Methods and terminal devices for enhanced discovery procedure

1 . A method in a first terminal device, comprising:

transmitting, to a second terminal device, a first message for initiating a discovery procedure over a sidelink,

wherein the first message contains information associated with the first terminal device, comprising:

first application or traffic related information,

first location or mobility related information, and

first connectivity related information comprising an indication of whether the first terminal device requests or is capable of providing a relay path towards a network node or a terminal device.

2 . The method of claim 1 , wherein the first message further contains a first validity timer indicating a duration during which the information associated with the first terminal device is valid.

3 . The method of claim 1 , wherein the first application or traffic related information comprises a Quality of Service, QoS, profile of an application or traffic the first terminal device requests or is capable of providing.

4 . The method of claim 3 , wherein the QoS profile comprises a type, a priority, and/or a QoS requirement of the application or traffic.

5 . The method of claim 1 , wherein the first location or mobility related information comprises one or more of:

location information of the first terminal device,

information on an area or proximity where the first terminal device requests or is capable of providing an application or traffic, or

mobility information of the first terminal device.

6 . The method of claim 5 , wherein the mobility information of the first terminal device indicates whether the first terminal device is static or moving.

7 . The method of claim 1 , wherein the first connectivity related information comprises:

a serving network node of the first terminal device,

a list of identifiers of terminal devices that have been obtained in a previous discovery procedure,

a radio quality indication of a PC5 or Uu link the first terminal device currently has,

a load or a congestion condition of the PC5 or Uu link,

a Radio Access Technology, RAT, of the PC5 or Uu link,

an indication of a relay type the first terminal device requests or is capable of providing, or

a number of hops or a maximum number of hops along a relay path the first terminal device requests or is capable of providing.

8 . The method of claim 1 , further comprising:

receiving, from the second terminal device, a second message as a response to the first message,

wherein the second message contains one or more of following information associated with the second terminal device:

identifier information,

second application or traffic related information,

second location or mobility related information, or

second connectivity related information.

9 . The method of claim 7 , wherein the identifier information comprises one or more of: a global identifier of the second terminal device, a temporary identifier of the second terminal device, and/or an identifier of the second terminal device used only when the second terminal device serves as a relay for the first terminal device.

10 . The method of claim 7 , wherein the second application or traffic related information comprises a Quality of Service, QoS, profile of an application or traffic the second terminal device requests or is capable of providing.

11 . The method of claim 10 , wherein the QoS profile comprises a type, a priority, and/or a QoS requirement of the application or traffic the second terminal device requests or is capable of providing.

12 . The method of claim 7 , wherein the second location or mobility related information comprises one or more of:

location information of the second terminal device,

information on an area or proximity where the second terminal device requests or is capable of providing an application or traffic, or

mobility information of the second terminal device.

13 . The method of claim 7 , wherein the second connectivity related information comprises:

a serving network node of the second terminal device,

an indication of whether the second terminal device requests or is capable of providing a relay path towards a network node or a terminal device,

a list of identifiers of terminal devices that have been obtained in a previous discovery procedure,

a radio quality indication of a PC5 or Uu link the second terminal device currently has,

a load or a congestion condition of the PC5 or Uu link,

a Radio Access Technology, RAT, of the PC5 or Uu link,

an indication of a relay type the second terminal device requests or is capable of providing, or

a number of hops or a maximum number of hops along a relay path the second terminal device requests or is capable of providing.

14 . The method of claim 7 , further comprising:

obtaining a set of relay candidates, including the second terminal device, based at least on the second message;

selecting, from the set of relay candidates, the second terminal device as a relay between the first terminal device and a network node or a third terminal device, based on the second application or traffic related information, the second location or mobility related information, and/or the second connectivity related information; and

establishing a relay path from the first terminal device to the network node or the third terminal device via the second terminal device.

15 . The method of claim 14 , further comprising:

selecting, from the set of relay candidates, a fourth terminal device as a relay between the first terminal device and the network node or the third terminal device in response to a failure of the relay path, based on application or traffic related information, location or mobility related information, and/or connectivity related information associated with the fourth terminal device; and

establishing a relay path from the first terminal device to the network node or the third terminal device via the fourth terminal device.

16 . The method of claim 14 , further comprising:

initiating another discovery procedure over the sidelink when all the relay candidates in the set have their respective validity timers expired.

17 . The method of claim 7 , wherein the first message further contains a measurement configuration for the second terminal device to measure a PC5 link towards the third terminal device or a fifth terminal device, or a Uu link towards the network node, and the second message further contains a measurement report for the PC5 link or the Uu link.

18 . The method of claim 1 , wherein the first location or mobility related information and/or the first connectivity related information is transmitted explicitly in one or more fields in the first message or included in a container in the first message.

19 . The method of claim 7 , wherein the second location or mobility related information and/or the second connectivity related information is received explicitly in one or more fields in the second message or included in a container in the second message.

20 . A method in a second terminal device, comprising:

receiving, from a first terminal device, a first message for initiating a discovery procedure over a sidelink,

wherein the first message contains information associated with the first terminal device, comprising:

first application or traffic related information,

first location or mobility related information, and

first connectivity related information comprising an indication of whether the first terminal device requests or is capable of providing a relay path towards a network node or a terminal device.

21 . A first terminal device, comprising a transceiver, a processor and a memory, the memory comprising instructions executable by the processor whereby the first terminal device is operative to:

transmit, to a second terminal device, a first message for initiating a discovery procedure over a sidelink,

wherein the first message contains information associated with the first terminal device, comprising:

first application or traffic related information,

first location or mobility related information, and

first connectivity related information comprising an indication of whether the first terminal device requests or is capable of providing a relay path towards a network node or a terminal device.