Multiuser OFDM with adaptive sub-carrier, bit, and power allocation
|Authors||Wong, Cheong Yui
Letaief, K. B.
Murch, Ross David
|Source||IEEE journal on selected areas in communications, v.17, (10), 1999, October , p. 1747-1758|
|Summary||Multiuser Orthogonal Frequency Division Multiplexing (OFDM) with adaptive multiuser sub-carrier allocation and adaptive modulation is considered. Assuming knowledge of the instantaneous channel gains for all users, we propose a multiuser OFDM sub-carrier, bit, and power allocation algorithm to minimize the total transmit power. This is done by assigning, to each user, a set of sub-carriers, and by determining, for each sub-carrier, the number of bits and the transmit power level. We obtain the performance of our proposed algorithm in a multiuser frequency selective fading environment for various time delay spread values and various numbers of users. The results show that our proposed algorithm outperforms multiuser OFDM systems with static TDMA or FDMA techniques which employ fixed and pre-determined time-slot or sub-carrier allocation schemes. We have also quantified the improvement in terms of the overall required transmit power, the bit error rate, or the area of coverage for a given outage probability.|
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