esources may be divided between the two systems. A legacy BS advertises the system information for its neighbor base stations and the legacy zones of its neighbor new base stations. The legacy zone (LZone) is a time-frequency region (i.e., an integer number of subframes over partial or full system bandwidth) where the legacy mobile stations are supported in a new base station radio frame. A new zone (MZone) is a time-frequency region in the radio frame where the new mobile stations are supported. A new BS advertises the system information of its neighbor legacy base stations in both legacy and new zones. It further advertises the legacy zone of its neighbor new base stations, as well as system configuration of its neighbor new base stations. A new BS may indicate its legacy support through broadcast information transmitted in its legacy zone. As soon as handover from a legacy BS to a new BS is triggered for a legacy MS, the MS is handed over from the serving legacy BS to the legacy zone of the target new BS using legacy handover signaling and procedures. A new MS may be handed over from the serving legacy BS to the legacy zone of the target new BS and then be switched to the new zones following the completion of handover procedure (i.e., zone switching). A new MS may also perform handover from a legacy BS to a new BS or directly to the new zone of the new BS, if the MS is capable of scanning the new BS prior to handover. If handover from a new serving to a legacy target BS is triggered for a legacy MS, the MS handover is from the legacy zone of the serving BS to the target BS using legacy handover signaling and procedures [1]. If handover from a new BS to a legacy BS is triggered for a new MS, the serving BS and the MS perform handover execution using handover signaling and procedures as specified by IEEE 802.16 [2]. If necessary, the serving BS performs context mapping and protocol inter-working from the new to the legacy system. The MS performs network re-entry with target legacy BS using network re-entry signa