Distributed spectral efficiency maximization in full-duplex cellular networks

Abstract

Abstract-Three-node full-duplex is a promising new transmission mode between a full-duplex capable wireless node and two other wireless nodes that use half-duplex transmission and reception respectively. Although three-node full-duplex transmissions can increase the spectral efficiency without requiring fullduplex capability of user devices, inter-node interference -in addition to the inherent self-interference -can severely degrade the performance. Therefore, as methods that provide effective self-interference mitigation evolve, the management of internode interference is becoming increasingly important. This paper considers a cellular system in which a full-duplex capable base station serves a set of half-duplex capable users. As the spectral efficiencies achieved by the uplink and downlink transmissions are inherently intertwined, the objective is to device channel assignment and power control algorithms that maximize the weighted sum of the uplink-downlink transmissions. To this end a distributed auction based channel assignment algorithm is proposed, in which the scheduled uplink users and the base station jointly determine the set of downlink users for fullduplex transmission. Realistic system simulations indicate that the spectral efficiency can be up to 89 % better than using the traditional half-duplex mode. Furthermore, when the selfinterference cancelling level is high, the impact of the user-to-user interference is severe unless properly managed.

On the spectral efficiency and fairness in full-duplex cellular networks

“…The in-band FD transmission mode can almost double the spectral efficiency of conventional HD wireless transmission modes, especially in the low transmit power domain [1], [2]. However, due to the increasing demand for supporting the transmission of large data quantities in scarce spectrum scenarios [1], [3], and thanks to the continued advances in self-interference (SI) cancellation technologies, FD is being considered as a technology component beyond small cell and short range communications [4], [5].…”

“…Another important objective is to improve the fairness and per-user quality of service (QoS) of FD cellular networks, as emphasized in [1], [2], [8], [9]. In our previous work, we proposed a weighted sum spectral efficiency maximization, where the weights represent path-loss compensation and are thus related to the rate distribution and fairness in the system [2].…”

“…In our previous work, we proposed a weighted sum spectral efficiency maximization, where the weights represent path-loss compensation and are thus related to the rate distribution and fairness in the system [2]. The results showed that FD cellular networks can outperform current HD mode if appropriate SI cancellation and pairing schemes are employed.…”

“…Therefore, in this work we aim to fill this research gap by proposing a multi-objective optimization problem to maximize simultaneously both the weighted sum spectral efficiency and the minimum spectral efficiency of all users. Such an optimization problem poses technical challenges that are markedly different from those investigated in our previous works [2], [9]. In particular, we develop an original and new solution approach based on the use of the scalarization technique to convert the multi-objective into a single-objective mixed integer nonlinear programming (MINLP) problem that considers jointly user pairing and UL/DL power control.…”

“…This centralized solution is tested in a realistic system simulator that indicates that the solution is near-optimal, and increases the sum spectral efficiency and fairness among the users. An important feature of the proposed solution is that there is no need to consider weights in the sum spectral efficiency as done in previous works from the literature [2]. This is advantageous, because defining the weights in a weighted sum objective function is typically cumbersome and difficult in practice.…”