Modified Block Diagonalization Precoding in Multicell Cooperative Networks

• Published in: IEEE transactions on vehicular technology Vol. 61; no. 8; pp. 3819 - 3824
• Main Authors: Yong Zeng, Gunawan, E., Yong Liang Guan
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2012; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Approximation methods; Block diagonalization; Coding, codes; convex optimization; Covariance matrix; Detection, estimation, filtering, equalization, prediction; Downlink; Equipments and installations; Exact sciences and technology; Information, signal and communications theory; Interference; interference management; MIMO; Mobile radiocommunication systems; precoding; Radiocommunications; Signal and communications theory; Signal to noise ratio; Signal, noise; sum-rate maximization; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Performance evaluation; Diagonalization; Block diagonalization; Noise reduction; Wireless telecommunication; Optimization method; Downlink; Cell network; precoding; Convex programming; Mean square error; Covariance; Coding; Pretreatment; Mobile radiocommunication; MIMO system; Multiple access; Cooperative systems; Interference suppression; sum-rate maximization; Algorithm performance; Signal processing; System simulation; convex optimization; interference management; Gain; Signal to noise ratio
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2012.2209211

In downlink multiuser multiple-input-multiple-output (MIMO) systems, block diagonalization (BD) is a practical linear precoding scheme that completely eliminates interuser interference. However, its sum rate performance is rather poor in practical signal-to-noise ratio (SNR) regions due to the transmit power boost problem. In this paper, we propose a modified BD precoding scheme to improve its low-to-medium SNR performance with the so-called "effective SNR enhancement" technique. The proposed transmit covariance matrices are obtained by first solving a power minimization problem subject to the minimum rate constraint achieved by BD and then properly scaling the solution until the power constraint is active. The power minimization problem is nonconvex in general. We therefore propose an efficient algorithm that approximately solves the problem. Simulation results demonstrate significant sum rate gains over BD and existing minimum mean square error (MMSE)-based precoding schemes.