An adaptive ISMA-DS/CDMA MAC protocol for third-generation mobile communications systems

In this paper, an inhibit sense multiple access-direct sequence/code divisi on multiple access (ISMA-DS/CDMA) medium access control protocol for a pack et transmission mobile radio network is presented. The main feature of this protocol is its ability to retain the inherent flexibility of random acces s protocols while at the same time reducing to some extent the randomness i n the access in order to increase the system capacity. In this framework, t he protocol is presented together with some adaptive mechanisms that improv e the protocol performance by means of regulating the access and varying th e transmission bit rate according to the channel load that is broadcast by the base station. As a result, an adaptive bit rate algorithm is presented that reaches a throughput value close to the theoretical maximum.