compared with sending one packet per TTI, bundling multiple packets together in one transmission can reduce related control channel signaling overhead and thus improve air interface efficiency. More details about packet bundling can be found in Section 10.6.2.1. Packet bundling is typically utilized in the downlink direction only, due to the UE power shortage. However, packet bundling is applicable in the UL direction as well if 10 ms TTI is used [12]. 10.6.1.2 HS-SCCH-Less Operation 3GPP Release 7 also allows HS-SCCH-less operation in the DL to minimize the interference from HS-SCCH. The high VoIP capacity typically requires 4-6 code multiplexed users on HS-DSCH in the DL of Release 6. Each code multiplexed user requires an HS-SCCH channel. HS-SCCH-less operation can be applied for VoIP when the packet interarrival time is constant. In HS-SCCH-less operation it is possible to send HS-PDSCH without associated HS-SCCH by using predefined transmission parameters (e.g., modulation and coding scheme, channelization code set, transport block size) configured by higher layers and signaled to UE via RRC signaling. HS-SCCH-less operation implies that UE has to blindly decode the HS-PDSCH that has been received without associated HS-SCCH. The interfer- ence from HS-SCCH transmissions can be avoided with HS-SCCH-less operation, leading to higher VoIP capacity. The dynamic HS-DSCH power allocation on HS-PDSCH and HS-SCCH channels in the case of HS-SCCH-less operation for VoIP service enables support- ing more than four code-multiplexed users on HS-DSCH due to the more efficient use of the scarce power resources. This improves performance, especially with the short 80 ms delay requirement, as buffering of VoIP packets in MAC-hs is becom- ing very restricted, leading to the higher power requirement. 10.6.2 Solutions in LTE 10.6.2.1 Packet Bundling The size of the VoIP packet is typically very small; for example, for the AMR 12.2 kbps codec, the size of the most common ROHC compressed packet is 40 bytes. This, together with st