Title :
Performance comparison of the multi-code fixed spreading length (MFSL) scheme and the variable spreading length (VSL) scheme for multi-rate MC-CDMA
Author :
Tan, Mizhou ; Bar-Ness, Yeheskel
Author_Institution :
Dept. of Electr. & Comput. Eng., New Jersey Inst. of Technol., Newark, NJ, USA
Abstract :
In this paper, we compare the performance of two important multi-rate transmission schemes: the variable spreading length (VSL) scheme and the multicode fixed spreading length (MFSL) scheme for MC-CDMA systems. Minimum mean square error combining (MMSEC) is applied for both schemes to cancel the multiuser interference (MUI). It is found that by selecting orthogonal Walsh Hadamard sequences as spreading codes and properly assigning codes for each user, the intercarrier interference (ICI) caused by the nonorthogonality of subcarriers in the VSL scheme can be eliminated and the self-interference (SI) caused by employing multiple codes for each user in the MFSL scheme can also be reduced. The bit error rate (BER) performance of each scheme is obtained by analysis and simulation in a correlated Rayleigh fading channel.
Keywords :
Hadamard codes; Rayleigh channels; Walsh functions; adjacent channel interference; binary sequences; channel coding; code division multiple access; error statistics; interference suppression; least mean squares methods; mobile radio; spread spectrum communication; variable rate codes; BER performance; ICI; MFSL scheme; MMSEC; MUI cancellation; VSL scheme; bit error rate; correlated Rayleigh fading channel; intercarrier interference; minimum mean square error combining; multi-rate MC-CDMA; multicode fixed spreading length; multiuser interference; orthogonal Walsh Hadamard sequences; performance comparison; self-interference reduction; spreading codes; variable spreading length scheme; Analytical models; Bit error rate; Error correction; Error correction codes; Fading; Interference cancellation; Interference elimination; Mean square error methods; Multicarrier code division multiple access; Performance analysis;
Conference_Titel :
Spread Spectrum Techniques and Applications, 2002 IEEE Seventh International Symposium on
Print_ISBN :
0-7803-7627-7
DOI :
10.1109/ISSSTA.2002.1049296
