1 什么是MR-DC
MR-DC：Multi-Radio Dual Connectivity，是把LTE双连接技术扩展到其他RAT，让UE可以同时接入LTE和NR，其中一个作为MN（Master Node），一个作为SN（Secondary Node），MN提供到核心网的控制面连接，SN不提供与核心网的控制面连接，只为UE提供额外的资源。MN和SN之间通过网络接口连接起来，至少MN要与核心网连接，SN可以与核心网连接，也可以不跟核心网连接。
如上图，按照核心网的不同一共可以分为4类，目前5G建网初期，为了实现快速布网，降低成本，运营商主要是使用EN-DC的建网模式。
2 UE能力
participant UE
participant Network
Network->UE:UECapabilityEnquiry
UE->Network:UECapabilityInformation
UECapabilityEnquiry
UECapabilityEnquiry ::= SEQUENCE {
rrc-TransactionIdentifier RRC-TransactionIdentifier,
criticalExtensions CHOICE {
ueCapabilityEnquiry UECapabilityEnquiry-IEs,
criticalExtensionsFuture SEQUENCE {}
}
}
UECapabilityEnquiry-IEs ::= SEQUENCE {
ue-CapabilityRAT-RequestList UE-CapabilityRAT-RequestList,
lateNonCriticalExtension OCTET STRING OPTIONAL,
ue-CapabilityEnquiryExt OCTET STRING (CONTAINING UECapabilityEnquiry-v1560-IEs) OPTIONAL
}
UECapabilityEnquiry-v1560-IEs ::= SEQUENCE {
capabilityRequestFilterCommon UE-CapabilityRequestFilterCommon OPTIONAL, -- Need N
nonCriticalExtension SEQUENCE{} OPTIONAL
}
UECapabilityInformation
UECapabilityInformation ::= SEQUENCE {
rrc-TransactionIdentifier RRC-TransactionIdentifier,
criticalExtensions CHOICE {
ueCapabilityInformation UECapabilityInformation-IEs,
criticalExtensionsFuture SEQUENCE {}
}
}
UECapabilityInformation-IEs ::= SEQUENCE {
ue-CapabilityRAT-ContainerList UE-CapabilityRAT-ContainerList OPTIONAL,
lateNonCriticalExtension OCTET STRING OPTIONAL,
nonCriticalExtension SEQUENCE{} OPTIONAL
}
从LOG看UE注册时会查询3次UE能力，
第一次和之前的一样，查询UE 234G的能力。
Interpreted PDU:
value DL-DCCH-Message ::=
{
message c1 : ueCapabilityEnquiry :
{
rrc-TransactionIdentifier 1,
criticalExtensions c1 : ueCapabilityEnquiry-r8 :
{
ue-CapabilityRequest
{
eutra,
utra,
geran-cs,
geran-ps,
cdma2000-1XRTT
}
}
}
}
第二次的信息中只保留了LTE，但是新增了NR和MRDC，但是从UE上报的信息，相对于第一次少了23G能力，但是只多了featureSetsEUTRA，参考TS36331-5.6.3.3
4> include into featureSetsEUTRA the feature sets that are applicable for the received requestedFreqBandsNR-MRDC and requestedCapabilityCommon as specified in TS 38.331 [82], clause 5.6.1.4.
Interpreted PDU:
value DL-DCCH-Message ::=
{
message c1 : ueCapabilityEnquiry :
{
rrc-TransactionIdentifier 2,
criticalExtensions c1 : ueCapabilityEnquiry-r8 :
{
ue-CapabilityRequest
{
eutra
},
nonCriticalExtension
{
nonCriticalExtension
{
nonCriticalExtension
{
nonCriticalExtension
{
nonCriticalExtension
{
requestedFreqBandsNR-MRDC-r15 '00200A0140'H
}
}
}
}
}
}
}
}
其中NR解析出来信息为：
value FreqBandList ::=
{
bandInformationEUTRA :
{
bandEUTRA 3 //锚点基站
},
bandInformationNR :
{
bandNR 41
}
}
sib2信息中如果有配置如下IE，说明这个小区是NR的锚点小区。
plmn-InfoList-r15
{
{
upperLayerIndication-r15 true
}
}
第三次相比第二次少了eutra，但是新增eutra-nr和nr。
Interpreted PDU:
value DL-DCCH-Message ::=
{
message c1 : ueCapabilityEnquiry :
{
rrc-TransactionIdentifier 3,
criticalExtensions c1 : ueCapabilityEnquiry-r8 :
{
ue-CapabilityRequest
{
eutra-nr,
nr
},
nonCriticalExtension
{
nonCriticalExtension
{
nonCriticalExtension
{
nonCriticalExtension
{
nonCriticalExtension
{
requestedFreqBandsNR-MRDC-r15 '00200A0140'H
}
}
}
}
}
}
}
}
参考TS38331-5.6.1.3
1> if the ue-CapabilityRAT-RequestLis t contains a UE-CapabilityRAT-Request with rat-Type set to eutra-nr:
2> if the UE supports (NG)EN-DC or NE-DC:
3> include in the ue-CapabilityRAT-ContainerList a UE-CapabilityRAT-Container of the type UE-MRDC-Capability and with the rat-Type set to eutra-nr
3> include the supportedBandCombinationList and featureSetCombinations as specified in clause 5.6.1.4;
如果UE支持EN-DC：
- rat-Type设置为eutra-nr
- 包括supportedBandCombinationList IE
- 包括featureSetCombinations IE
从这里可以知道UE支持两载波的EN-DC组合，即LTE 1cc + NR 1cc，Band3+n41。
UE如何支持SA组网，则会上报nr：
1> if the ue-CapabilityRAT-RequestList contains a UE-CapabilityRAT-Request with rat-Type set to nr:
2> include in the ue-CapabilityRAT-ContainerList a UE-CapabilityRAT-Container of the type UE-NR-Capability and with the rat-Type set to nr;
2> include the supportedBandCombinationList, featureSets and featureSetCombinations as specified in clause 5.6.1.4;
3 第一次RRC重配
这次RRC重配主要配置了SRB2、DRB1以及NR，NR的信息如下，相对于LTE，LTE中DRB没有配置PDCP，所以使用的是默认配置，但是在NR中配置了DRB的PDCP。
value RadioBearerConfig ::=
{
drb-ToAddModList
{
{
cnAssociation eps-BearerIdentity : 5, //EPS bearer ID
drb-Identity 1, //DRB ID, UE内唯一标识
pdcp-Config
{
drb
{
//pdcp pdu丢弃时间
discardTimer infinity,
//pdcp SN长度分为：12bits和18bits，对应PDCP报头为2字节或者3字节
pdcp-SN-SizeUL len18bits,
pdcp-SN-SizeDL len18bits,
//头压缩
headerCompression notUsed : NULL,
//上行是否发送PDCP status report
statusReportRequired true
},
//PDCP data pdu重排序timer
t-Reordering ms200
}
}
},
securityConfig
{
//DRB和SRB使用加密算法和完整性保护算法，所有的beares使用相同的算法
securityAlgorithmConfig
{
cipheringAlgorithm nea2,
integrityProtAlgorithm nia2
},
//发送加密或者完整性保护key使用master key还是secondary key
keyToUse master
}
}
4 第二次RRC重配
配置测量相关信息，和单独的LTE不同，增加了对NR小区的测量。
4.1 测量配置
value DL-DCCH-Message ::=
{
message c1 : rrcConnectionReconfiguration :
{
rrc-TransactionIdentifier 2,
criticalExtensions c1 : rrcConnectionReconfiguration-r8 :
{
measConfig
{
measObjectToAddModList
{
...
{
//NR测量配置
measObjectId 2,
measObject measObjectNR-r15 :
{
//SSB频率，对于同一个SSB Freq,LTE最多配置一个测量对象
carrierFreq-r15 633984,
rs-ConfigSSB-r15
{
measTimingConfig-r15
{
periodicityAndOffset-r15 sf20-r15 : 0,
ssb-Duration-r15 sf5 //测量持续时间
},
//SSB子载波间隔
subcarrierSpacingSSB-r15 kHz30
},
threshRS-Index-r15
{
//TS38311 36 - 156 = 120dBm
nr-RSRP-r15 36
},
maxRS-IndexCellQual-r15 8,
quantityConfigSet-r15 1,
deriveSSB-IndexFromCell-r15 TRUE,
bandNR-r15 setup : 78 //band78
}
}
},
reportConfigToAddModList
{
...
{
reportConfigId 3,
reportConfig reportConfigInterRAT :
{
triggerType event :
{
eventId eventB1-NR-r15 :
{
b1-ThresholdNR-r15 nr-RSRP-r15 : 50, //50-156=106dBm
reportOnLeave-r15 FALSE
},
hysteresis 0,
timeToTrigger ms40
},
maxReportCells 8,
reportInterval ms1024,
reportAmount r64,
reportQuantityCellNR-r15
{
ss-rsrp TRUE,
ss-rsrq FALSE,
ss-sinr FALSE
},
maxReportRS-Index-r15 1,
reportQuantityRS-IndexNR-r15
{
ss-rsrp TRUE,
ss-rsrq FALSE,
ss-sinr FALSE
},
reportRS-IndexResultsNR TRUE
}
},
...
},
measIdToAddModList
{
...
{
measId 3,
measObjectId 2,
reportConfigId 3
},
...
},
quantityConfig
{
quantityConfigEUTRA
{
},
quantityConfigNRList-r15
{
{
measQuantityCellNR-r15
{
},
measQuantityRS-IndexNR-r15
{
}
}
}
},
measGapConfig setup :
{
gapOffset gp1 : 59
},
s-Measure 0
}
}
}
}
全部的测量配置内容：
Num Measurement IDs = 6
Measurement IDs
-------------------------------------------
| | | |Report |
| |Measurement|Measurement|Configuration|
|# |ID |Object ID |ID |
-------------------------------------------
| 0| 1| 1| 1|
| 1| 2| 1| 2|
| 2| 3| 2| 3|
| 3| 4| 1| 4|
| 4| 5| 1| 5|
| 5| 6| 1| 6|
--------------------------------------------------------------------------------------------------------------------------------------
| |Report| |Max | | | | | |Report| | |Rx Tx | | |
| |Config| |Report|Report |Hysteresis|Trigger |Report |Time to|on |Report |Offset|Meas | | |
|# |ID |Trigger Type|Cells |Interval|(dBm) |Quantity|Quantity |Trigger|Leave |Amount |(dBm) |Enable|Threshold1|Threshold2|
--------------------------------------------------------------------------------------------------------------------------------------
| 0| 1| Event A3| 3| 240 ms| 1.0| RSRP| Both| 160 ms| No| 8 reports| 1.0| false| | |
| 1| 2| Event A2| 1| 1024 ms| 0.0| RSRP| Both| 320 ms| | 1 report| | false| -108| |
| 2| 3| B1| 8| 1024 ms| 0.0| RSRP| Trigger| 40 ms| No|64 reports| | false| -107| 0|
| 3| 4| Periodic| 8|10240 ms| 0.0| RSRP| Both| 0 ms| | Infinite| | false| | |
| 4| 5| Periodic| 1|10240 ms| 0.0| RSRP| Both| 0 ms| | Infinite| | false| | |
| 5| 6| Periodic| 8| 2048 ms| 0.0| RSRP| Both| 0 ms| | 1 report| | false| | |
NR测量时序配置，参考TS36331-5.5.2.13
SFN mod T = FLOOR(Offset/10);
if the Periodicity is larger than sf5:
subframe = Offset mod 10;
else;
subframe = Offset or (Offset +5);
with T = CEIL(Periodicity/10).
其中Offset和Periodicity由测量配置参数中的periodicityAndOffset确定。比如上面消息中，periodicityAndOffset-r15 sf20-r15 : 0
所以subframe = 0 或者 5， SFN mod 2 = 0；说明在偶数无线帧的子帧0或者5上进行NR的测量。
4.2 Event B1
Event B1：异系统邻区比阈值要好。
进入条件：
离开条件：
其中：
- ：异系统邻区没有任何偏移的测量结果。单位是dBm或者dB
- ：异系统邻区的特定频率偏移，对应测量对象中的参数offsetFreq。单位为dB
- ：Event中的滞后参数，对应参数hysteresis。单位为dB
- ：Event中的阈值参数，这里对应参数b1-ThresholdNR，单位同
4.3 测量报告
UE->EUTRAN:MeasurementReport
value UL-DCCH-Message ::=
{
message c1 : measurementReport :
{
criticalExtensions c1 : measurementReport-r8 :
{
measResults
{
measId 3,
//服务小区的信号强度和信号质量
measResultPCell
{
rsrpResult 82,
rsrqResult 23
},
//NR邻区的信号情况
measResultNeighCells measResultNeighCellListNR-r15 :
{
{
pci-r15 336, //cell phy id
measResultCell-r15
{
rsrpResult-r15 88 //88-156=-68dBm
},
measResultRS-IndexList-r15
{
{
ssb-Index-r15 0, //NR RS(0~63)
measResultSSB-Index-r15
{
rsrpResult-r15 88
}
}
}
},
{
pci-r15 337,
measResultCell-r15
{
rsrpResult-r15 76
},
measResultRS-IndexList-r15
{
{
ssb-Index-r15 0,
measResultSSB-Index-r15
{
rsrpResult-r15 76
}
}
}
}
}
}
}
}
}
网络接收到测量报告，然后判断是否添加NR小区，如果需要添加就下发RRC重配，把NR小区的信息提供给UE。
5 第三次RRC重配
配置NR小区相关信息，主要包含小区随机接入相关的信息和测量配置。NSA下NR小区的随机接入信息是通过RRC重配发给UE的，不需要通过SIB信息。
LTE下解析的RRC重配信息：
首先是把关于之前建立的DRB bearer给释放掉。
NR下解析的RRC重配信息，主要包括NR小区的基本配置和对NR小区的测量配置。
DRB也进行重配，这次跟第一次最大的区别是keyToUse时secondary，说明PCDP使用的是NR侧的。
value RadioBearerConfig ::=
{
drb-ToAddModList
{
{
cnAssociation eps-BearerIdentity : 5,
drb-Identity 3,
//TS38331
reestablishPDCP true,
pdcp-Config
{
drb
{
discardTimer ms500,
pdcp-SN-SizeUL len18bits,
pdcp-SN-SizeDL len18bits,
headerCompression notUsed : NULL,
statusReportRequired true
},
t-Reordering ms200
}
}
},
securityConfig
{
securityAlgorithmConfig
{
cipheringAlgorithm nea0
},
keyToUse secondary
}
}
5.1 spCellConfig
servCellIndex：PSCell的服务小区ID，主小区组的PCell使用ID=0
reconfigurationWithSync：与目标SpCell的同步重新配置的参数
rlf-TimersAndConstants：用于探测和触发小区级别RLF的定时器和常量。
rlmInSyncOutOfSyncThreshold：用于IS/OOS指示生成的BLER阈值对索引。n1对应值1，如果不配置这个值，UE默认使用0，无论何时重配时，UE重置N310和N311并停止T310。
spCellConfigDedicated: ServingCellConfig，用于配置UE的服务小区信息。
5.1.1 reconfigurationWithSync
spCellConfigCommon：ServingCellConfigCommon，用于配置小区指定的参数，该IE包含UE从IDLE接入小区时从SSB、MIB、SIBs获取的参数。通过专用信令配置给UE。
ServingCellConfigCommon ::= SEQUENCE {
physCellId PhysCellId OPTIONAL, -- Cond HOAndServCellAdd,
downlinkConfigCommon DownlinkConfigCommon OPTIONAL, -- Cond HOAndServCellAdd
uplinkConfigCommon UplinkConfigCommon OPTIONAL, -- Need M
supplementaryUplinkConfig UplinkConfigCommon OPTIONAL, -- Need S
n-TimingAdvanceOffset ENUMERATED { n0, n25600, n39936 } OPTIONAL, -- Need S
//SSB在时域上的位置
ssb-PositionsInBurst CHOICE {
shortBitmap BIT STRING (SIZE (4)),
mediumBitmap BIT STRING (SIZE (8)),
longBitmap BIT STRING (SIZE (64))
} OPTIONAL, -- Cond AbsFreqSSB
//SSB周期，默认是5ms
ssb-periodicityServingCell ENUMERATED { ms5, ms10, ms20, ms40, ms80, ms160, spare2, spare1 } OPTIONAL, -- Need S
//DM-RS TypeA的位置
dmrs-TypeA-Position ENUMERATED {pos2, pos3},
lte-CRS-ToMatchAround SetupRelease { RateMatchPatternLTE-CRS } OPTIONAL, -- Need M
rateMatchPatternToAddModList SEQUENCE (SIZE (1..maxNrofRateMatchPatterns)) OF RateMatchPattern OPTIONAL, -- Need N
rateMatchPatternToReleaseList SEQUENCE (SIZE (1..maxNrofRateMatchPatterns)) OF RateMatchPatternId OPTIONAL, -- Need N
//SSB子载波间隔
ssbSubcarrierSpacing SubcarrierSpacing OPTIONAL, -- Cond HOAndServCellWithSSB
//小区指定的TDD UL/DL配置
tdd-UL-DL-ConfigurationCommon TDD-UL-DL-ConfigCommon OPTIONAL, -- Cond TDD
ss-PBCH-BlockPower INTEGER (-60..50),
...
}
t304：启动：接收到包括reconfigurationWithSync的RRC重配消息时；停止：在对应的SpCell上完成随机接入之后，对于SCG的t304，当SCG释放时停止；超时：对于MCG的t304，从NR或NR内进行切换时，进行RRC重建流程，切换到NR时，按照原来RAT的spec进行处理；对于SCG的t304，启动SCG failure过程来通知网络同步失败的重新配置，参考TS38311-5.7.3
rach-ConfigDedicated：用于同步重配的随机接入配置，UE使用firstActiveUplinkBWP中参数进行随机接入。
RACH-ConfigDedicated ::= SEQUENCE {
cfra CFRA OPTIONAL, -- Need S
//给定目标小区的优先随机访问过程的参数
ra-Prioritization RA-Prioritization OPTIONAL, -- Need N
...
}
CFRA ::= SEQUENCE {
//cfra时机，如果不存在就使用UL BWP中的RACH-ConfigCommon
occasions SEQUENCE {
rach-ConfigGeneric RACH-ConfigGeneric,
//每个rach时机的ssb数量
ssb-perRACH-Occasion ENUMERATED {oneEighth, oneFourth, oneHalf, one, two, four, eight, sixteen}
OPTIONAL -- Cond SSB-CFRA
} OPTIONAL, -- Need S
resources CHOICE {
ssb SEQUENCE {
ssb-ResourceList SEQUENCE (SIZE(1..maxRA-SSB-Resources)) OF CFRA-SSB-Resource,
ra-ssb-OccasionMaskIndex INTEGER (0..15)
},
csirs SEQUENCE {
csirs-ResourceList SEQUENCE (SIZE(1..maxRA-CSIRS-Resources)) OF CFRA-CSIRS-Resource,
rsrp-ThresholdCSI-RS RSRP-Range
}
},
...,
[[
totalNumberOfRA-Preambles INTEGER (1..63) OPTIONAL -- Cond Occasions
]]
}
CFRA-SSB-Resource ::= SEQUENCE {
ssb SSB-Index,
//RA Preamble
ra-PreambleIndex INTEGER (0..63),
...
}
CFRA-CSIRS-Resource ::= SEQUENCE {
csi-RS CSI-RS-Index,
ra-OccasionList SEQUENCE (SIZE(1..maxRA-OccasionsPerCSIRS)) OF INTEGER (0..maxRA-Occasions-1),
ra-PreambleIndex INTEGER (0..63),
...
}
实网下LOG：
rach-ConfigDedicated uplink :
{
cfra
{
resources ssb :
{
ssb-ResourceList
{
{
ssb 0,
ra-PreambleIndex 8
}
},
ra-ssb-OccasionMaskIndex 0
}
}
}
smtc:用于配置测量定时（timing）配置，即UE测量SSB的时机。
SSB-MTC ::= SEQUENCE {
periodicityAndOffset CHOICE {
sf5 INTEGER (0..4),
sf10 INTEGER (0..9),
sf20 INTEGER (0..19),
sf40 INTEGER (0..39),
sf80 INTEGER (0..79),
sf160 INTEGER (0..159)
},
duration ENUMERATED { sf1, sf2, sf3, sf4, sf5 }
}
3> if reconfigurationWithSync was included in spCellConfig of an SCG:
4> initiate the Random Access procedure on the SpCell, as specified in TS 38.321 [3];
接收到这条RRC重配之后，UE就要在NR上发起随机接入。
6 NR随机接入
同LTE一样，NR随机接入也分为基于竞争随机接入和基于非竞争随机接入，NSA都是基于非竞争的随机接入，随机接入流程：
participant UE
participant Network
Network->UE: RACH Preamble (PRACH) Assignment
UE->Network: RACH Preamble (RA-RNTI, indication for L2/L3 message size)
Network->UE: RAR (TA, C-RNTI, UL grant for L2/L3 message)
UE解析出MIB，表示已经完成了下行同步。
value BCCH-BCH-Message ::=
{
message mib :
{
systemFrameNumber '000001'B,
subCarrierSpacingCommon scs30or120,
ssb-SubcarrierOffset 4,
dmrs-TypeA-Position pos2,
pdcch-ConfigSIB1
{
controlResourceSetZero 11,
searchSpaceZero 4
},
cellBarred notBarred,
intraFreqReselection notAllowed,
spare '0'B
}
}
随机接入配置：
rach-ConfigCommon setup :
{
rach-ConfigGeneric
{
//Preamble格式，时域发送时机，17表示任何帧的4/9号子帧上发送
prach-ConfigurationIndex 17,
//发送prach的频域大小[one,two,four,eight]
msg1-FDM one,
//发送prach的频域起始位置[0..274]
msg1-FrequencyStart 2,
//N-CS配置，TS38211-6.3.3.1
zeroCorrelationZoneConfig 6,
preambleReceivedTargetPower -104,
//RA preamble传输最大次数
preambleTransMax n8,
//PRACH功率步进值
powerRampingStep dB2,
//rar窗口长度，单位是slot
ra-ResponseWindow sl20
},
ssb-perRACH-OccasionAndCB-PreamblesPerSSB four : 8,
groupBconfigured
{
//Msg3 TB大小阈值，单位是bit，低于该值时，UE使用GroupA的基于竞争的RA前导
ra-Msg3SizeGroupA b144,
//单位dB，选择的前导阈值，dB0=0
messagePowerOffsetGroupB dB0,
//GroupA中每个SSB基于竞争的前导数量
numberOfRA-PreamblesGroupA 6
},
//竞争解决timer的初始值，sf64表示64个子帧
ra-ContentionResolutionTimer sf64,
//SSB的RSRP阈值，
rsrp-ThresholdSSB 16,
//TS38311-6.3.3.1-3
prach-RootSequenceIndex l839 : 456,
//是否是限制集
restrictedSetConfig unrestrictedSet
},
RRC重配中已经给出了Preamble index=8。
2020 Mar 31 01:48:10.671 [F7] 0xB889 NR5G MAC RACH Trigger
Subscription ID = 1
MAC Version
Major.Minor = 2. 1
Log Fields Change BMask = 0
Header
Num Records = 1
//同RRC重配参数newUE-Identity 28440
CRNTI = 28440
//随机接入原因
Rach Reason = CONNECTION_REQUEST
Carrier Id = 0
//选择的UL BWP
First Active UL BWP = 0
//基于非竞争的随机接入
RACH Contention = CONT_FREE
RA Id = 255
MSG3 Size = 0
MSG3 = { 0, 0, 0, 0, 0, 0 }
rach attempt：
2020 Mar 31 01:48:10.683 [E3] 0xB88A NR5G MAC RACH Attempt
Subscription ID = 1
MAC Version
Major.Minor = 2. 3
Log Fields Change BMask = 0x0
Sub ID = 0
Header
Num Records = 1
Num Attempt = 1
SSB ID = 0
CSI RS ID = 0
Carrier ID = 0
RACH Result = SUCCESS
Contention Type = CONT_FREE
Contention Type Value = 0
RACH Msg Bitmask = 0x07
Msg1 SCS = 1_25 KHz
UL BWP SCS = 30KHZ
RACH Msg1
-------------------------------------------------------------------------------------------------------------------------------------------------------------
| | | | | | | | | | |RAR Window Start | | |
| |System Time | | | | | | | | |SFN |RAR Window End SFN |Backoff |
| | |Sub | |Symbol|Prach |Preamble | | | |Cyclic Shift| | |Sub | | |Sub | |Duration |
|# |Frame |Frame |Slot |Start |Config|Format |RA Id|FDM |Uroot |V |RA RNTI |Frame |Frame |Slot |Frame |Frame |Slot |(usec) |
-------------------------------------------------------------------------------------------------------------------------------------------------------------
| 0| 20| 9| 0| 0| 17| FORMAT_0| 8| 0| 230| 256| 127| 21| 0| 0| 22| 0| 0| 0|
RACH Msg2
-------------------------------------------------------
| |SFN |Max | | | |
| | |Sub | |Backoff | |TA | |
|# |Frame |Frame |Slot |Duration|T RNTI |Value|Result|
-------------------------------------------------------
| 0| 21| 3| 1| 5| 28440| 1| 1|
RACH Msg3
----------------------------------------------------------------------------------------------
| | |Msg3 | | |
| |Msg3 Grant |Grant |HARQ | |
|# |Raw |Bytes |Id |Mac PDU |
----------------------------------------------------------------------------------------------
| 0| 0x44868C0| 0| 0| 00 00 00 00 00 00 00 00 00 00 00 00|
RA-RNTI = 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id
其中
- s_id: 第一个ofdm符合位置，0 ≤ s_id < 14
- t_id: 第一个slot的位置，0 ≤ t_id < 80
- f_id: 频域RO index
- ul_carrier_id: 0 表示：NUL载波，1 表示SUL载波
Msg1在SFN#20，subframe#9上发送，RAR监听窗口为210~220共10ms。
UE在RAR监听窗口内使用RA-RNTI进行解码PDCCH (DCI format 1_0)，UE根据DCI1_0指示的时频位置接收PDSCH的MAC PDU内容，然后根据解析出RAPID，如果跟Msg1中的RAPID相同就说明接收到了正确的RAR。
UE在SFN#21的slot#7上接收到DCI。
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | | |DCI Info |
| | | | | | | | | | | | |DL |
| | | | | | | | | | | |UL | | | | | |TPC | | | | | | | | |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |DMRS| | | | | | | | | | | | |Command| |PDSCH | | | | | | |
| | | | | | | | | | | | | | |Freq | | | |UL |Symbol| | |Beta | |UL | | |SRS |Precoding| |Seq | | | |Reserved| | | |Bandwidth|Time |TB |TB 1 New |DL |For |PUCCH |Harq |CBG |CBG | | | | |
| |System Time |Num|Carrier| | |Aggregation|Raw DCI | | | |Carrier| | |Hopping| |HARQ|PUSCH|SUL|Alloc |BWP|PTRS DMRS |Offset|RB |SCH|DAI|DAI|Resource |Layer |Antenna|Init|SRS |CSI | |MCE |RA | |Pruned |Part |Resource |1 |Data |Assignment|Sched |Resource |Feedback|Transmission|Flushing|Transmission|SRS |Carrier|HARQ|
|# |Slot|Num |Frame|DCI|ID |RNTI Type |DCI Format |Level |Included|Raw DCI[2]|Raw DCI[1]|Raw DCI[0]|ID |NDI|MCS|Flag |RV|ID |TPC |Ind|Index |Ind|Association|Ind |Assignment|Ind|1 |2 |Indication|Info |Ports |Flag|Request|Request|CBGTI|Enable |Type|Prune Reason MSB |Mask |Indicator|Assignment|MCS|Indicator|Index |PUCCH |Indicator|Timing |Info |Out Info|Config Ind |Request|ID |ID |
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| 0| 7| 30kHz| 21| 1| 0| RA_RNTI| DL_1_0| LEVEL_4| 0| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 0| 3| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|
Msg3发送，SFN#21,subframe#7，slot#14上进行发送。
2020 Mar 31 01:48:10.686 [89] 0xB8D2 NR5G LL1 FW MAC TX IU Power
Version = 1
...
Version 1[2]
Code = POWER INFO
Length = 16
TX IU Power Sub Packet
Version = 2
Log Header
Sequence Number = 2
SFN = 21
Fractional Unit Slot Number = 56
Log2 Slot To Unit Slot = 2
Subframe Num = 7
Slot Num = 14
Power Info
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | | |CarrierIdType |
| | | |PUSCH Data |PUCCH Data |SRS Data |PRACH Data |
| |Carrier|Channel|Transmit| |TPC | |Delta|Is |Minimum|Transmit| |TPC | |Delta|PUCCH |PUCCH |Minimum|Transmit| |TPC | |SRS |M |Minimum|Transmit|RACH | | |Minimum|
|# |Id |Type |Power |Pathloss|Adjustment|MTPL|TF |Msg3|Power |Power |Pathloss|Adjustment|MTPL|TF |Number|Format|Power |Power |Pathloss|Adjustment|MTPL|Number|SRS|Power |Power |Attempt|Pathloss|MTPL|Power |
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| 0| 0| PUSCH| -9| 87| 0| 0| 0| 1| -38| | | | | | | | | | | | | | | | | | | | |
7 第四次RRC重配
首先是把关于NR的测量配置给删除，更新之后的测量配置如下：
Num Measurement IDs = 4
Measurement IDs
-------------------------------------------
| | | |Report |
| |Measurement|Measurement|Configuration|
|# |ID |Object ID |ID |
-------------------------------------------
| 0| 1| 1| 1|
| 1| 2| 1| 2|
| 2| 4| 1| 4|
| 3| 5| 1| 5|
Num Reporting Configurations = 5
--------------------------------------------------------------------------------------------------------------------------------------
| |Report| |Max | | | | | |Report| | |Rx Tx | | |
| |Config| |Report|Report |Hysteresis|Trigger |Report |Time to|on |Report |Offset|Meas | | |
|# |ID |Trigger Type|Cells |Interval|(dBm) |Quantity|Quantity |Trigger|Leave |Amount |(dBm) |Enable|Threshold1|Threshold2|
--------------------------------------------------------------------------------------------------------------------------------------
| 0| 1| Event A3| 3| 240 ms| 1.0| RSRP| Both| 160 ms| No| 8 reports| 1.0| false| | |
| 1| 2| Event A2| 1| 1024 ms| 0.0| RSRP| Both| 320 ms| | 1 report| | false| -108| |
| 2| 4| Periodic| 8|10240 ms| 0.0| RSRP| Both| 0 ms| | Infinite| | false| | |
| 3| 5| Periodic| 1|10240 ms| 0.0| RSRP| Both| 0 ms| | Infinite| | false| | |
| 4| 6| Periodic| 8| 2048 ms| 0.0| RSRP| Both| 0 ms| | 1 report| | false| | |
相对于之前的测量配置只是少了NR相关的，其他还继续保留。
看了几份日志这条消息跟NR随机接入时间差不多，但是RRC重配完成是在随机接入之后，应该可以理解为NR随机接入之后的处理。
8 第五次RRC重配
这次RRC重配主要是配置IMS的承载，配置DRB4
radioResourceConfigDedicated
{
drb-ToAddModList
{
{
eps-BearerIdentity 6,
drb-Identity 4,
pdcp-Config
{
discardTimer infinity,
rlc-AM
{
statusReportRequired FALSE
},
headerCompression notUsed : NULL
},
rlc-Config am :
{
ul-AM-RLC
{
t-PollRetransmit ms55,
pollPDU p16,
pollByte kBinfinity,
maxRetxThreshold t32
},
dl-AM-RLC
{
t-Reordering ms45,
t-StatusProhibit ms20
}
},
logicalChannelIdentity 4,
logicalChannelConfig
{
ul-SpecificParameters
{
priority 4,
prioritisedBitRate infinity,
bucketSizeDuration ms500,
logicalChannelGroup 0
}
}
}
},
mac-MainConfig explicitValue :
{
timeAlignmentTimerDedicated infinity,
phr-Config setup :
{
periodicPHR-Timer sf1000,
prohibitPHR-Timer sf10,
dl-PathlossChange dB3
}
}
}
缩写
PCell：Primary Cell
PSCell：Primary SCG Cell
SCell：Secondary Cell
SpCell：Special Cell
MCG：Master Cell Group
SCG：Secondary Cell Group
Primary Cell: 在主要频率上操作的MCG小区，UE可以在其中执行初始连接建立过程或发起连接重建过程。
Primary SCG Cell: 对于双连接操作，当执行带有同步的重新配置过程时，UE在其中进行随机访问的SCG小区。
Secondary Cell: 对于配置有CA的UE，在特殊小区之上提供额外无线资源的小区。
Secondary Cell Group:对于配置有双连接的UE，服务小区的子集包括PSCell和零个或多个辅助小区。
Serving Cell: 对于RRC_CONNECTED状态下没有配置CA/DC的UE，只有一个服务小区由主小区组成。对于配置了CA/DC的UE，服务小区指由特殊小区和所有辅助小区组成一组小区。
Special Cell:对于双连接操作指MCG中的PCell或者SCG中的PSCell，否则指的就是PCell。