t to the MS in response to the AAI_MC-REQ message, it may also be sent by the BS to update the list of assigned carriers in an unsolicited manner. AAI_CM-CMD The activation or deactivation Carrier Management Multi-carrier of secondary carriers is Command decided by the BS based on Operation/Normal Encrypted/ICV Unicast Operation QoS requirement, load condition of carriers, and other criteria. The BS activates and/or deactivates the secondary carrier with the AAI_CM-CMD message. The BS sends the AAI_CM-CMD message on the primary carrier and includes the following parameters: Indication Type per DL/UL (Activation or Deactivation); list of secondary carriers (addressed by physical carrier index); and the Ranging Indicator for the activated carrier. The AAI_CM-CMD message may allocate feedback channel for the activated carriers without paired UL; e.g., partially configured carrier or asymmetrically activated DL carrier. AAI_CM-IND In response to the AAI_CM- Carrier Management Multi-carrier CMD message, the MS Indication Operation/Normal Encrypted/ICV Unicast transmits the AAI_CM-IND Operation MAC control message through the primary carrier. This message confirms that the MS has successfully (Continued) Table 6-8 IEEE 802. 16m MAC Management/Control Messages [1,2] Continued 802.16- IEEE 802.16m Standard MAC Management Equivalent Security Connection Message Message Description Usage Message Attributes activated/deactivated the carriers listed in the AAI_CM- CMD message. In the case of activation, the confirmation is sent by the MS when the DL/ UL of the newly activated carrier is ready to be used to transport data traffic. AAI_SingleBS, This message is sent by an Normal Operation Encrypted/ICV Unicast MIMO_FBK MS to respond to Feedback Single-BS MIMO Polling A-MAP IE requesting Feedback to feedback the sub-band information for MIMO Feedback Modes 2, 3, 5, or 6. It is also used to feedback the transmit correlation matrix when the BS has 8 transmit antennas. AAI_MultiBS This message is sent by an Normal Operation Encrypt