UAC统一接入控制

Unified Access ControlUnified Access Control（通用接入控制）（通用接入控制） 上周将 NR 重选的时候，在 SIB2 中定义了 UAC，当时由于时间问题，没有展开来 进行解释，所以考虑补充一个专题文档。 UAC 是 UE 接入控制或状态改变的机制集合。 在 LTE 中，我们就经常会碰到需要接入控制的时候，比如某个小区超载了，大量 UE 接入到一个小区，导致 UE 间相互干扰严重，无法成功解码。在 4G 中，接入 控制主要有两种类型 UE 初始接入请求的时候，网络下发拒绝消息； 自己阻止 UE 尝试初始接入（也就是 CellBar） Case1SIB1 配置 bar，所有 UE 都不能接入，含紧急呼叫 Case2SIB2 配备 Bar，只针对特定服务特定的 UE 禁止接入 在 LTE 中，接入控制主要在 RRC 层进行，但是，在 NR 中，不仅在 RRC 层进行控 制，还可以在 NAS 层进行控制。具体如下 Factors RRC NAS USIM Description uac-BarringInfo in SIB1 RRC State Idle, Connected,Inactive 见下文 EFUAC_AIC, EFACC UACUAC 触发触发 根据 24.501 4.5.1 总结如下 TriggerDescription NAS 状态改变 5GMM-IDLE 5GMM-CONNECTED MO-MMTEL-voice-call-started indication MO-MMTEL-video-call-started indication MO-SMSoIP-attempt-started MO SMS over NAS ULNASTRANSPORTmessageforPDUsession establishment except for the purpose of IDLE - CONNECTED NAS State change ULNASTRANSPORTmessageforPDUsession modification except for the purpose of IDLE - CONNECTED NAS State change Requesttore-establishtheuser-plane resources for an existing PDU session Notification for an uplink user data packet to be sent for a PDU session with suspended user- plane resources 服 务 请 求in 5GMM-CONNECTED SIMSIM 卡信息相关的卡信息相关的 UACUAC EFUAC_AIC UAC Access Identities Configuration，31.102 定义如下 b8b7b6b5b4b3b2b1 b10 UE is not configured for Multimedia Priority Service in the HPLMN,EHPLMN or a visited PLMN of the home country. b11 UE is configured for Multimedia Priority Service in the HPLMN,EHPLMN or a visited PLMN of the home country. b20 UE is not configured for Mission Critical Services in the HPLMN,EHPLMN or a visited PLMN of the home country. b21 UE is configured for Mission Critical Services in the HPLMN,EHPLMN or a visited PLMN of the home country. RFU EFACC Access Control Class Byte 1 b8 15 b7 14 b6 13 b5 12 b4 11 b3 10 b2 09 b1 08Number of the ACC except for bit b3 Byte 2 b8 07 b7 06 b6 05 b5 04 b4 03 b3 02 b2 01 b1 00Number of the ACC Identifier 6F78 SFI 06 File size 2 bytes Access Conditions Bytes 1 to 2 READ UPDATE DEACTIVATE ACTIVATE Structure transparentMandatory Update activity low PIN ADM ADM ADM Description Access control classes M/O M Length 2 bytes 如何获取接入标识符 Access identitiesAccess identities Access IdentityAccess Identity numbernumber 0 1 NOTE 1 2 NOTE 2 3-10 11 NOTE 3 12 NOTE 3 13 NOTE 3 14 NOTE 3 15 NOTE 3 NOTE 1Access identity 1 is valid when - the USIM file EFUAC_AIC indicates the UE is configured for access identity 1 and the selected PLMN, if a new PLMN is selected, or RPLMN is the HPLMN if the EHPLMN list is not present or is empty or EHPLMN if the EHPLMN list is present, or a visited PLMN of the home country see the definition of home country in 3GPP TS 24.301 [15]; or - the UE receives the 5GS network feature support IE with the MPS indicator bit set to “Access identity 1 valid“ from the RPLMN as described in subclause 5.5.1.2.4 and subclause 5.5.1.3.4. NOTE 2Access identity 2 is use