Decentralized PHY/MAC Design for the Uplink of Multi-Packet Reception Wireless Networks

Decentralized PHY/MAC techniques for the uplink of Multi-Packet Reception (MPR) schemes are of great interest in future wireless communication systems (e.g. IEEE 802.11ax). In MPR schemes the average number of successful received packets depends on the radio propagation effects, the number of nodes simultaneously transmitting and the capture threshold that characterizes the PHY-layer MPR technology. In this paper we adopt a MPR capture model capable of describing the average number of successful packets simultaneously received. The capture model is then used in an optimal reservation-based medium access control (MAC), designed to operate in a decentralized way through a random access policy. This work describes the PHY/MAC cross-layer design, as well as the rationale required to understand its optimality. While the main objective of the proposed MAC is to achieve the optimal number of simultaneous transmissions that maximize the PHY-layer performance, a cost due to the MAC reservation period must also be considered in the optimization process. A model of the PHY/MAC performance is derived, which allows the optimization of the parameters that regulate the nodes' random access. Different simulation results are described and compared with numerical results obtained with the proposed PHY/MAC model. The paper ends up discussing possible solutions to implement the proposed methodology in practical wireless networks formed by a high number of competing nodes.