Peak to Average Ratio Reduction of Space-Time Codes That Achieve Diversity-Multiplexing Gain Tradeoff
Date Issued
2007
Date
2007
Author(s)
Lee, Chung-Pi
DOI
en-US
Abstract
A result of Zheng and Tse [1] states that over a quasi-static channel, there exists a fundamental tradeoff, known as diversity-multiplexing gain (D-MG) tradeoff. The quest for space-time codes that achieve D-MG tradeoff has generated numerous work [2-7],etc. However, these space-time codes generally have a pretty high peak to average power ratio (PAR) value on each antenna. In a realistic system, to avoid inefficiently operating the power amplifier, one should put constraints on PAR value. In the following context, we investigate D-MG tradeoff with PAR constraints. The results show D-MG tradeoff remains the same even with PAR constraints, but space-time codes devised to achieve D-MG tradeoff need some modifications to meet the PAR constraints. Therefore, we propose two general ways to reduce PAR without affecting codes structure and without any side information being transmitted. They are both based on constellation shaping, that is, a constellation is used such that the transmitted signals have low PAR values. The first method is similar as [8] except we choose the Hermite Normal Form (HNF) decomposition instead of Smith Normal Form (SNF); the second one takes the idea of integer reversible mapping [9], [10]. If the approximately cubic shaping is used, both techniques would lead to an asymptotical PAR value equalto 3 when SNR is large.
Subjects
分集,多工,峰均比
diversity,multiplexing,par
Type
thesis