Relay-pair selection in buffer-aided successive opportunistic relaying using a multi-antenna source

Abstract

We study a cooperative network with a buffer-aided multi-antenna source, multiple half-duplex (HD) buffer-aided relays and a single destination. Such a setup could represent a cellular downlink scenario, in which the source can be a more powerful wireless device with a buffer and multiple antennas, while a set of intermediate less powerful devices are used as relays to reach the destination. The main target is to recover the multiplexing loss of the network by having the source and a relay to simultaneously transmit their information to another relay and the destination, respectively. Successive transmissions in such a cooperative network, however, cause inter-relay interference (IRI). First, by assuming global channel state information (CSI), we show that the detrimental effect of IRI can be alleviated by precoding at the source, mitigating or even fully cancelling the interference. A cooperative relaying policy is proposed that employs a joint precoding design and relay-pair selection. Note that both fixed rate and adaptive rate transmissions can be considered. For the case when channel state information is only available at the receiver side (CSIR), we propose a relay selection policy that employs a phase alignment technique to reduce the IRI. The performance of the two proposed relay pair selection policies are evaluated and compared with other state-of-the-art relaying schemes in terms of outage and throughput. The results show that the use of a powerful source can provide considerable performance improvements.

LoLa4SOR: Leveraging Successive Transmissions for Low-Latency Buffer-Aided Opportunistic Relay Networks

“…In networks with multi-antenna nodes, Kim and Bengtsson in [30] recovered the loss of HD relaying through joint relay selection and beamforming to suppress the IRI due to successive transmissions, showing that almost ideal FD operation can be obtained. Finally, in SuR networks with a multi-antenna BA source and multiple BA single-antenna relays, it was shown that joint precoding design and relaypair selection alleviated IRI for both fixed and adaptive rate cases when channel state information (CSI) was available [31].…”

Cooperative Communications Based on Deep Learning Using a Recurrent Neural Network in Wireless Communication Networks

“…Te computational complexity and statistics of projected CSI are also examined for these predictors [30][31][32]. Unlike feed-forward neural networks, which have unidirectional input fow, RNNs include recurrent self-connections that allow them to memories previous data and show a signifcant promise in timeseries prediction [33]. Te previous time step's activation is transmitted back as part of the current step's input.…”

“…How about we utilize the l th stowed away layer as an illustration to reveal insights into how an initiation signal goes through the organization? Tere are two secret states-the present moment S (l) t−1 and the long-term state C (l) t−1 ; the input d (l) t and S (l) t−1 the activation vectors for the gates are generated by combining the activation vectors of four fully connected (FC) layers [29,33].…”

Interference Management in 5G and Beyond Network: Requirements, Challenges and Future Directions

“…Like it is presumed that the current 5G wireless communication network is disastrously affected by the interferences. Thus, in [133] authors, demonstrated IRI due to successive transmission of source and relay to another relay and destination links in a network. To fulfill the requirement, two-relay pair selection relies on available CSI in a network that is equipped with a cluster of HD buffer-aided relays, buffer-aided multi-antenna source, and a destination.…”