Interference suppression in the presence of quantization errors

Omar Bakr; Mark Johnson; Raghuraman Mudumbai; Upamanyu Madhow

doi:10.1109/ALLERTON.2009.5394552

Back

Conference proceeding

Interference suppression in the presence of quantization errors

Omar Bakr, Mark Johnson, Raghuraman Mudumbai and Upamanyu Madhow

2009 47th Annual Allerton Conference on Communication, Control, and Computing (Allerton), pp.1161-1168

09/2009

DOI: 10.1109/ALLERTON.2009.5394552

View Online

Abstract

Multi-element antennas offer the possibility of increasing the spatial reuse of wireless spectrum by ¿nulling¿ out interfering signals. However, the interference suppression performance is highly sensitive to small errors in the gains applied to the antenna elements. In this paper, we examine in detail the effect of one specific source of error that arises from quantizing array weights. We show that a simple approach based on scalar quantization that ignores the correlation of the quantization errors fails to fully utilize the interference suppression capability of the array: the residual interference level does not decrease with the number of antennas. Unfortunately, the optimum approach to computing the weights involves vector quantization over a space that grows exponentially with the number of antennas and number of quantization bits, and is therefore computationally intractable. We propose instead a simple suboptimal method that greedily optimizes the SIR, coefficient-by-coefficient. Simulations show that this greedy approach provides substantial SIR gains over the naive approach, with SIR growing polynomially in the number of antennas. We derive analytical bounds that indicate that even larger SIR gains (exponential in the number of antennas) are potentially achievable, so that finding tractable algorithms that improve upon our suboptimal approach is an important open problem.

Polynomials

Array signal processing

Cities and towns

Computer errors

Degradation

Interference suppression

Performance gain

Signal to noise ratio

Vector quantization

Wireless sensor networks

Details

Title: Subtitle: Interference suppression in the presence of quantization errors
Creators: Omar Bakr - University of California, Berkeley
Mark Johnson - University of California, Berkeley
Raghuraman Mudumbai - University of Iowa
Upamanyu Madhow - University of California, Santa Barbara
Resource Type: Conference proceeding
Publication Details: 2009 47th Annual Allerton Conference on Communication, Control, and Computing (Allerton), pp.1161-1168
DOI: 10.1109/ALLERTON.2009.5394552
Publisher: IEEE
Language: English
Date published: 09/2009
Academic Unit: Electrical and Computer Engineering
Record Identifier: 9984197185802771

Metrics

17 Record Views

2 Times Cited - Web of Science