Title :
FIR zero-forcing equalizer for ISI MIMO channels using space-time modulated codes
Author :
Kwan, Man-Wai ; Kok, Chi-Wah
Author_Institution :
Dept. of Electr. & Electron. Eng., Hong Kong Univ. of Sci. & Technol., Kowloon, China
Abstract :
Abstract-A systematic method for designing a finite-impulse response (FIR) zero-forcing equalizer (ZFE) of the space-time modulated code (STMC) system based on nonmaximally decimated filterbank is proposed. The physical channel considered is assumed to be multiple-input-multiple-output (MIMO) with intersymbol interference (ISI) and space-time correlated noise. STMC is a space-time block code (STBC) system. Most of the STMC systems require a long guard period to avoid interblock interference (IBI), but, with the proposed equalizer, the length of the guard period is greatly reduced. This can enhance the spectral efficiency of the STMC especially when the channel dispersion is large. The existence conditions for FIR ZFE of the STMC system were derived. These include the maximal code rate STMC for a given channel and the minimal filter order of the FIR ZFE. For a given STMC precoder, the equalizability of the system was verified. The solution of FIR ZFE of STMC was parameterized, which allows the design of optimal FIR ZFE through unconstrained optimization. It is further shown that FIR ZFE could be improved by adding a simple permutation in the system. Design examples and simulation results were presented to evaluate the proposed design method.
Keywords :
FIR filters; MIMO systems; block codes; channel bank filters; channel coding; equalisers; intersymbol interference; modulation coding; space-time codes; ISI MIMO channels; decimated filterbank; finite impulse response; interblock interference; intersymbol interference; multiple-input-multiple-output; space-time block code system; space-time correlated noise; space-time modulated codes; zero-forcing equalizer; Block codes; Broadband antennas; Design methodology; Equalizers; Fading; Finite impulse response filter; Intersymbol interference; MIMO; Modulation coding; Narrowband;
Journal_Title :
Wireless Communications, IEEE Transactions on
DOI :
10.1109/TWC.2006.1576536