Content for TS 23.256 Word version: 19.0.0

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5.14 Support of Network-Based/Assisted DAA 5.14.1 Functional Description 5.14.2 Procedure for UAV Triggered Network-assisted DAA 5.14.3 Procedure for AAM Triggered Network-assisted DAA 5.14.4 Procedure for USS Triggered Network-assisted DAA
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5.14 Support of Network-Based/Assisted DAA |R19| p. 82

5.14.1 Functional Description p. 82

This clause provides a network-based/assisted DAA mechanism. To enable NWDAA, the following information can be utilised:

Absolute location of a UAV provided by the LoCation Service;
Relative Location of UAVs provided by the Ranging Service;
Output of Relative Proximity Analytics provided by NWDAF.

Absolute location of a UAV is generated/derived in 5G network by using the existing LCS feature defined in TS 23.273. USS may request to GMLC to obtain one or multiple UAV location as defined in clauses 6.2.1, 6.3.1 or 6.20.5 of TS 23.273. As an example, USS may use the absolute location of the UAV(s) provided by the network to e.g. calculate relative distance of the pair of UAVs, and based on that to deal with the UAV tactical deconfliction, collision avoidance etc.

Relative location of a UAVs is provided in 5G network by using the existing LCS Ranging feature defined in TS 23.273. USS may send a Ranging request to GMLC to obtain relative location between one and multiple UAVs as defined in clauses 6.20.3 or 6.20.4 of TS 23.273. USS may use the relative location of the UAV(s) to avoid collision.

USS (acting as an AF) may request Relative Proximity Analytics provided by NWDAF for the purpose of DAA.

To deconflict the potential collisions, the USS notifies the potential collision to the UAV UE or AAM or UAV-C which is responsible to inform the paired UAV about the collision. When the notification of the potential collision is received by AAM, it performs the deconfliction by triggering the mechanism specified for ground-based DAA for an area in clause 5.7.2. When the UAV UE receives the potential collision notification from USS or the paired UAV-C, it performs the deconfliction by triggering the mechanism specified for DAA based on PC5 in clause 5.6.1.

5.14.2 Procedure for UAV Triggered Network-assisted DAA p. 83

Reproduction of 3GPP TS 23.256, Fig. 5.14.2-1: Procedure for UAV/UAV-C Triggered Network-assisted DAA

Figure 5.14.2-1: Procedure for UAV/UAV-C Triggered Network-assisted DAA

Step 1.

The UAV establishes a PDU Session for communication with the USS as described in clause 5.2.3.

Step 2.

The DAA service may be triggered by UAV(s). The UAV(s) (via its paired UAV-C) requests DAA service from USS. The request message includes identifier of the UAV(s) (e.g. GPSI(s), CAA-Level UAV ID(s)). USS derives information on DAA service and decides to subscribe/request to 5GC for GMLC service on Ranging/Sidelink Positioning location and/or Relative Proximity predictions on collision from NWDAF.

Step 3a.

The USS may request GMLC service via NEF for Ranging/Sidelink Positioning location results, i.e. the relative positioning between UAV UEs as described in clause 6.20.3 of TS 23.273 for one notification, or clause 6.20.4 of TS 23.273 for notifications (steps 1-20 for initiation monitoring, steps 21-31 for monitoring periodic).

Step 3b.

USS as AF/LCS client may send the absolute positioning request to GMLC, including UAV UE1 ID (UE1 GPSI) and UAV UE2 ID (UE2 GPSI) as described in clauses 6.2.1 and 6.3.1. GMLC replies to USS of the absolute location of UAV 1 and UAV 2. USS calculates the relative positioning result based on the UAV UE1 absolute location and UAV UE2 absolute location.

Step 4.

The USS may subscribe or request notification on Relative Proximity predictions provided by NWDAF via NEF by invoking Nnef_AnalyticsExposure_Subscribe service operation as defined in clause 6.1.1.2 of TS 23.288 or Nnef_AnalyticsExposure_Fetch service operation as defined in clause 6.1.2.2 of TS 23.288. The subscribe/request message include identifier of the UAV(s) (e.g. GPSI(s)). The other parameters included in the request are described in clause 6.5.3.3.

Step 5.

After NEF receive the request from the USS, the NEF interacts with the NWDAF as described in the procedure in clause 6.19.4 of TS 23.288. The NEF maps the parameters in the request from the USS to information used by the 3GPP system.

Step 6.

If the NEF receives the response from the NWDAF, the NEF notifies the USS with the Relative Proximity predictions by invoking Nnef_AnalyticsExposure_Notify service operation for a Subscribe-Notify model as defined in clause 6.1.1.2 of TS 23.288 or Nnef_AnalyticsExposure_Fetch service operation for a Request-Response model as defined in clause 6.1.2.2 of TS 23.288.

Step 7.

If receiving the location of UAV1 and UAV2, USS calculates the relative positioning result for UAV UE1 location and UAV UE2 location from step 1 and step 2. The USS estimates the potential collision based on the information received in step 3 and/or the predictions from step 6. The USS informs the UAV-C(s) the potential collision. The message may include collision alert, predicted time of collision, CAA-level UAV IDs of the paired UAVs which may collision (e.g. UAV 1 and UAV 2), deconflicting specific parameters (e.g. trajectory correction information to avoid collision).

USS may be replaced by TPAE.

Step 8.

The UAV-C(s) informs its paired UAV(s) the potential collision, and information received from the USS, include collision alert, predicted time of collision, CAA-level UAV IDs of the paired UAVs which may collision, and deconflicting specific parameters (e.g. trajectory correction information to avoid collision).

Step 9.

UAVs performs operations to avoid collision.

Step 9a.

If both the two UAVs which may collision (e.g. UAV 1 and UAV 2) been informed by their paired UAV-C(s), the UAVs can be steered to avoid collision in accordance with the received information (e.g. trajectory correction information to avoid collision) and using mechanisms that are out of scope for 3GPP.

Step 9b.

If only one of the two UAVs which may collision (e.g. UAV 1) been informed by its paired UAV-C, the UAV 1 triggers conflict resolution procedure with UAV 2 as described in steps 4-7 in clause 5.6.1.

5.14.3 Procedure for AAM Triggered Network-assisted DAA p. 84

Reproduction of 3GPP TS 23.256, Fig. 5.14.3-1: Procedure for AAM Triggered Network-assisted DAA

Figure 5.14.3-1: Procedure for AAM Triggered Network-assisted DAA

Step 1.

As described in clause 5.7.2 steps 1-6, the UAV(s) listens for signals on the correspondingly destination Layer-2 ID configured for the used service type. The AAM scans the airspace over the area/arena for UAV(s), retrieves for each detected UAV the corresponding Remote-ID, and establishes a PC5 direct communication link with the discovered UAV. Using the PC5 unicast direct communication link the AAM and the UAV establishes a bidirectional communication channel for exchange of messages.

Step 2.

The AAM establishes a PDU Session for communication with the USS as described in clause 5.2.3.

Step 3.

The AAM may request network assist DAA service from USS. The request message includes identifier of the UAV(s) (e.g. GPSI(s), CAA-Level UAV ID(s)). USS derives information on DAA service and decides, e.g. to request GMLC service for Ranging/Sidelink Positioning location, to subscribe/request to NWDAF for Relative Proximity predictions on collision.

Step 4.

The USS requests GMLC service for Ranging/Sidelink Positioning location, and/or subscribes/requests notification on Relative Proximity predictions provided by NWDAF via NEF, as described in steps 3-6 of clause 5.7.2.

Step 5.

The USS estimates the potential collision based on the received information/analytics in step 4. The USS informs the AAM the potential collision. The message may include collision alert, predicted time of collision, CAA-level UAV IDs of the paired UAVs which may collision (e.g. UAV 1 and UAV 2), deconflicting specific parameters (e.g. trajectory correction information to avoid collision).

Step 6.

The AAM provides the determined steering policy to the specific UAVs (e.g. UAV 1 and UAV 2) according to the information received in step 5, and the UAVs are steered to avoid collisions in accordance with received policy and using mechanisms that are out of scope for 3GPP, as described in clause 5.7.2 steps 7-8.

5.14.4 Procedure for USS Triggered Network-assisted DAA p. 85

Reproduction of 3GPP TS 23.256, Fig. 5.14.4-1: Procedure for USS Triggered Network-assisted DAA

Figure 5.14.4-1: Procedure for USS Triggered Network-assisted DAA

Step 1.

The UAV and UAV-C establish PDU Session for communication with the USS as described in clause 5.2.3.

Step 2.

The USS may decide to trigger NWDAA based on application layer request.

Step 3.

The USS requests absolute location of UAV(s) based on the identifiers received in step 2 by invoking the 5GC-MT-LR procedure for the commercial location service in clause 6.1.2 or Initial and Reporting of Location Events in clause 6.3.1 or 5GC-MT-LR procedure using SL positioning in clause 6.20.5 of TS 23.273.

Step 4.

[Optional] The USS may subscribe or request notification on Relative Proximity predictions provided by NWDAF via NEF by invoking Nnef_AnalyticsExposure_Subscribe service operation as defined in clause 6.1.1.2 of TS 23.288 or Nnef_AnalyticsExposure_Fetch service operation as defined in clause 6.1.2.2 of TS 23.288. The subscribe/request message include identifier of the UAV(s) (e.g. GPSI(s)).

Step 5.

[Optional] If the step 4 is performed, after NEF receive the request from the USS, the NEF interacts with the NWDAF as described in the procedure in clause 6.19.4 of TS 23.288. The NEF maps the parameters in the request from the USS to information used by the 3GPP system.

Step 6.

[Optional] If the NEF receives the response from the NWDAF, the NEF notifies the USS with the Relative Proximity predictions by invoking Nnef_AnalyticsExposure_Notify service operation for a Subscribe-Notify model as defined in clause 6.1.1.2 of TS 23.288 or Nnef_AnalyticsExposure_Fetch service operation for a Request-Response model as defined in clause 6.1.2.2 of TS 23.288.

Step 7.

The USS performs step 7a and 7b or step 7C.

Step 7a.

If the USS detects the potential collision based on the information received in step 3 and/or step 6, the USS notifies the potential collision to UAV-C.

Step 7b.

[Conditional] If the step 7a is performed, the UAV-C further notifies the potential collision to UAV.

Step 7c.

If the USS detects the potential collision based on the information received in step 3 and/or step 6 is performed, the USS notifies the potential collision to UAV UE.

Step 8.

If the USS detects the potential collision based on the information received in step 3 and/or step 6, the USS notifies to potential collision to AAM.

Step 9.

[Conditional] If the step 8 is performed, to avoid confliction, steps 6-8 in high-level procedure for Ground-based DAA for an Area in clause 5.7.2 are performed.

Step 10.

[Conditional] If the step 7b or step 7c is performed, to avoid confliction, steps 4a-7 in DAA procedure based on PC5 in clause 5.6.1 are performed.