Performance of Hybrid ARQ for NDMA Access Schemes With Uniform Average Power Control
Traditionally, a packet with errors, either due to channel noise or collisions is discarded and needs to be retransmitted, leading to performance losses. Network Diversity Multiple Access (NDMA) handles collisions by combining a multipacket detection scheme with time diversity. In NDMA, the Base Station (BS) forces mobile terminals (MTs) to transmit P copies of each packet when P MTs collide. Diversity combining is limited to P copies of the packets, not allowing it to adapt to severe errors due to channel noise. This paper considers a multipacket detection scheme recently proposed, which reduces the Packet Error Rate (PER) when more than P packet copies are available.