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Recommended by Xavier Mestre M-PSK cooperative trellis codes are proposed for two-user coordinate interleaved coded cooperation operating over quasistatic Rayleigh fading channels. The coding approach properly combines cooperative and modulation diversity techniques to take their full advantage. Two selective cooperation schemes are considered related to whether users know the cooperation status or not. Upper bounds on the pairwise error probability of the considered schemes are derived for each cooperation case which lead to new code design criteria. Based on these criteria, 4-, 8-, 16-state QPSK and 8-, 16-state 8PSK cooperative trellis codes are obtained by means of exhaustive computer search. The error performance evaluation of the new codes by computer simulations shows that they outperform the corresponding best space-time codes used in cooperation with coordinate interleaving.

ÖZETÇEBu çalışmada, LMS (En Küçük Kareler -Least Mean Square) algoritması için en-iyi adım-boyu bulma algoritması önerilmiştir. Algoritma döngüsel olarak çalışmakta ve her bir döngüde durağan-durum hata oranını enküçükleyecek en-iyi adım-boyu bulunarak dengeleyici katsayılarına yakınsanmaktadır. Adım-boyu değeri için herhangi bir başlangıç değerine ihtiyaç yoktur. En-iyi adım-boylu LMS dengeleme yöntemi (EA-LMS) ile diğer LMS tabanlı çalışmalar arasında başarım karşılaştırmaları yapılarak önerilen yöntemin üstünlüğü ortaya konulmuştur. ABSTRACTIn this paper, an optimal step-size finding algorithm for LMS is presented. The algorithm runs iteratively and convergence to the equalizer coefficients by finding the optimal step-size which minimizes the steady-state error rate at each iteration. No initialization for the step-size value is required. Efficiency of the proposed algorithm is shown by making a performance comparison between some of the other LMS based algorithms and optimal step-size LMS algorithm.

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In this paper, code design criteria for coded cooperation systems with coordinate interleaving are derived from pairwise error probability upper bounds. Optimum 4, 8 and 16-state trellis codes are designed by means of exhaustive computer search. The error performances of the new codes evaluated by the computer simulations show their superiority compared to the corresponding best space-time codes used in cooperation with coordinate interleaving.