Methods, communications device and infrastructure equipment

1. A method of operating a communications device for transmitting user plane data to a wireless communications network via a wireless access interface provided by a cell of the wireless communications network when the communications device is not in an active radio resource connected mode, the method comprising

transmitting the user plane data using one of a preconfigured set of uplink radio resources of the wireless access interface and a scheduled random access procedure message, and

monitoring a preconfigured set of downlink radio resources of the wireless access interface for a downlink signal, the preconfigured set of downlink radio resources being provided in response to the transmitted user plane data.

2. A method according to claim 1 , comprising

receiving the downlink signal in the preconfigured set of downlink radio resources.

3. A method according to claim 1 , wherein the downlink signal comprises an application layer acknowledgement of the transmitted user plane data.

4. A method according to claim 1 , wherein the downlink signal comprises an application layer downlink message comprising data for the communications device in response to and in accordance with the transmitted user plane data.

5. A method according to claim 1 , wherein when the user plane data is transmitted using the preconfigured set of uplink radio resources, the method comprises

transmitting the user plane data using the preconfigured set of uplink radio resources in advance of receiving any signalling information comprising an indication of radio resources in which the user plane data can be transmitted.

6. A method according to claim 1 , wherein when the user plane data is transmitted using the scheduled random access procedure message, the method comprises

transmitting, using a first message of a random access procedure, one of a reserved set of preambles, the preambles of the reserved set indicating that the communications device has the user plane data to transmit,

receiving, using a second message of the random access procedure, an indication of radio resources in which the user plane data can be transmitted, the radio resources in which the user plane data can be transmitted forming at least a part of the scheduled random access procedure message, and

transmitting the scheduled random access procedure message in the indicated radio resources, the scheduled random access procedure message being a third message of the random access procedure.

7. A method according to claim 1 , wherein the preconfigured set of downlink radio resources comprises one or more temporally spaced sub-Paging Occasions, PO, a sub-PO having a period of less than a period of a conventional PO.

8. A method according to claim 7 , comprising

receiving the downlink signal in one of the sub-POs, and

stopping the monitoring of one or more sub-POs located later in time to the sub-PO in which the downlink signal is received.

9. A method according to claim 7 , comprising

receiving an indication that the communications device should monitor one or more further sub POs located later in time to the one or more sub POs of the preconfigured set of downlink radio resources.

10. A method according to claim 7 , comprising

performing a reselection procedure to a new cell such that the communications device is served by the new cell of the wireless communications network, and

stopping the monitoring of the one or more sub-POs subsequent to the performing reselection procedure to the new cell.

11. A method according to claim 7 , comprising

performing a reselection procedure to a new cell such that the communications device is served by the new cell of the wireless communications network,

receiving an indication from the new cell that the new cell supports the use of sub-POs, and

monitoring, in the new cell, one or more remaining sub-POs of the preconfigured set of downlink radio resources.

12. A method according to claim 7 , comprising

receiving an indication that the communications device should monitor the one or more sub POs of the preconfigured set of downlink radio resources, the indication being received in a downlink message of a message exchange subsequent to an uplink message of the message exchange comprising the transmitted user plane data.

13. A method according to claim 1 , comprising

receiving an indication of a unique identifier associated with the communications device, the indication being received in a downlink message of a message exchange subsequent to an uplink message of the message exchange comprising the transmitted user plane data, and

monitoring the preconfigured set of downlink radio resources for signalling information comprising the unique identifier, the signalling information indicating a location of radio resources scheduled for the transmission of the downlink signal in the preconfigured set of downlink resources.

14. A method according to claim 13 ,

receiving an indication of a timer, the timer being started upon configuration of the unique identifier,

determining that the timer has expired, and

determining that the communications device is no longer associated with the unique identifier subsequent to the expiry of the timer.

15. A method according to claim 13 , comprising stopping the monitoring of the preconfigured set of downlink radio resources, and

determining that the communications device is no longer associated with the unique identifier subsequent to the stopping of the monitoring of the preconfigured set of downlink radio resources.

16. A method according to claim 1 , comprising

receiving an indication of a unique preamble signal associated with the communications device, the indication being received in a downlink message of a message exchange subsequent to an uplink message of the message exchange comprising the transmitted user plane data,

receiving a paging message in the preconfigured set of downlink radio resources,

transmitting a signal comprising the unique preamble in response to the received paging message, and

receiving the downlink data in the preconfigured set of downlink resources subsequent to transmitting the signal comprising the unique preamble.

17. A method according to claim 1 , wherein the preconfigured set of downlink radio resources are located within a time window, the time window defining a time period over which the preconfigured set of downlink radio resources extend.

18. A method according to claim 17 , comprising

receiving a physical layer acknowledgement of the transmitted uplink data in a downlink message of a message exchange subsequent to an uplink message of the message exchange comprising the transmitted user plane data,

wherein the time window comprising the preconfigured set of downlink radio resources begins at the time at which the physical layer acknowledgement is received.

19. A communications device for transmitting user plane data to a wireless communications network via a wireless access interface provided by a cell of the wireless communications network when the communications device is not in an active radio resource connected mode, the communications device comprising transceiver circuitry and controller circuitry configured in combination

to transmit the user plane data using one of a preconfigured set of uplink radio resources of the wireless access interface and a scheduled random access procedure message, and

to monitor a preconfigured set of downlink radio resources of the wireless access interface for a downlink signal, the preconfigured set of downlink radio resources being provided in response to the transmitted user plane data.

20. Circuitry for a communications device for transmitting user plane data to a wireless communications network via a wireless access interface provided by a cell of the wireless communications network when the communications device is not in an active radio resource connected mode, the circuitry comprising transceiver circuitry and controller circuitry configured in combination

to transmit the user plane data using one of a preconfigured set of uplink radio resources of the wireless access interface and a scheduled random access procedure message, and

to monitor a preconfigured set of downlink radio resources of the wireless access interface for a downlink signal, the preconfigured set of downlink radio resources being provided in response to the transmitted user plane data.