5G（NR）網(wǎng)絡(luò)無線資源控制(RRC)中引入了下列計(jì)時(shí)器、計(jì)數(shù)器和常量，以便UE在RRC setuprequest, RRC reestablishment, RRC resume, RRC suspend等進(jìn)程的可靠運(yùn)行。

        RRC計(jì)時(shí)器，指示計(jì)時(shí)器持續(xù)時(shí)間及在事件中何時(shí)開始和停止；如果計(jì)時(shí)器超時(shí)，UE將采取的行動。這些計(jì)時(shí)器由字母“T”表示，后跟3位數(shù)字，例如 T300。每個(gè)計(jì)時(shí)器起始值為零；UE應(yīng)用的計(jì)時(shí)器值倒計(jì)數(shù)為零時(shí)，則計(jì)為超時(shí)；除非明確說明另有規(guī)定。

•         Timer: T300

•         Start Point:（起始點(diǎn)）

•         Upon transmission of RRCSetupRequest

•         Stop Point:（結(jié)束點(diǎn)）

•         Upon reception of RRCSetup or RRCReject message

•         Upon Cell re-selection

•         Upon abortion of connection establishment by        upper layers

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         Timer: T301

•         Start Point:（起始點(diǎn)）

•         Upon transmission of RRCReestabilshmentRequest

•         Stop Point:（結(jié)束點(diǎn)）

•         Upon reception of RRCReestablishment or RRCSetupmessage

•         when the selected cell becomes unsuitable

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         Go to RRC-IDLE

•         Timer: T302

•         Start Point:（起始點(diǎn)）

•         Upon reception of RRCReject while        performing RRC connection establishment or resume,

•         Upon reception of RRCRelease with        waitTime

•         Stop Point:（結(jié)束點(diǎn)）

•         Upon entering RRC-CONNECTED or RRC-IDLE

•         Upon cell re-selection

•         Upon reception of RRCReject message

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         Inform upper layers about barring        alleviation

•         Timer: T304

•         Start Point:（起始點(diǎn)）

•         Upon detecting physical layer problems for        the SpCell i.e. upon receiving N310 consecutive        out-of sync indications from lower layers

•         Stop Point:（結(jié)束點(diǎn)）

•         Upon receiving N311 consecutive in-sync indications        from lower layers for the SpCell,

•         Upon receiving RRCReconfiguration with        reconfiguration With Sync for that cell group, and upon initiating the        connection re-establishment procedure.

•         Upon SCG release, if the T310 is        kept in SCG

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         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 of specification 38.331

•         Timer: T311

•         Start Point:（起始點(diǎn)）

•         Upon initiating the RRC connection reestablishment procedure

•         Stop Point:（結(jié)束點(diǎn)）

•         Upon selection of a suitable NR cell        or a cell using another RAT

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         Enter RRC_IDLE

•         Timer: T319

•         Start Point:（起始點(diǎn)）

•         Upon transmission of RRCResumeRequest

•         Stop Point:（結(jié)束點(diǎn)）

•         Upon reception of RRCResume, RRCSetup,        RRCRelease, RRCRelease with suspendConfig or RRCReject message, cell        re-selection

•         Upon abortion of connection establishment by        upper layers

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         Perform the actions as specified in 5.3.13.5 of        3GPP specification 38.331

•         Timer: T320

•         Start Point:（起始點(diǎn)）

•         Upon reception of t320

•         upon cell (re)selection to NR from another        RAT with validity time configured for dedicated priorities (in        which case the remaining validity time is applied)

•         Stop Point:（結(jié)束點(diǎn)）

•         Upon entering RRC-CONNECTED,

•         Upon reception of RRC Release,        when PLMN selection is performed on request by NAS

•         Upon cell (re)selection to another RAT (in        which case the timer is carried on to the other RAT)

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

• Discard the cell re-selection priority        information provided by dedicated signalling

•         Timer: T321

•         Start Point:（起始點(diǎn)）

•         Upon receiving measConfig including        a reportConfig with the purpose set to report CGI

•         Stop Point:（結(jié)束點(diǎn)）

•         Upon acquiring the information needed to set        all fields of cgiinfo

•         Upon receiving measConfig that        includes removal of the reportConfig with the purpose        set to reportCGI

•         upon detecting that a cell is not        broadcasting SIB1

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         Initiate the measurement reporting procedure,        stop performing the related measurements and remove the corresponding measId

•         Timer: T325

•         Start Point:（起始點(diǎn)）

•         Upon reception of RRCRelease message        with deprioritisationTimer

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         Stop deprioritisation of all    frequencies or NR signalled by RRCRelease

•         Timer: T380

•         Start Point:（起始點(diǎn)）

•         Upon reception of RRCRelease including suspendConfig

•         Stop Point:（結(jié)束點(diǎn)）

•         Upon reception of RRCResume,        RRCSetup or RRCRelease

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         Perform the actions as specified in 5.3.13 of        3GPP 38.331

•         Timer: T390

•         Start Point:（起始點(diǎn)）

•         When access attempt is barred at        access barring check for an Access Category

•         The UE shall maintain one instance of this        timer per Access Category

•         Stop Point:（結(jié)束點(diǎn)）

•         As specified in 5.3.14.3 of 3GPP 38.331

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         Perform the actions as specified in        5.3.14.4  of 3GPP 38.331

•         Timer: T3xx

•         Start Point:（起始點(diǎn)）

•         Upon transmitting UEAssistanceInformation message        with DelayBudgetReport

•         Stop Point:（結(jié)束點(diǎn)）

•         Upon initiating the connection re-establishment        procedures

•         Action upon Timer Expiry:（超時(shí)后續(xù)動作）

•         No action.

RRC常量和計(jì)數(shù)器：計(jì)數(shù)與否或針對特定事件嘗試。計(jì)數(shù)器用字母“n”表示，后面跟著3個(gè)數(shù)字。例如 n310。

•         N310: Maximum number of consecutive “out-of-sync” indications   for the PCell received from lower layers

•         Reset

•         Upon  reception of “insync” indication     from lower layers

•         Upon receiving RRCReconfiguration with reconfigurationWithSync for     that cell group

•         Upon initiating the connection reestablishment     procedure

•         Incremented

•         Upon reception of “out-of-sync” from    lower layer while the timer T310 is stopped

•         When reaching max value

•         Start timer T310

•         N311: Maximum number of consecutive “in-sync” indications   for the PCell received from lower layers

•         Reset

•         Upon reception of “outof-sync” indication     from lower layers

•         Upon receiving RRCReconfiguration with reconfigurationWithSync for   that cell group

•         Upon initiating the connection reestablishment     procedure

•         Incremented

•         Upon reception of the “in-sync”from   lower layer while the timer T310 is  running

•         When reaching max value

•         Stop the timer T310

原文來自：http://www.techplayon.com/5g-nr-rrc-timers-counters-and-constants/