5G(NR)网络中的波束失败探测和恢复 在TS 38.321-5.17有详细介绍，其中过程可简单描述如下：整理：kangguoying20200804
1.波束失败检测及恢复整理：kangguoying20200804
Step | Direction方向 | 说明 |
1 | < UE > | 波束失败（终端测量L1 RSRP低于设定门限） |
2 | < UE > | 搜索其他质量好的波束 |
3 | UE -> NW | 如果检测到预定的波束失效次数，用候选波束(PRACH)触发波束失效恢复过程。 预定义的波束失效次数引发这一过程是由RRC中波束失败最大计数定义的。 / ue 发送的PRACH中带有 BFR-SSB-Resource中指定的ID 的 prach。 |
4 | UE <- NW | （网络）回复波束故障恢复请求((RACH Response)。网络通过msg2中的DCI 指定（恢复）的搜索空间 |
2.RRC波束失败探测参数配置
RadioLinkMonitoringConfig ::= SEQUENCE {整理：kangguoying20200804
failureDetectionResourcesToAddModList SEQUENCE (SIZE(1..maxNrofFailureDetectionResources))
OF RadioLinkMonitoringRS
failureDetectionResourcesToReleaseList SEQUENCE (SIZE(1..maxNrofFailureDetectionResources))
OF RadioLinkMonitoringRS-Id整理：kangguoying20200804
beamFailureInstanceMaxCount ENUMERATED {n1, n2, n3, n4, n5, n6, n8, n10}整理：kangguoying20200804
beamFailureDetectionTimer ENUMERATED {pbfd1, pbfd2, pbfd3, pbfd4, pbfd5,
pbfd6, pbfd8, pbfd10} ...} 整理：kangguoying20200804
RadioLinkMonitoringRS ::= SEQUENCE {整理：kangguoying20200804
radioLinkMonitoringRS-Id RadioLinkMonitoringRS-Id,整理：kangguoying20200804
purpose ENUMERATED {beamFailure, rlf, both},
detectionResource CHOICE {整理：kangguoying20200804
ssb-Index SSB-Index,整理：kangguoying20200804
csi-RS-Index NZP-CSI-RS-ResourceId },...} 整理：kangguoying20200804
3.RRC波束恢复参数配置
BeamFailureRecoveryConfig ::= SEQUENCE {整理：kangguoying20200804
rootSequenceIndex-BFR INTEGER (0..137) OPTIONAL, -- Need M整理：kangguoying20200804
rach-ConfigBFR RACH-ConfigGeneric OPTIONAL, -- Need M
rsrp-ThresholdSSB RSRP-Range OPTIONAL, -- Need M整理：kangguoying20200804
candidateBeamRSList SEQUENCE (SIZE(1..maxNrofCandidateBeams))整理：kangguoying20200804
OF PRACH-ResourceDedicatedBFR OPTIONAL, -- Need M整理：kangguoying20200804
ssb-perRACH-Occasion ENUMERATED {oneEighth, oneFourth, oneHalf, one, two,
four, eight, sixteen} OPTIONAL, -- Need M整理：kangguoying20200804
ra-ssb-OccasionMaskIndex INTEGER (0..15) OPTIONAL, -- Need M整理：kangguoying20200804
recoverySearchSpaceId SearchSpaceId OPTIONAL, -- Need R
ra-Prioritization RA-Prioritization OPTIONAL, -- Need R整理：kangguoying20200804
beamFailureRecoveryTimer ENUMERATED {ms10, ms20, ms40, ms60, ms80, ms100, ms150, ms200} OPTIONAL, -- Need M
..., [[ msg1-SubcarrierSpacing-v1530 SubcarrierSpacing OPTIONAL -- Need M ]]}整理：kangguoying20200804
PRACH-ResourceDedicatedBFR ::= CHOICE {
ssb BFR-SSB-Resource,整理：kangguoying20200804
csi-RS BFR-CSIRS-Resource}
BFR-SSB-Resource ::= SEQUENCE {整理：kangguoying20200804
ssb SSB-Index,整理：kangguoying20200804
ra-PreambleIndex INTEGER (0..63), ...} 整理：kangguoying20200804
BFR-CSIRS-Resource ::= SEQUENCE {整理：kangguoying20200804
csi-RS NZP-CSI-RS-ResourceId,整理：kangguoying20200804
ra-OccasionList SEQUENCE (SIZE(1..maxRA-OccasionsPerCSIRS))整理：kangguoying20200804
OF INTEGER (0..maxRA-Occasions-1) OPTIONAL, -- Need R整理：kangguoying20200804
ra-PreambleIndex INTEGER (0..63) OPTIONAL, -- Need R ...} 整理：kangguoying20200804
RACH-ConfigGeneric ::= SEQUENCE {整理：kangguoying20200804
prach-ConfigurationIndex INTEGER (0..255),整理：kangguoying20200804
msg1-FDM ENUMERATED {one, two, four, eight},整理：kangguoying20200804
msg1-FrequencyStart INTEGER (0..maxNrofPhysicalResourceBlocks-1),整理：kangguoying20200804
zeroCorrelationZoneConfig INTEGER(0..15),整理：kangguoying20200804
preambleReceivedTargetPower INTEGER (-202..-60),整理整理：kangguoying20200804：kangguoying20200804
preambleTransMax ENUMERATED {n3,n4,n5,n6,n7,n8,n10,n20,n50,n100,n200},
powerRampingStep ENUMERATED {dB0, dB2, dB4, dB6},整理：kangguoying20200804
ra-ResponseWindow ENUMERATED {sl1, sl2, sl4, sl8, sl10, sl20, sl40, sl80}, ...}
RA-Prioritization ::= SEQUENCE {整理：kangguoying20200804
powerRampingStepHighPriority ENUMERATED {dB0, dB2, dB4, dB6},整理：kangguoying20200804
scalingFactorBI ENUMERATED {zero, dot25, dot5, dot75} OPTIONAL, -- Need R ...}
原文来自：http://www.sharetechnote.com/ 整理：kangguoying20200804
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