Communications device, infrastructure equipment and methods

1 . A method of receiving downlink data associated with an end-to-end connection between a communications device and an endpoint by an access stratum infrastructure equipment in a wireless communications network, the wireless communications network comprising a core network, the access stratum infrastructure equipment and another access stratum infrastructure equipment, the access stratum infrastructure equipment connected to the core network and to the other access stratum infrastructure equipment, the other access stratum infrastructure equipment providing a wireless access interface, wherein the wireless access interface is for the transmission of data to and the reception of data from the communications device and the downlink data is for transmission to the communications device, the method comprising:

receiving the downlink data from the core network,

determining that the downlink data corresponds to an end-to-end protocol providing reliable, in-order delivery of data,

determining that the downlink data comprises a positive acknowledgement indication generated by the endpoint, the positive acknowledgement indication indicating that uplink data associated with the end-to-end connection transmitted by the communications device has been successfully received at the endpoint, and

in response to determining that the downlink data comprises the positive acknowledgement indication, discarding, by the access stratum infrastructure equipment, the downlink data and not forwarding the downlink data for transmission to the communications device,

wherein both the access stratum infrastructure equipment and the other access stratum infrastructure equipment communicate with the communications device.

2 . The method according to claim 1 , wherein the downlink data does not comprise any data generated by an application or higher layer protocol which uses the end-to-end protocol to ensure reliable and in-order delivery of that data.

3 . The method according to claim 1 , the method comprising:

receiving from the other access stratum infrastructure equipment uplink data, the uplink data transmitted by the communications device,

determining that the uplink data comprises a header generated in accordance with the end-to-end protocol and comprises a sequence number associated with the uplink data, and

storing the sequence number associated with the uplink data.

4 . The method according to claim 1 , the method comprising:

receiving second downlink data from the core network,

determining that the second downlink data comprises a negative acknowledgement indication generated in accordance with the end-to-end protocol indicating that at least a portion of uplink data transmitted by the communications device associated with the end-to-end connection has not been successfully received at the endpoint, and

in response to determining that the second downlink data comprises a negative acknowledgement indication, forwarding the second downlink data to the other access stratum infrastructure equipment for transmission to the communications device.

5 . The method according to claim 4 , wherein the negative acknowledgement indication comprises a selective acknowledgement indicating that data associated with a range of sequence numbers has not been received.

6 . The method according to claim 1 , the method comprising:

receiving third downlink data from the core network,

determining that the third downlink data comprises data which is associated with the end-to-end connection and is generated by an application or higher layer protocol which uses the end-to-end connection for the transmission of data, and

based on the determining that the third downlink data comprises data which is associated with the end-to-end connection and is generated by an application or higher layer protocol which uses the end-to-end connection for the transmission of data, forwarding the third downlink data to the other access stratum infrastructure equipment for transmission to the communications device.

7 . The method according to claim 1 , the method comprising:

determining a round trip time between the communications device and the endpoint, the round trip time comprising a total time from the transmission of data by the communications device using the end-to-end connection to the reception by the communications device of an acknowledgement indication transmitted by the endpoint in response to receiving the data, and

transmitting an indication of the determined round trip time to the other access stratum infrastructure equipment for transmission to the communications device.

8 . The method according to claim 1 , the method comprising:

receiving fourth downlink data from a core network,

determining that the fourth downlink data comprises a positive acknowledgement indication generated in accordance with the end-to-end protocol associated with the end-to-end connection, and does not comprise data which is associated with the end-to-end connection and is generated by an application or higher layer protocol which uses the end-to-end connection for the transmission of data,

determining that the fourth downlink data satisfies predetermined conditions for forwarding to the communications device, and

in response to determining that the fourth downlink data satisfies the predetermined conditions, forwarding the fourth downlink data to the other access stratum infrastructure equipment for transmission to the communications device.

9 . The method according to claim 8 , wherein the fourth downlink data satisfies the predetermined conditions if a time period since a most recent downlink data associated with the end-to-end connection has been forwarded to the other access stratum infrastructure equipment for transmission to the communications device exceeds a predetermined time period.

10 . The method according to claim 8 , wherein the fourth downlink data satisfies the predetermined conditions if number of downlink data packets associated with the end-to-end connection discarded by the access stratum infrastructure equipment since a most recent downlink data associated with the end-to-end connection has been forwarded to the other access stratum infrastructure equipment for transmission to the communications device exceeds a predetermined maximum discard count threshold.

11 . Access stratum infrastructure equipment for use in a wireless communications network, the wireless communications network comprising a core network, the access stratum infrastructure equipment and another access stratum infrastructure equipment, the access stratum infrastructure equipment connected to the core network and to the other access stratum infrastructure equipment, the other access stratum infrastructure equipment providing a wireless access interface, wherein the wireless access interface is for the transmission of data to and the reception of data from a communications device, the access stratum infrastructure equipment comprising:

a network interface configured to transmit signals to and receive signals from the other infrastructure equipment and to transmit signals to and receive signals from the core network, and

a controller, configured to control the network interface so that the access stratum infrastructure equipment is configured:

to receive downlink data for transmission to the communications device via the wireless access interface from the core network,

to determine that the downlink data corresponds to an end-to-end protocol providing reliable, in-order delivery of data, to an endpoint,

to determine that the downlink data comprises a positive acknowledgement indication generated by the endpoint, the positive acknowledgement indication indicating that uplink data transmitted by the communications device has been successfully received at an endpoint, the downlink data associated with an end-to-end connection between the communications device and the endpoint, and

in response to determining that the downlink data comprises the positive acknowledgement indication, to discard, at the access stratum infrastructure equipment, the downlink data and to not forward the downlink data for transmission to the communications device,

wherein both the access stratum infrastructure equipment and the other access stratum infrastructure equipment communicate with the communications device.

12 . A communications device for use in a wireless communications network, the wireless communications network comprising a first access stratum infrastructure equipment connected to a core network, and a second access stratum equipment providing a wireless access interface and connected to the first access stratum infrastructure equipment, the communications device comprising:

a transmitter configured to transmit uplink data associated with an end-to-end connection via the wireless access interface, the uplink data having as a destination an endpoint,

a receiver configured to receive signals, and

a controller configured to control the transmitter and the receiver so that the communications device is configured:

to determine that the transmitter is to transmit the uplink data in accordance with an end-to-end protocol providing reliable, in-order delivery of data,

to determine an estimated maximum round-trip time, the maximum round trip time comprising a total time from the transmission of data by the communications device using the end-to-end connection to the reception by the communications device of an acknowledgement indication generated and transmitted by the endpoint in response to receiving the data,

to transmit via the wireless access interface the uplink data in accordance with the end-to-end protocol providing reliable, in-order delivery of data, wherein the end-to-end connection was established in accordance with the end-to-end protocol,

to determine that the estimated maximum round-trip time has passed since transmitting the uplink data without receiving downlink data indicating a positive acknowledgement of receipt of the uplink data,

in response to determining that the estimated maximum round-trip time has passed since transmitting the data, to update stored state information associated with the end-to-end connection to indicate that the uplink data has been successfully received at the endpoint, and

to transmit second uplink data associated with the end-to-end connection in accordance with the end-to-end protocol and the updated stored state information,

wherein both the first access stratum infrastructure equipment and the second access stratum infrastructure equipment communicate with the communications device.

13 . A method according to claim 1 , wherein the end-to-end protocol is a transmission control protocol (TCP).

14 . A method according to claim 1 , wherein the end-to-end protocol is a Quick User Datagram Protocol (UDP) Internet Connections (QUIC) protocol.

15 . The method according to claim 13 , wherein the downlink data includes only TCP control data.

16 . The communications device according to claim 12 , wherein the processor determines the estimated maximum round-trip time based on past transmissions and receptions.