n on the primary carrier. In this case, the BS may allocate one uplink fast-feedback channel per secondary carrier on the primary carrier. In multi-carrier aggregation with a downlink-only secondary partially-configured carrier, the MS is instructed to report the CINR measurements corresponding to downlink-only secondary carriers through the fast-feedback channel(s) on the primary carrier. In this case, the feedback region is allocated using the physical carrier index for the primary carrier. The starting logical index and the number of the distributed LRUs allo- cated to fast-feedback channels and the number of HARQ feedback channels are signaled in the AAI_SCD MAC control message that is transmitted on the active DL-only secondary carrier. The feedback region of the active DL-only secondary carriers are located after the feedback region of the primary carrier. Figure 11-9 illustrates an example of allocation of uplink control channels in the primary carrier uplink control region for downlink-only component carriers in a multi-carrier 11.4 MAC aspects of multi-carrier operation Aggregation of one Primary and Multiple Secondary Component Carriers Downlink Downlink Downlink Uplink Downlink Uplink Downlink Paired Downlink-Only Paired Downlink-Only Downlink-Only Component Component Component Component Component Carrier Carrier i Carrier Carrier j Carrier k (Primary) (Secondary) (Secondary) (Secondary) (Secondary) DL-UL Frequency Separation DL-UL Frequency Separation Frequency Spectrum and Component Carrier Aggregation -Index of Distributed Logical Resource Units in a Frequency Partition Bandwidth Feedback Feedback Request Feedback Feedback Feedback Feedback Channels Channels Channels Channels Channels Channels Channels Channels Downlink-Only Downlink-Only Primary Component Carrier Component Carrier i Component Carrier k Uplink Control Channels Uplink Control Channels Uplink Control Channels Allocation of Uplink Control Channels in Time and Frequency Uplink Control Region Data Channels Uplink Radio Frame Uplink Subfr