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4

Wireless protocols

A MAC protocol for a wireless LAN provides two types of data-transfer Service Access

Points (SAP): network and native. The network SAP offers an access to a legacy network

protocol (e.g., IP). The native SAP provides an extended service interface that may be

used by custom network protocols or user applications capable of fully exploiting the

protocol specific Quality of Service (QoS) parameters within the cell service area.

Broadband Radio Access Integrated Network (BRAIN) is used for millimeter wave

band multimedia communications. In BRAIN, all Access Points (APs) need to have only

an optical/electrical (OE) converter because BRAIN incorporates radio on fiber technolo￾gies, which allow for transmitting radio signals through optical fiber cables.

The Hybrid and Adaptive MAC (HAMAC) protocol integrates fixed assignment Time

Division Multiple Access (TDMA) protocols, reservation-based protocols, and contention￾based protocols into a wireless network, simultaneously and efficiently supporting various

classes of traffic such as Constant Bit Rate (CBR), Variable Bit Rate (VBR), and Avail￾able Bit Rate (ABR) traffic. The HAMAC protocol uses a preservation slot technique to

minimize the packet contention overhead in Packet Reservation Multiple Access (PRMA)

protocols, while retaining most isochronous service features of TDMA protocols to serve

voice and CBR traffic streams.

Adaptive Request Channel Multiple Access (ARCMA) is a Demand Assignment Multi￾ple Access (DAMA) protocol with dynamic bandwidth allocation. This scheme is designed

to function in a cell-based wireless network with many Mobile Stations (MSs) commu￾nicating with the Base Station (BS) of their particular cell. Transmissions are done on

a slot-by-slot basis without any frames. Each slot is divided into a Transmission Access

(TA) slot and a Request Access (RA) minislot. The RA channel in ARCMA is capable

of carrying additional information for different classes of Asynchronous Transfer Mode

(ATM) service (e.g., CBR, VBR, etc.). This additional information is used by the BS to

provide better QoS support for different classes of traffic. Transmission from CBR traffic

may reserve an incremental series of slots in the duration of their transmission. No further

request is needed until the CBR transmission finishes.

Mobile Telecommunications Protocols For Data Networks. Anna Hac´

Copyright ¶ 2003 John Wiley & Sons, Ltd.

ISBN: 0-470-85056-6