LTE, LTE-Advanced and WiMAX: Towards IMT-Advanced Networks

7

Mobility Management

IEEE 802.16 provides efficient mobility support for higher management structures, for example, Mobile IP. As is typical of cellular systems, BSs in IEEE 802.16-2009 oversee much of the mobility management signaling. In relay systems, some responsibilities can be assigned to scheduling ntRSs in order to maintain their autonomy and network efficiency. While inter-RAT handovers are accommodated in IEEE 802.16-2009, the IEEE 802.16m amendment expands this accommodation to allow greater flexibility in management and operation.

This chapter is organized as follows. Section 7.1 discusses mobility management in IEEE 802.16-2009, while Sections 7.2 and 7.3 discuss mobility managements in the amendments IEEE 802.16j-2009 and IEEE 802.16m, respectively. A particular emphasis is made in Section 7.1 in describing the handover process, which underwent certain optimizations in IEEE 802.16m. Section 7.2 elaborates on the added considerations made when relay networks are employed, including when a relay station itself is mobile. Section 7.3, on the other, describes both purely Advanced and mixed Advanced-Legacy IEEE 802.16 handovers will be carried. The section also describes particulars of handovers of inter-RAT and femtocell mobility.