assign the newly arrived user to the carrier that has the least number of users. Thus, it tries to distribute the load evenly over all the component carriers. However, there might be small load variations on different component carriers, as the number of users per cell does not always divide equally into the number of component carriers, or because of the random departure of users. Mobile Hashing load balancing, also known as the Independent Carrier Channel Assignment, relies on the output from the Downlink Uplink Band i Band i Network A Network B Network C Network D Network A Network B Network C Network D Intra-band No Carrier Aggregation Band i Band i Network A Network A Network C Network D Network A Network A Network C Network D Intra-band Contiguous Carrier Aggregation Band i Band i Network A Network B Network C Network A Network A Network B Network C Network A Intra-band Non-contiguous Carrier Aggregation Band i Band j Band i Band j Network A Network B Network C Network D Network A Network B Network C Network D Inter-band No Carrier Aggregation Band i Band j Band i Band j Network A Network B Network C Network A Network A Network B Network C Network A Inter-band Non-Contiguous Carrier Aggregation FIGURE 11-15 Carrier aggregation scenarios sportson CHAPTER 11 Multi-Carrier Operation terminal's hashing algorithm. The output hash values are uniformly distributed among a finite set, which maps directly onto the component carrier indices. Thereby, it provides a balanced load across the component carriers in the long-term. However, at each time-instant, the load across component carriers is not guaranteed to be balanced, and as a consequence the system will suffer from reduced trunking efficiency. [5,10,14,15]. In multi-carrier aggregation, each component carrier can have an independent control region due to the different number of users and allocation sizes on each carrier. In order to maintain backward compatibility, the 3GPP LTE Rel-8 PCFICH design (modulation, coding, and mapping to resource elements) is reused