5GNR之EN-DC介紹(基于日志)

1 什么是MR-DC

MR-DCMulti-Radio Dual Connectivity,是把LTE雙連接技術(shù)擴(kuò)展到其他RAT胡本,讓UE可以同時(shí)接入LTE和NR,其中一個(gè)作為MN(Master Node),一個(gè)作為SN(Secondary Node)庶香,MN提供到核心網(wǎng)的控制面連接四敞,SN不提供與核心網(wǎng)的控制面連接泛源,只為UE提供額外的資源。MN和SN之間通過(guò)網(wǎng)絡(luò)接口連接起來(lái)忿危,至少M(fèi)N要與核心網(wǎng)連接达箍,SN可以與核心網(wǎng)連接,也可以不跟核心網(wǎng)連接铺厨。

如上圖缎玫,按照核心網(wǎng)的不同一共可以分為4類,目前5G建網(wǎng)初期解滓,為了實(shí)現(xiàn)快速布網(wǎng)赃磨,降低成本,運(yùn)營(yíng)商主要是使用EN-DC的建網(wǎng)模式洼裤。

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
}

從LOG看UE注冊(cè)時(shí)會(huì)查詢3次UE能力邻辉,

第一次和之前的一樣,查詢UE 234G的能力腮鞍。

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值骇,但是新增了NR和MRDC,但是從UE上報(bào)的信息移国,相對(duì)于第一次少了23G能力吱瘩,但是只多了featureSetsEUTRA,參考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解析出來(lái)信息為:
value FreqBandList ::= 
{
  bandInformationEUTRA : 
    {
      bandEUTRA 3   //錨點(diǎn)基站
    },
  bandInformationNR : 
    {
      bandNR 41
    }
}  

sib2信息中如果有配置如下IE迹缀,說(shuō)明這個(gè)小區(qū)是NR的錨點(diǎn)小區(qū)使碾。

plmn-InfoList-r15 
{
  {
    upperLayerIndication-r15 true
  }
}

第三次相比第二次少了eutra皱卓,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
                      }
                    }
                  }
                }
              }
            }
      }
}

參考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設(shè)置為eutra-nr
  • 包括supportedBandCombinationList IE
  • 包括featureSetCombinations IE

從這里可以知道UE支持兩載波的EN-DC組合部逮,即LTE 1cc + NR 1cc娜汁,Band3+n41。

UE如何支持SA組網(wǎng)兄朋,則會(huì)上報(bào)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

這次RRC重配主要配置了SRB2掐禁、DRB1以及NR,NR的信息如下颅和,相對(duì)于LTE傅事,LTE中DRB沒(méi)有配置PDCP,所以使用的是默認(rèn)配置峡扩,但是在NR中配置了DRB的PDCP蹭越。

value RadioBearerConfig ::= 
{
  drb-ToAddModList 
  {
    {
      cnAssociation eps-BearerIdentity : 5,  //EPS  bearer ID
      drb-Identity 1,           //DRB ID, UE內(nèi)唯一標(biāo)識(shí)
      pdcp-Config 
      {
        drb 
        {
          //pdcp pdu丟棄時(shí)間
          discardTimer infinity,
          //pdcp SN長(zhǎng)度分為:12bits和18bits,對(duì)應(yīng)PDCP報(bào)頭為2字節(jié)或者3字節(jié)
          pdcp-SN-SizeUL len18bits,
          pdcp-SN-SizeDL len18bits,
          //頭壓縮
          headerCompression notUsed : NULL,
          //上行是否發(fā)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護(hù)算法教届,所有的beares使用相同的算法
    securityAlgorithmConfig 
    {
      cipheringAlgorithm nea2,
      integrityProtAlgorithm nia2
    },
    //發(fā)送加密或者完整性保護(hù)key使用master key還是secondary key
    keyToUse master 
  }
}

4 第二次RRC重配

配置測(cè)量相關(guān)信息响鹃,和單獨(dú)的LTE不同,增加了對(duì)NR小區(qū)的測(cè)量案训。

4.1 測(cè)量配置

value DL-DCCH-Message ::= 
{
  message c1 : rrcConnectionReconfiguration : 
      {
        rrc-TransactionIdentifier 2,
        criticalExtensions c1 : rrcConnectionReconfiguration-r8 : 
            {
              measConfig 
              {
                measObjectToAddModList 
                {
                  ...
                  {
                    //NR測(cè)量配置
                    measObjectId 2,
                    measObject measObjectNR-r15 : 
                      {
                        //SSB頻率买置,對(duì)于同一個(gè)SSB Freq,LTE最多配置一個(gè)測(cè)量對(duì)象
                        carrierFreq-r15 633984,
                        rs-ConfigSSB-r15 
                        {
                          measTimingConfig-r15 
                          {
                            periodicityAndOffset-r15 sf20-r15 : 0,
                            ssb-Duration-r15 sf5  //測(cè)量持續(xù)時(shí)間
                          },
                          //SSB子載波間隔
                          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
              }
            }
      }
}

全部的測(cè)量配置內(nèi)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測(cè)量時(shí)序配置,參考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由測(cè)量配置參數(shù)中的periodicityAndOffset確定强霎。比如上面消息中忿项,periodicityAndOffset-r15 sf20-r15 : 0

所以subframe = 0 或者 5, SFN mod 2 = 0城舞;說(shuō)明在偶數(shù)無(wú)線幀的子幀0或者5上進(jìn)行NR的測(cè)量轩触。

4.2 Event B1

Event B1:異系統(tǒng)鄰區(qū)比閾值要好。

進(jìn)入條件:

  • Mn+Ofn-Hys>Thresh

離開(kāi)條件:

  • Mn+Ofn-Hys<Thresh

其中:

  • Mn:異系統(tǒng)鄰區(qū)沒(méi)有任何偏移的測(cè)量結(jié)果家夺。單位是dBm或者dB
  • Ofn:異系統(tǒng)鄰區(qū)的特定頻率偏移脱柱,對(duì)應(yīng)測(cè)量對(duì)象中的參數(shù)offsetFreq。單位為dB
  • Hys:Event中的滯后參數(shù)秦踪,對(duì)應(yīng)參數(shù)hysteresis褐捻。單位為dB
  • Thresh:Event中的閾值參數(shù)掸茅,這里對(duì)應(yīng)參數(shù)b1-ThresholdNR椅邓,單位同Mn

4.3 測(cè)量報(bào)告

UE->EUTRAN:MeasurementReport
value UL-DCCH-Message ::= 
{
  message c1 : measurementReport : 
      {
        criticalExtensions c1 : measurementReport-r8 : 
            {
              measResults 
              {
                measId 3,
                //服務(wù)小區(qū)的信號(hào)強(qiáng)度和信號(hào)質(zhì)量
                measResultPCell 
                {
                  rsrpResult 82,
                  rsrqResult 23
                },
                //NR鄰區(qū)的信號(hào)情況
                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
                          }
                        }
                      }
                    }
                  }
              }
            }
      }
}

網(wǎng)絡(luò)接收到測(cè)量報(bào)告,然后判斷是否添加NR小區(qū)昧狮,如果需要添加就下發(fā)RRC重配景馁,把NR小區(qū)的信息提供給UE。

5 第三次RRC重配

配置NR小區(qū)相關(guān)信息逗鸣,主要包含小區(qū)隨機(jī)接入相關(guān)的信息和測(cè)量配置合住。NSA下NR小區(qū)的隨機(jī)接入信息是通過(guò)RRC重配發(fā)給UE的绰精,不需要通過(guò)SIB信息。

LTE下解析的RRC重配信息:

首先是把關(guān)于之前建立的DRB bearer給釋放掉透葛。

NR下解析的RRC重配信息笨使,主要包括NR小區(qū)的基本配置和對(duì)NR小區(qū)的測(cè)量配置。

DRB也進(jìn)行重配僚害,這次跟第一次最大的區(qū)別是keyToUse時(shí)secondary硫椰,說(shuō)明PCDP使用的是NR側(cè)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的服務(wù)小區(qū)ID萨蚕,主小區(qū)組的PCell使用ID=0

reconfigurationWithSync:與目標(biāo)SpCell的同步重新配置的參數(shù)

rlf-TimersAndConstants:用于探測(cè)和觸發(fā)小區(qū)級(jí)別RLF的定時(shí)器和常量靶草。

rlmInSyncOutOfSyncThreshold:用于IS/OOS指示生成的BLER閾值對(duì)索引。n1對(duì)應(yīng)值1岳遥,如果不配置這個(gè)值奕翔,UE默認(rèn)使用0,無(wú)論何時(shí)重配時(shí)浩蓉,UE重置N310和N311并停止T310派继。

spCellConfigDedicated: ServingCellConfig,用于配置UE的服務(wù)小區(qū)信息捻艳。

5.1.1 reconfigurationWithSync

spCellConfigCommonServingCellConfigCommon互艾,用于配置小區(qū)指定的參數(shù),該IE包含UE從IDLE接入小區(qū)時(shí)從SSB讯泣、MIB纫普、SIBs獲取的參數(shù)。通過(guò)專用信令配置給UE好渠。

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在時(shí)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周期昨稼,默認(rèn)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子載波間隔
    ssbSubcarrierSpacing                SubcarrierSpacing                                                   OPTIONAL, -- Cond HOAndServCellWithSSB
    //小區(qū)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:?jiǎn)?dòng):接收到包括reconfigurationWithSync的RRC重配消息時(shí);停止:在對(duì)應(yīng)的SpCell上完成隨機(jī)接入之后拳锚,對(duì)于SCG的t304假栓,當(dāng)SCG釋放時(shí)停止;超時(shí):對(duì)于MCG的t304霍掺,從NR或NR內(nèi)進(jìn)行切換時(shí)匾荆,進(jìn)行RRC重建流程,切換到NR時(shí)杆烁,按照原來(lái)RAT的spec進(jìn)行處理牙丽;對(duì)于SCG的t304,啟動(dòng)SCG failure過(guò)程來(lái)通知網(wǎng)絡(luò)同步失敗的重新配置兔魂,參考TS38311-5.7.3

rach-ConfigDedicated:用于同步重配的隨機(jī)接入配置烤芦,UE使用firstActiveUplinkBWP中參數(shù)進(jìn)行隨機(jī)接入。

RACH-ConfigDedicated ::=        SEQUENCE {
    cfra                            CFRA                                                                    OPTIONAL, -- Need S
    //給定目標(biāo)小區(qū)的優(yōu)先隨機(jī)訪問(wèn)過(guò)程的參數(shù)
    ra-Prioritization               RA-Prioritization                                                       OPTIONAL, -- Need N
    ...
}

CFRA ::=                    SEQUENCE {
    //cfra時(shí)機(jī)析校,如果不存在就使用UL BWP中的RACH-ConfigCommon
    occasions                       SEQUENCE {
        rach-ConfigGeneric              RACH-ConfigGeneric,
        //每個(gè)rach時(shí)機(jī)的ssb數(shù)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),
    ...
}

實(shí)網(wǎng)下LOG:

rach-ConfigDedicated uplink : 
  {
    cfra 
    {
      resources ssb : 
        {
          ssb-ResourceList 
          {
            {
              ssb 0,
              ra-PreambleIndex 8
            }
          },
          ra-ssb-OccasionMaskIndex 0
        }
    }
  }

smtc:用于配置測(cè)量定時(shí)(timing)配置构罗,即UE測(cè)量SSB的時(shí)機(jī)铜涉。

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];

接收到這條RRC重配之后,UE就要在NR上發(fā)起隨機(jī)接入遂唧。

6 NR隨機(jī)接入

同LTE一樣芙代,NR隨機(jī)接入也分為基于競(jìng)爭(zhēng)隨機(jī)接入和基于非競(jìng)爭(zhēng)隨機(jī)接入,NSA都是基于非競(jìng)爭(zhēng)的隨機(jī)接入盖彭,隨機(jī)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链蕊,表示已經(jīng)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
    }
}

隨機(jī)接入配置:

rach-ConfigCommon setup : 
  {
    rach-ConfigGeneric 
    {
      //Preamble格式谬泌,時(shí)域發(fā)送時(shí)機(jī)滔韵,17表示任何幀的4/9號(hào)子幀上發(fā)送
      prach-ConfigurationIndex 17,
      //發(fā)送prach的頻域大小[one,two,four,eight]
      msg1-FDM one,
      //發(fā)送prach的頻域起始位置[0..274]
      msg1-FrequencyStart 2,
      //N-CS配置,TS38211-6.3.3.1
      zeroCorrelationZoneConfig 6,
      preambleReceivedTargetPower -104,
      //RA preamble傳輸最大次數(shù)
      preambleTransMax n8,
      //PRACH功率步進(jìn)值
      powerRampingStep dB2,
      //rar窗口長(zhǎng)度掌实,單位是slot
      ra-ResponseWindow sl20
    },
    ssb-perRACH-OccasionAndCB-PreamblesPerSSB four : 8,
    groupBconfigured 
    {
      //Msg3 TB大小閾值陪蜻,單位是bit,低于該值時(shí)贱鼻,UE使用GroupA的基于競(jìng)爭(zhēng)的RA前導(dǎo)
      ra-Msg3SizeGroupA b144,
      //單位dB宴卖,選擇的前導(dǎo)閾值,dB0=0
      messagePowerOffsetGroupB dB0,
      //GroupA中每個(gè)SSB基于競(jìng)爭(zhēng)的前導(dǎo)數(shù)量
      numberOfRA-PreamblesGroupA 6
    },
    //競(jìng)爭(zhēng)解決timer的初始值邻悬,sf64表示64個(gè)子幀
    ra-ContentionResolutionTimer sf64,
    //SSB的RSRP閾值症昏,
    rsrp-ThresholdSSB 16,
    //TS38311-6.3.3.1-3
    prach-RootSequenceIndex l839 : 456,
    //是否是限制集
    restrictedSetConfig unrestrictedSet
  },

RRC重配中已經(jīng)給出了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重配參數(shù)newUE-Identity 28440
CRNTI                          = 28440
//隨機(jī)接入原因
Rach Reason                    = CONNECTION_REQUEST
Carrier Id                     = 0
//選擇的UL BWP
First Active UL BWP            = 0
//基于非競(jìng)爭(zhēng)的隨機(jī)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: 第一個(gè)ofdm符合位置父丰,0 ≤ s_id < 14
  • t_id: 第一個(gè)slot的位置肝谭,0 ≤ t_id < 80
  • f_id: 頻域RO index
  • ul_carrier_id: 0 表示:NUL載波,1 表示SUL載波

Msg1在SFN#20蛾扇,subframe#9上發(fā)送攘烛,RAR監(jiān)聽(tīng)窗口為210~220共10ms。

UE在RAR監(jiān)聽(tīng)窗口內(nèi)使用RA-RNTI進(jìn)行解碼PDCCH (DCI format 1_0)镀首,UE根據(jù)DCI1_0指示的時(shí)頻位置接收PDSCH的MAC PDU內(nèi)容坟漱,然后根據(jù)解析出RAPID,如果跟Msg1中的RAPID相同就說(shuō)明接收到了正確的RAR更哄。

UE在SFN#21的slot#7上接收到DCI芋齿。

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|   |                   |   |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發(fā)送,SFN#21,subframe#7成翩,slot#14上進(jìn)行發(fā)送觅捆。

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

首先是把關(guān)于NR的測(cè)量配置給刪除,更新之后的測(cè)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|          |          |

相對(duì)于之前的測(cè)量配置只是少了NR相關(guān)的捕传,其他還繼續(xù)保留惠拭。

看了幾份日志這條消息跟NR隨機(jī)接入時(shí)間差不多,但是RRC重配完成是在隨機(jī)接入之后庸论,應(yīng)該可以理解為NR隨機(jī)接入之后的處理职辅。

8 第五次RRC重配

這次RRC重配主要是配置IMS的承載,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
        }
    }
}

縮寫

PCell:Primary Cell

PSCell:Primary SCG Cell

SCell:Secondary Cell

SpCell:Special Cell

MCG:Master Cell Group

SCG:Secondary Cell Group

Primary Cell: 在主要頻率上操作的MCG小區(qū)聂示,UE可以在其中執(zhí)行初始連接建立過(guò)程或發(fā)起連接重建過(guò)程域携。

Primary SCG Cell: 對(duì)于雙連接操作,當(dāng)執(zhí)行帶有同步的重新配置過(guò)程時(shí)鱼喉,UE在其中進(jìn)行隨機(jī)訪問(wèn)的SCG小區(qū)秀鞭。

Secondary Cell: 對(duì)于配置有CA的UE,在特殊小區(qū)之上提供額外無(wú)線資源的小區(qū)扛禽。

Secondary Cell Group:對(duì)于配置有雙連接的UE锋边,服務(wù)小區(qū)的子集包括PSCell和零個(gè)或多個(gè)輔助小區(qū)。

Serving Cell: 對(duì)于RRC_CONNECTED狀態(tài)下沒(méi)有配置CA/DC的UE编曼,只有一個(gè)服務(wù)小區(qū)由主小區(qū)組成豆巨。對(duì)于配置了CA/DC的UE,服務(wù)小區(qū)指由特殊小區(qū)和所有輔助小區(qū)組成一組小區(qū)掐场。

Special Cell:對(duì)于雙連接操作指MCG中的PCell或者SCG中的PSCell往扔,否則指的就是PCell。

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