Content for TR 23.733 Word version: 15.1.0
4 Architectural considerations
5 Key issues
6 Solutions
7 Overall evaluation
8 Conclusions
A Combined Solution 1
B Solution based on L3 Relay architecture
$ Change History
4 Architectural considerations p. 9
4.1 Architectural assumptions and requirements p. 9
4.2 Control and user plane stacks p. 10
5 Key issues p. 12
5.1 Key Issue 1: Authentication and Authorisation for Indirect 3GPP Communication p. 12
5.2 Key Issue 2: eRelay-UE Discovery and Selection p. 12
5.3 Key Issue 3: Enhancements to Connection Setup between an eRemote-UE and an eRelay-UE p. 12
5.4 Key Issue 4: EPS Bearer handling for Indirect 3GPP Communication p. 13
5.5 Key Issue 5: Service Continuity p. 13
5.6 Key Issue 6: Idle Mode Operation p. 13
5.7 Key Issue 7: Support for Emergency and eMPS call from eRemote-UE p. 14
6 Solutions p. 15
6.1 Solutions to Key Issue 1 p. 15
6.1.1 Solution 1: Subscription based authorisation p. 15
6.1.2 Solution 2: Authorisation of eRelay-UE and eRemote-UE p. 16
6.1.2.1 Description p. 16
6.1.2.1.1 General p. 16
6.1.2.1.2 Authorisation of an eRelay-UE to be a layer 2 relay p. 16
6.1.2.1.3 Authorisation of an eRemote-UE to access the LTE network through a layer 2 relay UE p. 17
6.1.2.2 Impact analysis p. 20
6.1.2.3 Evaluation p. 20
6.1.3 Solution 3: Authorisation for Indirect 3GPP Communication via MME p. 20
6.1.3.1 Description p. 20
6.1.3.1.1 General p. 20
6.1.3.1.2 Option A: Two phase authorisation alternative p. 20
6.1.3.1.3 Option B: One phase authorisation alternative p. 22
6.1.3.2 Impact analysis p. 23
6.1.3.3 Evaluation p. 24
6.1.4 Solution 4: Dynamic Trust relationship establishment using ProSe function/PC3 p. 24
6.1.4B Solution 4B: Dynamic Trust relationship establishment for MME based authorisation p. 26
6.1.5 Solution 5: Independent UE Authentication and Authorisation for Indirect 3GPP Communication via MME p. 28
6.1.5.1 Description p. 28
6.1.5.1.1 General p. 28
6.1.5.1.2 Independent Authorisation p. 28
6.1.5.2 Impact analysis p. 30
6.1.5.3 Evaluation p. 31
6.1.6 Solution 6: Simplified authorisation of eRelay-UE and eRemote-UE p. 31
6.1.6.1 Description p. 31
6.1.6.1.1 General p. 31
6.1.6.1.2 Authorisation of an eRelay-UE to be a layer 2 relay p. 31
6.1.6.1.3 Authorisation of an eRemote-UE to access LTE via a layer 2 relay p. 31
6.1.6.1.4 Procedures of an eRemote-UE to access the LTE network through a layer 2 relay UE p. 32
6.1.6.1.5 Solution for PC5 trust relationship establishment p. 34
6.1.6.2 Impact analysis p. 34
6.1.6.3 Evaluation p. 34
6.2 Solutions to Key Issue 2 p. 35
6.2.1 Solution 1: eRelay Discovery p. 35
6.2.1.1 Description p. 35
6.2.1.1.1 General p. 35
6.2.1.1.2 Discovery messages p. 35
6.2.1.2 Impact analysis p. 35
6.2.1.3 Evaluation p. 36
6.2.2 Solution 2: Reusing Rel-13 PC5_DISCOVERY message p. 36
6.2.3 Solution 3: L2 (eRelay-UE) or L3 (ProSe UE-to-Network Relay) discovery for Public Safety p. 37
6.3 Solutions to Key Issue 3 p. 39
6.3.1 Solution 1: Fast Connection setup by optimizing eRemote-UE security procedures p. 39
6.3.2 Solution 2: eRemote-UE initiated indirect 3GPP communication procedure p. 40
6.3.2.1 Description p. 40
6.3.2.1.1 General p. 40
6.3.2.1.2 Procedure description p. 41
6.3.2.2 Impact analysis p. 42
6.3.2.3 Evaluation p. 42
6.4 Solutions to Key Issue 4 p. 42
6.5 Solutions to Key Issue 5 p. 42
6.5.1 Solution 1: NAS Based Service Continuity Solution p. 42
6.5.1.1 Description p. 42
6.5.1.1.1 General p. 42
6.5.1.1.2 eRemote-UE mobility under same eNB p. 43
6.5.1.1.3 eRemote-UE mobility under different eNBs p. 44
6.5.1.1.4 eRelay-UE does handover p. 46
6.5.1.1.5 Change of eRelay-UE's LTE-Uu radio p. 46
6.5.1.2 Impact analysis p. 46
6.5.1.3 Evaluation p. 47
6.5.2 Solution 2: AS based Service Continuity Solution p. 47
6.5.2.1 Description p. 47
6.5.2.1.1 General p. 47
6.5.2.1.2 eRemote-UE mobility under the same eNB p. 48
6.5.2.1.3 eRemote-UE mobility under different eNBs p. 49
6.5.2.2 Impact analysis p. 53
6.5.2.3 Evaluation p. 53
6.5.3 Solution 3: Switching between direct and indirect communication p. 54
6.5.3.1 Description p. 54
6.5.3.1.1 Path Switch to Indirect 3GPP communication p. 54
6.5.3.1.2 Path Switch to Direct 3GPP communication p. 55
6.5.3.2 Impact analysis p. 56
6.5.3.3 Evaluation p. 56
6.5.4 Solution 4: Simplified NAS Based Service Continuity Solution p. 56
6.5.4.1 Description p. 56
6.5.4.1.1 General p. 56
6.5.4.1.2 From direct to indirect 3GPP communication under the same eNB p. 57
6.5.4.1.4 Change of eRelay-UE's LTE-Uu radio p. 60
6.5.4.2 Impact analysis p. 60
6.5.4.3 Evaluation p. 61
6.5.5 Solution 5: Handover of eRelay-UE with eRemote-UE(s) having an active indirect connection p. 61
6.6 Solutions to Key Issue 6 p. 64
6.6.1 Solution 1: Idle Mode Operation and Paging p. 64
6.6.1.1 Description p. 64
6.6.1.1.1 General p. 64
6.6.1.1.2 UE Idle Mode behaviour in idle mode p. 64
6.6.1.1.3 UE Paging IE sharing solution p. 65
6.6.1.1.4 eRemote-UE Paging solution p. 66
6.6.1.1.5 eRemote-UE Paging solution when PC5 DRX value is configured in the eRelay-UE p. 67
6.6.1.2 Impact analysis p. 68
6.6.1.3 Evaluation p. 68
6.6.2 Solution 2: eRelay-UE monitors RRC Paging message for eRemote-UE separately p. 69
6.6.2.1 Description p. 69
6.6.2.1.1 Means for eRelay-UE to know the eRemote-UE's paging parameters p. 69
6.6.2.1.2 Means for eRelay-UE to monitor RRC Paging message p. 69
6.6.2.1.3 Paging procedure via eRelay-UE p. 69
6.6.2.2 Impact analysis p. 69
6.6.2.3 Evaluation p. 70
6.6.3 Solution 3: Based on Option 1 and Option 2 p. 70
7 Overall evaluation p. 72
7.0 Further assumptions p. 72
7.1 Key Issue 1 p. 73
7.2 Key Issue 2 p. 73
7.3 Key Issue 3 p. 74
7.4 Key Issue 4 p. 74
7.5 Key Issue 5 p. 75
7.6 Key Issue 6 p. 76
7.7 Key Issue 7 p. 76
8 Conclusions p. 76
A Combined Solution 1 p. 77
A.0 General p. 77
A.1 Terminology p. 77
A.2 Overall procedure for enabling indirect 3GPP communication p. 77
B Solution based on L3 Relay architecture p. 79
B.1 General p. 79
B.2 Support of commercial usage p. 79
B.3 Visibility of Remote UE in Core Network p. 79
B.3.1 Authentication and authorization of indirect 3GPP communication p. 79
B.3.2 Awareness of the use of Relay connection p. 79
B.3.3 Charging support for Remote UE p. 79
B.4 Session continuity support p. 80
B.5 QoS control and bearer management over PC5 p. 80
B.6 Support of Non-IP Data delivery p. 80
B.7 Security protection over the PC5 p. 80
B.8 Identified Issues p. 80
B.9 Normative specification impacts p. 81
$ Change History p. 81
