A low-complexity bandwidth allocation algorithm for frequency-selective multiuser OFDM systems

This paper addresses the problem of efficient bandwidth allocation for multiuser orthogonal frequency division multiplexing (OFDM) systems over frequency-selective channels. For a given coding and medium access scheme and for specific channel gains, the achievable data rates depend on the assignment of the available subchannels to the different users. However, in frequency-selective channels, the various users experience different channel conditions, thus the application of effective bandwidth allocation rules results in enhanced multiuser diversity. This paper presents a computationally efficient solution for dynamic subchannel assignment. The proposed algorithm provides enhanced system performance compared with the fixed time division multiple access (TDMA) solution and also results in proportional data rates according to channel quality of each user. As a case study, we demonstrate the performance of the proposed algorithm in the indoor power line network with multiple OFDM links between a central station and a number of user devices.