Title :
Noise Reduction with Sub-Channel Sorting for OFDM-CDM
Author :
Chen Zhe ; Liu Fang ; Yang Da-cheng ; Feng Hai-Liang
Author_Institution :
Wireless Commun. Res. Center, Beijing Univ. of Posts & Telecommun., Beijing
Abstract :
In this paper, we consider an Orthogonal Frequency Division Multiplexing-Code Division Multiplexing (OFDM-CDM) system. The noise reduction method based on Least Squares (LS) is introduced into the OFDM-CDM receiver to improve the signal-to-noise ratio (SNR), while the system does not work under full load. In this paper, Walsh code is considered to be used in CDM module. The relationship between the spreading codes and the variance of the noise after noise reduction is investigated. Based on this relationship, a simple noise reduction after channel frequency response (CFR) sorting is proposed to improve the Bit Error Rate (BER) performance of system further. Simulation results suggest that good performance can be achieved with proposed scheme.
Keywords :
OFDM modulation; code division multiplexing; error statistics; frequency response; least squares approximations; receivers; transmitters; Walsh code; bit error rate; channel frequency response; code division multiplexing; least squares approximation; noise reduction; orthogonal frequency division multiplexing; sub-channel sorting; Bit error rate; Frequency division multiplexing; Intersymbol interference; Multiaccess communication; Noise reduction; OFDM; Signal to noise ratio; Sorting; Transmitters; Wideband;
Conference_Titel :
Wireless Communications, Networking and Mobile Computing, 2008. WiCOM '08. 4th International Conference on
Conference_Location :
Dalian
Print_ISBN :
978-1-4244-2107-7
Electronic_ISBN :
978-1-4244-2108-4
DOI :
10.1109/WiCom.2008.208
