A downlink adaptive distributed precoding scheme is proposed for coordinated multi-point (CoMP) transmission systems. The serving base station (BS) obtains the optimal precoding vector via user feedback. Meanwhile, th...
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A downlink adaptive distributed precoding scheme is proposed for coordinated multi-point (CoMP) transmission systems. The serving base station (BS) obtains the optimal precoding vector via user feedback. Meanwhile, the precoding vector of each coordinated BS is determined by adaptive gradient iteration according to the perturbation vector and the adjustment factor based on the vector perturbation method. In each transmission frame, the CoMP user feeds the precoding matrix index back to the serving BS, and feeds back the adjustment factor index to the coordinated BSs, which can reduce the uplink feedback overhead. The selected adjustment factor for each coordinated BS is obtained via the precoding vector of the coordinated BS used in the previous frame and the preferred precoding vector of the serving BS in this frame. The proposed scheme takes advantage of the spatial non-correlation and temporal correlation of the distributed MIMO channel. The design of the adjustment factor set is given and the channel feedback delay is considered. The system performance of the proposed scheme is verified with and without feedback delay respectively and the system feedback overhead is analyzed. Simulation results show that the proposed scheme has a good trade-off between system performance and the system control information overhead on feedback.
An adaptive distributed precoding scheme is proposed for coordinated multi-point transmission systems. The precoding vector used by coordinated base station (BS) is determined by adaptive gradient iteration according ...
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ISBN:
(纸本)9781424483273
An adaptive distributed precoding scheme is proposed for coordinated multi-point transmission systems. The precoding vector used by coordinated base station (BS) is determined by adaptive gradient iteration according to the perturbation vector and adjustment factor. The user equipment only feeds one quantized adjustment factor back to each coordinated BS. The adjustment factor is selected based on the precoding vector of the coordinated BS in the previous frame and the perturbation vector predefined in this frame. The proposed scheme takes advantage of the spatial non-correlation and temporal correlation of the distributed MIMO channel. The design of the perturbation vector set is given. Simulation results show that the proposed scheme has a good trade-off between system performance and the system control feedback overhead.
Coordinated multi-point transmission/reception (CoMP),in which base stations cooperation during the downlink,has been considered as a attractive way of achieving higher performance and mitigating interference,especial...
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Coordinated multi-point transmission/reception (CoMP),in which base stations cooperation during the downlink,has been considered as a attractive way of achieving higher performance and mitigating interference,especially for terminals at cell *** this paper,distributed precoding for multicell-MISO downlink CoMP is *** previous work in the area is on the assumption that base stations have knowledge of both data symbols and full channel state information (CSI),which leads to heavy exchange of channel state information and signal information over backhaul *** this paper,several distributed precoding strategies (distributed MRT,distributed ZF,distributed LVSINR and DVSINR) for multicell-MISO downlink CoMP are analyzed,which supposes that each base station only has local CSI and the precoders can be devised at each BS in a distributed manner,and Monte Carlo simulations demonstrate the performance of such strategies.
aim at the problem of the adjacent cell interference in LTE (long Term Evolution) system, a distributed pre-coding technology based on singular Value Decomposition (SVD) was presented, which need not to exchange u...
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aim at the problem of the adjacent cell interference in LTE (long Term Evolution) system, a distributed pre-coding technology based on singular Value Decomposition (SVD) was presented, which need not to exchange user date between the cooperation base station, just need to know the channel state information (CSI) from the baste station to all users (include expected users and adjacent cell users). According to the CSI, The base station can get the pre-coding matrix based on EVO and implementing distributed precoding. Simulation results show that the presented distributed pre-coding method can reduce the inter cell interference and increase the spectral efficiency of users at the cell edge. At the same time, the computational complexity of the presented algorithm is lower than the BD-GMD algorithm and its error bit performance can improve 8dB relative to BD-GMD algorithm when date stream number is 1.
We investigate distributed multiple-input multiple-output (MIMO) precoding schemes for coping with the intercell interference in a multicell environment. In particular, we introduce the effective channel matrix for tw...
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We investigate distributed multiple-input multiple-output (MIMO) precoding schemes for coping with the intercell interference in a multicell environment. In particular, we introduce the effective channel matrix for two different precoding strategies, referred to as received interference-aware precoding (RIAP) and generated interference-aware precoding (GIAP). Then, we propose a hybrid precoding scheme and a switching scheme. Simulation results are provided to compare the performance in a multicell environment.
Vectoring based on Tomlinson-Harashima precoding (THP) has been proposed for downstream FEXT cancellation in G. fast DSL system. However, it suffers from the lack of scalability and latency accumulation due to nonline...
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ISBN:
(纸本)9781509034239
Vectoring based on Tomlinson-Harashima precoding (THP) has been proposed for downstream FEXT cancellation in G. fast DSL system. However, it suffers from the lack of scalability and latency accumulation due to nonlinear THP, especially for a large number of ports. In this paper, we propose a novel precoding technique based on a single DSL Access Multiplexer (DSLAM) that hosts multiple Vector Processors (VPs) to achieve parallel and scalable THP structure. Inter-VP signaling enables FEXT mitigation among the twisted pairs within the same vectored group (in-domain (ID) self-FEXT) as well as the FEXT among the different vectored groups (out-of-domain (OD) FEXT). In the proposed multi-VP FEXT mitigation technique, OD FEXT is minimized by linear processing based on Block Diagonalization, while conventional THP is used in parallel at each VP for ID self-FEXT cancellation. Numerical simulations using two different measured cables show that the proposed multi-VP THP attains the performance of the centralized THP, even for the practical near-far scenario.
This paper considers a two-cell multiple-input single-output (MISO) interference channel, where the Pareto boundary of the achievable rate region is computed through linear beamforming design. A distributed beamformin...
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ISBN:
(纸本)9781479941469
This paper considers a two-cell multiple-input single-output (MISO) interference channel, where the Pareto boundary of the achievable rate region is computed through linear beamforming design. A distributed beamforming strategy is provided by solving the signal-to-leakage-plus-noise (SLNR) maximization problem with per base station (BS) power constraints. After some conversion, a single real-valued parameter per BS is derived to achieve all points on the Pareto boundary with local channel state information (CSI), where the points on the Pareto boundary corresponds to beamforming vectors that are linear combinations of the zero forcing (ZF) and maximum-ratio transmission (MRT) beamformers. The proposed algorithm can be extended to multi-cell MISO interference channels. Simulation results demonstrate that the proposed distributed algorithm is Pareto optimal and has lower computational complexity than the iterative algorithms.
Base station cooperation is an attractive way of increasing the spectral efficiency in multiantenna communication. By serving each terminal through several base stations in a given area, intercell interference can be ...
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Base station cooperation is an attractive way of increasing the spectral efficiency in multiantenna communication. By serving each terminal through several base stations in a given area, intercell interference can be coordinated and higher performance achieved, especially for terminals at cell edges. Most previous work in the area has assumed that base stations have common knowledge of both data dedicated to all terminals and full or partial channel state information (CSI) of all links. Herein, we analyze the case of distributed cooperation where each base station has only local CSI, either instantaneous or statistical. In the case of instantaneous CSI, the beamforming vectors that can attain the outer boundary of the achievable rate region are characterized for an arbitrary number of multiantenna transmitters and single-antenna receivers. This characterization only requires local CSI and justifies distributed precoding design based on a novel virtual signal-to-interference noise ratio (SINR) framework, which can handle an arbitrary SNR and achieves the optimal multiplexing gain. The local power allocation between terminals is solved heuristically. Conceptually, analogous results for the achievable rate region characterization and precoding design are derived in the case of local statistical CSI. The benefits of distributed cooperative transmission are illustrated numerically, and it is shown that most of the performance with centralized cooperation can be obtained using only local CSI.
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