 of contiguous component carriers. If the network supports multiple groups of contiguous component carriers, each group of the contiguous carriers is identified in the AAI_MC-ADV MAC control message by an index in this table. As an example, the multi-carrier configuration {5, 10} represents two contiguous component carriers of 5 and 10 MHz. Based on the center frequency of the component carrier on which the MS receives the AAI_MC-ADV message, and the bandwidth of each component carrier, the center frequency of each component carrier before sub-carrier alignment can be calculated. Thus, the MS can obtain the frequency offset offset to be applied to each component carrier based on the multi-carrier configuration index, the physical carrier index of the current carrier, and the information in Table 11-1. If two adjacent component carriers are used to deploy the IEEE 802.16m and the legacy systems, they are considered as two non-contiguous carriers and identified with different carrier group indices in the CHAPTER 11 Multi-Carrier Operation AAI_MC-ADV message. The BS and the (multi-carrier capable) MS are required to encode and decode all multi-carrier configurations in Table 11-1, and to apply the corresponding frequency offset before activating multi-carrier operation. Under the conditions discussed earlier, the guard sub-carriers between contiguous frequency channels may be utilized for data transmission. During the secondary carrier assignment procedure, the serving BS sends the information about available guard sub-carriers, which can be used for data transmission, to the MS. The support for multiple component carriers is provided with the same frame structure as that used for single-carrier operation; however, some considerations in the design of protocol and channel structure may be needed to facilitate multi-carrier operation. In general, each MS compliant with the IEEE 802.16m standard is served by one component carrier, which is referred to as the primary component carrier. When multi-carrier operation is e