urrent and target cell operates on the same carrier frequency. Neighbor cell measurements performed by the UE are inter-frequency measurements when the neighbor cell operates on a different carrier frequency compared to the current cell. 6.13.2 Scheduling and Rate Control Functions In order to efficiently utilize the shared radio resources, a scheduling function is used in the MAC sub- layer. In this section, an overview of the scheduler is provided in terms of scheduler operation, signaling of scheduler decisions, and measurements to support scheduler operation. The MAC in eNB includes dynamic resource schedulers that allocate physical layer resources for the downlink and uplink transport channels. Different schedulers operate for the downlink and uplink shared channels. The scheduler takes into account the system load and the QoS requirements of each UE and associated radio bearers when allocating resources to mobile terminals. Per UE grants are used to allow trans- mission on the uplink shared channel. The schedulers may assign resources considering the radio conditions at the UE identified through measurements conducted at the eNB and/or reported by the UE. The radio resource allocations can be valid for one or multiple Transmission Time Intervals (TTIs). The resource assignment consists of physical resource blocks, and modulation and coding schemes. Allocations for time periods longer than one TTI might also require additional information. In the downlink, the E-UTRAN can dynamically allocate resources to UEs at each TTI via the C- RNTI (similar to STID in IEEE 802.16m) on Physical Downlink Control Channel (PDCCH). A UE always monitors the PDCCH in order to find possible allocation when its downlink reception is CHAPTER 6 The IEEE 802.16m MAC CPS (Part I) Serving eNB Target eNB Serving Gateway SO: Area Restriction Provided S1: Measurement Control L3 signaling User Data User Data L1/L2 signaling UL allocation User Data S2: Measurement Reports S3: HO decision Handover Request S5: Admission Control DL allocatio