3,276 research outputs found
Nonregenerative MIMO Relaying with Optimal Transmit Antenna Selection
We derive optimal SNR-based transmit antenna selection rules at the source
and relay for the nonregenerative half duplex MIMO relay channel. While antenna
selection is a suboptimal form of beamforming, it has the advantage that the
optimization is tractable and can be implemented with only a few bits of
feedback from the destination to the source and relay. We compare the bit error
rate of optimal antenna selection at both the source and relay to other
proposed beamforming techniques and propose methods for performing the
necessary limited feedback
Adaptive Bit Partitioning for Multicell Intercell Interference Nulling with Delayed Limited Feedback
Base station cooperation can exploit knowledge of the users' channel state
information (CSI) at the transmitters to manage co-channel interference. Users
have to feedback CSI of the desired and interfering channels using
finite-bandwidth backhaul links. Existing codebook designs for single-cell
limited feedback can be used for multicell cooperation by partitioning the
available feedback resources between the multiple channels. In this paper, a
new feedback-bit allocation strategy is proposed, as a function of the delays
in the communication links and received signal strengths in the downlink.
Channel temporal correlation is modeled as a function of delay using the
Gauss-Markov model. Closed-form expressions for bit partitions are derived to
allocate more bits to quantize the stronger channels with smaller delays and
fewer bits to weaker channels with larger delays, assuming random vector
quantization. Cellular network simulations are used to show that the proposed
algorithm yields higher sum-rates than an equal-bit allocation technique.Comment: Submitted to IEEE Transactions on Signal Processing, July 201
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