Non-real time packet transmission for a microcell (hotspot) embedded in CDMA macrocell systems

In a macrocell network, there will remain some geographical areas within the cell coverage where mobile stations require further services. These are mainly in terms of downloading data, in particular in temporary or permanent hotspot areas, such as exhibitions, conference centers, etc. The objective of this study is to obtain extra capacity for W-CDMA systems by adding hotspot base stations to an already present continuous macrocell layer. IP-based services are offered to local mobile stations, using packet switched transmission without additional bandwidth; i.e. using the same frequency band in both the hotspot and macrocell. In order to maximize the hotspot base station throughput, and at the same time, to minimize the interlayer interference from hotspot to macrocell, a new link quality control scheme is designed. Downlink system level simulations are also carried out to prove the feasibility of the idea and to show the effect of required E_b/(I_o + N_o) for macrocell users, on the hotspot data throughput.