In UL, the UE has no dedicated resources to transmit directly when new data arrived in the buffer from higher layer.
It requests resources to transmit them.
It receives radio resources.
It transmits them.
- Scheduling Request to grant resources in UL
- Radio measurement report from the UEs
- User data
- User Signaling
- The resources are dynamically assigned in time and frequency.
- The PUSCH supports the H-ARQ.
- Data demodulation reference signal (DM-RS)
- Sent with each packet transmission in order to demodulate data
- Occupies center SC-FDMA symbol of the slot, only sent over bandwidth allocated for data transmission
- Used to sound uplink channel to support frequency selective scheduling
- SRS parameters are UE specific and configured semi-statically
- 1 symbol in subframe used for SRS
- Periodicity: {2, 5, 10, 20, 40, 80, 160, 320} ms
- Bandwidth: typically transmitted over the entire PUSCH
bandwidth (does not include PUCCH region) - SRS is not sent when there is a scheduling request (SR) or CQI to be sent on PUCCH (to avoid multicarrier transmission)