On the economic aspects of downlink scheduling in DS-CDMA systems : base station density perspective

Abstract

The rapid growth of wireless telephony gives rise to an increasing demand for transmission capacity. Moreover wireless systems have been evolved to support multirate data services. However, as the data rates for the services increase, the number of base stations per service area is needed to expand, which leads to a high-degree of base station density. On the other hands, the so called best-effort resource management has been extensively studied for such non-real-time data services. One representative example of such efforts can be found in the packet scheduling. The main purpose of this thesis is to investigate the economic impact of the downlink scheduling, in terms of the required base station density. For the purpose, we have derived equations that can calculate the base station density under given QoS requirements. With specific environments we assumed, it is found that the one-by-one downlink scheduling (round-robin) requires about 30 ~ 40 percentages of the base stations required by the conventional simultaneous transmission. We have also found that this impact is almost same as simply doubling the bandwidth on the simultaneous transmission. The base station density is directly related to infrastructure cost, and thus may be translated into service prices. Therefore, our analysis provides an insight into an economic aspect; how much service prices for downloading non-real-time data would decrease with the introduction of a packet scheduling in the CDMA downlink.