DocumentCode :
390824
Title :
Efficient random access channel transmission method utilizing soft-combining of retransmitted message packets according to QoS
Author :
Lizuka, Y. ; Tanno, Motohiro ; Sawahashi, Mamoru
Author_Institution :
Wireless Labs., NTT DoCoMo, Inc, Kanagawa, Japan
Volume :
1
fYear :
2002
fDate :
25-28 Nov. 2002
Firstpage :
441
Abstract :
This paper proposes an efficient random access channel (RACH) transmission method that utilizes soft-combining of consecutively retransmitted message data packets according to the quality of service (QoS) requirements for broadband multi-carrier/DS-CDMA (MC/DS-CDMA) in the reverse link. In the proposed scheme, the relative transmission power of message data compared to that of a successfully detected preamble for non-real time (NRT) traffic data is significantly reduced to achieve error-free transmission by soft-combining several retransmitted message data packets thanks to time diversity since the delay requirement is relaxed. Meanwhile, for real time (RT) traffic data with rigid delay requirements, the relative transmission power of the message data compared to that of the detected preamble is increased to reduce the residual packet error rate with a limited number of retransmissions. Simulation results elucidate that the total required average received signal energy per bit-to-background noise power spectrum density ratio (Eb/N0) for error-free transmission with time diversity for NRT traffic data is reduced by approximately 2.4 dB compared to that for RT traffic data in a 12-path fading channel with exponential distribution at the fading maximum Doppler frequency of fD = 20 Hz.
Keywords :
3G mobile communication; broadband networks; code division multiple access; data communication; delays; diversity reception; fading channels; multipath channels; multiuser channels; noise; packet radio networks; quality of service; radio links; spread spectrum communication; 3GPP; 3rd Generation Partnership Project; MC/DS-CDMA; QoS; average received signal energy per bit; background noise power spectrum density ratio; broadband multi-carrier/DS-CDMA; delay requirements; detected preamble; error-free transmission; exponential distribution; maximum Doppler frequency; message data packets; multipath fading channel; nonreal time traffic data; quality of service; random access channel transmission; real time traffic data; residual packet error rate reduction; retransmitted message packets; reverse link; simulation results; soft-combining; time diversity; transmission power; Delay effects; Error analysis; Exponential distribution; Fading; Frequency diversity; Multiaccess communication; Noise reduction; Quality of service; Signal to noise ratio; Traffic control;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Communication Systems, 2002. ICCS 2002. The 8th International Conference on
Print_ISBN :
0-7803-7510-6
Type :
conf
DOI :
10.1109/ICCS.2002.1182513
Filename :
1182513
Link To Document :
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