5G NR Scheduling Request Procedure | Uplink Grant

This page describes 5G NR Scheduling Request Procedure between UE and gNB. It mentions messages exchanged between UE and gNB in 5G NR Scheduling request procedure such as SR, uplink grant as defined in 3GPP PHY and MAC layer specifications.

5G NR Scheduling Request Procedure

• It is one of the many services expected by MAC layer from Physical layer.
• Whenever there is data to be transmitted, UE asks gNB (i.e. network) about uplink grant using "scheduling request" message over PUCCH channel.
• Network (i.e. gNB) replies the UE with uplink grant in DCI 0_0 or DCI 0_1 messages over PDCCH channel.
• After this, UE starts transmitting data over PUSCH channel.
• Some of the PUCCH formats are used to transport Scheduling Request message.
• Scheduling procedure is controlled by MAC layer processes as mentioned in the following pdf. The pdf is part of the 3GPP TS 38.321 document section 5.4.4.

References

• 3GPP TS 38.321 V15.2.0 (2018-06), MAC specification (Release 15)
• 3GPP TS 38.211 V15.2.0 (2018-06), Physical channels and modulation
• 3GPP TS 38.300 V15.2.0 (2018-06), NR and NG-RAN Overall Description