 leveraged for the UL and DL performance. HS-SCCH and E-DPCCH overhead associated with the data transmission Other control channel constraints for VoIP over HSPA would be the overhead from the VoIP packet transmission associated control channels such as HS-SCCHs in the DL and E-DPCCHs in the UL. The HS-SCCH is a DL physical channel used to carry DL signaling related to HS-DSCH transmission, whereas the E-DPCCH is a physi- cal channel used to transmit control information associated with the E-DCH. When a large number of users are served at a time, the control overhead (i.e., HS-SCCH overhead and E-DPCCH overhead) increases and the respective share of resources for the VoIP packet transmission of the user is reduced. Otherwise, more HARQ retransmissions would also increase this overhead. Thus, there would be a trade-off between the allowed retransmission number and the control overhead. 10.5.1.2 To support the transmission of DL and UL transport channels, certain associated UL and DL control signaling is needed. This is often referred to as L1/L2 control signaling, as the control information originates from both the physical layer (L1) and the MAC (L2). The DL L1/L2 control signaling, transmitted by using the Physical Downlink Control Channel (PDCCH), includes both PDSCH scheduling related information for each scheduled terminal and PUSCH related scheduling messages (aka scheduling grants). PDSCH scheduling information includes information about the used resource assignment and MCS, and it is necessary to the scheduled terminal to receive, demodulate, and decode PDSCH properly. PDCCH overhead limitations to VoIP DL capacity are discussed in the "PDCCH overhead" subsection. Like LTE DL, LTE UL needs for certain associated L1/L2 control signaling to support the transmission of DL and UL transport channels. The L1/L2 control sig- naling is carried by the Physical Uplink Control Channel (PUCCH), and the car- ried L1/L2 control signaling includes HARQ acknowledgments for scheduled and received PDSCH resource blocks in D