LTE E-UTRA Uplink Reference Signals

•Two types of E-UTRA/LTE Uplink Reference
Signals:
• Demodulation reference signal
– Associated with transmission of PUSCH or PUCCH
– Purpose: Channel estimation for uplink coherent demodulation/detection of the uplink control and data channels
– Transmitted in time/frequency depending on the channel type (PUSCH/PUCCH), format, and cyclic prefix type
• Sounding reference signal
– Not associated with transmission of PUSCH or PUCCH
– Purpose: Uplink channel quality estimation feedback to the uplink scheduler (for Channel Dependent Scheduling) at the e-NodeB
– Transmitted in time/frequency depending on the SRS bandwidth and the SRS bandwidth configuration (some rules apply if overlap with PUSCH and PUCCH)

Notes
•The same set of base sequences is used to generate demodulation and sounding reference signals
•The base sequences and the reference signals are derived from Zadoff-Chu sequences
•Cyclic shifts can be applied to a base sequence to obtain multiple reference signal sequences