Dynamic Idle Mode Procedures for Femtocells

The concept of a user-deployed femtocell which operates in licensed spectrum and provides cellular coverage in the home has attracted much interest in the wireless industry and an extensive deployment of femtocells is expected in the future. However, several issues arise when femtocells become more widely deployed. One concern is the additional energy consumption caused by femtocells due to their continuous receiver processing and signal transmissions, which can be significant with a large number of femtocells. Secondly, the increase in the number of active cells can result in a high increase in core networks signalling for mobility procedures. Finally, the continuous pilot transmissions can cause interference, particularly in dense urban areas. In this paper all these issues are addressed by a novel idle mode procedure which allows the femtocell transmissions and associated processing to be switched off completely for all times when the femtocell does not need to support an active call.