Performance Analysis of an Hybrid ARQ Adaptation of NDMA Schemes
Rui Ganhão, Miguel Pereira, Luís Bernardo, Rui Dinis, Rodolfo Oliveira, Paulo Pinto · IEEE Transactions on Communications · 2013
Traditionally, an unsuccessful packet reception, either due to channel conditions or interference from multiple sources (collisions), is discarded and followed by a new reception of the same packet. Network diversity multiple access (NDMA) handles collisions by using time diversity multipacket reception: the base station forces terminals to transmit P copies of each packet when P terminals collide. This rigidity of having P copies is unsuitable for poor propagation conditions. It might be desirable to have more than P copies of a given packet, adopting a technique for single packet reception called hybrid-ARQ. Hybrid-ARQ effectively decreases the packet error rate. This paper proposes such mechanism for multi-packet reception, called hybrid-ARQ NDMA (H-NDMA), a gated slotted random access protocol, where the access mechanism forces the terminals involved in a collision with reception errors to transmit more than P times. Analytical models for the throughput, delay and energy per useful packet are proposed. The energy performance is analyzed for bounded average delay constraints. The proposed system's performance is evaluated for a single-carrier with frequency domain equalization (SC-FDE) scheme, and compared with the classical NDMA protocol. The comparison highlights that H- NDMA is scalable for an increasing number of terminals and network load.