Adaptive Bit Partitioning for Multicell Intercell Interference Nulling with Delayed Limited Feedback

TL;DR

This paper proposes an adaptive feedback-bit allocation strategy for multicell cooperation in wireless networks, optimizing interference nulling by considering delays and channel strengths to improve sum-rate performance.

Contribution

It introduces a novel bit partitioning method based on delay and signal strength, enhancing multicell interference management with limited feedback.

Findings

Higher sum-rates achieved compared to equal-bit allocation

Effective allocation favors stronger, less-delayed channels

Closed-form expressions for bit partitioning derived

Abstract

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.