A Distributed Contention Resolution Algorithm in Multi-Packet Reception ALOHA Systems

In this paper, we propose a distributed contention resolution algorithm for multi-packet reception slotted ALOHA systems, which is based on backlog estimation. In the algorithm, a base station broadcasts a binary-valued collision indicator and the identifications of the packets successfully received, when some of packets simultaneously transmitted collide. Then, mobile terminals (MTs) estimate the expected number of MTs involved in the collision given the number of packets successfully transmitted and the collision indicator. Based on this estimation, MTs construct the backlog information and choose their retransmission probability in order to maximize the system throughput. In simulations, the proposed algorithm shows 67% throughput efficiency against the maximum achievable system throughput. The stability of the algorithm is evaluated by examining negative drift from simulation.