Wireless telecommunications system including a first terminal device and a second terminal device wherein the second terminal achieves synchronisation for receiving data from the first terminal using synchronisation signalling transmitted by the first terminal or another network entity
A wireless telecommunications system including first and second terminal devices operable to communicate with one another in a synchronized device-to-device manner. The second terminal device is operable to selectively achieve synchronization for receiving data transmissions from the first terminal device using direct synchronization signalling transmitted by the first terminal device or indirect synchronization signalling transmitted by another network entity, such as a base station. The second terminal device is configured to preferentially seek indirect synchronization over direct synchronization, unless the second terminal device detects synchronization signalling transmitted by the first terminal device is associated with a predefined characteristic that indicates the synchronization signalling transmitted by the first terminal device is high priority synchronization signalling, in which case the second terminal device is configured to preferentially seek synchronization using the high priority direct synchronization signalling from the first terminal device over indirect synchronization signalling transmitted by the other network entity.
1. A terminal device for use in a wireless telecommunications system, the terminal device comprising:
integrated circuitry that includes a controller and a transceiver configured to operate together such that the terminal device is configured to transmit data to a second terminal device in a synchronised device-to-device manner,
wherein the second terminal device is configured to achieve synchronisation for receiving data from the terminal device using synchronisation signalling transmitted by the terminal device or synchronisation signalling transmitted by a base station operating in the wireless telecommunications system,
wherein the second terminal device synchronizes with the synchronisation signalling transmitted by the terminal device based on a predefined characteristic indicating the synchronisation signalling transmitted by the terminal device is high priority synchronisation signalling rather than synchronisation signalling transmitted by the base station.
2. The terminal device of claim 1 , wherein a predefined characteristic which indicates the synchronisation signalling is high priority synchronisation signalling is transmitted with the synchronisation signalling, and the predefined characteristic is the use of predefined radio resources for transmitting the synchronisation signalling.
3. The terminal device of claim 1 , wherein a predefined characteristic which indicates the synchronisation signalling is high priority synchronisation signalling is transmitted with the synchronisation signalling.
4. The terminal device of claim 2 , wherein the predefined radio resources are defined by an operating standard of the wireless telecommunication system and the terminal device and the second terminal device are operable to receive an indication of the predefined radio resources from configuration signalling received from another entity operating in the wireless telecommunication system and from a Subscriber Identity Module (SIM) configuration setting and from a subscription-based configuration setting.
5. The terminal device of claim 2 , wherein the predefined radio resources are defined by an operating standard of the wireless telecommunication system.
6. The terminal device of claim 2 , wherein the predefined radio resources are defined by an operating standard of the wireless telecommunication system and the terminal device and the second terminal device are operable to receive an indication of the predefined radio resources from configuration signalling that is received.
7. The terminal device of claim 1 , wherein a predefined characteristic which indicates the synchronisation signalling is high priority synchronisation signalling is transmitted with the synchronisation signalling, and the predefined characteristic is presence of a predefined indicator flag transmitted in association with the synchronisation signalling.
8. The terminal device of claim 1 , wherein a predefined characteristic which indicates the synchronisation signalling is high priority synchronisation signalling is transmitted with the synchronisation signalling, and the predefined characteristic is the use of a predefined format for the synchronisation signalling.
9. The terminal device of claim 1 , wherein the terminal device is configured to transmit high priority synchronisation signalling on determining an event has occurred in response to which the terminal device is configured to transmit high priority data relating to the event in a device-to-device manner.
10. The terminal device of claim 2 , wherein the terminal device is configured to transmit high priority synchronisation signalling on determining an event has occurred in response to which the terminal device is configured to transmit high priority data relating to the event in a device-to-device manner.
11. A communications method for a terminal device that includes processing circuitry, the method comprising:
transmitting data, from the terminal device, to a second terminal device in a synchronised device-to-device manner, wherein the second terminal device is configured to achieve synchronisation for receiving data from the terminal device using synchronisation signalling transmitted by the terminal device or synchronisation signalling transmitted by a base station operating in a wireless telecommunication system,
wherein the second terminal device synchronizes with the synchronisation signalling transmitted by the terminal device based on a predefined characteristic indicating the synchronisation signalling transmitted by the terminal device is high priority synchronisation signalling rather than synchronisation signalling transmitted by the base station.
12. The communications method of claim 11 , wherein a predefined characteristic which indicates the synchronisation signalling is high priority synchronisation signalling is transmitted with the synchronisation signalling, and the predefined characteristic is the use of predefined radio resources for transmitting the synchronisation signalling.
13. The communications method of claim 11 , wherein a predefined characteristic which indicates the synchronisation signalling is high priority synchronisation signalling is transmitted with the synchronisation signalling.
14. The communications method of claim 12 , wherein the predefined radio resources are defined by an operating standard of the wireless telecommunication system and the terminal device and the second terminal device are operable to receive an indication of the predefined radio resources from configuration signalling received from another entity operating in the wireless telecommunication system and from a Subscriber Identity Module (SIM) configuration setting and from a subscription-based configuration setting.
15. The communications method of claim 12 , wherein the predefined radio resources are defined by an operating standard of the wireless telecommunication system.
16. The communications method of claim 12 , wherein the predefined radio resources are defined by an operating standard of the wireless telecommunication system and the terminal device and the second terminal device are operable to receive an indication of the predefined radio resources from configuration signalling that is received.
17. The communications method of claim 11 , wherein a predefined characteristic which indicates the synchronisation signalling is high priority synchronisation signalling is transmitted with the synchronisation signalling, and the predefined characteristic is presence of a predefined indicator flag transmitted in association with the synchronisation signalling.
18. The communications method of claim 11 , wherein a predefined characteristic which indicates the synchronisation signalling is high priority synchronisation signalling is transmitted with the synchronisation signalling, and the predefined characteristic is the use of a predefined format for the synchronisation signalling.
19. The communications method of claim 11 , further comprising:
transmitting, by the terminal device, high priority synchronisation signalling on determining an event has occurred in response to which the terminal device transmits high priority data relating to the event in a device-to-device manner.
20. The communications method of claim 12 , further comprising:
transmitting, by the terminal device, high priority synchronisation signalling on determining an event has occurred in response to which the terminal device transmits high priority data relating to the event in a device-to-device manner.