MAC (Medium Access Control). The function in IEEE networks that arbitrates use of network capacity and determines which stations are allowed to use the transmission medium.

Macrocells. Cells which are used mainly where few base transceiver stations are required to provide coverage for remote or sparsely populated areas. These cells typically have a radius between 10-35 km.

MAHO (Mobile Assisted Handoff). MAHO is an example of decentralized call processing where signal strength measurements performed at the mobile terminal are used to decide when handoff is to occur.

Manual exchange. A telephone exchange that uses an attendant to manually connect calls.

Master agent. An employer of agents who sell telecommunications services.

Master station. A telecommunications station that controls all other stations within a network.

Matrix. A network switch that connects calls from their source to their requested destination.

Matrix switching. A type of switching used with ATM to allow the use of the required bandwidth for the duration of a connection.

Mbps: Megabits per second. A convenient measure of the data rate in digital communications systems is the number of millions of bits per second transmitted.

MC-CDMA: Multi-carrier CDMA. A variant of CDMA based upon the use of multiple frequency carriers. It is used in the cdma2000 specification.

Measured rate service. The charging for a telecommunications service based on the frequency of usage of the service.

Mediation device. Located between the MSC and the billing and rating system, it collates all the toll tickets generated by a single call producing a call data record.

Medium. The pathway that carries a signal. Wireless telecommunications use radio waves as media whereas non-wireless media includes, for example, cables and fibers.

Medium frequency. A frequency within the 300 to 3000 KHz range.

Medium speed. The transmission of data at speeds between 2,400 bps and 9,600 bps. Voice signals are transmitted at speeds of 9,600 bps and above.

Megahertz (MHz). A measurement of frequency equal to one million cycles per second. One cycle per second is one hertz.

Message control packet. The control information sent with a message that is necessary for the transmission and reception of a message between two communication devices.

MHP (Multimedia Home Platform). A DVB -defined generic interface between interactive digital applications and the terminals on which those applications execute.

Microbrowser. Client software that is designed to overcome the restrictions of wireless handheld devices and allows access to a range of information services such as the Internet.

Microwave. Radio frequency signals between 890 MHz and 20 GHz.

Microcells. Microcells are used for urban or densely populated areas where the traffic is too high for macrocells. These cells typically have a radius up to 2 km.

MIMO (Multiple-In-Multiple-Out). A technology that uses multiple antennas and RF chains to achieve high data-rate throughputs and minimal multi-path interference.

MIN (Mobile Identification Number). The MIN represents the telephone number of the mobile handset. It is the number that must be dialed in order to reach the mobile subscriber.

Mobile Equipment (ME). The term used to refer to a handset. A mobile station is comprised of the mobile equipment and a subscriber identity module (SIM).

Mobile signal. The signal transmitted from the mobile terminal.

Mobile Station (MS). A mobile station is used by the subscriber to communicate with the GSM network and consists of the mobile equipment (ME) and the subscriber identity module (SIM).

Mobile terminal. The handheld mobile phone.

Mobile terminal display. The window or display on each mobile telephone that indicates the status of the mobile connection.

Modulation. The process of changing some parameters of an information carrier, in sympathy with the information, so that it can be transmitted over the air.

Motion Compensation. See Inter-frame Coding.

MPDU (MAC Protocol Data Unit). The MAC PDU, or frame.

MPEG-2 (Moving Pictures Expert Group). MPEG is a group which MPEG develops international standards for compression, decompression, processing and coding of moving pictures and audio. MPEG-2 is the most sophisticated set of standards, and is used in DVB.

MS (Mobile Station). The MS is the mobile terminal (that is, the mobile phone) used by the subscriber to access the cellular network.

MSC (Mobile services Switching Center). The hub of the network system. Its main purpose is to control calls to and from other telephone and data systems such as PSTN. It plays a major role in subscriber roaming by providing all the necessary functionality involved in registering, authenticating, location updating, and call routing for a roaming subscriber.

MSC service area. The geographical area controlled by a single MSC. Within a PLMN, there may be several MSC service areas.

MSC/VLR: Mobile Switching Center/Visitor Location Register. The MSC/VLR is a network component within the GSM mobile phone system.

MSISDN (Mobile Station ISDN). The number used to call a mobile subscriber. An MSISDN consists of a country code, a national destination code and a subscriber number.

MSRN (Mobile Station Routing Number). A temporary number that is allocated by the VLR and is used for routing a call for a mobile subscriber.

MSS (Mobile Satellite Service). A satellite service used for communication between land and mobile devices.

Multi-Path Fading. A loss of signal that occurs when a radio signal takes more than one path between the mobile station and the base transceiver station as a result of signal reflections off obstacles in the environment.

Multiplexer. A device that can combine and transmit several signals over a single line. The signals are then separated at the receiving end of the link. Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA) both use multiplexing.

Multiprotocol Encapsulation. A DVB data broadcasting service that supports transmission of datagrams of communication protocols, by encapsulating them in MPEG-2 sections. It is optimized for IP, but can be also used for other protocols.

MUSICAM (Masking Pattern Adapted Universal Sub-band Integrated Coding And Multiplexing). ). MPEG-2 audio coding is based on this. It is flexible and produces good quality at low bit rates.