Distributed Peer-to-Peer Multiplexing using Ad Hoc Relay Networks

Abstract

We consider an ad hoc network consisting of d source-destination pairs and R relaying nodes. Each source wishes to transmit its data to its corresponding destination through the relay network. Each relay in the network transmits a properly scaled version of its received signal thereby cooperating with other relays to deliver each source's data to the corresponding destination. Assuming a minimal cooperation among the relaying nodes, we design a distributed beamformer such that the total relay transmit power dissipated by all relays is minimized while, at the same time, the quality of services at all destinations are guaranteed to be above certain pre-defined thresholds. We show that using a semi-definite relaxation approach, the power minimization problem can be turned into a semi-definite programming (SDP) optimization, and therefore, it can be solved efficiently using interior point methods. Our results show that the distributed relay multiplexing is possible and may be beneficial depending on the channel conditions. Index Terms-Distributed beamforming, relay networks, semidefinite programming, convex feasibility problem, distributed signal processing.

Filter-and-forward distributed beamforming for relay networks in frequency selective fading channels

“…Similar to [14] and [16]- [18], it is assumed that there is no direct link between the transmitter and destination nodes and that the network is perfectly synchronized. Each transmission is assumed to consist of two stages.…”

“…1 In the latter case, no extra receiver-to-relay feedback is needed. Note that quite similar assumptions have been used in [14]- [18] in the frequency flat fading case.…”

“…Similar to the techniques of [14]- [18], the receiver is assumed to use a perfect source-to-relay and relay-to-destination CSI to compute the relay weight coefficients and feed them back to the relay nodes using a low-rate receiver-to-relays feedback link. Alternatively, the relays can directly compute their weight coefficients, provided that the CSI is available at the relay nodes.…”

Optimal network beamforming for bi-directional relay networks

“…Recently, decentralized beamforming techniques have been presented for relaying schemes where the relays re-transmit an amplitude-and phase-adjusted version of their received signals [3][4][5][6]. Also, the problem of joint uplink-downlink beamforming has been studied for a single-relay network where the relay is equipped with multiple antennas [7].…”

On Robust MMSE-Based Filter Designs for Multi-User Peer-to-Peer Amplify-and-Forward Relay Systems

“…그러나 최근 무선 ad-hoc 네트워크 시스템 응용 분야의 발전과 더불어 multi-user peer-to-peer 무선 릴레이 네트워크에 대한 연구가 증가하고 있다 [4][5][6][7][8][9][10][11][12][13] . 이러한 multi-user peer-to-peer 무선 릴레이 네트워크에 대해, quality-of-service (QoS) 제약 조건하에서 전송 전력을 최소화하는 릴레이 설계 방법이 multiple 릴레이 모 델을 기준으로 연구되었다 [4][5][6] . 그러나 multiple independent 릴레이 보다는 하나의 다중 안테나 릴레 이나 유선으로 연결된 multiple 릴레이가 릴레이간 동기나 채널 정보 교환 면에서 효율적이다 [7] .…”