Performance of Macro and Co-channel Femto Cells in a Hierarchical Cell Structure

In this paper, the feasibility of user deployed femto cells in the same frequency band as an existing macro-cell network is investigated. Key requirements for co-channel operation of femto cells such as auto-configuration and public access are discussed. A method for power control for pilot and data that ensures a constant femto cell radius in the downlink and a low pre-definable uplink performance impact to the macro cells is proposed, and the theoretical performance of randomly deployed femto cells in such a hierarchical cell structure is analysed for one example of a cellular UMTS network using system level simulations. The resulting impact on the existing macro-cellular network is also investigated