Throughput analysis of spread slotted ALOHA systems using multiuser receivers

This paper analyzes the throughput of spread slotted ALOHA systems employing multiuser receivers. It is shown that when the packet arrival rate λ approaches the capacity of the multiuser receiver K from the left, the maximum utilization of the system can be reached. The maximum utilization of the system is 1 - √(log K/K) - O √(1/K(log K)). It is found that if the arrival rate is less than K, the higher the K, the higher the utilization of the system. Otherwise, less system utilization will be obtained. The throughput of the spread slotted ALOHA system employing multiuser receiver is compared with that of the traditional slotted ALOHA system employing single user receivers. It is shown that the spread slotted ALOHA system employing the multiuser receivers can achieve much higher throughput than that can be achieved by the compatible traditional slotted ALOHA system using single user receivers. Employing a virtual server model, we explain why multiuser receivers can help to improve the throughput in spread slotted ALOHA systems.