Statistical upper bounds and performance evaluation of packet reservation-based multiple access protocols in cellular communications systems

Abstract

Packet reservation multiple access (PRMA) and advanced time division multiple access (ATDMA) protocols (proposed in the RACE project such as PRMA++) are multiaccess protocols proposed for the third generation mobile communications systems. The main factor apart from channel impairments, which affects the performance of such protocols is collision either within an information time slot (in PRMA) or a reservation time slots (in PRMA++). These collisions waste available channel resources and can cause undesirable congestion and lower the service quality. We generalise the idea of PRMA which results in the upper-bound capacity calculation and reveals new insight into the relationship between the parameters of such protocols. The performance dependent parameters such as delay, throughput, statistics, capacity and packet dropping probability are mathematically analysed and generalised such that they can be applicable to all reservation-based multiple access schemes. Through such analysis the upper-bound performance for such protocols is derived. The sensitivity of the system performance to different system measures (such as throughput, delay, packet dropping statistics) are evaluated for a range of system parameters (bandwidth, number of users, voice activity factor). Finally, the performance of PRMA and PRMA++ with their upper-bound values are compared.