System-Level Performance of In-Band Full-Duplex Relaying on M2M Systems at 920 MHz

Relays can be used to improve the coverage in blind spots as well as increase the signal strength at locations where the signal from the access point undergoes fading. In-band full-duplex relaying is a promising technique which improves the spectral efficiency over traditional half-duplex relaying by relaying at the same time slot and frequency. Relays are expected to play a major role in IEEE 802.11ah systems for below 1 GHz WLAN in order to cover a large area of 1 km around the access point. In this contribution, the impact of deploying in-band full- duplex relays is studied over traditional half- duplex relays in improving the coverage and throughput at the stations for M2M applications. System-level realistic evaluation of in-band full- duplex relaying is performed using the COST-2100 channel model to model the propagation and self- interference channels at 920 MHz. The channel is combined with realistic antenna design to determine the end-to-end throughput at the location of each station in a 1 sq.km area. For the downlink scenario, it is shown that such in-band full-duplex relays can increase the number of users for a given throughput over half-duplex relays. Also, a single in-band full-duplex relay can decrease the outage by 0.9% compared to half-duplex relays and 12.6% without a relay to cover 97.8% of the stations in a 1 sq.km area with downlink throughput of 100 kbps.