In this paper, we present laboratory and field experimental results using High Speed Downlink Packet Access (HSDPA) test-beds in order to reveal the actual HSDPA performance based on key technologies such as base station (BS) scheduling, adaptive modulation and coding, hybrid automatic repeat request, and advanced receiver design. First, this paper evaluates the effects of advanced user equipment capabilities such as the maximum number of multi-codes, transmit diversity, receive diversity, and a chip equalizer. Increases in throughput of 60% and 85% due to using 10 and 15 codes were observed compared to 5 codes, respectively. The gain of 22% was obtained by applying closed-loop transmit diversity to the HSDPA network. Receive diversity improves the throughput in the region from low to high signal-to-interference ratio, and the gain of 45% was obtained by applying receive diversity to the conventional RAKE receiver. A throughput gain of approximately 17% due to the use of the chip equalizer was obtained and it was observed mainly in the high Ior/Ioc region and under multi-path conditions. Second, field experiments are conducted to elucidate the effects of multi-user diversity using a BS scheduling algorithm, and reveal that proportional fairness scheduling provides both the increase in sector throughput of 18% and a sufficient degree of fairness among users. The transmit control protocol (TCP)-level throughput performance is also investigated in order to reveal the actual end-user throughput. The results show that the throughput rate of approximately 90% of the throughput of the MAC-hs layer is achieved in the TCP layer in the laboratory experiments and in the field experiments.

This paper proposes an efficient random access channel (RACH) transmission method that utilizes soft-combined 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 a message from that of a successfully detected preamble for non-real time (NRT) type traffic data is significantly reduced by soft-combining several retransmitted message data packets thanks to time diversity since the delay requirement is relaxed. Meanwhile, for real time (RT) type traffic data, the relative transmission power of the message from that of the detected preamble is increased in order to reduce the 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 type traffic data is reduced by more than 2 dB compared to that for conventional RACH without the relative transmission power control for a wide rage of fading maximum Doppler frequencies.