Title :
Performance comparison of linear MMSE and coherent RAKE receivers in multipath asynchronous random-CDMA
Author :
Mirbagheri, Arash ; Yoon, Young C.
Author_Institution :
Centre for Wireless Commun., Waterloo Univ., Ont., Canada
Abstract :
This paper investigates the design of a linear minimum mean square error (MMSE) receiver for interference suppression in asynchronous random code-division multiple-access (random-CDMA) systems, such as IS-95 and wideband-CDMA (WCDMA), operating in multipath environments. Its performance is compared with that of the coherent RAKE receiver. The figure of merit is average output signal-to-noise-ratio (SNR). The proposed receiver maximizes SNR and considers all the desired user´s paths unlike the standard RAKE receiver which selects a subset of them. The performance improvement is supported and quantified by numerical examples. The achieved gain is shown to be substantial in nonuniform power conditions (typical of next-generation CDMA systems) and dense multipath environments where the signals are received via many paths. The chip pulse shape is the square-root raised cosine (Sqrt-RC) pulse with 22% excess bandwidth
Keywords :
AWGN channels; interference suppression; land mobile radio; least mean squares methods; multipath channels; multiuser channels; radio receivers; radiofrequency interference; spread spectrum communication; AWGN channel; DS-CDMA; IS-95; SNR; WCDMA; asynchronous random-CDMA; average output signal-to-noise-ratio; code-division multiple-access; coherent RAKE receiver; direct sequence code-division multipleaccess; excess bandwidth; figure of merit; interference suppression; linear MMSE receiver; linear minimum mean square error; multipath environments; nonuniform power conditions; performance comparison; square-root raised cosine pulse; wideband-CDMA; Bandwidth; Fading; Interference suppression; Mean square error methods; Multiaccess communication; Multipath channels; Pulse shaping methods; RAKE receivers; Shape; Signal to noise ratio;
Conference_Titel :
Spread Spectrum Techniques and Applications, 2000 IEEE Sixth International Symposium on
Conference_Location :
Parsippany, NJ
Print_ISBN :
0-7803-6560-7
DOI :
10.1109/ISSSTA.2000.876488
