Distributed Full-Duplex via Wireless Side-Channels: Bounds and Protocols

Abstract

Abstract-In this paper, we study a three-node full-duplex network, where a base station is engaged in simultaneous upand downlink communication in the same frequency band with two half-duplex mobile nodes. To reduce the impact of internode interference between the two mobile nodes on the system capacity, we study how an orthogonal side-channel between the two mobile nodes can be leveraged to achieve full-duplex-like multiplexing gains. We propose and characterize the achievable rates of four distributed full-duplex schemes, labeled bin-andcancel, compress-and-cancel, estimate-and-cancel and decodeand-cancel. Of the four, bin-and-cancel is shown to achieve within 1 bit/s/Hz of the capacity region for all values of channel parameters. In contrast, the other three schemes achieve the near-optimal performance only in certain regimes of channel values. Asymptotic multiplexing gains of all proposed schemes are derived to show that the side-channel is extremely effective in regimes where inter-node interference has the highest impact.

Downlink Error Rates of Half-Duplex Users in Full-Duplex Networks Over a Laplacian Inter-User Interference Limited and EGK Fading

“…This section characterizes the downlink decoding errors that may occur due to the Laplacian inter-user interference with the PDF shown in (6). In particular, we evaluate the probability of BPSK, PAM, QAM, and MPSK.…”

“…Following similar methodology to [35], the decision regions are obtained by defining the two coordinates rotations (X 1 , Y 1 ), with rotation angle φ−θ, and (X 2 , Y 2 ), with rotation angle φ + θ, where φ is the symbol phase and θ = π M . The circular symmetry of the interference PDF in (6) implies that all symbols have similar error probability. Hence, the total error probability can be deduced by considering a generic single symbol, with angle ϕ lies between 0 and π 2 , and the error probability can be explicitly expressed in terms of Y 1 and Y 2 as…”

“…The aforementioned benefits brought by FD communication are all derived from its ability to simultaneously transmit and receive within the same frequency band. The ability of simultaneous transmission and reception for FD transceivers emerges from recent advances in radio frequency circuit design that enables sufficient self-interference (SI) cancellation [2], [3], and hence, eliminates the necessity for transmission/reception orthogonalization employed by HD transceivers [1], [4]- [6]. To reap the aforementioned benefits of FD communication, FD enabled transceivers are required at both sides of the Cellular networks operators can only enforce FD upgrade in their networks from the base stations' (BS) side and do not have direct access to upgrade the users equipment (UE) side.…”

“…This is because the BW improvement, offered by the 3NT, comes at the expense of creating SI at the BS side and inter-user interference at the UE side, which impose decoding errors. The BS exactly knows the interfering codeword and can accurately estimate the SI channel, and hence, SI can be sufficiently suppressed using SI cancellation techniques [1], [4]- [6]. However, the UE does not have information about the signal being transmitted by the interfering UE, and hence, interference cancellation is not always viable.…”

Vector bin-and-cancel for MIMO distributed full-duplex

“…The conventional use of D2D involves establishing peer-to-peer communication [2], forming virtual MIMO by cooperative communication [3] or offloading cellular traffic [4]. In contrast, we propose to use the D2D side channel for interference management to improve the cellular capacity, *Correspondence: jingwen.bai@intel.com Department of Electrical and Computer Engineering, Rice University, Houston, USA a scenario which we labeled as ISM-in-cellular communication [5][6][7].…”