Can full-duplex more than double the capacity of wireless networks?

Abstract

Usually, wireless radios are half-duplex, i.e. they can not transmit and receive at the same time over the same frequency band. However, building on self-interference cancellation techniques, full-duplex radios have emerged as a viable paradigm over the recent years. In this paper, we ask the following question: how much can full-duplex increase the capacity of wireless networks? Intuitively, one may expect that full-duplex radios can at most double the capacity of wireless networks, since they enable nodes to transmit and receive at the same time. In this paper, we show that the capacity gain can indeed be larger than a factor of 2; in particular, we construct a specific instance of a wireless relay network where the capacity with full-duplex radios is triple the capacity of the network when the relays are half-duplex. We also propose a universal schedule for half-duplex networks composed of independent, memoryless, point-to-point channels which achieves at least a fraction of 1/4 of the corresponding full-duplex capacity. This means that for wireless networks composed of point-to-point channels full-duplex capability at the relays cannot more than quadruple the capacity of network.