5G NR Timers | T304, T310, T311 timer used in 5G NR

This page covers 5G NR timers which include T304 timer, T310 timer and T311 timer used in 5G NR (New Radio) for various functions. It mentions usage of constants N310 and N311.

5G NR Timers	Start	Stop	at Expiry
T304	Reception of RRCReconfiguration message including reconfigurationWithSync	Successful completion of random access on the corresponding SpCell For T304 of SCG, upon SCG release	For T304 of SCG, inform network about the reconfiguration with sync failure by initiating the SCG failure information procedure as specified in 5.7.3 of TS 38.331 (3GPP).
T310	Upon detecting physical layer problems for the SpCell i.e. upon receiving N310 consecutive out-of-sync indications from lower layers.	Upon receiving N311 consecutive in-sync indications from lower layers for the SpCell, upon receiving RRCReconfiguration with reconfigurationWithSync for that cell group, and upon initiating the connection re-establishment procedure. Upon SCG release, if the T310 is kept in SCG.	If the T310 is kept in MCG: If security is not activated: go to RRC_IDLE else: initiate the connection re-establishment procedure. If the T310 is kept in SCG, Inform E-UTRAN/NR about the SCG radio link failure by initiating the SCG failure information procedure as specified in 5.7.3.
T311	Upon initiating the RRC connection re-establishment procedure	Selection of a suitable NR cell or a cell using another RAT.	Enter RRC_IDLE

When the 5G NR UE applies zero value for the timer, the timer shall be started and immediately expire unless explicitly stated otherwise.

5G NR constants | N310, N311

Following table mentions usage of constants N310 and N311 in 5G NR system.
• N310: Maximum number of consecutive "out-of-sync" indications for the PCell received from lower layers.
• N311: Maximum number of consecutive "in-sync" indications for the PCell received from lower layers

GSM Timers | WCDMA Timers | LTE Timers

Following links are on useful GSM timers, WCDMA timers and LTE timers other than 5G timers mentioned on this page.
•  GSM Timers
•  WCDMA Timers
•  GSM MS Timers
•  GSM BTS Timers
•  LTE Timers

5G NR Numerology | 5G NR Terminology

• 5G NR PHY timing unit • 5G NR SLIV • 5G NR Mini Slot • 5G NR Bandwidth Part • 5G NR CORESET • 5G NR DCI Formats • 5G NR UCI • 5G NR slot formats • 5G NR RRC IEs • 5G NR RSRP RSRQ SINR

5G NR Control channels | 5G NR Traffic Channels | 5G NR Reference Signals and sequences

• 5G NR SSB, SS, PBCH • 5G NR PRACH • 5G NR PDCCH • 5G NR PUCCH • 5G NR Reference Signals • 5G NR m-Sequence • 5G NR Gold Sequence • 5G NR Zadoff Chu Sequence

RF and Wireless Terminologies

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