# Simultaneous Transmit and Receive Operation in Next Generation IEEE 802.11 WLANs: A MAC Protocol Design Approach

## TL;DR

This paper proposes a practical MAC protocol for enabling simultaneous transmit and receive (STR) mode in next-generation IEEE 802.11 WLANs, effectively supporting full-duplex communication while maintaining backward compatibility.

## Contribution

It introduces a protocol that enables STR mode with minimal modifications, handling coexistence of FD and HD stations and ensuring backward compatibility.

## Key findings

- Enhanced throughput in FD environments
- Effective coexistence of FD and HD stations
- Improved fairness and protocol efficiency

## Abstract

Full-duplex (FD) technology is likely to be adopted in various legacy communications standards. The IEEE 802.11ax working group has been considering a simultaneous transmit and receive (STR) mode for the next generation wireless local area networks (WLANs). Enabling STR mode (FD communication mode) in 802.11 networks creates bi-directional FD (BFD) and uni-directional FD (UFD) links. The key challenge is to integrate STR mode with minimal protocol modifications, while considering the co-existence of FD and legacy half-duplex (HD) stations (STAs) and backwards compatibility. This paper proposes a simple and practical approach to enable STR mode in 802.11 networks with co-existing FD and HD STAs. The protocol explicitly accounts for the peculiarities of FD environments and backwards compatibility. Key aspects of the proposed solution include FD capability discovery, handshake mechanism for channel access, node selection for UFD transmission, adaptive acknowledgement (ACK) timeout for STAs engaged in BFD or UFD transmission, and mitigation of contention unfairness. Performance evaluation demonstrates the effectiveness of the proposed solution in realizing the gains of FD technology for next generation WLANs.