Efficient common channel transmission employing multi-beam antenns in W-CDMA forward link

This paper proposes an efficient transmission method for common channels such as the common control physical channel (CCPCH) that utilizes multi-beam antennas instead of the conventional sectored antenna to achieve a harmonized adaptive antenna array beam forming system in the W-CDMA forward link. In the proposed method, by transmitting common channels using multi-beam antennas associated with fixed transmitter antenna weights, the transmission powers of the common channels are dispersed over all the array antennas with which dedicated physical channels (DPCHs) are transmitted by adaptive antenna array beam forming, thereby avoiding unnecessary additional sectored antenna along with power amplifier with large transmission power. The simulation results elucidate that the multi-beam transmission with a conformal array antenna arrangement suppresses the variance in the transmission power of the common channels among the array antennas more than does a linear array antenna arrangement. The results also show that when the conformal array antenna arrangement employing eight antennas is used, the maximum transmission power per antenna is reduced by more than 8.0 dB compared to that using sectored-antenna transmission, and the variance in the transmission powers among array antennas is less than 2.5 dB. We also show that from the viewpoint of the achievable received signal-to-interference power ratio (SIR) and bit error rate (BER) performance of the CCPCH, the proposed common channel transmission using multi-beam antennas is slightly superior to the conventional sectored-antenna transmission.