Pushing the limits of Full-duplex: Design and Real-time Implementation

TLDR

Full‑duplex wireless can transmit and receive simultaneously on a single channel, as recent work has demonstrated. The study designs a real‑time 64‑subcarrier 10 MHz full‑duplex OFDM PHY (FD‑PHY) and proposes a full‑duplex MAC protocol (FD‑MAC) extending IEEE 802.11. FD‑PHY implements synchronous and selective asynchronous full‑duplex OFDM over 64 subcarriers at 10 MHz, while FD‑MAC introduces shared random backoff, header snooping, and virtual backoffs to detect and exploit full‑duplex opportunities in a distributed manner. Over‑the‑air tests achieved 80 dB self‑interference suppression—10 dB better than prior work—and more than 70 % throughput gains compared to half‑duplex.

Abstract

Recent work has shown the feasibility of single-channel full-duplex wireless physical layer, allowing nodes to send and receive in the same frequency band at the same time. In this report, we first design and implement a real-time 64-subcarrier 10 MHz full-duplex OFDM physical layer, FD-PHY. The proposed FD-PHY not only allows synchronous full-duplex transmissions but also selective asynchronous full-duplex modes. Further, we show that in over-the-air experiments using optimal antenna placement on actual devices, the self-interference can be suppressed upto 80dB, which is 10dB more than prior reported results. Then we propose a full-duplex MAC protocol, FD-MAC, which builds on IEEE 802.11 with three new mechanisms -- shared random backoff, header snooping and virtual backoffs. The new mechanisms allow FD-MAC to discover and exploit full-duplex opportunities in a distributed manner. Our over-the-air tests show over 70% throughput gains from using full-duplex over half-duplex in realistically used cases.