Data transmission in inactive state connection

1 . A user equipment, comprising:

at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the user equipment to perform:

in response to determining that a condition is fulfilled, forming a data packet comprising the data and a first identity of the user equipment; otherwise, forming the data packet comprising the data and a second identity of the user equipment; wherein the condition comprises at least that a cell was a last serving cell of the user equipment before the user equipment transitioned to an inactive state; wherein the first identity is different from the second identity;

transmitting the data packet to a base station,

wherein the at least one memory and the computer program code being configured to, with the at least one processor, cause the user equipment to transmit data in accordance with a radio interface protocol, wherein the condition further comprises that a size of the data packet formed with the data and the second identity is larger than a size of a transport block defined for data transmission in the inactive state according to the radio interface protocol, wherein the difference between the size of the data packet and the size of the transport block is smaller than a maximum difference size.

2 . The user equipment of claim 1 , wherein the first identity comprises an identifier of the user equipment, the second identity comprises the identifier of the user equipment and an identifier of a last serving base station of the last serving cell.

3 . The user equipment of claim 1 , wherein the condition further comprises that a frequency of cell change and/or a frequency of beam change by the user equipment is smaller than a predefined threshold.

4 . The user equipment of claim 1 , wherein the at least one memory and the computer program code being configured to, with the at least one processor, cause the user equipment to perform: receiving, before forming the data packet, from the last serving base station the first identity and the second identity.

5 . The user equipment of claim 1 , wherein the at least one memory and the computer program code being configured to, with the at least one processor, cause the user equipment to perform: receiving, before forming the data packet, from the last serving base station the first and second identities in one or more beams, wherein each identity of the received first identity and the received second identity comprises information indicative of the beam on which it is received, wherein the first identity of the formed data packet is the received first identity excluding the beam identifier if the user equipment is attempting data transmission from the same beam on which it received the first identity.

6 . The user equipment of claim 1 , wherein the data has a size smaller than a predefined maximum size.

7 . The user equipment of claim 1 , wherein the inactive state is a radio resource control (RRC) inactive state, wherein the data packet further comprises a RRC message.

8 . The user equipment of claim 1 , wherein the inactive state is a RRC inactive state, wherein the data packet excludes RRC messages.

9 . A method, comprising:

in response to determining that a condition is fulfilled, forming a data packet comprising the data and a first identity of the user equipment; otherwise, forming the data packet comprising the data and a second identity of the user equipment;

wherein the condition comprises at least that the cell was a last serving cell of the user equipment before the user equipment transitioned to the inactive state; wherein the first identity is different from the second identity;

transmitting the data packet to the base station,

wherein the method further comprises:

transmitting data in accordance with a radio interface protocol, wherein the condition further comprises that a size of the data packet formed with the data and the second identity is larger than a size of a transport block defined for data transmission in the inactive state according to the radio interface protocol, wherein the difference between the size of the data packet and the size of the transport block is smaller than a maximum difference size.

10 . A user equipment, comprising:

at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the user equipment to perform:

in response to determining that a condition is fulfilled, forming a data packet comprising the data and a first identity of the user equipment; otherwise, forming the data packet comprising the data and a second identity of the user equipment; wherein the condition comprises at least that a cell was a last serving cell of the user equipment before the user equipment transitioned to an inactive state; wherein the first identity is different from the second identity;

transmitting the data packet to a base station,

wherein the at least one memory and the computer program code being configured to, with the at least one processor, cause the user equipment to perform: receiving, before forming the data packet, from the last serving base station the first and second identities in one or more beams, wherein each identity of the received first identity and the received second identity comprises information indicative of the beam on which it is received, wherein the first identity of the formed data packet is the received first identity excluding the beam identifier if the user equipment is attempting data transmission from the same beam on which it received the first identity.