jected MS Authorization and Key Re-registration Exchange Cell Rejected Reestablishment of Service Registration with BS Flows IP Connection IP Connection Normal Operation Establishment Reestablishment Operations with the Base Station Transfer of Operational Parameters HO Execution Connection Establishment Cell Reselection Scanning Intervals for Detecting and Normal Operation Evaluating Neighbor Cells HO Decision FIGURE 6-14 The handover process [1] 6.4 Mobility management and handover messages, etc.) and dynamic information consists of all counters, timers, state machine status, and data buffer contents (e.g., ARQ window). The transaction states, which may impact configuration parameters, are considered dynamic context until complete, which by then is considered static context [1]. The security information is always considered static context. Depending on the amount of information, the target BS may decide to skip one or several of the following network entry steps: (1) basic capability negotiation; (2) PKM viii authentication; (3) TEK establishment; (4) REG-REQ message; and (5) unsolicited REG-RSP message. 5. Termination of MS Context: the final step in handover is termination of MS context that is defined as serving BS termination of context of all connections belonging to the MS and the context associated with them (i.e., information in queues, ARQ state machine, counters, timers, header suppression information, etc., are discarded). 6. Handover Cancellation: an MS may cancel handover via a MOB_HO-IND message at any time prior to expiration of Resource_Retain_Time after transmission of MOB_MSHO-REQ (in case of MS-initiated handover) or MOB_BSHO-REQ (in case of BS-initiated handover). 6.4.3 IEEE 802.16m Handover Scenarios The following handover scenarios are supported in IEEE 802.16m: 1. Handover from a legacy BS to a legacy BS; 2. Handover from a new BS to a legacy BS; 3. Handover from a legacy BS to a new BS; 4. Handover from a new BS to a new BS. The IEEE 802.16m radio access network and mobile station use le