LTE Acronyms

1xRTT

CDMA2000 1x Radio Transmission Technology. The original version of the CDMA2000 system. It operates using a single (hence ‘1x’) Radio Frequency (RF) carrier in each direction, each occupying the same bandwidth (1.25 MHz) as the earlier Interim Standard-95 (IS-95). See www.cdg.org.

3GPP

3rd Generation Partnership Project. The joint standardization partnership re-sponsible for standardizing UMTS, HSPA and LTE. See www.3gpp.org.

3GPP2

3rd Generation Partnership Project 2. The joint standardization partner-ship responsible for standardizing CDMA2000 and its derivatives. See www.3gpp2.org.

AAA

Authentication, Authorization and Accounting. These processes involve es-tablishing a terminal’s identity, configuring authorizations to access particu-lar types of service, and monitoring traffic volumes for each user. See 3GPP TS29.273, and TS23.002 Sections 4.1.4.6 and 4.1.4.7.

ABM

Asynchronous Balanced Mode. A mode of packet data transfer used, for example, by the Logical Link Control (LLC) layer for acknowledged bi- directional communication between a mobile station and a Serving GPRS Support Node (SGSN), which includes error recovery procedures and provides in-sequence delivery. Balanced mode implies that the station at either end of the link has the right to set-up, reset, or disconnect a link at any time (i.e. there is no master/slave relationship). See 3GPP TS44.064.

ABQP

Aggregate Base Station Subsystem Quality of Service Profile. Defines the Quality of Service (QoS) profile for a Base Station Subsystem (BSS) packet flow context. See 3GPP TS48.018 Section 11.3.43 and TS24.008 Section 10.5.6.5.

AC

Access Class. All UEs are randomly allocated to one of ten ACs, the allocated AC being stored in the Subscriber Identity Module/Universal Subscriber Iden- tity Module (SIM/USIM). In addition, UEs may belong to a special AC (e.g. for emergency services or network operators). The AC is used in determin- ing whether the UE may attempt to access the network. See 3GPP TS22.011 Section 4.

ACI

Adjacent Channel Interference. Received interference arising from transmis- sions in an adjacent Radio Frequency (RF) channel.

ACIR

Adjacent Channel Interference Ratio. The ratio of the total power transmitted from a source to the total interference power affecting a victim receiver, re- sulting from both transmitter and receiver imperfections. It is a function of the Adjacent Channel Leakage Ratio (ACLR) and the Adjacent Channel Selectiv- ity (ACS

ACK

ACKnowledgment. A signal transmitted to indicate that one or more blocks of data have been successfully received and decoded. It is used in Hybrid Auto- matic Repeat reQuest (HARQ), as well as in Radio Link Control (RLC) level ARQ.

ACLR

Adjacent Channel Leakage Ratio. A measure of the power which leaks into cer- tain 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 trans- mitter. 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 6.6.2.3.

ACRR

Adjacent Channel Rejection Ratio. Used in the context of repeaters. It is the ra- tio 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 an analogue input signal to convert it to a digital output signal.

ADM

Asynchronous Disconnected Mode. A mode of packet data transfer used by the Logical Link Control (LLC) layer for unacknowledged communication be- tween a mobile station and a Serving GPRS Support Node (SGSN), without prior establishment of a logical connection. Error recovery procedures are not provided, 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 www.csrc.nist.gov.

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 func- tion. 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) emis- sions testing. See 3GPP TS36.113 Section 8.3.2 and www.iec.ch.