Title :
Switched Interleaving Techniques with Limited Feedback for Interference Mitigation in DS-CDMA Systems
Author :
Cai, Yunlong ; de Lamare, Rodrigo C. ; Fa, Rui
Author_Institution :
Dept. of Inf. Sci. & Electron. Eng., Zhejiang Univ., Hangzhou, China
fDate :
7/1/2011 12:00:00 AM
Abstract :
In this paper we propose a novel switched-interleaving algorithm based on limited feedback for both uplink and downlink DS-CDMA systems. The proposed switched chip-interleaving DS-CDMA scheme requires the cooperation between the transmitter and the receiver, and a feedback channel sending the index of the interleaver to be used. The transmit chip-interleaver is chosen by the receiver from a codebook of interleaving matrices known to both the receiver and the transmitter and the codebook index is sent back using a limited number of bits. In order to design the codebook, we consider a number of different chip patterns by using random interleavers, block interleavers and a proposed frequently selected patterns method (FSP). The best interleaving patterns are chosen by the selection functions of the received signal to interference plus noise ratio (SINR) for both downlink and uplink systems. Since the selection function needs to determine the best interleaver based on the channel state information, it is necessary to predict reliably the channel state information for typical delay values. We present symbol-based and block-based linear minimum mean squared error (MMSE) receivers for interference suppression. Simulation results show that our proposed algorithm achieves significantly better performance than the conventional DS-CDMA (C-CDMA) systems and the existing chip-interleaving, linear precoding and adaptive spreading techniques.
Keywords :
code division multiple access; feedback; interference suppression; interleaved codes; least mean squares methods; matrix algebra; radio transmitters; spread spectrum communication; DS-CDMA systems; MMSE receivers; block interleavers; channel state information; codebook; feedback channel; frequently selected patterns method; interference mitigation; interference suppression; interleaving matrices; limited feedback; minimum mean squared error; signal to interference plus noise ratio; switched interleaving techniques; transmitter; Downlink; Indexes; Interference; Multiaccess communication; Receivers; Signal to noise ratio; Transmitters; Direct sequence code division multiple access (DS-CDMA); chip-interleaving; interference suppression; limited feedback; multiuser detection;
Journal_Title :
Communications, IEEE Transactions on
DOI :
10.1109/TCOMM.2011.051711.090120A