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Asynchronous Bidirectional Communication in Cell-Free Networks

delete2024-01-01
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OA
AI
Z
Zahra Pourgharehkhan
S
Shahram Shahbazpanahi *
M
Majid Bavand
G
Gary Boudreau
DOI:10.1109/TWC.2023.3277821delete
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Abstract

Abstract

En 中文
We consider a bidirectional communication between two single-antenna transceivers using multiple multi-antenna access points (APs) in a cell-free network architecture. In such a network, because of different propagation delays associated with different APs, the end-to-end link is a multi-path channel that results in inter-symbol-interference (ISI) in the signals received at the transceivers. To tackle ISI, we resort to cyclic prefix (CP) assisted block transmission of the information symbols and employ joint pre- and post-channel equalizers at both the transceivers to mitigate the impact of intra-block interference. Considering the amplify-and-forward technique at the APs, we cast the joint design of equalizers, beamforming matrices, and transceivers' transmit powers as a power minimization problem while guaranteeing predefined data rates at the transceivers. Assuming symmetric beamforming matrices at the APs, we devise a semi-closed-form solution for this problem. We prove rigorously that at the optimum only a synchronous subset of the APs should participate in the information exchange between the two transceivers. This is achieved by proving that at the optimum, the pre-equalizer matrices should be unitary and the post-equalizer matrices should be invertible.
Keywords:
Cell-free
massive MIMO (mMIMO)
distributed MIMO
resource allocation
two-way relaying
distributed beamforming
asynchronous relaying

Journal

IEEE Transactions on Wireless Communications cover
IEEE Transactions on Wireless Communications
IF:
10.7
Papers:
1.3W
Citations:
5.3W

Organization

E
Ericsson
Scholars:
1.1K
Papers: 1.0K
Citations: 0