Non-regenerative multi-way relaying: Combining the gains of network coding and joint processing

Abstract

Abstract-In this paper, we consider a non-regenerative multigroup multi-way relaying scenario in which each group consists of multiple half-duplex nodes. Each node wants to share its data with all other nodes within its group. The transmissions are performed via an intermediate non-regenerative half-duplex multi-antenna relay station, termed RS, which spatially separates the different groups. In our proposal, all nodes simultaneously transmit to RS during a common multiple access phase and RS retransmits linearly processed versions of the received signals back to the nodes during multiple broadcast (BC) phases. We propose a novel transmit strategy which exploits analog network coding (ANC) and efficiently combines spatial transceive processing at RS with joint receive processing at each node over multiple BC phases. A closed-form solution for an ANC aware relay transceive filter is introduced and closed-form solutions for the joint receive processing filters at the nodes are presented. Furthermore, self-interference cancellation and successive interference cancellation are exploited at the nodes to improve the joint receive processing. By numerical results, it is shown that the proposed transmit strategy significantly outperforms existing multi-way strategies.Index Terms-Multi-way relaying, non-regenerative relay, analog network coding (ANC), minimum mean-squared error (MMSE).

A resource requirement aware transmit strategy for non-regenerative multi-way relaying

“…Perfect channel state information (CSI) is assumed at the RS and at the nodes. The required CSI can be obtained through channel training and estimation [11]. It is assumed that the nodes know the overall channel coefficients and can perform selfinterference cancellation as well as SIC.…”

“…Recent work on non-regenerative multi-way relaying has focused on designing transceive filters at the relay station to handle the interferences and to increase the sum rate [8]- [11]. In [8], [9], low complexity transceive filters at the relay station, such as zero forcing (ZF) and minimum mean squared error (MMSE) are presented.…”

“…Pseudo random precoding at the relay station with an MMSE receiver with successive interference cancellation (SIC) at the nodes is introduced in [10]. Moreover, in [11], the sum rate is increased by efficiently combining spatial transceive processing at the relay station with joint receive processing at the nodes. However, when the number of antennas at the relay station is smaller than the number of nodes, the sum rate of these approaches is interference limited.…”

“…In Section IV, the transceiver filter at the relay station and the receive filters at the nodes are described. The filters are based on the work of [11] but modified for the proposed transmit strategy. Numerical performance results of the proposed transmit strategy are presented in Section V and Section VI concludes the paper.…”

Distributed User Scheduling for MIMO-Y Channel

“…The capacity and degrees-of-freedom of multi-way relay channel have been partially studied by [2]- [4] assuming specific system configurations and traffic patterns. The more general multi-group multi-way relay scenario is considered in [5] with a novel and efficient joint spatial and temporal signal processing. Currently, two basic representatives of the multi-way relay channel have been focused.…”