Radio link performance using coherent adaptive antenna array diversity receiver coupled with inter-cell macro diversity in W-CDMA reverse link

This paper investigates by laboratory and field experiments the inter-cell macro diversity effect in the coherent adaptive antenna array diversity (CAAAD) receiver in the W-CDMA reverse link. We propose a fast receiver antenna weight convergence method for the destination cell site at the beginning of inter-cell macro diversity in which the transmission power of the user equipment (UE) is temporarily increased over a very short interval by increasing the target E_b/I_o (signal energy per bit-to-interference plus background noise power spectrum density ratio) in fast transmission power control (TPC) of the original cell site. The experimental results elucidate that this increase in the transmission power of the UE brings about a significantly fast convergence of the receiver antenna weights or the destination cell site, which is caused by the improved received signal-to-interference plus background noise power ratio (SIR). Furthermore, in inter-cell macro diversity, since the transmission power of the UE is controlled according to the TPC bits from the dominant base transceiver station (BTS), the received E_b/I_o of another BTS with greater path loss becomes much lower than that of the dominant BTS. Field experimental results for the average moving speed of approximately 30 km/h elucidate that even under such severe conditions, the receiver beam patterns at both BTSs are accurately generated and updated by satisfactorily tracking the movement of the UE. Consequently, the field experiments clarify that the required average transmission power of the UE at the average block error rate (BLER) of 10^-2 with inter-cell macro diversity associated CAAAD reception at a BTS used between two cell sites is decreased by approximately 2.0 dB compared bared to that with a one-cell site connection caused by the beneficial space diversity effect against shadowing and instantaneous fading variation.