he packets are lost (i.e., lost or erroneous) during the whole call. 10.7.2.2 Simulation Results and Analysis VolP performance in LTE VoIP capacity numbers for LTE are summarized in Table 10.10 for both DL and UL directions. Let us analyze the DL results first. As described in Section 10.5.1.2, the performance of the fully dynamic PS with- out packet bundling is limited by the available PDCCH resources, due to which savings in VoIP packet size are not mapped directly to capacity gains. This can be verified from the results showing almost identical performance for AMR 7.95 and AMR 12.2. With packet bundling, control channel limitations can be partly avoided and, hence, the VoIP capacity with fully dynamic PS can be boosted up © 2009 by Taylor & Francis Group, LLC Radio Access Network VoIP Optimization Table 10.9 Main UL Related Simulation Assumptions Description Settings Multiple access SC-FDMA UE transmission power Max 24 dBm Power dynamics of UEs at eNodeB 17 dB Transmission scheme 1 X 2 Receivers 2-antenna with MRC combining UL control overhead 2 PRBs per TTI MCS set As in [17] 8 HARQ SAW channel. Synchronous, adaptive HARQ with incremental redundancy (IR). Maximum 6 retransmissions Packet scheduler Dynamic PS, semi-persistent PS PDCCH assumption 10 CCEs reserved for UL per TTI (max 10 users could be scheduled dynamically per TTI) to 90%. With bundling, the performance of fully dynamic PS starts to suffer from data limitation as well, due to which small gains in capacity (8%) can be achieved when AMR 7.95 is used instead of AMR 12.2. On the other hand, the perfor- mance of semi-persistent PS is data limited instead and, hence, savings in VoIP packet size are nicely mapped to gains in capacity-approximately 35% higher capacity is obtained if AMR 7.95 is used instead of AMR 12.2. When comparing the performances of fully dynamic PS and semi-persistent PS with each other, it is concluded that if packet bundling is not allowed, then the performance of fully dynamic PS is badly control channel limited and, hence, sem