Field experiments on multipath interference canceller associated with AMC in HSDPA

This paper presents field experimental results on a multipath interference canceller (MPIC) associated with adaptive modulation and channel coding (AMC) in an actual multipath fading channel in high-speed downlink packet access (HSDPA). In the implemented MPIC receiver with four Rake fingers at maximum, a multipath interference (MPI) replica of each resolved path is precisely generated utilizing the common pilot channel (CPICH), and subtracted from the received signal in a four-stage parallel configuration, thereby resulting in an improvement in throughput caused by suppression of strong MPI from the high-speed downlink shared channel (HS-DSCH). Furthermore, we employ four modulation and channel coding schemes (MCSs), MCS1 (QPSK data modulation with the channel coding rate R = 1/2, hereafter simply referred to as QPSK with R = 1/2), MCS2 (QPSK with R = 3/4), MCS3 (16QAM with R = 1/2), and MCS4 (16QAM with R = 3/4) along with nine-code multiplexing with the spreading factor of SF = 16. Experimental results elucidate that the measured throughput employing MPIC is significantly improved compared to that with a matched filter (MF)-based Rake receiver in an actual multipath fading channel at the average vehicular speed of approximately 30 km/h. Furthermore, the peak throughput of approximately 6.5 Mbps is achieved at nine-code multiplexing under sufficiently high received signal-to-interference power ratio (SIR) conditions (thus, the throughput of approximately 6.5 Mbps at nine-code multiplexing suggests possibility of peak throughput above 10 Mbps when 15-code multiplexing is applied).