Experiments on Reservation-Based Packet Transmission in Reverse Link CDMA Broadband Wireless Access Controlling Transmission-Power of Data Packet According to QoS Requirements

摘要

This paper proposed an efficient reservation-based packet transmission method, which adaptively controls the transmission-power offset Δ{sub}(offset) and the power ratio of pilot channel to data channel according to the Quality of Service (QoS) requirements transmitted by reservation packet and experimentally presents packet error rate (PER) performance in the reverse link for CDMA broadband wireless access. Experimental results using the CDMA transceiver with a 40-MHz bandwidth in the reverse link elucidated that whenΔ{sub}(offset), is set to -2 dB, the total required average received signal energy per bit-to-background noise power spectrum density ratio (E{sub}b/N{sub}0) for satisfying error-free reception assuming non-real time traffic data was reduced by approximately 3 dB by applying Chase combining to the data packet compared to that with a constantΔ{sub}(offset) without retransmission in a four-path Rayleigh fading channel with the fading maximum Doppler frequency of 20 Hz. Furthermore, it was confirmed that in real time traffic data, for which the delay requirement was rigid, the required average residual packet error rate was achieved by controllingΔ{sub}(offset), according to the maximum allowable number of retransmissions, i.e., a few, within the delay requirement of each traffic data type.