Creating protocol data unit for early data transmission
Various communication systems may benefit from improved random access procedures. For example, it may be helpful to improve random access procedure when changing a coverage enhancement level. A method, according to certain embodiments, may include changing a coverage enhancement level in response to a failure of a random access procedure. The method may also include determining whether early data transmission may be initiated in the changed coverage enhancement level. In addition, the method may include building at a user equipment a protocol data unit corresponding to the changed coverage enhancement level when the early data transmission is initiated in the changed coverage enhancement level. Further, the method may include transmitting the early data from the user equipment to a network entity in the built packet data unit on the changed coverage enhanced level.
1. A method comprising:
changing a coverage enhancement level in response to a failure of a random access procedure;
determining that early data transmission is to be transmitted in the changed coverage enhancement level, wherein the changed coverage enhancement level corresponds to a new maximum transport block size;
building at a user equipment a protocol data unit corresponding to the new maximum transport block size; and
transmitting the early data from the user equipment to a network entity in the built protocol data unit on the changed coverage enhancement level.
2. The method according to claim 1 , wherein the transmitting of the early data is a retransmission.
3. The method according to claim 1 , further comprising:
receiving at the user equipment the new maximum transport block size corresponding to the changed coverage enhancement level.
4. The method according to claim 1 , further comprising:
storing at the user equipment an initial protocol data unit in a transmit buffer, wherein the initial protocol data unit is for transmission by the user equipment to the network entity.
5. The method according to claim 4 , further comprising:
removing at least one of a padding or a padding sub-header from the stored initial protocol data unit to obtain a clean protocol data unit.
6. The method according to claim 1 , further comprising:
storing at the user equipment an initial service data unit and corresponding control elements in a transmit buffer, wherein the initial service data unit and the corresponding control elements are for transmission by the user equipment to the network entity, and wherein the building of the protocol data unit comprises adding one or more bytes to the initial service data unit and the corresponding control elements for padding or padding subheader.
7. The method according to claim 5 , further comprising:
comparing a length of the clean protocol data unit and the new maximum transport block size corresponding to the changed coverage enhancement level; and
initiating the early data transmission when the clean protocol data unit is smaller than or equal to the new maximum transport block size corresponding to the changed coverage enhancement level.
8. The method according to claim 5 , further comprising:
transmitting the protocol data unit stored in the buffer after the random access procedure is complete when the clean protocol data unit is larger than the new maximum transport block size corresponding to the changed coverage enhancement level.
9. The method according to claim 5 , further comprising:
selecting at the user equipment a new transport block size for early data transmission that is equal to or smaller than the new maximum transport block size corresponding to the changed coverage enhancement level, and that is larger than or equal to the clean protocol data unit.
10. The method according to claim 1 , wherein the transmitted early data is comprised in a message 3 transmission of the random access procedure.
11. The method according to claim 5 , wherein the building of the protocol data unit comprises adding one or more bytes to the clean protocol data unit for padding or padding subheader.
12. An apparatus, comprising:
at least one memory comprising computer program code;
at least one processor, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to:
change a coverage enhancement level in response to a failure of a random access procedure;
determine that early data transmission is to be transmitted in the changed coverage enhancement level, wherein the changed coverage enhancement level corresponds to a new maximum transport block size;
build a protocol data unit corresponding to the new maximum transport block size; and
transmit the early data to a network entity in the built protocol data unit on the changed coverage enhanced level.
13. The apparatus according to claim 12 , wherein the transmitting of the early data is a retransmission.
14. The apparatus according to claim 12 , wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to:
receive the new maximum transport block size corresponding to the changed coverage enhancement level.
15. The apparatus according to claim 12 , wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to:
store an initial protocol data unit in a transmit buffer, wherein the initial protocol data unit is for transmission by the user equipment to the network entity.
16. The apparatus according to claim 15 , wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to:
remove at least one of a padding or a padding sub-header from the stored initial protocol data unit to obtain a clean protocol data unit.
17. The apparatus according to claim 12 , wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to:
store an initial service data unit and corresponding control elements in a transmit buffer, wherein the initial service data unit and the corresponding control elements are for transmission to the network entity, and wherein the building of the protocol data unit comprises adding one or more bytes to the initial service data unit and the corresponding control elements for padding or padding subheader.
18. The apparatus according to claim 16 , wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to:
compare a length of the clean protocol data unit and the new maximum transport block size corresponding to the changed coverage enhancement level; and
initiate the early data transmission when the clean protocol data unit is smaller than or equal to the new maximum transport block size corresponding to the changed coverage enhancement level.
19. The apparatus according to claim 16 , further comprising:
transmit the protocol data unit stored in the buffer after the random access procedure is complete when the clean protocol data unit is larger than the new maximum transport block size corresponding to the changed coverage enhancement level.
20. The apparatus according to claim 16 , wherein the clean protocol data unit is smaller than or equal to the new maximum transport block size of the changed coverage enhancement level.
21. The apparatus according to claim 16 , wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to:
select a new transport block size for early data transmission that is equal to or smaller than the new maximum transport block size corresponding to the changed coverage enhancement level, and that is larger than or equal to the clean protocol data unit.
22. The apparatus according to claim 12 , wherein the transmitted early data is comprised in a message 3 transmission of the random access procedure.
23. The apparatus according to claim 16 , wherein the building of the protocol data unit comprises adding one or more bytes to the clean protocol data unit for padding or padding subheader.