HCS: decision procedure for an interlayer handover

The implementation of a hierarchical cell structure (HCS) for covering areas with high traffic load can increase the network performance. In general, three types of cells (layers) can be distinguished. These are picocells (picolayer), microcells (microlayer), and macrocells (macrolayer). The HCS technique is especially suitable if the traffic is generated from different user classes with regards to their average speed (e.g. pedestrians, slow vehicles, fast vehicles, etc.). There are two driving factors: (i) increasing the network capacity, which promotes use of small cells (e.g. microcells); and (ii) decreasing the number of handovers, which promotes use of larger cells (e.g. macrocells). An HCS system has one major impact on the radio resource management (RRM) that is dividing the available radio resources into parts for each layer. The amount of dedicated bandwidth should provide an acceptable quality of service (QoS) for the offered traffic in a particular layer. However, due to the scarcity of the radio bandwidth these resources should be used very efficiently. An interlayer handover is a step forward in achieving higher bandwidth utilization. In this investigation the focus is on the interaction between the macrolayer and microlayer through the interlayer handover procedure.