Chapter 16
Uplink Physical Channel Structure
16.1 Introduction
The LTE Single-Carrier Frequency Division Multiple Access (SC-FDMA) uplink provides separate physical channels for the transmission of data and control signalling, the latter being predominantly to support the downlink data transmissions. The detailed structure of these channels, as explained in this chapter, is designed to make efficient use of the available frequency-domain resources and to support effective multiplexing between data and control signalling.
LTE Release 8 also incorporates uplink multiple antenna techniques, including closed-loop antenna selection and Spatial Division Multiple Access (SDMA) or Multi-User Multiple-Input Multiple-Output (MU-MIMO). More advanced multiple-antenna techniques, including closed-loop spatial multiplexing for Single-User MIMO (SU-MIMO) and transmit diversity for control signalling are introduced in Release 10 for LTE-Advanced, as explained in Section 29.4.
The physical layer transmissions of the LTE uplink comprise three physical channels and two signals:
- PRACH – Physical Random Access CHannel (see Chapter 17);
- PUSCH – Physical Uplink Shared CHannel (see Section 16.2);
- PUCCH – Physical Uplink Control CHannel (see Section 16.3);
- DM-RS – DeModulation Reference Signal (see Section 15.5);
- SRS – Sounding Reference Signal (see Section 15.6).
The uplink physical channels, and their relationship to the higher-layer channels, are summarized in Figure ...
