surement report, filtering parameters and time to trigger the measurement report. Inter-layer measurement: UE measures the configured frequencies and RATs during mea- surement gaps that are repeated at either 40-ms or 80-ms interval. The measurement gap length is ms. 5 During a measurement gap the UE cannot be scheduled in uplink or down- link and therefore measurement gaps induce throughput loss for the UE; there is no loss of cell throughput, however. The measurement phase consists of cell search and cell mea- surement phase, similar to the idle mode measurement process. The measurement results are averaged prior to evaluation of an event trigger. If connected mode DRX (C-DRX) is active the UE is allowed to use relaxed measurement schedule. 3. Measurement report: If one or more cells satisfy a measurement event the UE sends a measurement report. Unless reporting amount is restricted by measurement configuration, the UE will keep sending measurement reports for all cells that trigger a configured event until measurement gaps are deactivated, UE is moved to idle or it receives a handover command. If C-DRX is active, the UE is allowed to wait until next C-DRX active time before sending the measurement report. 4. Handover command: After receiving measurement report, eNodeB makes target cell selec- tion based on the reported cells. If successful, it initiates handover preparation towards the target cell or system. If the preparation succeeds, the target eNodeB sends the handover command to the UE through the source cell (transparent to source eNodeB). Figure 15.4 illustrates the cell search and measure procedure similar to what is used in some commercial modems at the time of writing. Connected mode DRX is not in use in the example. After measurement gap configuration has been completed the UE searches for cells in the target LTE layer; this can take several measurement gaps since all 504 PCIs need to scanned. After the search step has been completed, the UE enters measurement mode where within one gap it measures u