Abstract
In this paper, we present a linear precoder design for cognitive radio (CR) multi-user multiple-input multiple-output (MU-MIMO) downlink systems where unlicensed secondary users (SUs) can simultaneously utilize the same spectrum used by a licensed primary user (PU). Although a zero-forcing block diagonalization (ZF-BD) precoder is extended to the CR network with the PU, a transmit power boost problem occurs. Therefore, we propose a regularized BD precoder method based on the minimum mean-squared error (MMSE) criteria subject to the interference power constraint under a predetermined threshold for the PU. As a result, the proposed CR-MMSE-BD scheme improves the signal-to- interference-plus-noise ratio at each SU's receiver, compared to the ZF-BD based method. The simulation results demonstrate that the proposed algorithm outperforms the ZF based technique for CR MU-MIMO downlink systems.
Original language | English |
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Article number | 6002431 |
Pages (from-to) | 3139-3144 |
Number of pages | 6 |
Journal | IEEE Transactions on Wireless Communications |
Volume | 10 |
Issue number | 10 |
DOIs | |
Publication status | Published - 2011 Oct |
Keywords
- Cognitive radio
- block diagonalization (BD)
- minimum mean-squared error (MMSE)
- multi-user MIMO
ASJC Scopus subject areas
- Computer Science Applications
- Electrical and Electronic Engineering
- Applied Mathematics