g BS via the core network. The serving BS will then send this information to the MS using the AAI_HO-CMD MAC control message. As a result, the pre-assigned secondary carriers (identified by the Carrier Status Bitmap) may be activated on completion of the network re-entry. The MS starts the activation CHAPTER 11 Multi-Carrier Operation (Serving) Fully- Fully- Fully- Fully- Primary Secondary Fully- Fully- Carrier Carrier Configured Configured Configured Configured Configured Configured Carrier 1 Carrier 2 Carrier 1 Carrier 2 Carrier 1 Carrier 2 AAI_NBR-ADV (N_Neighbors=2) (Multi-carrier Configuration) AAI_SCN-REQ (Scan Duration = N Frames) (ID of Carriers for Scanning) AAI_SCN-RSP (Start Frame = M Frames) (Duration = N Frames) M Frames Synchronize with Carrier 2 of BS 1 Synchronize with Carrier 1 of BS 2 Synchronize with Carrier 2 of BS 2 Synchronize with Carrier of BS 3 Synchronize with Carrier 2 of BS FIGURE 11-12 Scanning procedure in multi-radio mobile station [2] procedure for these secondary carriers after receiving the AAI_RNG-RSP message from the target BS. The target BS may initiate data transmission on the activated secondary carriers on reception of the AAI_CM-IND message from the MS after network re-entry. If the AAI_CM-IND message is not received by the target BS within the Activation Deadline specified in the AAI_RNG-RSP, the target BS concludes that the secondary carrier activation for this mobile station has failed. In this case, the target BS may send an AAI_CM-CMD message to the MS to activate another secondary carrier. It must be noted that the serving BS is required to inform the target base stations of the multi-carrier capability of the MS. During this process, if the multi-carrier configuration of the target BS is different from the serving BS and unsuitable for the MS, the MS may negotiate its desirable multi-carrier configuration with the target BS through AAI_MC-REQ/RSP messages. If the Carrier_Preassignment_Indication flag in the AAI_HO-CMD message is set to zero, the MS follows the norma