SRS (LTE)

SRS Signaling Reference Signal is the Sounding Reference Signal and can be transmitted by each uplink user. SRS is used by the base station to get a more accurate calculation of a particular user's uplink channel.

The sounding reference signal (SRS) is transmitted separately from PUCCH and PUSCH. SRS can be transmitted on any number of subcarriers in the last symbol in a subframe. SRS takes precedence over all other allocated channels except PUCCH Physical Uplink Control Channel Format 1 transmissions.

In TDD Time Division Duplex: A duplexing technique dividing a radio channel in time to allow downlink operation during part of the frame period and uplink operation in the remainder of the frame period. mode, SRS can also be transmitted in the last two symbols of the special subframe when UpPTS Uplink Pilot Time Slot (LTE TDD) is configured to be long enough.

SRS is transmitted by a UE User Equipment (e.g. cell phone) to give the base station an idea of the uplink channel characteristics for that UE. The base station can use the information to assign good uplink allocations for the UE to transmit on.

SRS is transmitted as a Zadoff-Chu sequence.