Title :
Iterative minimum bit error rate multiuser detection in multiple antenna aided OFDM
Author :
Xu, L. ; Tan, S. ; Chen, S. ; Hanzo, L.
Author_Institution :
Sch. of ECS, Southampton Univ.
Abstract :
A novel iterative multiuser detector (MUD) is proposed for employment in space division multiple access (SDMA) aided orthogonal frequency division multiplexing (OFDM) systems, where the uplink transmissions of the users share the same bandwidth. The individual users´ signals are differentiated with the aid of their unique user-specific channel impulse responses (CIRs). The MUD commences its operation on a subcarrier by subcarrier basis from the minimum mean square error (MMSE) MUD antenna array weight vector and invokes the conjugate gradient (CG) algorithm for the sake of iteratively adjusting the array weight vector in the direction of the MUD´s true minimum bit error rate (MBER) solution. Recursive systematic convolutional (RSC) codes are used for enhancing the system´s attainable BER performance, which exchange extrinsic information with the MBER MUD for the sake of achieving a turbo-detection aided iteration gain, resulting in the creation of a powerful turbo MBER MUD for employment in multiuser SDMA OFDM systems. The novel benefit of the proposed system is that it is capable of supporting up to a factor two higher number of users than the number of receiver antennas. Explicitly, the technique advocated outperforms other SDMA MUDs with the advent of its MBER optimization criterion and turbo detection structure. Up to 2 dBs of iteration gains are attained
Keywords :
OFDM modulation; antenna arrays; conjugate gradient methods; convolutional codes; error statistics; least mean squares methods; multiuser detection; radio links; space division multiple access; turbo codes; OFDM; SDMA; channel impulse responses; conjugate gradient algorithm; iterative minimum bit error rate; iterative multiuser detector; minimum mean square error; multiple antenna; multiuser detection; orthogonal frequency division multiplexing; receiver antennas; recursive systematic convolutional codes; space division multiple access; turbo-detection; uplink transmissions; Antenna arrays; Bandwidth; Bit error rate; Detectors; Directive antennas; Employment; Mean square error methods; Multiaccess communication; Multiuser detection; OFDM;
Conference_Titel :
Wireless Communications and Networking Conference, 2006. WCNC 2006. IEEE
Conference_Location :
Las Vegas, NV
Print_ISBN :
1-4244-0269-7
Electronic_ISBN :
1525-3511
DOI :
10.1109/WCNC.2006.1696527