An efficient MAC based on a decentralised channel load sensing protocol for wide-band CDMA systems

The distributed queuing request update multiple access protocol (DQRUMA) in conjunction with multi-code DS-CDMA (MC-DS-CDMA) is discussed. DQRUMA was proposed for wireless ATM networks to obtain higher effectiveness for multimedia traffic by using centralised control. As the retransmission control is a key issue in DQRUMA, we propose the use of a technique, which allows optimal retransmission probabilities under any dynamic load conditions. The backlogged estimate is performed by considering the centralised feedback channel information provided by the base station. As the goal of the paper is optimising DQRUMA protocol for both, access and scheduling, several ways to attend mobile terminals requests have been implemented for both fair sharing and best effort scheduling. Through computer simulation many interesting results have been obtained, some of are explained.