ut optimizing for a large number of UEs being simultaneously scheduled on multiple downlink component carriers. The scheduling request is transmitted on PUCCH and is semi-statically mapped to one UE-specific uplink component carrier. Periodic CSI reporting on PUCCH is supported for up to five downlink component carriers. The CSI is semi-statically mapped onto one UE-specific UL component carrier and the design follows the Rel-8 principles for the transmission of CQI/PMI/RI. This option can provide for maximum reuse of Rel-8 functionalities and better HARQ performance, due to a carrier component-based link adaptation, with the drawback of multiple HARQ feedback in The capacity gain provided by cellular systems is offset to some extent by loss of trunking efficiency, which is the queuing efficiency resulting from a large number of users receiving service from a set of servers, rather than proportionally assigning each user to one of the servers. If a disproportionate number of mobile stations are simultaneously located in a single cell, a cellular system might practically end up supporting fewer users than a wide area radio system. Because relatively few of the users who are aggregated in the cell can receive service, due to the fact that only a subset of channels is available in the cell, the cellular system may appear ineffective. If the cell can only support m channels, the (m + 1)th simultaneous user could be blocked from receiving service. 11.5 3GPP LTE-Advanced multi-carrier operation each TTI. This also implies that the uplink transmission format will be a multi-carrier transmission consisting of aggregation of N DFT-S-OFDM carriers (N X DFT-S-OFDM). The alternative case of multiple transport blocks and HARQ entities where each transport block can be mapped into multiple component carriers was studied during the development of IEEE 802.16m, and was ruled out due to complexity. From the UE perspective, the Layer 2 aspects of HARQ operation are similar to that of 3GPP LTE Rel-8. There is one transport block wi