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Null-space projection and waterfilling resource allocation in multi-antenna cognitive radio networks

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Journal of Electronics (China)

Abstract

Cognitive Radio (CR) is a promising technique for the next generation mobile communication system for its capability to solve the conflicts between the scarcity and underutilization of spectrum. In this paper, aiming at maximizing the system capacity of a multi-antenna CR system on the premise that avoid interference to the primary system in the same band simultaneously, a resource allocation method which is able to avoid interference between PRimary (PR) and CR users by projecting the transmit signals of CR users on the null space of the PR users’ channels is proposed. CR users with better channel condition are selected, and the interference from CR system to PR users can be removed completely by projecting the transmit signals of CR system on the null-space of PR users’ channels. Parallel sub-channels are constructed for CR users through Singular Value Decomposition (SVD). At last, waterfilling is also adopted to increase the CR users’ capacity. Simulation result demonstrates that compared with existing methods, our method can improve the achievable sum rate of CR users as well as reduce the outage probability of PR users.

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Authors and Affiliations

  1. Department of Information and Communication Engineering, Xi’an Jiaotong University, Xi’an, 710049, China

    Rong Mei & Zhu Shihua

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  1. Rong Mei
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  2. Zhu Shihua
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Correspondence to Zhu Shihua.

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Communication author: Zhu Shihua, born in 1950, male, Professor.

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Mei, R., Shihua, Z. Null-space projection and waterfilling resource allocation in multi-antenna cognitive radio networks. J. Electron.(China) 27, 701–707 (2010). https://doi.org/10.1007/s11767-011-0504-1

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  • DOI: https://doi.org/10.1007/s11767-011-0504-1

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