16.23.6 Inventory Procedure

Figure 16.23.6-1 depicts the basic communication between the gNB and the A-IoT CN node for the Inventory procedure.

1. The A-IoT CN node initiates the Inventory procedure over NG-C by sending the Inventory Request message to the gNB. The Inventory Request message includes a Correlation ID and A-IOTF Identifier to identify the inventory session. The Inventory Request message also includes an A-IoT Device Identification Requested corresponding to the A-IoT device(s) which are targeted for the inventory. The A-IoT Device Identification Requested indicates inventory being requested either for a single device or a group of devices or for all devices.

The Inventory Request message also includes Requested Service Area Information (list of A-IoT Area IDs and/or reader list). If the Requested Service Area Information contains:

• Neither the Requested AIoT Area List nor the Requested Reader List, the gNB shall select all readers it serves to perform inventory;
• The Requested AIoT Area List, the gNB shall select readers within the indicated AIoT Area(s) to perform inventory;
• The Requested Reader List, the gNB shall take the reader list into account to perform inventory.

The Inventory Request message also includes the Inventory Assistance Information. The Inventory Assistance Information includes the expected D2R message size and may also include e.g., approximate number of Target A-IoT devices, time interval.

The Inventory Request message may also include a follow-on command indicator to indicate that at least for one of the targeted A-IoT device(s) a Command procedure will follow.

The Inventory Request message also includes the A-IoT Security Information, as specified in TS 33.369 [72].

2. The gNB allocates and co-ordinates the usage of A-IoT radio resources.

3. The gNB confirms the request from the A-IoT CN node by replying with the Inventory Response message. The Inventory Response message includes the AIOTF Identifier and the Correlation ID received in the Inventory Request message.

NOTE 1: If the gNB is not able to perform the Inventory procedure, it rejects the request and sends an Inventory Failure message to the A-IoT CN node.

4. The Inventory procedure over the A-IoT radio interface is performed, i.e., A-IoT paging, A-IoT Access Procedure and D2R data transmission, as specified in section 16.23.5.

5./6. Upon receiving the response(s) from the A-IoT device(s), the gNB sends the Inventory Report message to the A-IoT CN node. If the Inventory procedure concerns multiple A-IoT devices, multiple Inventory Report messages may be sent to the A-IoT CN node.

The Inventory Report message includes the AIOTF Identifier and the Correlation ID received in the Inventory Request message and further includes the A-IoT NAS PDU(s) carrying the inventoried A-IoT device ID(s).

If a follow-on Command indicator was received at step 1, the Inventory Report message also includes a RAN A-IoT device NGAP ID for each A-IoT device which was inventoried.

Upon completion of the inventory procedure the gNB sends an Inventory Complete Indication in the Inventory Report message.

NOTE 2: If the Inventory procedure concerns multiple A-IoT devices, an Inventory Report may include reports from multiple A-IoT devices.

7. If there is no follow-on command, the A-IOT CN triggers the A-IoT CN node initiated A-IoT Session Release procedure as defined in clause 16.23.8.