Mobile communications network, infrastructure equipment, communications device and methods

1. A method for use in a mobile communications network, the mobile communications network including

a plurality of infrastructure equipment each providing wireless connectivity within at least one cell, and

a communications device configured to communicate wirelessly with at least a first infrastructure equipment including use of a radio bearer, wherein the first infrastructure equipment performs the method comprising:

determining that there is a requirement to alter data handling resources allocated for handling the radio bearer in one or both of the first infrastructure equipment and the communications device,

re-establishing, in response to the determination, its radio link control protocol layer,

transmitting a reconfiguration message to the communications device to effect re-establishment of its radio link control protocol layer, and subsequently

adding a new bit in a header of data packets transmitted to the communications device for a predetermined time after re-establishment of the radio link control protocol layer of the first infrastructure equipment.

2. A method according to claim 1 , wherein the cells are arranged into a master cell group under control of the first infrastructure equipment, the first infrastructure equipment being a master infrastructure equipment, and a secondary cell group under control of a secondary infrastructure equipment, and the communications device is configured to communicate wirelessly with the master infrastructure equipment and the secondary infrastructure equipment, and

wherein the radio bearer is configured in dual connectivity and receivable at the secondary infrastructure equipment for splitting between the second infrastructure equipment and the master infrastructure equipment before delivery to the communications device.

3. A method according to claim 2 , wherein determining that there is a requirement to alter data handling resources comprises receiving at the master infrastructure equipment a notification transmitted by the secondary infrastructure equipment when the secondary infrastructure equipment exhausts a supply of unique parameter sets used in security ciphering of received radio bearers configured in dual connectivity.

4. A method according to claim 1 , wherein the cells are arranged into a master cell group under control of a master infrastructure equipment and a secondary cell group under control of the first infrastructure equipment, the first infrastructure equipment being a secondary infrastructure equipment, and the communications device is configured to communicate wirelessly with the master infrastructure equipment and the secondary infrastructure equipment, and

wherein the radio bearer is configured in dual connectivity and receivable at the secondary infrastructure equipment for splitting between the secondary infrastructure equipment and the master infrastructure equipment before delivery to the communications device.

5. A method according to claim 4 , wherein the determining that there is a requirement to alter data handling resources comprises exhausting at the secondary infrastructure equipment a supply of unique parameter sets used in security ciphering of received radio bearers configured in dual connectivity.

6. A method according to claim 1 , further comprising toggling a value of the new bit.

7. A method according to claim 6 , wherein the value of the new bit is toggled for a predetermined time after the re-establishment of the radio link control protocol layer of the first infrastructure equipment.

8. A method according to claim 1 , wherein the communications device re-establishes its radio link control protocol layer in response to the reconfiguration message, and subsequently discards from a buffer of the communications device one or more data packets with headers that have not been changed by the first infrastructure equipment in response to the determination.

9. A method according to claim 1 , wherein the communications device re-establishes its radio link control protocol layer in response to the reconfiguration message, and subsequently, controls storage of received data packets with headers that have or have not been changed by the first infrastructure equipment in response to the determination in separate buffers of the communications device.

10. A method according to claim 1 , wherein the communications device duplicates a radio link control entity of the communications device, the radio link control entity and the duplicate radio link control entity being used to separately handle received data packets with headers that have or have not been changed by the first infrastructure equipment in response to the determination.

11. A method according to claim 1 , wherein the communications device duplicates a packet data convergence protocol entity of the communications device, the packet data convergence protocol entity and the duplicate packet data convergence protocol being used to separately handle received data packets with headers that have or have not been changed by the first infrastructure equipment in response to the determination.

12. A method according to claim 2 , wherein the master infrastructure equipment and the secondary infrastructure equipment operate in accordance with the same radio access technology.

13. A method according to claim 2 , wherein the master infrastructure equipment and the secondary infrastructure equipment operate in accordance with different radio access technologies.

14. An infrastructure equipment for use in a mobile communications network, the mobile communications network including one or more other infrastructure equipment, the infrastructure equipment and other infrastructure equipment each providing wireless connectivity within at least one cell, and a communications device configured to communicate wirelessly with the infrastructure equipment including use of a radio bearer, wherein the infrastructure equipment comprises:

transmitter circuitry configured to transmit signals to the communications device and to the other infrastructure equipment,

receiver circuitry configured to receive signals from the communications device and from the other infrastructure equipment, and

controller circuitry configured to control the transmitter and the receiver circuitry

to determine that there is a requirement to alter data handling resources allocated for handling the radio bearer in one or both of the infrastructure equipment and the communications device,

to re-establish, in response to the determination, its radio link control protocol layer,

to transmit a reconfiguration message to the communications device to effect re-establishment of its radio link control protocol layer, and subsequently

to add a new bit in a header of data packets transmitted to the communications device for a predetermined time after re-establishment of the radio link control protocol layer of the infrastructure equipment.

15. A method for use in a mobile communications network, the mobile communications network including

a plurality of infrastructure equipment each providing wireless connectivity within at least one cell, and

a communications device configured to communicate wirelessly with at least a first of the infrastructure equipment including by the use of a radio bearer, the method comprising the first infrastructure equipment, wherein the method comprises:

determining that there is a requirement to alter data handling resources allocated for handling the radio bearer in one or both of the first infrastructure equipment and the communications device,

re-establishing, in response to the determination, its radio link control protocol layer,

transmitting a reconfiguration message to the communications device to effect re-establishment of its radio link control protocol layer, and subsequently effecting a change in a header of data packets transmitted to the communications device, wherein

the cells are arranged into a master cell group under control of the first infrastructure equipment, the first infrastructure equipment being a master infrastructure equipment, and a secondary cell group under control of a secondary infrastructure equipment, and the communications device is configured to communicate wirelessly with the master infrastructure equipment and the secondary infrastructure equipment,

the radio bearer is configured in dual connectivity and receivable at the secondary infrastructure equipment for splitting between the secondary infrastructure equipment and the master infrastructure equipment before delivery to the communications device, and

determining that there is a requirement to the alter data handling resources comprises receiving at the master infrastructure equipment a notification transmitted by the secondary infrastructure equipment when the secondary infrastructure equipment exhausts a supply of unique parameter sets used in security ciphering of received radio bearers configured in dual connectivity.