1. An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: receive, by a user device from at least one network node, information for a plurality of on-demand positioning signal preconfigurations that are supported by one or more network nodes, wherein the information for the plurality of on-demand positioning signal preconfigurations includes information indicating a preconfiguration identifier and at least one quality of service (QoS) requirement or radio condition associated with each of the on-demand positioning signal preconfigurations; select, by the user device, based on at least one of a measured radio condition or a QoS requirement of a positioning session for the user device, one of the on-demand positioning signal preconfigurations; transmit, by the user device to the at least one network node, a preconfiguration identifier associated with the selected on-demand positioning signal preconfiguration; and receive, by the user device from the at least one network node, an on-demand positioning signal based on the transmitted preconfiguration identifier.

2. The apparatus of claim 1, wherein the positioning session for the user device comprises a positioning session to obtain and/or provide a signal measurement of the received on-demand positioning signal, for use by either the user device, the network node or a location management function in estimating a position of the user device.

3. The apparatus of claim 1: wherein the plurality of on-demand positioning signal preconfigurations comprise a plurality of on-demand positioning signal configurations that may be selected or requested, by the user device, for transmission; and

wherein the computer program code configured to, with the at least one processor, cause the apparatus to receive an on-demand positioning signal comprises the computer program code configured to, with the at least one processor, cause the apparatus to receive, by the user device from the at least one network node, including the first network node, an on-demand positioning reference signal based on the received preconfiguration identifier.

4. The apparatus of claim 1, further comprising: the computer program code configured to, with the at least one processor, cause the apparatus to measure, as part of the positioning session to at least assist in determining a position of the user device, at least one signal parameter of the received on- demand positioning signal.

5. The apparatus of claim 1, wherein the QoS requirement associated with the positioning session for the user device comprises at least one of: a positioning accuracy required by the positioning session; or a maximum latency required by the positioning session of an on-demand positioning signal; or a QoS class priority associated with a service priority of the positioning session with respect to other communication sessions.

6. The apparatus of claim 1, wherein an on-demand positioning reference signal preconfiguration indicates or includes, at least one of following positioning signal attributes: a positioning signal bandwidth; a positioning signal periodicity; a positioning signal transmission power; time and frequency resources of the positioning signal; one or more spatial parameters of the positioning signal; and/or a directivity or beam width or beam shape used for transmission of the positioning signal.

7. The apparatus of claim 1 : wherein the computer program code configured to, with the at least one processor, cause the apparatus to receive information for a plurality of on-demand positioning signal preconfigurations comprises the computer program code configured to, with the at least one processor, cause the apparatus to receive, by the user device from each of a plurality of network nodes, information for a plurality of on-demand positioning signal preconfigurations that are supported by each network node, wherein the information for the plurality of on-demand positioning signal preconfigurations includes information indicating a preconfiguration identifier and at least one quality of service (QoS) requirement or radio condition associated with each of the on-demand positioning signal preconfigurations; and wherein the computer program code configured to, with the at least one processor, cause the apparatus to select comprises the computer program code configured to, with the at least one processor, cause the apparatus to select, by the user device, based on at least one of a measured radio condition or a QoS requirement of a positioning session for the user device, one of the on-demand positioning signal preconfiguration for each of the plurality of network nodes.

8. The apparatus of claim 7, wherein: the computer program code configured to, with the at least one processor, cause the apparatus to transmit comprises the computer program code configured to, with the at least one processor, cause the apparatus to transmit, by the user device to each of the plurality of network nodes, a preconfiguration identifier associated with the selected on- demand positioning signal preconfiguration that was selected for each of the network nodes; and wherein the computer program code configured to, with the at least one processor, cause the apparatus to receive an on-demand positioning signal comprises the computer program code configured to, with the at least one processor, cause the apparatus to receive, by the user device from each of the plurality of network nodes, an on-demand positioning signal based on the preconfiguration identifier transmitted to each of the network nodes.

9. The apparatus of claim 8, further comprising: the computer program code configured to, with the at least one processor, cause the apparatus to measure, as part of the positioning session for the user device to at least assist in determining a position of the user device, at least one signal parameter of each of the received on-demand positioning signals

10. The apparatus of claim 1, wherein the on-demand positioning signal comprises an on-demand positioning reference signal

11. An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: transmit, by a network node to a user device, information for a plurality of on- demand positioning signal preconfigurations that are supported by one or more network nodes, wherein the information for the plurality of on-demand positioning signal preconfigurations includes information indicating a preconfiguration identifier and at least one quality of service (QoS) requirement or radio condition associated with each of the on-demand positioning signal preconfigurations; receive, by the network node, a preconfiguration identifier associated with a selected on-demand positioning signal preconfiguration that was selected based on at least one of a measured radio condition or a QoS requirement of a positioning session for the user device; and transmit, by the network node to the user device, an on-demand positioning signal based on the received preconfiguration identifier

12. The apparatus of claim 11, wherein the positioning session for the user device comprises a positioning session to obtain and/or provide a signal measurement of the

received on-demand positioning signal, for use by either the user device, the network node or a location management function in estimating a position of the user device

13. The apparatus of claim 11, wherein the plurality of on-demand positioning signal configurations comprise a plurality of on-demand positioning reference signal configurations for an on-demand positioning reference signal, which is requested by the user device for transmission

14. The apparatus of claim 11, wherein the QoS requirement associated with the positioning session for the user device comprises at least one of: a positioning accuracy required by the positioning session; a maximum latency required by the positioning session of an on-demand positioning signal; or a QoS class priority associated with a service priority of the positioning session with respect to other communication sessions.15. The apparatus of claim 11, wherein an on-demand positioning signal preconfiguration indicates or includes, at least one of following positioning signal attributes: a positioning signal bandwidth; a positioning signal periodicity; a positioning signal transmission power; time and frequency resources of the positioning signal; one or more spatial parameters of the positioning signal; and/or a directivity or beam width or beam shape used for transmission of the positioning signal.16. The apparatus of claim 11, wherein the on-demand positioning signal comprises an on-demand positioning reference signal.17. An apparatus comprising:

at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: receive, by a user device from at least one network node, information for a plurality of on-demand positioning signal preconfigurations that are supported by one or more network nodes, wherein the information for the plurality of on-demand positioning signal preconfigurations includes information indicating a preconfiguration identifier and at least one quality of service (QoS) requirement or radio condition associated with each of the on-demand positioning signal preconfigurations; receive, by the user device from the at least one network node, a preconfiguration identifier associated with a selected on-demand positioning signal preconfiguration that was selected based on at least one of a radio condition or a QoS requirement associated with a positioning session for the user device; receive, by the user device from the network node, at least one on-demand positioning signal based on the received preconfiguration identifier received from the at least one network node; measure, by the user device as part of the positioning session to at least assist in determining a position of the user device, at least one signal parameter of the received at least one on-demand positioning signals; and either determine, by the user device, a position of the user device based on the at least one measured signal parameter, or transmit, by the user device to another node or a location management function, the at least one measured signal parameter of each of the received at least one on-demand positioning signal.18. The apparatus of claim 17, wherein the positioning session for the user device comprises a positioning session to obtain and/or provide at least a signal measurement of an on-demand positioning signal for use by either the user device, the network node or a location management function, in estimating a position of the user device, based on an on-demand positioning signal preconfiguration that is selected by the network node or a location management function.19. The apparatus of claim 17: wherein the computer program code configured to, with the at least one processor, cause the apparatus to receive a preconfiguration identifier comprises the computer program code configured to, with the at least one processor, cause the apparatus to receive, by the user device from each of a plurality of network nodes, a preconfiguration identifier associated with a selected on-demand positioning signal preconfiguration that was selected by the network node based on at least one of a radio condition or a QoS requirement associated with a positioning session for the user device; and wherein the computer program code configured to, with the at least one processor, cause the apparatus to receive an on-demand positioning signal comprises the computer program code configured to, with the at least one processor, cause the apparatus to receive, by the user device from each of the plurality of network nodes, an on-demand positioning signal based on the preconfiguration identifier received from each of the plurality of network nodes.

20. The apparatus of claim 17, wherein the on-demand positioning signal comprises an on-demand positioning reference signal.

21. An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: receive, by a user device from a first network node, information for a plurality of on-demand positioning signal preconfigurations that are supported by one or more network nodes, wherein the information for the plurality of on-demand positioning signal preconfigurations includes information indicating a preconfiguration identifier and at least one quality of service (QoS) requirement or radio condition associated with each of the on-demand positioning signal preconfigurations;

receive, by the user device from the first network node, a preconfiguration identifier of a selected on-demand positional signal preconfiguration that was selected based on at least one of a measured radio condition or at least one QoS requirement associated with a positioning session for the user device; and transmit, by the user device to a plurality of network nodes, including the first network node, an on-demand positioning signal based on the received preconfiguration identifier.

22. The apparatus of claim 21: wherein the plurality of on-demand positioning signal preconfigurations comprise a plurality of on-demand sounding reference signal preconfigurations; and wherein the computer program code configured to, with the at least one processor, cause the apparatus to transmit comprises the computer program code configured to, with the at least one processor, cause the apparatus to transmit, by the user device to a plurality of network nodes, including the first network node, an on-demand sounding reference signal based on the received preconfiguration identifier.

23. The apparatus of claim 21, wherein the on-demand positioning signal comprises an on-demand sounding reference signal.

24. An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:', 'receive, by a user device from a first network node, information for a plurality of on-demand positioning signal preconfigurations that are supported by one or more network nodes, wherein the information for the plurality of on-demand positioning signal preconfigurations includes information indicating a preconfiguration identifier and at least one quality of service (QoS) requirement or radio condition associated with each of the on-demand positioning signal preconfigurations; select, by the user device, based on at least one of a measured radio condition or a QoS requirement of a positioning session for the user device, one of the on-demand positioning signal preconfigurations; transmit, by the user device to one or more network nodes, a preconfiguration identifier associated with the selected on-demand positioning signal preconfiguration; and transmit, by the user device to one or more network nodes, including the first network node, an on-demand positioning signal based on the received preconfiguration identifier.

25. The apparatus of claim 24, wherein the on-demand positioning signal comprises an on-demand sounding reference signal.

26. An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: transmit, by a network node to a user device, information for a plurality of on- demand positioning signal preconfigurations that are supported by one or more network nodes, wherein the information for the plurality of on-demand positioning signal preconfigurations includes information indicating a preconfiguration identifier and at least one quality of service (QoS) requirement or radio condition associated with each of the on-demand positioning signal preconfigurations; transmit, by the network node to the user device and at least one second network node, a preconfiguration identifier associated with a selected uplink on-demand

positioning signal preconfiguration, to cause the user device to transmit the uplink positioning signal associated with the transmitted preconfiguration identifier; and receive, by the network node from the user device, an on-demand uplink positioning signal based on the transmitted preconfiguration identifier.

27. The apparatus of claim 26: wherein the plurality of on-demand positioning signal preconfigurations comprise a plurality of on-demand sounding reference signal preconfigurations; and wherein the computer program code configured to, with the at least one processor, cause the apparatus to receive comprises the computer program code configured to, with the at least one processor, cause the apparatus to receive, by the network node from the user device, an on-demand sounding reference signal based on the transmitted preconfiguration identifier.

28. The apparatus of claim 26, further comprising the computer program code configured to, with the at least one processor, cause the apparatus to perform at least one of the following: selecting, by the network node based on at least one of a measured radio condition or a QoS requirement associated with a positioning session for the user device, the preconfiguration identifier of the selected on-demand uplink positioning signal preconfiguration; or receiving, by the network node, from either a location management function or another network node, based on at least one of a measured radio condition or a QoS requirement associated with a positioning session for the user device, the preconfiguration identifier of the selected on-demand uplink positioning signal preconfiguration.

29. The apparatus of claim 28, wherein the on-demand positioning signal comprises an on-demand sounding reference signal.']