A Blind Interference-Blocking RAKE Receiver for CDMA Communications Systems

Tsui-Tsai LIN
Chih-Peng LI

Publication
IEICE TRANSACTIONS on Communications   Vol.E88-B    No.5    pp.2073-2080
Publication Date: 2005/05/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.5.2073
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
Keyword: 
interference-blocking RAKE,  code-division multiple-access,  beamforming,  strong interference,  multipath,  

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Summary: 
A space-time RAKE (ST-RAKE) receiver with a blind interference-blocking (IB) pre-processor, termed as the IB-RAKE receiver, is proposed for spread spectrum communications systems. The design of the proposed architecture consists of three components. A blind IB transformer is first constructed based on the received data, and then applied on the undespread data for the suppression of strong interference. After despreading, optimal beamforming is then performed on the IB despread data to extract the signals of interest (SOIs) from the desired user. Finally, a RAKE receiver with a maximum ratio combining technique is employed to constructively collect all the SOI energies. Since strong interference has been removed in the first stage, the RAKE receiver combines only those SOIs plus negligible interference, leading to robustness against strong interference. Numerical results have shown that substantial improvement can be obtained from the proposed ST-RAKE receiver with the blind IB pre-processing scheme.