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Simplified group interference cancelling for asynchronous DS‐CDMA
Author(s) -
W. Matolak David
Publication year - 2006
Publication title -
international journal of communication systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.344
H-Index - 49
eISSN - 1099-1131
pISSN - 1074-5351
DOI - 10.1002/dac.800
Subject(s) - computer science , fading , single antenna interference cancellation , additive white gaussian noise , asynchronous communication , interference (communication) , code division multiple access , algorithm , co channel interference , telecommunications , electronic engineering , channel (broadcasting) , decoding methods , engineering
A simplified group interference cancelling (IC) approach is investigated for asynchronous direct‐sequence code‐division multiple access on flat fading channels. The technique employs grouping by estimated signal‐to‐noise‐plus‐interference ratio (SNIR), and interference cancellation is performed blockwise, for a subset of the total number of users. We consider long random spreading codes, and include the effects of imperfect amplitude, carrier phase, and delay estimation. Performance of the technique shows SNIR gains of several dB, and concomitant improvements in error probability, with lower computational complexity than that of parallel or serial interference cancelling techniques. We also show that our SNIR expressions are applicable to both the AWGN and flat fading channels, and for moderate near–far conditions. In addition, we determine optimal group sizes for our technique, where optimality is in terms of average error probability over all users. Copyright © 2006 John Wiley & Sons, Ltd.