A Comparison Between Unitary and Non-Unitary Precoder Design for MIMO Channels with MMSE Detection and Limited Feedback

Summary, in English

This work studies the design of linear precoder codebooks for N-r x N-t MIMO channels with MMSE detection at the receiver. A natural split of precoder-design is unitary precoding and non-unitary precoding. Unitary precoding is only performing rotation of the data in a way beneficial for the channel. Non-unitary precoding additionally also uses power-loading to further improve the performance. Somewhat surprisingly, unitary precoding facilitates a performance boosting by a re-enumeration of the antenna elements at the receiver side that can not be accomodated in the non-unitary precoding setting. This operation leads to substantial performance gains. The question investigated in this paper is whether this re-enumeration can compensate for the lack of power-loading. The outcome is that for small precoder codebooks, unitary precoding performs as good as non-unitary, while for larger codebooks non-unitary precoding outperforms unitary precoding.

• Author: Dzevdan Kapetanovic; Fredrik Rusek
• Department/s: Department of Electrical and Information Technology; ELLIIT: the Linköping-Lund initiative on IT and mobile communication
• Publishing year: 2010
• Language: English
• Publication/Series: 2010 IEEE Global Telecommunications Conference Globecom 2010
• Document type: Conference paper
• Publisher: IEEE - Institute of Electrical and Electronics Engineers Inc.
• Topic: Electrical Engineering, Electronic Engineering, Information Engineering
• Conference name: IEEE Global Telecommunications Conference GLOBECOM 2010
• Conference date: 2010-12-06 - 2010-12-10
• Conference place: Miami, FL, United States
• Status: Published
• Research group: Telecommunication Theory
• ISBN/ISSN/Other: ISSN: 1930-529X