L, CQI information indicating the channel quality estimated by the terminal, and UL scheduling requests indicating that the terminal needs UL resources for PUSCH transmissions. The biggest part of UL L1/ L2 control signaling originates from CQI signaling, which is required by the chan- nel aware scheduler at eNodeB to exploit the time and frequency domain schedul- ing gains of PDSCH. With VoIP traffic the CQI signaling overhead may start to © 2009 by Taylor & Francis Group, LLC Radio Access Network VolP Optimization limit VoIP UL capacity, as the number of supported users in E-UTRA is large. The CQI overhead issue is handled in the "CQI overhead" subsection. PDCCH overhead As in HSPA, the baseline scheduler for VoIP traffic is the fully dynamic packet scheduling method, where each packet is transmitted by L1 control signaling. As described in Section 10.4.2, multiuser channel sharing plays an important role when optimizing air interface capacity for VoIP traffic. As PDCCH should be transmitted to each scheduled terminal, PDCCH overhead may become a limiting factor for VoIP capacity. Due to this reason, there are not enough control chan- nel resources to schedule all physical resource blocks (PRBs), and hence part of PDSCH capacity is wasted. For example, at 5 MHz bandwidth with an AMR 12.2 kbps codec, the PDSCH utilization rate for fully dynamic PS is only 35%. One way to avoid control channel limitations with fully dynamic PS, is that several of a user's VoIP packets can be bundled at L1 for one transmission, as described in Section 10.6.2.1. The main benefit from bundling is that more users could be fitted to the network with the same control channel overhead, as good users are scheduled less often. This will lead to significant capacity improvements in the control channel limited situation. For example, at 5 MHz bandwidth with an AMR 12.2 kbps codec, VoIP DL capacity is improved by 75-80% and the PDSCH utilization rate is increased from 35% to 70% when packet bundling (up to two packets bundled together) is us