DS-CDMA蜂巢式行動電話網路中的功率控制

Abstract

功率控制對 DS-CDMA 蜂巢式行動電話網路(cellular mobile radio system) 而言是相當重要的一環。如果沒有功率控制的話，該系統高容量 的目標是無法達到的。在過去的研究中，用電腦模擬的方式，已對固定調 度式強度型 (fixed-step strength-based) 及固定調度式 SIR 型 (fixed-step SIR-based) 這兩種功率控制有所探討。 本篇論文則將 這方面的研究推展至多重調度式 (variable-step) 的強度型及 SIR 型的 功率控制。對於短程削弱性信號 (short-term fading signal) 的電腦模 擬方面，本篇論文提有一嶄新的方法可以節省模擬的時間。從模擬的的結 果中， 我們發現多重調度式功率控制可以達到較低的損耗機率 (outage probability) ，因此較好。 Power control is an important issue in a DS-CDMA cellular radio system. A high system capacity could not be achieved for such a system unless a power control mechanism is employed in the system. In past works, the fixed-step strength-based and SIR-based power control mechanism on the uplink communication were studied, by simulation analysis. This thesis extend the study to the variable-step strength-based as well as the SIR-based power control mechanisms. A novel method of simulating the short-term fading signal is proposed to save the simulation time. From the simulation results, we find that the variable-step power control could achieve a lower outage probability than the fixed-step power control could do.