Description: In a multiple transmit antenna, single antenna per receiver downlink channel with limited channel state feedback, we consider the following question: given a constraint on the total system-wide feedback load, is it referable to get low-rate/coarse channel feedback from a large number of receivers or high-rate/high-quality feedback from a smaller number of receivers? Acquiring feedback from many receivers allows multi-user diversity to be exploited, while high-rate feedback allows
for very precise selection of beamforming directions. We show that there is a strong preference for obtaining high-quality feedback, and that obtaining near-perfect channel information from as many receivers as possible provides a significantly larger sum rate than collecting a few feedback bits from a large number of users. Platform: |
Size: 2106368 |
Author:xinpha |
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Description: We present a user-scheduling scheme for multiuser multiple-input–multiple-output (MIMO) systems with random unitary beamforming (RUB) in this paper. The new scheme, which is termed as adaptive beam activation based on the conditional best beam index feedback (ABA-CBBI), requires low average feedback load by imposing a feedback threshold on the users’ signal-to-interference-plus-noise ratio (SINR) and suffers less multiuser interference by only activating those beams requested by at least one user. Platform: |
Size: 12401664 |
Author:diwakar pandey |
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Description: 采用多天线的认知无线电系统相对于单天线认知无线电系统，既有传统的资源（频域，时域，码域），又有空域资源。本文研究基于博弈论的有限反馈认知MIMO系统的资源分配，涉及发射功率、空域（采用波束成形）和反馈速率等资源的分配。利用有限的反馈信道反馈量化的信道状态信息(CSI)，基于量化CSI，本文主要研究联合功率分配与波束成形优化、次用户（认知用户或非授权用户）反馈速率控制、联合功率分配与反馈速率控制等相关资源分配问题。-Multi-antenna cognitive radio system with respect to a single antenna cognitive radio systems, both traditional resource (frequency domain, time domain, code domain), there airspace resources. In this paper, a limited resource allocation game theory of cognitive MIMO system based on feedback, involving the launch distribution power, airspace (using beam-forming) and feedback rate and other resources. With limited feedback channel feedback quantized channel state information (CSI), based on quantified CSI, this paper studies the joint power allocation and beamforming optimization, secondary users (cognitive user or unauthorized user) feedback rate control, joint power allocation and feedback rate control and other issues related to resource allocation. Platform: |
Size: 52224 |
Author:sunjing |
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Description: CSI feedback allows downlink transmission
to be adaptively optimized based on the
instantaneous DL channel, so that closedloop
beamforming and adaptive link adaptation
can be enabled to optimize the system
performance. The DL reference signal used
for CSI measurement is different in Rel-8
and Rel-10. In Rel-8, CSI measurement is
based on CRS, which is also used for data
demodulation. In contrast, CSI measurement
in Rel-10 is based on a set of newly introduced
CSI-RS signals, which is low-dutycycle
and low-density, and allows a higher
reuse factor than Rel-8 CRS. Platform: |
Size: 161792 |
Author:nebiyu |
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Search - beamforming feedback