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

Mobility Management in IEEE 802.16j-2009

The IEEE 802.16j amendment describes how the MR-BSs and the RSs should behave during MS mobility between MR-BSs and RSs, and between different RS. The amendment also details the signaling required for RS mobility. In both cases, the MR-BS maintains substantial control of MS handover, even when scheduling ntRSs are involved.

MR-BS and RS Behavior during MS Handover

Depending on the type of the MS's target superordinate station, the MR-BS ensures sufficient resources are provided so that signaling between the MR-BS and the MS can be delivered. If the superordinate is an ntRS with centralized scheduling, MR-BS inserts a Fast Ranging IE in the UL-MAP to be broadcast on the access link and provides sufficient bandwidth on the relay link for forwarding the RNG-REQ. If the superordinate station is a scheduling ntRS, it is instructed by the MR-BS to send the Fast Ranging IE. For tRSs, the MR-BS inserts the Fast Ranging IE in the UL-MAP and provides sufficient bandwidth in the tRS's uplink; the tRS, in turn, would forward the RNG-REQ on the access link.

For topology advertisement, each ntRS may advertise differently from the MR-BS's own MOB_NBR-ADV. Under centralized scheduling, the MR-BS must allocate bandwidth for its advertisement; under distributed scheduling, the RSs are autonomous in their allocation.

MR-BS controls the scanning procedure. Scheduling ntRSs coordinate with MR-BS to schedule scanning, and may terminate scanning procedures if ...