cyclic because it is applied before insertion of the Cyclic Prefix (CP).

CDL:Clustered Delay Line. A type of channel model in which the received signal is composed of a number of separate delayed clusters. Each cluster comprises a number of multipath components with the same delay but different Angle of Departure (AoD) and Angle of Arrival (AoA).

CDM : Code Division Multiplex(ed/ing). A method of multiplexing different data sig- nals by means of different codes, rather than different frequencies or timeslots. The codes used for different signals may be orthogonal to each other, or may be pseudo-random. They have a wider bandwidth than the data signals. CDM is the main multiplexing mode in UMTS.

CDMA:Code Division Multiple Access. A scheme allowing multiple users to access a given radio channel by the use of CDM to multiplex the data signals of the different users. CDMA is the main multiple access mode of UMTS.

CDN:Coupling/Decoupling Network. A capacitor/inductor network used to connect equipment being tested for ElectroMagnetic Compatibility (EMC) compliance to a power supply. The coupling network allows Radio Frequency (RF) common mode current disturbance signals through the various conductors to the equipment under test, while the decoupling network is designed to handle signals emitted by the equipment under test. See 3GPP TS36.113 and IEC 61000 (

CF:Contention-Free. Referring to the random access procedure, CF is an access mode in which only one user has permission to access a given transmission resource. CF random access operates in LTE by assigning a dedicated Random Access CHannel (RACH) preamble signature to a particular UE for transmission in a particular RACH slot. This is in contrast to contention-based random access, where multiple users may transmit a signal in the same time-frequency resources, and a contention resolution procedure is then required to separate the different users. See 3GPP TS36.321 Section Referring to turbo-code interleaver design, CF describes an interleaver in which the turbo-decoder can operate to perform the necessary exchanges of mutual in- formation between the consitutent decoders without reading and writing from the same memory block at the same time. The turbo-code interleaver adopted for LTE is CF.

CFI : Control Format Indicator. Indicates the number of Orthogonal Frequency Division Multiplexed (OFDM) symbols used for control signalling in each downlink subframe. See 3GPP TS36.212 Section 5.3.4.

CFO:Carrier Frequency Offset. The difference between a reference frequency and the frequency of a received Radio Frequency (RF) carrier. Typically the reference frequency is provided by a local oscillator in the radio receiver.

CGI:Cell Global Identification. The globally unique identity of a cell in GSM/EDGE Radio Access Network (GERAN) or CDMA2000.

CHAP:Challenge Handshake Authentication Protocol. Used by the Point-to-Point Protocol (PPP) to validate the identity of users. See IETF RFC1994,

CID:Cell IDentifier. In LTE, an identifier of a particular cell, either a Physical CID or a Global CID. Up to 504 Physical CIDs are available.

CID:Context IDentifier. A RObust Header Compression (ROHC) parameter which is associated with each compressed data flow and which identifies the state maintained by the compressor and decompressor in order to compress/decompress the headers of the packet stream. The CID is transmitted together with the compressed headers and feedback information. See IETF RFC3095,

CINR:Carrier-to-Interference-and-Noise Ratio. The ratio between the power of the Radio Frequency (RF) carrier bearing the wanted signal and the total power of interfering signals and thermal noise.

CIR:Channel Impulse Response. The time-domain complex signal received at the output of a radio propagation channel in response to the transmission of a single signal impulse of vanishingly short duration. It provides information on the power, phase and delay of the different paths of the channel.

CKSN:Ciphering Key Sequence Number. In a UMTS authentication challenge, theCKSN enables the network to verify the instance of the ciphering key andintegrity key which are stored in the mobile terminal without invoking the authentication procedure. See 3GPP TS24.008 Section

CM:Cubic Metric. The CM of a given signal is a measure of the transmit power de-rating needed to enable a Power Amplifier (PA) to transmit the signal com- pared to the de-rating required for transmission of a reference signal for the same Adjacent Carrier Leakage Ratio (ACLR). The CM characterizes the effects of the third-order (cubic) non-linearity of the PA. See for example 3GPP TS25.101 Section 6.2.2.

CMC: Connection Mobility Control. Comprises the functions executed by the eNodeB to manage mobility and handover in both idle and connected modes. See 3GPP TS36.300 Section 16.1.3 and TS36.133.

CMHH:Constant Modulus Householder. A Householder matrix is given byWH = I − 2uuH/uHu where I is the identity matrix and u is a predefined column vector. If all the column vectors in the matrix have equal magnitude, the matrix is said to possess the constant modulus property. Codebooks comprised of CMHH matrices were considered for precoding in LTE. In such an application, the constant modulus property limits the Peak to Average Power Ratio (PAPR) of the transmitted signals.

CN:Core Network. The part of the 3GPP system which is independent of the connection technology (e.g. the Radio Access Technology (RAT)) of the terminals. The terminals connect to the core network via the access network (which is RAT-specific).

COFDM:Coded Orthogonal Frequency Division Multiplexing. An OFDM scheme associated with a Forward Error Correction (FEC) code.

CP:Cyclic Prefix. A set of samples which are duplicated from the end of a transmitted symbol and appended cyclically to the beginning of the symbol. This can form a type of guard interval to absorb Inter-Symbol Interference (ISI). The cyclic construction preserves orthogonality of the subcarriers in an OFDM transmission.

CPICH:Common Pilot CHannel. A Wideband Code Division Multiple Access (WCDMA) downlink physical channel transmitted from every NodeB to provide the default phase reference for demodulation of the other downlink channels. It is used for signal quality measurements for handover from an LTE cell to a WCDMA cell. See 3GPP TS25.211 Section 5.3.3.

CPICH Ec/No:Common Pilot CHannel (CPICH) Ec/No. The CPICH received energy per chipdivided by the noise power density in the band. A measurement used for handover to Wideband Code Division Multiple Access (WCDMA) cells. See 3GPPTS25.215 Section 5.1.5.

C-plane:Control-plane. Carries signalling (for example for Radio Resource Control (RRC)), as opposed to user data, which is carried by the User-plane (U-plane). See 3GPP TS36.300 Section 4.3.2.

CPT:Control Protocol Data Unit Type. A field in the header of LTE Radio Link Control (RLC) Control Protocol Data Units (PDUs), indicating the type of the RLC Control PDU. In Release 8, the only type of RLC Control PDU defined is the STATUS PDU; the CPT field allows more types to be defined in a later release. See 3GPP TS36.322 Section

CQI:Channel Quality Indicator. Information signalled by a UE to the base station to indicate a suitable data rate (typically a Modulation and Coding Scheme (MCS) value) for downlink transmissions, usually based on a measurement of the received downlink Signal to Interference plus Noise Ratio (SINR) and knowledge of the UE’s receiver characteristics. See 3GPP TS36.213 Section 7.2.3.

CR:Change Request. A formal description of a proposed or agreed change to a 3GPP specification. Any change to a 3GPP specification v3.0.0 or above needs to be formulated and agreed by means of a CR.

CRC:Cyclic Redundancy Check. An error detecting code appended to a block of data to be transmitted. The value of the CRC is calculated only from the block of data itself. The length of the CRC determines the number of errors which can be detected in the block of data on reception. A CRC is not able to correct errors or determine which bits are erroneous.

C-RNTI:Cell Radio Network Temporary Identifier. A UE identifier allocated by an eNodeB and unique within one cell controlled by that eNodeB. The C-RNTI can be reallocated when a UE moves to a new cell. See 3GPP TS36.321 Section 7.1.

CS:Circuit Switched. A CS connection reserves dedicated transmission resources for data transfer at a fixed rate for the duration of the communication session. The reserved resources are not accessible to any other user.

CSFB:Circuit Switched FallBack. CSFB in the Evolved Packet System (EPS) enables the provisioning of voice and other CS-domain services by reuse of GSM/EDGE Radio Access Network (GERAN) or UTRAN CS infrastructure when the UE is served by E-UTRAN. This function is only available if E- UTRAN coverage is overlapped by GERAN or UTRAN coverage.

CSG:Closed Subscriber Group. A set of subscribers who are permitted to access a particular cell to which access is restricted. See 3GPP TS25.367 and TS36.304.

CSI:Channel State Information. A general term for information describing characteristics of the radio channel, typically indicating the complex transfer function matrix between one or more transmit antennas and one or more receive antennas.

CSIT:Channel State Information at the Transmitter. Channel State Information (CSI) which is available at the transmitter side of the channel, for example as a result of feedback signalling from the receiver (closed loop) or open loop estimation exploiting reciprocity.

CTF:Channel Transfer Function. A set of coefficients describing the complex im- pulse response (or frequency-domain characteristic) of a radio channel from one or more transmit antennas to one or more receive antennas.

CW:Continuous-Wave. An unmodulated Radio Frequency (RF) carrier of constant amplitude and frequency, used to model interference in some RF performance requirements. See 3GPP TS36.101.


d.c:. direct current. In general, a signal of fixed polarity (i.e. non-oscillating). Used to refer to the subcarrier corresponding to zero-frequency in a baseband Orthogonal Frequnecy Domain Multiplexed (OFDM) signal. DAC Digital to Analogue Converter. A processor which converts a sampled, quantized digital input signal into a continuous-time analogue-valued output signal.

DAI:Downlink Assignment Index. A field in the downlink resource grant signalled to a UE, indicating how many subframes in a previous time window have contained transmissions to that UE. This is applicable only when LTE is operated in Time Domain Duplex (TDD) mode, and enables the UE to determine whether it has received all the downlink transport blocks for which it should transmit a combined ACKnowledgement/Negative ACKnowledgement (ACK/NACK). See 3GPP TS36.213 Section 7.3.

DCCH:Dedicated Control CHannel. In LTE, a logical channel used to deliver dedicated control information relating to a specific UE (in both uplink and downlink di- rections), when the UE has a Radio Resource Control (RRC) connection with the eNodeB. See 3GPP TS36.321.

DCI:Downlink Control Information. The term used to describe the control signalling messages transmitted on the Physical Downlink Control CHannel (PDCCH), including for example downlink resource assignments (for the Physical Downlink Shared CHannel (PDSCH)) and uplink transmission grants (for the Physical Uplink Shared CHannel (PUSCH)). See 3GPP TS36.212 Section 5.3.3.

DFT: Discrete Fourier Transform. A transformation which acts on a sampled time- domain signal of finite duration to give the corresponding series of frequency- domain components.

DFT-SOFDM: Discrete Fourier Transform- Spread- Orthogonal Frequency Division Multiplexing. A transmission scheme similar to Orthogonal Frequency DivisionMultiplexing (OFDM), but with a Discrete Fourier Transform (DFT) precodingstage applied before the Inverse Fast Fourier Transform (IFFT) at the transmitter, resulting in a single-carrier signal with significantly lower Peak to AveragePower Ratio (PAPR) than OFDM. It is also known as Single Carrier-FrequencyDivision Multiplexing (SC-FDM), and is the basis of the LTE uplink.

DHCP:Dynamic Host Configuration Protocol. A protocol used to allocate Internet Protocol (IP) addresses and other configuration parameters to devices in an IP network. See IETF RFC1531,

Diffserv: Differentiated Services. Diffserv is a coarse-grained mechanism for classifying data traffic into classes depending on the Quality of Service (QoS) requirements of each data traffic flow. It facilitates interoperability between different networks, enabling data from each class to be handled with appropriate priority and latency. See IETF RFC2475,

DL:DownLink. The radio link in the direction from the base station to the mobile terminal.

DL-SCH:DownLink Shared CHannel. An LTE transport channel used to transport downlink user data or Radio Resource Control (RRC) messages, as well as system information which are not transported via the Broadcast CHannel (BCH). See 3GPP TS36.321.

DM RS:DeModulation Reference Signal. Reference Signals (RS) which are embedded in the Physical Uplink Control CHannel (PUCCH) and Physical Uplink Shared CHannel (PUSCH) transmissions to provide the phase reference for demodulation of the PUCCH/PUSCH data. See 3GPP TS36.211 Section 5.5.2.

DoA:Direction of Arrival. The angle (usually azimuth) from which a signal arrives relative to a reference angle of an antenna array.

DRA:Dynamic Resource Allocation. The process of assigning resource blocks to different radio bearers in each subframe. This function is managed by the eNodeB. See 3GPP TS36.300 Section 16.1.4.

DRB:Data Radio Bearer. A radio bearer which carriers user data as opposed to control plane signalling.

DRX:Discontinuous Reception. The periodic switching off of a receiver, usually to save energy. DRX cycles can be configured in the LTE downlink so that the UE does not have to decode the Physical Downlink Control CHannel (PDCCH) or receive Physical Downlink Shared CHannel (PDSCH) transmissions in certain subframes. See 3GPP TS36.321 Section 5.7 for connected mode, and TS36.304 Section 7.1 for idle mode.

DSAC:Domain Specific Access Control. A mechanism which allows the utilization of a specific Core Network (CN) domain resource while another domain is restricted, for example when a natural disaster occurs. See 3GPP TR23.898.

DS-CDMA:Direct Sequence- Code Division Multiple Access. A method of Code Division Multiple Access (CDMA) whereby the signal of each user is spread in frequency by multiplying it by a wideband code sequence of ‘chips’. This is used in UMTS.

DSP:Digital Signal Processor. A processor for manipulating digital signals.

DTCH:Dedicated Traffic CHannel. A logical channel used in LTE to deliver dedicated user data for a specific UE (in both uplink and downlink directions). See 3GPP TS36.321.

DTX:Discontinuous Transmission. The periodic switching off of a transmitter, usually to save energy.

DUT:Device Under Test. Typically refers to a device undergoing conformance test ing.

DwPTS:Downlink Pilot TimeSlot. A special downlink timeslot occurring in the second (and in some configurations the 7th) subframe of each radio frame when LTE is operated in Time Division Duplex (TDD). Its length is variable, to allow for different DownLink (DL) – UpLink (UL) switching periods to be configured. The name DwPTS originates from Time Division Synchronous Code Division Multiple Access (TD-SCDMA). See 3GPP TS36.211 Section 4.2.


A bearer service is a link between two points, which is defined by a certain set of characteristics. Whenever a UE is being provided with any service (CS/PS service), the service has to be associated with a Radio Bearer specifying the configuration for Layer-2 and Physical Layer in order to have its QOS clearly defined. Radio bearers are channels offered by Layer 2 to higher layers for the transfer of either user or control data. In other words, Layer 2 offers to the upper layers the service of information transmission between the UE and the UTRAN by means of the Radio Bearers (RBs) and Signaling Radio Bearers (SRBs). Therefore, the service access points between Layer 2 and upper layers are RBs.

Radio Access Bearers (RAB)[edit]

The purpose of a Radio Access Bearer (RAB) is to provide a connection segment using the WCDMA Radio Access Network (WCDMA RAN) for support of a UMTS bearer service. The WCDMA RAN can provide Radio Access Bearer connections with different characteristics in order to match requirements for different UMTS bearers.

  • The conversational speech RAB is tailored to 12.2 kbit/s Adaptive Multi Rate (AMR) speech and will also be used to carry emergency calls.
  • Video telephony and ftp services may be offered across the Conversational 64 kbit/s Circuit Switched (CS) RAB.
  • The streaming 57.6 kbit/s is offered to support a specific modem.
  • The new PS streaming 8/54 kbit/s RAB will be implemented on DCH. This streaming RAB will be supported only in combination with PS interactive 8/8 kbit/s RB, no standalone PS streaming RAB will be supported.
  • The maximum data rate supported by the Interactive RAB (Packet Switched, PS) is 384 kbit/s in the downlink and 64 kbit/s in the uplink, making it ideal for email or web browsing.
  • It is also possible to use the speech RAB together with the interactive RAB that is usually called a MultiRAB.

Signalling Radio Bearer (SRB) Parameters[edit]

A Signalling Radio Bearer (SRB) is a radio bearer that carries DCCH signalling data. An SRB is used during connection establishment to establish the Radio Access Bearers (RABs) and then also to deliver signalling while on the connection (for example, to perform a handover, reconfiguration or release).

The test set supports three SRBs:

3.4k DCCH - see 3GPP TS 34.108

13.6k DCCH - see 3GPP TS 34.108

2.2k DCCH - this signalling radio bearer has the following properties:

Transport Channel Parameters
TB size100
TF 00 x 100
TF 11 x 100
TTI (ms)40
Coding TypeConv, 1/3
CRC12 bit
Downlink Physical Channel
DTX Positionn/a
Slot Structure5
Uplink Physical Channel
Min Spreading Factor256
DPCCH slot format0

During connection establishment, an RRC Connection Setup procedure establishes the SRB. The SRB is then used to send all subsequent signalling to start the desired service and establish the radio bearers for the service. Establishment of the radio bearers is achieved using an RB Setup procedure. The RB Setup procedure configures how both the DCCH and DTCH will be carried on the radio bearers.

The RB Setup may specify a different DCCH RLC block size from the DCCH RLC block size that was being used when only an SRB was present. For example, the DCCH RLC block size for the default 3.4k DCCH SRB is 144 bits, but all RMCs (Reference Measurement Channels) call for a DCCH RLC block size of 96 bits. If the RB Setup specifies a change in the DCCH RLC block size from the stand-alone SRB configuration, the UE and network must change the DCCH RLC block size and then perform an RLC Re-establishment procedure to reset the RLC buffers. If your UE does not support changing the DCCH RLC block size during connection setup, you must establish the call using an SRB with a DCCH RLC block size that is equal to the DCCH RLC block size defined for the service you wish to establish.

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