DocumentCode :
3861612
Title :
Low-complexity equalization for /spl pi//4 DQPSK signals based on the method of projection onto convex sets
Author :
Z. Kostic
Author_Institution :
AT&T Labs.-Res., Red Bank, NJ, USA
Volume :
48
Issue :
6
fYear :
1999
Firstpage :
1916
Lastpage :
1922
Abstract :
An equalizer adaptation technique for compensation of degradations caused by multipath Rayleigh fading channels to /spl pi//4 differential quadrature phase shift keying (DQPSK)-modulated signals is presented. The technique is applied to linear and nonlinear transversal-filter-type equalizers. It is based on the method of projection onto convex sets (POCS), realized in a particular form of the iterative least mean squares (LMS) procedure. The convergence speed of the proposed equalizer coefficient adaptation technique and its computational complexity depend on the newly introduced look-back parameter. Both can be tailored to the characteristics of the channel. For achieving convergence speeds comparable to speeds of recursive least squares (RLS) techniques, the computational load of the presented equalization is of the order of the load required of RLS techniques. However, its algorithmic implementation is notably simpler and its code and storage size requirements are smaller. The technique is numerically stable, and it is suitable for low-power implementations in digital signal processors or custom very large-scale integration (VLSI) circuits. Performed simulations verify good performance of the technique in various channel conditions for 900-MHz multipath fading radio channels.
Keywords :
"Equalizers","Fading","Convergence","Resonance light scattering","Degradation","Differential quadrature phase shift keying","Iterative methods","Least squares approximation","Computational complexity","Least squares methods"
Journal_Title :
IEEE Transactions on Vehicular Technology
Publisher :
ieee
ISSN :
0018-9545
Type :
jour
DOI :
10.1109/25.806784
Filename :
806784
Link To Document :
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