Analyzing the potential of full duplex in 5G ultra-dense small cell networks

Abstract

Full-duplex technology has become an attractive solution for future 5th generation (5G) systems for accommodating the exponentially growing mobile traffic demand. Full duplex allows a node to transmit and receive simultaneously in the same frequency band, thus, theoretically, doubling the system throughput over conventional half-duplex systems. A key limitation in building a feasible full-duplex node is the self-interference, i.e., the interference generated by the transmitted signal to the desired signal received on the same node. This constraint has been overcome given the recent advances in the self-interference cancellation technology. However, there are other limitations in achieving the theoretical full-duplex gain: residual self-interference, traffic constraints, and inter-cell and intra-cell interference. The contribution of this article is twofold. Firstly, achievable levels of self-interference cancellation are demonstrated using our own developed test bed. Secondly, a detailed evaluation of full-duplex communication in 5G ultra-dense small cell networks via system level simulations is provided. The results are presented in terms of throughput and delay. Two types of full duplex are studied: when both the station and the user equipments are full duplex capable and when only the base station is able to exploit simultaneous transmission and reception. The impact of the traffic profile and the inter-cell and intra-cell interferences is addressed, individually and jointly. Results show that the increased interference that simultaneous transmission and reception causes is one of the main limiting factors in achieving the promised full-duplex throughput gain, while large traffic asymmetries between downlink and uplink further compromise such gain.

Achievable rates for full-duplex massive MIMO systems with low-resolution ADCs/DACs under imperfect CSI environment

“…υ = 3.8 is the path loss exponent. The large-scale channel fading can be modeled as β n = a n (r n /r min ) −υ , [19][20][21]. In this simulation, we assume that the number of users is N = 10, the variances of the noise are σ D = σ U = 1, and the residual LI power is ρ=β LI = 0dB, P U = 10 dB and P D = NP U .…”

Cancelation of LNA distortions in in‐band full‐duplex systems

“…cir1 cir 2 FIGURE 2 A full-duplex system capable to reduce the nonlinear distortion (NLD) of the receiver low-noise amplifier (LNA). The circuit cir1 (green color) stands for the estimation of the NLD coefficients using a wire in order to avoid the effect of the wireless channel, in this case, the switches are on position (2). When the switches are on the first position (1), the transceiver works in ordinary conditions, and the circuit cir2 (pink color) helps in reducing the NLD before estimating the channel.…”

“…In‐band full‐duplex (FD) communication may double the spectrum efficiency. Thus, it has been proposed as a key solution for the coming standard of fifth generation, where an enormous demand on the wireless spectrum is expected . FD transmission is not a new idea in the field of telecommunication, but several problems such as receiver imperfections and channel estimation have limited its application.…”

“…Thus, it has been proposed as a key solution for the coming standard of fifth generation, where an enormous demand on the wireless spectrum is expected. [1][2][3] FD transmission is not a new idea in the field of telecommunication, but several problems such as receiver imperfections and channel estimation have limited its application. The recent advances in both self-interference cancelation (SIC) and hardware imperfection mitigation techniques make the attenuation of the residual self-interference (RSI) to the noise floor feasible, which is the main challenge of SIC techniques in a FD transceiver.…”

On the ergodic secrecy capacity with full duplex communication

“…In that respect, it has the potential of becoming a key technology component in addressing the challenging design targets of the 5th Generation (5G) wireless system [1]. The potential of full duplex (FD) communication in providing a throughput (TP) gain [1], [2], and/or improving the transmission latency [3], [4] is well studied.…”