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6.4 Solution #4: Handling awareness of supported TAIs when RAN is onboard
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6.4.1 Description
This is a candidate solution for Key Issue 1 - "Support of Regenerative-based satellite access ". In contrast to Rel-17/Rel-18, where transparent payload was defined for satellite access and backhaul, the introduction of regenerative payload in Rel-19 involves deploying gNB on board, leading to impacts on the interface...
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6.4.2 Procedures
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6.4.2.1 Procedures of gNB connect to the same AMF via the same gateway
Figure 6.4.2-1: Procedures of efficient RAN context management on AMF 0. Pre-condition: AMF and RAN both are pre-configured with the mapping relationship among Global RAN Node ID, supporting TAI list, and valid period. 1. When the feeder link with gateway-1 is available, the NG-RAN node initiates the procedure by sendi...
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6.4.2.2 Procedures of gNB connect to a different AMF via a different gateway
The procedure as defined in clause 6.4.2.1 can be reused.
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6.4.2.3 Procedures of gNB connect to the same AMF via different gateway
Whenever gNB connects to a different gateway, if the gNB changes its Global RAN Node ID. procedures as defined in clause 6.4.2.2 can be reused, as shown in Figure 6.4.1-2. Editor's note: if gNB does not change Global RAN Node ID, the procedure is FFS.
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6.4.3 Impacts to Services, Entities and Interfaces
AMF: - Preconfigure mapping relationship among Global RAN Node ID, supporting TAI list and valid period. - Update mapping relationship, especially the valid period starting time-based on NG Setup Request. - Suspend RAN context when the connection between RAN and AMF is interrupted. - Active RAN context when the connect...
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6.5 Solution #5: Support of Feeder Link Switchover with TAU for Non-Pooled MMEs
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6.5.1 Description
This is a candidate solution to address Key Issue #1. The proposed solution follows the following assumptions and principles. - One eNB on a satellite for regenerative based satellite access for LEO/MEO deployment. - Single satellite deployment. - Feeder link switchover causes eNB to be served by a different MME than s...
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6.5.2 Procedures
Figure 6.5.2-1 illustrates the call flow and system changes for feeder link switchover-triggered Tracking Area Update (TAU) procedure. Figure 6.5.2-1: High-level procedure for TAU triggered by Feeder Link Switchover 1. As described in clause 6.5.1, the feeder link switchover triggers UE to start TAU procedure, after be...
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6.5.3 Impacts to Services, Entities and Interfaces
This solution impacts the following entities. RAN: - Release S1-AP based on feeder link switchover information. - Broadcast feeder link switchover information MME: - Release S1-AP based on feeder link switchover information. - New triggering condition, feeder link switchover, for TAU - New IE in NAS message to include ...
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6.6 Solution #6: Load re-balancing for feeder link switchover
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6.6.1 Description
Key Issue #1 focus on the deployment of regenerative payload on LEO/MEO satellite access, and whether there is any impact on 5GS and EPS. In the regenerative payload configuration, the feeder link switchover, due to eNB/gNB moving, might require a reconfiguration of connections, leading to increased NAS signalling over...
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6.6.2 Procedures
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6.6.2.1 MME procedures
The deployment of MMEs is usually based on factors such as geography, latency, network load, and specific service requirements. During feeder link switchover, as a LEO/MEO satellite moves beyond the coverage of a source NTN GW, the eNB could be served, before and after the feeder link switchover, by different MMEs. Eve...
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6.6.2.2 AMF procedures
Figure 6.6.2.2-1 provides procedures to support feeder link switchover in 5GS. Figure 6.6.2.2-1: High-level procedures for load re-balancing driven feeder link switchover in 5GS 0. Feeder link switchover preparation: In 5GS, 5G-AN node shall have the capability to support multiple TNL associations per AMF. Based on sat...
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6.6.3 Impacts to Services, Entities and Interfaces
This solution impacts the following entities. RAN: - Release NG-AP or S1-AP taking into consideration of feeder link switchover information. MME: - Release S1-AP taking into consideration of feeder link switchover information. AMF: - Release NG-AP taking into consideration of feeder link switchover information.
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6.7 Solution #7 for Key Issue #1: Feeder link switchover with DL data continuity
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6.7.1 Description
It is observed that the feeder link switchover for Regenerative-based satellite access is different from Transparent-based satellite access. Also there is a potential issue of DL data continuity in case of hard feeder link switchover. In this solution a procedure for Feeder link switchover for Regenerative-based satell...
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6.7.2 Procedures
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6.7.2.1 Feeder link switchover without AMF change
Figure 6.7.2-1 describes the procedures for Feeder link switchover without AMF change. Figure 6.7.2.1-1: Feeder link switchover without AMF change 1. The NG-RAN onboard the satellite connects to 5GC via NTN Gateway 1. For the upcoming Feeder link switchover, the NG-RAN may perform switchover preparation depending on a ...
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6.7.3 Impacts to Services, Entities and Interfaces
The following impacts are foreseen by this solution: AMF: - Reception of new TNLA from old NG-RAN or new NG-RAN due to Feeder link switchover. Possible normative impact in SA2 depends on RAN WGs. SMF/UPF: - Buffering of the DL data. NG-RAN - Connecting to AMF with new TNLA. - Provision to AMF the N3 DL TNLA correspondi...
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6.8 Solution #8 for Key Issue #1: QoS/ Policy handling for Regenerative-based satellite access
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6.8.1 Description
It is observed that the QoS, RAT Type for Regenerative-based satellite access and Transparent-based satellite access is different. The differences can be illustrated by the figure below: Figure 6.8.1-1: QoS for Regenerative-based and Transparent-based satellite access Additionally, considering the potential inclusion o...
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6.8.2 Procedures
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6.8.2.1 General
The general procedure is based on PDU session Establishment or Modification procedures described in clauses 4.3.2 or 4.3.3 TS 23.502 [3], with additional treatment for Regenerative-based satellite access. Figure 6.8.2-1 describes the general procedures of the solution. Figure 6.8.2.1-1: General procedures for QoS/ Poli...
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6.8.3 Impacts to Services, Entities and Interfaces
The following impacts are foreseen by this solution: AMF: - Determination of the RAT Type information for Regenerative-based satellite access of the UE. - Provision to other NFs the RAT Type information for Regenerative-based satellite access. SMF: - Provision to other NFs the RAT Type information for Regenerative-base...
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6.9 Solution #9: Support of Regenerative-based satellite access with deploying RAN-agent and Proxy RAN node or Link Layer Proxy NF
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6.9.1 Description
This solution resolves KI#1 about any impact of RAN nodes changing for any given 5GC/EPC and for a given area in the case of RAN nodes on-board moving. Embarking gNB on-board LEO/MEO implies the on-board gNB serving for the UE access will be change as the satellite moving, which may cause the following network impacts ...
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6.9.1.1 Support of Regenerative-based satellite access with RAN-agent and Proxy RAN node
The solution proposes to enhance 5G network architecture to reduce the impact of 5GC. Solution#8 in TR 23.737-h20 is proposed to reuse to address the above mentioned issues. In this solution: 1. Deploying RAN agent close to gateways on earth as shown in Figure 6.9.1.1-1. The RAN agent is used to process control plane s...
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6.9.1.2 Support of Regenerative-based satellite access with Link Layer Proxy
RAN agent and Proxy RAN node in clause 6.9.1.1 can also be integrated as a core network function called Link Layer Proxy, the LLP is decoupled from NTN gateways and has a 1:1 mapping relationship to MME/AMF set. The control plane and user plane in the LLP can be separated based on internal private interface. Figure 6.9...
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6.9.2 Procedures
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6.9.2.1 NG Setup, RAN configuration Update and UE registration
The following call flow should be applied to RAN agent or LLP, the call flow uses RAN agent in 5GS as an example. Figure 6.9.2: Call Flow for RAN agent 1. The address of an RAN agent is configured to the earth station, so that the NG setup messages sent by satellite RAN nodes can be sent to the RAN agent. 2. The RAN ag...
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6.9.2.2 Handover with LLP and MME relocation
This procedure presents how LLP relocation happens when MME relocation is needed, e.g. as presented in Figure A-4 of Annex A, MME relocation may happen with UE handover between satellites using different earth station location. The following call flow can be applied to RAN agent and Proxy RAN node or LLP, the call flow...
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6.9.3 Impacts to Services, Entities and Interfaces
There is no impact to the existing NFs or Entities (e.g. gNB, AMF, SMF). However, the proposed solution needs to deploy two new NFs if it is RAN agent and Proxy RAN node to deploy, as the following: RAN agent: - New NF, which is located near the satellite ground station. The functionalities can be referred to clause 6....
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6.10 Solution #10: Regenerative-based satellite access with IWF on S1 or N2/N3 interface
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6.10.1 Key Issue mapping
This solution addresses Key Issue #1 (Support of Regenerative-based satellite access).
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6.10.2 Description
Depicted in Figure 6.10.2-1 is the 5GS architecture for regenerative-based satellite access with N2/N3 interworking function (IWF). Figure 6.10.2-1: 5GS architecture for regenerative-based satellite access with N2/N3 IWF The following are the salient features of the architecture in Figure 6.10.2-1: - Earth-fixed Tracki...
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6.10.3 Procedures
There is no impact on existing S1 or N2/N3 procedures from EPC and 5GC perspective, respectively.
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6.10.4 Impacts on services, entities and interfaces
The solution has no impact on UE, 5GC or EPC. The Interworking Function (IWF) is perceived by 5GC as a static gNB/eNB and is not supposed to require any standardisation in SA2 specifications, other than description of the IWF functionality in an informative annex. The OAM aspects of the IWF are expected to be defined b...
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6.11 Solution #11: MME Split Architecture to support Control plane procedure for S&F
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6.11.1 Key Issue mapping
This solution aims to resolve Key Issue #2, "Support of Store and Forward Satellite operation".
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6.11.2 Description
In this proposal, the MME, which is the mobility anchor for the UE, is split into 2 network elements, MME-NT (MME on board satellite) and MME-T (MME terrestrial). The MME-NT shall act as a mobility anchor point to UE and does only subset of MME functionality such as assist in Store and Forward operations i.e. combinati...
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6.11.3 Procedures
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6.11.3.1 Architecture enhancement to support S&F
In regenerative architecture, the RAN will be placed in Satellite. In the Store & Forward (S&F) scheme, the MME is at Satellite will be responsible for providing Store and Forward feature. MME in the satellite is represented as MME-NT-1 (non-terrestrial) in the above diagram. E.g. in above figure 6.11.2-2 for the time ...
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6.11.3.2 Attach Procedure in EPC in S&F scenario
Figure 6.11.3-2: Attach procedure in S&F 1. A UE, camping on an E-UTRAN cell reads the related System Information Broadcast including whether supports S&F operation. If the UE is able to perform the S&F operation, it initiates the Attach procedure by the transmission, to the eNodeB, of an Attach Request (IMSI or old GU...
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6.11.3.3 MO Data Transport in Control Plane CIoT EPS Optimisation in S&F
High level procedure of Control plane CIoT EPS optimization in Store and Forward scenario be shown as following. Figure 6.11.3.1-1: High-level Procedure of S&F Operation for MO Data Transport in Control Plane CIoT EPS Optimisation 0. The UE is ECM-IDLE. 1. The UE establishes a RRC connection and sends as part of it an ...
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6.11.3.4 Connection Suspend and Resume Procedure
Figure 6.11.3.4-1: Connection Suspend and Resume procedure 0. The UE is in RRC connected and ECM-Connected. 1. The eNodeB (RAN-1) in first satellite initiates the Connection Suspend procedure. 2. The eNodeB (RAN-1) indicates to the MME-NT-1 that the UE's RRC connection is to be suspended. Data related to the S1AP assoc...
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6.11.3.5 MT Data Transport in Control Plane CIoT EPS Optimisation in S&F
Figure 6.11.3.5-1 depicts a high-level Procedure of S&F Operation for MT Data Transport in Control Plane CIoT EPS Optimisation. Figure 6.11.3.5-1: High-level Procedure of S&F Operation for MT Data Transport in Control Plane CIoT EPS Optimisation 0. The UE is ECM-IDLE. 1. PGW sends the downlink data to the SGW. SGW buff...
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6.11.4 Impacts on services, entities and interfaces
UE: - NAS impact to handle larger delay due to S&F mode of operation. - NAS impact due to new interim GUTI allocation. MME-T: - Handling of new S10 messages to carry both ciphered and plain text NAS messages to/from MME-NTs. - Transmits Resume notification messages to MME-NT, in case of connection Suspend and Resume pr...
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6.12 Solution #12: S&F for multiple satellite deployment with anchor MME-ground
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6.12.1 Description
For control plane management of registration and connection management procedures, we propose to have eNB and MME onboard the satellite. Below are the principles of the solution: 1. MME-ground is an anchor node situated in ground network which has the UE context. MME-ground synchronizes the UE context with all the MME-...
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6.12.2 Procedures
Figure 6.12.2-1: Attach without PDN connectivity The eNB, MME-onboard are assumed to be onboard the satellite, there is a ground MME which is acting like an anchor for the MMEs onboard the satellite. The attach procedure as described in clause .5.3.2.1 of TS 23.401 [5] are executed with below modifications. At time T0 ...
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6.12.2.1.1 Periodic timer and mobile reachable timer
The Mobile Reachable Timer (MRT) is run only at the MME-ground, each time UE gets in connected mode with any of the MME-onboard, the MME-onboard informs the MME-ground, then MME-ground restart the MRT timer. The mobile reachable timer value has to be increased at network so that it takes into account delay in receiving...
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6.12.2.1.2 How UE identifies that it is allowed to attach with network for S/F
If UE determines that it has no other network which can provide normal services then UE may determine to attach in store and forward mode. Similar to CAG mechanism available in 5GS, we propose that UE is configured with S&F information and if configured S&F ID is broadcasted along with the indication of support for S/F...
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6.12.2.1.3 GUTI management and MME selection
The GUTI is assigned to the UE only by the MME-ground which is stored commonly with all the MME(s)-onboard in the UE context. The eNB-onboard selects the MME-onboard: a) Based on the MME-group ID which can be kept common for all the MME(s)-onboard which can serve the UE based on UE serving area and the MME-ground; or b...
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6.12.2.1.4 MME-ground selection by MME-onboard
MME-onboard selects the MME-ground when UE first attaches the network. MME-onboard should follow same selection mechanism as eNB selects MME in Rel-18 to select a MME-ground. The MME-onboard is assume to support all the features MME-ground supports. MME-ground once assigns the GUTI, MME-onboard can uniquely identify th...
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6.12.2.1.5 Authentication procedure/subscription details fetch during any other procedure
If network determines to execute authentication procedure/fetch subscription details etc during any time for e.g. during service request procedure execution then the concept of partial attach accept discussed above is applicable. i.e. UE is indicated in NAS message that network has stored uplink message and network wil...
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6.12.2.1.6 Attach with PDN connectivity, multiple satellite
The gNB, MME, S-GW and P-GW are assumed to be onboard the satellite. Assumption-1: If we assume there is no need for PCRF because PCC policies can be configured in the P-GW onboard satellite because. communication is for delay tolerant devices there is no specific or very small policies may need to be applied. Assumpti...
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6.12.3 Impacts on services, entities and interfaces
a) MME-ground is an anchor node situated in ground network which has the UE context. MME-ground synchronizes the UE context with all the MME-onboard(s). b) The eNB and MME-onboard are onboard the satellite. Thus they can provide basic connection management procedures with the UE. The MME-onboard executes all the proced...
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6.13 Solution #13: S&F for single satellite deployments with eNB and MME-onboard
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6.13.1 Description
a) Single satellite deployment in this solution implies out of possible N satellites deployed by network, the UE is served by only one satellite. The N can be one or more than one i.e. network can choose to deploy only one satellite for all UEs or more than one satellites catering to different subset of UEs. b) The eNB...
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6.13.2 Procedures
Figure 6.13.2-1: Attach without PDN connectivity Case-1: Attach without PDN connectivity, single satellite. The eNB, MME are assumed to be onboard the satellite. rest of the system is on the ground. The attach procedure as described in clause .5.3.2.1 of TS 23.401 [5] are executed with below modifications: At time T0 (...
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6.13.2.1 Other changes:
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6.13.2.1.1 Periodic timer and mobile reachable timer
The mobile reachable timer value has to be increased at network so that it takes into account delay in serving the UE after PTAU timer has expired at the UE. For e.g. Mobile reachable timer = PTAU timer given to UE + Maximum potential delay for MME-onboard to again serve the UE.
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6.13.2.1.2 How UE identifies that it is allowed to attach with network for S/F
If UE determines that it has no other network which can provide normal services, then UE may determine to attach in store and forward mode. Similar to CAG mechanism available in 5GS, we propose that UE is configured with S&F information and if configured S&F ID is broadcasted along with the indication of support for S/...
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6.13.2.1.3 UE selecting single satellite in a given area
If an area can be served by multiple satellites, it is assumed that each eNB onboard the satellite will broadcast different TAI(s). This TAI(s) other than of serving satellite are provided as forbidden TAIs to the UE, so that UE can avoid selecting other satellites(except the serving satellite). Editor's note: If any a...
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6.13.2.1.4 Authentication procedure/subscription details fetch during any other procedure
If network determines to execute authentication procedure/fetch subscription details etc during any time for e.g. during service request procedure execution then the concept of partial attach accept discussed above is applicable. i.e. UE is indicated in NAS message that network has stored uplink message and network wil...
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6.13.3 Impacts on services, entities and interfaces
This solution impacts the following system entities: a) The eNB and MME-onboard are onboard the satellite. Thus they can provide basic connection management procedures. The MME-onboard executes all the procedures with the UE which does not need interaction with other core network nodes on the ground when the service li...
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6.14 Solution #14: Initial Registration with prior rejection in satellite network for S&F operation
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6.14.1 Key Issue mapping
This solution addresses the Initial Attach / Initial Registration of Key Issue #2 (Support of Store and Forward Satellite operation). The Initial Attach / Initial Registration procedure is assumed to be common to all S&F services.
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6.14.2 Description
Consider the extreme case depicted in Figure 6.14.2-1 with a satellite orbit consisting of only one LEO satellite: Figure 6.14.2-1: Incomplete satellite orbit with only one satellite Assuming that the satellite orbit is located at 500 km altitude, the orbital period is roughly equal to 90 minutes. The size of the satel...
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6.14.3 Procedures
The procedure for Initial Attach in a Satellite network for S&F operation is depicted in Figure 6.14.3-1. The steps enclosed in dashed line boxes are executed as atomic procedures. Figure 6.14.3-1: Initial Attach in satellite network for S&F operation 1-3. When UE determines that it is in satellite coverage, the UE att...
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6.14.4 Impacts on services, entities and interfaces
MME impact: - Ability for split operation with MME-SAT and MME-GND component on the satellite and on the ground, respectively. - Ability for differentiated handling of UEs: sending Accept Reject including protected Cause and Timer value to UE enhanced for S&F; sending Accept Reject with Cause = "Congestion" for legacy ...
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6.15 Solution #15: S&F solution for multi-satellite IoT NTN
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6.15.1 Description
The description of the solution principles and architecture assumptions for the proposed solution are conducted taking as a reference architecture the Optimized EPS architecture option for CIoT as specified in TS 23.401 [5]. The consideration of such architecture is mainly motivated for the sake of clarity in the prese...
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6.15.2 Procedures
Based on the architecture depicted in Figure 6.15.1-4 and giving special relevance to the following architecture assumption "Impacts to UE, network functions and entities are minimised. To the extent possible, existing procedures and functionality is reused", this section describes high-level procedures and information...
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6.15.2.1 Advertising capabilities and activation of S&F Satellite operation
A E-UTRAN cell with satellite access for Cellular IoT (CIoT) should be able to inform a UE of: - Whether the satellite cell is being operated in S&F Satellite operation mode or in normal/default mode. - Whether there is any service restriction/limitation, or alternatively which services/options are available, while the...
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6.15.2.2 NAS procedures spanning several satellite passes
In a satellite cell operating in S&F Satellite operation mode, if a UE initiates a signalling procedure during a satellite pass (e.g. E-UTRAN Initial Attach procedure) and the procedure cannot be completed within the duration of the pass because some information is missing in the serving satellite (e.g. E-UTRAN Authent...
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6.15.2.3 Data transfer in S&F Satellite operation mode
Following successful registration with the satellite PLMN and establishment of a valid UE/MME context across all or a subset of the satellites of the constellation, data transfer can take place between the UE and any of those satellites when in reach of the UE. Without preventing other approaches, this scenario conside...
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6.15.3 Impacts to Services, Entities and Interfaces
No impacts foreseen in terms of defining new entities or interfaces for the EPS architecture. However, the following extensions would be needed to support S&F Satellite operation in a multi-satellite constellation scenario: 1) For the network to advertise the support of S&F capabilities and/or activation of S&F satelli...
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6.16 Solution #16: Enabling S&F operation with C-SGN onboard
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6.16.1 Description
This is a candidate solution for Key Issue 2 - "Support of Store and Forward Satellite operation". To facilitate Store-and-Forward (S&F) operations for delay-tolerant services, the assumption is made to activate the entire C-SGN on board. The architecture is derived from Annex L, specifically the "Optimised EPS Archite...
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6.16.2 Procedures
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6.16.2.1 Procedures of NAS Pause/Recovery of S&F Operation
This procedure can be applied to any NAS interactions between UE and MME as listed in TS 23.401 [5]. An example of how to utilize NAS Pause/Recovery to complete the initial attach procedure is given in clause 6.16.2.4, and how to utilize NAS pause/recovery to complete the MO/MT data transmission is given in clause 6.16...
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6.16.2.2 Procedures of Store/Forward of SMS transmission
The procedures are used for SMS service. NOTE: this procedure can also be used for CP CIoT optimizations.
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6.16.2.2.1 Procedure of MO SMS transmission
Figure 6.16.2.2.1-1 Pre-condition: UE is registered to the S&F network. A NAS pause timer was assigned by the MME when the service link was about to be unavailable as defined in clause 6.16.2.1. UE has a NAS pause timer running. 1. UE has a SMS message to be sent. When the service link is available, and the UE's NAS pa...
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6.16.2.2.2 Procedure of MT SMS transmission
Figure 6.16.2.2.2-1 Pre-condition: SMS-GMSC is assumed to be informed the S&F operation and is aware of the availability information of onboard P-GW/S-GW/MME. 1. SMS-GMSC receives a SMS message for a UE, SMS-GMSC checks the availability of MME onboard based on the fetched the routing information from HSS. When the avai...
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6.16.2.3 Procedure of Store/Forward of Data transmission
This procedure applies to CP CIoT EPS Optimizations, UP CIoT EPS Optimizations, non-IP data transmissions.
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6.16.2.3.1 Procedure of MO Data transmission
Figure 6.16.2.3.1-1 Pre-condition: same precondition as defined in clause 6.15.2.2.1. 1. UE sends UL data via RAN and S-GW with NAS recovery firstly, similar procedure as defined in step 1 in clause 6.16.2.2.1. When the delay-tolerant service is CP CIoT optimizations, the path is: UERANMMES-GW; When the delay-tolera...
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6.16.2.3.2 Procedure of MT data transmission
Figure 6.16.2.3.2-1 Pre-condition: CIoT service server is assumed to be informed the S&F operation and is aware of the availability information of onboard P-GW/S-GW/MME. 1. P-GW and S-GW receives DL data. CIoT service center receives MT data for a UE, CIoT service center checks the availability of P-GW/S-GW/MME onboard...
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6.16.2.4 Example of initial attach procedure
This provides an example of how the UE can complete the attach procedure with C-SGN onboard. Generally, if the UE hasn't established any connection with the network before, it needs at least 3 rounds of satellite orbiting periods, each round of orbiting UE and network can complete some parts of the procedure.
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6.16.2.4.1 1st round orbiting
Figure 6.16.2.4.1-1 1. When service link is available, UE initiates the RRC connection with RAN and sends Attach Request to MME. 2. MME pause the NAS because MME needs to wait for the response from HSS . As MME has not completed the interactions with the HSS (on ground), MME cannot assign a GUTI to the UE yet. Therefor...
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6.16.2.4.2 2nd round orbiting
Figure 6.16.2.4.2-1 1. When service link is available, MME recovers the interactions with UE to complete the authentication and authorization procedure. The NAS recovery procedure will be executed as described in clause 6.16.2.1. 2. MME pause the NAS because MME needs to wait for the response from HSS, S-GW-P-GW and et...
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6.16.2.4.3 3rd round orbiting
Figure 6.16.2.4.3-1 1. When the service link is available, MME recovers the interactions with UE to complete the attach procedure. The NAS recovery procedure will be executed as described in clause 6.16.2.1. Afterwards, UE can send UL data.
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6.16.3 Impacts to Services, Entities and Interfaces
MME: - Detection of service link/feeder link availability. - Initiate NAS pause/recover procedure when CN interactions with CN NFs on the ground is needed. - Pause/recover NAS based on service link's availability. - Store/Forward SMS data RAN: - Optionally, initiate AS pause procedure if NAS is paused, and initiate AS ...
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6.17 Solution #17 for KI#2: Support of Store and Forward Satellite operation for small data transmission
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6.17.1 Description
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6.17.1.1 General
This solution resolves KI#2 to support Store and Forward Satellite operation for small data transmission. Since the UE-satellite-ground network connectivity is intermittent for the Store and Forward Satellite Operation, the UE's initial attach cannot be completed at one time when the UE is in the coverage of the satell...
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6.17.1.2 Reference Architecture
In order to support Store and Forward Satellite operation for small data transmission, the following figure shows the high level reference architecture. Figure 6.17.1.2: Reference Architecture for support of Store and Forward Satellite operation for small data transmission The core network elements/functions to be depl...