Efficient water-filling algorithms for a Gaussian multiaccess channel with ISI

• Published in: Vehicular Technology Conference Fall 2000. IEEE VTS Fall VTC2000. 52nd Vehicular Technology Conference (Cat. No.00CH37152) Vol. 3; pp. 1072 - 1077 vol.3
• Main Authors: Chaohuang Zeng, Hoo, L.M.C., Cioff, J.M.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 2000
• Subjects: Approximation algorithms; Chaos; Computational complexity; Computational modeling; Filling; Frequency conversion; Gaussian channels; Heuristic algorithms; Intersymbol interference; Transfer functions
• ISBN: 0780365070; 9780780365070
• ISSN: 1090-3038; 2577-2465
• DOI: 10.1109/VETECF.2000.886272

Although the optimum transmit power spectral density (PSD) of each user in a Gaussian multiaccess channel is theoretically available, efficient algorithms are needed to obtain the optimal PSD numerically. This paper presents two water-filling algorithms for the scenario where all users have the same priorities. First we propose for a two-user channel an exact algorithm with a computational complexity of O(Nlog/sub 2/N), where N is the number of subchannels. Then we develop a heuristic algorithm for K>2 users that has O(K/sup 2/Nlog/sub 2/N) complexity and achieves more than 98% of the optimum data rate in all of the channels we simulated.