vides responses (e.g., adjustments, ranging status, etc.) to all successfully received and decoded initial ranging requests in the initial ranging slots in a previous UL subframe, in a predefined, subsequent DL subframe. AAI_SBC-REQ A message containing the Network Entry/ SBC-REQ Unicast MS Basic Capability maximum "Capability Class" Re-entry Request that the MS can support. The maximum value of CAPABILITY_INDEX is denoted by N bits. A "Capability Class" is defined as a unique set of functions, configuration parameters, air interface protocol revision, and/or services that can uniquely describe a mobile station implementation or configuration while operating in the network. The MS, by default, is required to support (Continued) Table 6-8 IEEE 802.1 16m MAC Management/Control Messages [1,2] Continued 802.16- IEEE 802.16m MAC Management Standard Message Equivalent Message Description Security Usage Connection Message Attributes the basic capabilities associated with "Capability Class 0." If the MS is capable of supporting higher revisions of physical layer or medium access control layer protocols or further wishes to use enhanced features, it sends an AAI_SBC-REQ message to the BS indicating the highest "CAPABILITY_INDEX" that it can support. The CAPABILITY_INDEX = 0 indicates the default capability index and basic feature set or configuration parameters and may not need to be signaled. AAI_SBC-RSP Upon receipt of the AAI_SBC- Network Entry/ MS Basic Capability SBC-RSP REQ message containing the Unicast Re-entry Response "CAPABILITY_INDEX" from the MS, the BS determines whether it could allow or could support the requested feature set or MAC and/or PHY protocol revisions. If the BS does support or can allow the use of enhanced features, it responds with an AAI_SBC- RSP message to inform the MS of its decision. The BS may signal a "CAPABILITY_INDEX" which is numerically different than the one requested by the MS. The "CAPABILITY_ INDEX" values range from 0 to N, where N denotes the maximum CAPABILITY_INDEX value. Th