Packet reservation multiple access over erroneous channels

A reservation-ALOHA protocol in microcellular structure, packet reservation multiple access (PRMA) suits well the characteristics of future microcellular telecommunication systems. However, in erroneous channels, the performance of PRMA degrades because terminals can lose their reservations before talkspurts end. This can lead to increased delay and packet dropping in the middle of the talkspurts, which are highly perceptible. A variation of the PRMA protocol, called modified-PRMA (MPRMA), is proposed for improved performance in erroneous channels. Its performance is investigated mathematically and validated by simulations. Performance improvement is observed for both error-free and erroneous channels. MPRMA supports 36 speech terminals with less than 1% packets dropped when packet header error rate is 0.01. In comparison, PRMA supports only 32 terminals under similar conditions.