Full-duplex communications for wireless links with asymmetric capacity requirements

Abstract

Asymmetric capacity requirements between the uplink and down-link channels are common in many communication standards and are usually satisfied by using time-division or frequency-division duplexing with asymmetric resource allocation. In-band full-duplex communication can reduce the overhead associated with the aforementioned duplexing methods, but, unfortunately, practical full-duplex systems suffer from residual self-interference. However, in asymmetric links the impact of residual self-interference can be partially mitigated by reducing the transmit powers with the goal of maximising the down-link capacity. Compared to time-division half-duplex systems, it is found that power-adjusted full-duplex operation can improve the down-link capacity of an asymmetric IEEE 802.11 system by 20% at a link distance of 10 m, even with pessimistic assumptions on the achievable amount of self-interference suppression. For highly asymmetric traffic, the operation range where a full-duplex system outperforms a corresponding time-division half-duplex system can extend up to 2 km, covering a typical urban LTE macro-cell.