Sequential opportunistic decoding for spread spectrum wireless networks

In general, the instantaneous signal-to-interference-plus-noise ratio varies across a received frame. This variation is considerable in wireless systems in particular, due to the time-varying nature of wireless channels. To exploit this variation, we divide the received frame into a number of constituent mini-frames, each mini-frame containing the received versions of every symbol in the frame. We select a subset of these mini-frames, combine them and attempt to decode the frame. If this attempt fails, we select another subset of the mini-frames and make another attempt. We continue the process until the frame is decoded without errors or all predetermined subsets of the mini-frames have been exhausted. We implement the proposed protocol in a CDMA system. Our study shows that deploying our proposed protocol in a CDMA system results in a significant reduction in the frame error rate.

[1]  Moe Z. Win,et al.  Pilot-aided chip-interleaved DS-CDMA transmission over time-varying channels , 2006, IEEE Journal on Selected Areas in Communications.

[2]  Arumugam Nallanathan,et al.  On the performance of chip-interleaved turbo coded DS-CDMA system under impulse noise , 2003, 14th IEEE Proceedings on Personal, Indoor and Mobile Radio Communications, 2003. PIMRC 2003..

[3]  Georgios B. Giannakis,et al.  Chip-interleaved block-spread code division multiple access , 2002, IEEE Trans. Commun..

[4]  Khaled Fazel,et al.  Multi-Carrier and Spread Spectrum Systems , 2003 .

[5]  Fumiyuki Adachi,et al.  Chip interleaved turbo codes for DS-CDMA mobile radio in fading channel , 2002 .

[6]  Marc Moonen,et al.  MUI-free receiver for a synchronous DS-CDMA system based on block spreading in the presence of frequency-selective fading , 2000, IEEE Trans. Signal Process..

[7]  Jean-Paul M. G. Linnartz,et al.  Multi-Carrier Cdma In Indoor Wireless Radio Networks , 1994 .

[8]  Moe Z. Win,et al.  Characterization of ultra-wide bandwidth wireless indoor channels: a communication-theoretic view , 2002, IEEE J. Sel. Areas Commun..

[9]  K. Fazel,et al.  Multi-Carrier and Spread Spectrum Systems: Fazel/Spread Spectrum , 2004 .

[10]  Lajos Hanzo,et al.  Performance Comparison of FH/MC DS-CDMA with Single- and Multi-Carrier DS-CDMA , 2000 .

[11]  Moe Z. Win.  Spectral density of random UWB signals , 2002, IEEE Communications Letters.

[12]  David W. Lin,et al.  Multiple access over fading multipath channels employing chip-interleaving code-division direct-sequence spread spectrum , 2003 .

[13]  Moe Z. Win,et al.  Fade-resistant CDMA transmission and reception over time-varying wireless channels , 2006, IEEE Transactions on Wireless Communications.

[14]  John G. Proakis,et al.  Mitigating multiple access interference and intersymbol interference in uncoded CDMA systems with chip-level interleaving , 2002, IEEE Trans. Wirel. Commun..

[15]  Moe Z. Win,et al.  Impulse radio: how it works , 1998, IEEE Communications Letters.

[16]  A. Viterbi.  CDMA: Principles of Spread Spectrum Communication , 1995 .

[17]  C. Laot,et al.  A chip-interleaving pattern retaining orthogonality in DS-CDMA systems: application to the multicode downlink , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[18]  Moe Z. Win,et al.  Fade-resistant transmission over time-varying wireless channels , 2004, IEEE Signal Processing Letters.

[19]  Tung-Sang Ng,et al.  A novel chip-interleaving DS SS system , 2000, IEEE Trans. Veh. Technol..

[20]  Li Ping,et al.  On interleave-division multiple-access , 2004, 2004 IEEE International Conference on Communications (IEEE Cat. No.04CH37577).

[21]  Hakan A. Çirpan,et al.  Chip interleaving in direct sequence CDMA systems , 1997, 1997 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[22]  Moe Z. Win,et al.  Ultra-wide bandwidth time-hopping spread-spectrum impulse radio for wireless multiple-access communications , 2000, IEEE Trans. Commun..