Coordinating Interfering Transmissions in Cooperative Wireless LANs

TL;DR

This paper introduces a cooperative MAC protocol for wireless LANs that leverages physical layer decoding of interfering transmissions, enabling simultaneous unicast transmissions to improve throughput and delay.

Contribution

It proposes a novel protocol that allows independent unicast transmissions to interfere constructively, with a dynamic relay selection mechanism for optimal performance.

Findings

Enhanced throughput demonstrated in simulations

Reduced delay compared to traditional methods

Effective interference management in cooperative WLANs

Abstract

In this paper we present a cooperative medium access control (MAC) protocol that is designed for a physical layer that can decode interfering transmissions in distributed wireless networks. The proposed protocol pro-actively enforces two independent packet transmissions to interfere in a controlled and cooperative manner. The protocol ensures that when a node desires to transmit a unicast packet, regardless of the destination, it coordinates with minimal overhead with relay nodes in order to concurrently transmit over the wireless channel with a third node. The relay is responsible for allowing packets from the two selected nodes to interfere only when the desired packets can be decoded at the appropriate destinations and increase the sum-rate of the cooperative transmission. In case this is not feasible, classic cooperative or direct transmission is adopted. To enable distributed, uncoordinated, and adaptive operation of the protocol, a relay selection mechanism is introduced so that the optimal relay is selected dynamically and depending on the channel conditions. The most important advantage of the protocol is that interfering transmissions can originate from completely independent unicast transmissions from two senders. We present simulation results that validate the efficacy of our proposed scheme in terms of throughput and delay.