Robust Linear Beamformer Designs for Coordinated Multi-Point AF Relaying in Downlink Multi-Cell Networks

Kuo, Chia‐Wei; Tseng, Chun-Kai

doi:10.1109/twc.2012.072512.111764

Cited by 11 publications

(6 citation statements)

References 30 publications

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“…Based on the above assumptions, we only consider the CSIT uncertainty in the second hop. The authors in [22] also used this model for exploiting the situation when the relays are located closer to the source than to the destination, while this assumption is reasonable because of the high signal quality between the source and the relays. This model has also been widely used in the literatures such as [4], [15]- [17], [20], [23], [24].…”

Section: B Channel Uncertainty Modelmentioning

confidence: 99%

Robust Joint Source-Relay-Destination Design Under Per-Antenna Power Constraints

Tang

Chen

2015

IEEE Trans. Signal Process.

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This paper deals with joint source-relay-destination beamforming (BF) design for an amplify-and-forward (AF) relay network. Considering the channel state information (CSI) from the relay to the destination is imperfect, we first aim to maximize the worst case received SNR under per-antenna power constraints. The associated optimization problem is then solved in two steps. In the first step, by revealing the rank-one property of the optimal relay BF matrix, we establish the semi-closed form solution of the joint optimal BF design that only depends on a vector variable. Based on this result, in the second step, we propose a low-complexity iterative algorithm to obtain the remaining unknown variable. We also study the problem for minimizing the maximum per-antenna power at the relay while ensuring a received signal-to-noise ratio (SNR) target, and show that it reduces to the SNR maximization problem. Thus the same methods can be applied to solve it. The differences between our result and the existing related work are also discussed in details. In particular, we show that in the perfect CSI case, our algorithm has the same performance but with much lower cost of computational complexity than the existing method. Finally, in the simulation part, we investigate the impact of imperfect CSI on the system performance to verify our analysis.Index Terms-Amplify-and-forward, multi-antenna relay system, per-antenna power, beamforming I. INTRODUCTIONRelay communications have been studied extensively over the past decades as a means of extending the coverage of wireless network and improving the spatial diversity of the system. Transmission schemes at the relay can be categorized into several groups, i.e., the Amplify-and-Forward (AF) scheme, the Decode-and-Forward scheme [1] etc. Among them, the AF scheme is the most simple scheme, as the relay only performs linear processing on the received signal and re-transmits it to the destination. AF scheme has been efficiently used to exploit the benefit of relaying in the multiple access relay channels [2], the broadcast relay channels [3], and the two-hop relay channels [4]-[6], [11].Performing joint source-relay linear beamforming (BF) can achieve higher data rate [2], [3]. For the relay BF design, many previous works concentrate on the sum power constraints. It

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Section: B Channel Uncertainty Modelmentioning

confidence: 99%

Robust Joint Source-Relay-Destination Design Under Per-Antenna Power Constraints

Tang

Chen

2015

IEEE Trans. Signal Process.

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“…Then the CSI feedback from the destination to the relays are usually outdated, and the channel uncertainty must be considered. [22] also uses this model for exploiting the situation when the relays are located closer to the source than to the destination, while this assumption is reasonable because of the high signal quality between the source and the relays. Many existing works [11], [18], [23] assume that the CSI error is bounded in a bundle manner, i.e, △f 2 ≤ ε for some small ε > 0, where △f [△f T 1 , · · · , △f T R ] T .…”

Section: B Channel Uncertaintymentioning

confidence: 99%

Achieving Global Optimality for Joint Source and Relay Beamforming Design in Two-Hop Relay Channels

Tang

Chen

et al. 2014

IEEE Trans. Veh. Technol.

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This paper deals with joint source and relay beamforming (BF) design for an amplify-and-forward (AF) multiantenna multirelay network. Considering that the channel state information (CSI) from relays to destination is imperfect, we aim to maximize the worst case received signal-to-noise ratio (SNR). The associated optimization problem is then solved in two steps. In the first step, by fixing the source BF vector, a semi-closed form solution of the relay BF matrices is obtained, up to a power allocation factor. In the second step, the global optimal source BF vector is obtained based on the Polyblock outer Approximation (PA) algorithm. We also propose two low-complexity methods for obtaining the source BF vector, which are different in their complexities and performances. The optimal joint sourcerelay BF solution obtained by the proposed algorithms serves as the benchmark for evaluating the existing schemes and the proposed low-complexity methods. Simulation results show that the proposed robust design can significantly reduce the sensitivity of the channel uncertainty to the system performance.

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“…The impact of the traffic intensity and BS density are also investigated in [17]. Few literatures discuss CoMP relaying [18,19]. On the other hand, there have been a limited number of works in the literature on the shared relay (i.e.…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of relay‐assisted CoMP transmissions with non‐ideal transceiver

Hassan

2017

IET Communications

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Robust Linear Beamformer Designs for Coordinated Multi-Point AF Relaying in Downlink Multi-Cell Networks

Cited by 11 publications

References 30 publications

Robust Joint Source-Relay-Destination Design Under Per-Antenna Power Constraints

Robust Joint Source-Relay-Destination Design Under Per-Antenna Power Constraints

Achieving Global Optimality for Joint Source and Relay Beamforming Design in Two-Hop Relay Channels

Performance analysis of relay‐assisted CoMP transmissions with non‐ideal transceiver

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