Method and device for communicating with a selected transport block size

1. A method of operating a communications device in a wireless communications system that supports a random access procedure, the method comprising:

receiving, from an infrastructure equipment of the wireless communications system, a scheduling message comprising an indication of allocated radio resources to be used for a random access procedure message for the random access procedure;

selecting a transport block size (TBS) from a plurality of permitted TBS values for the transmission of the random access procedure message, wherein each permitted TBS value of the plurality of permitted TBS values is associated with a repetition number, and the repetition number is a maximum number of times that the random access procedure message can be transmitted in the allocated radio resources for the each permitted TBS value of the plurality of permitted TBS values;

determining whether the selected TBS is lower than a maximum TBS of the plurality of permitted TBS values; and

in a case that the determining indicates the selected TBS is lower than the maximum TBS:

selecting, based on an identifier of the communications device, a starting transmission time for starting transmission of the random access procedure message from a set of one or more permitted starting transmission times associated with the selected TBS; and

transmitting the random access procedure message to the infrastructure equipment in the allocated radio resources using the selected TBS, the repetition number associated with the selected TBS, and the selected starting transmission time.

2. The method according to claim 1 , wherein the selecting the starting transmission time is performed by randomly selecting the starting transmission time form the set of one or more permitted starting transmission times.

3. The method according to claim 1 , wherein the selecting the starting transmission time is performed by selecting a default starting transmission time from the set of one or more permitted starting transmission times.

4. The method according to claim 3 , further comprising:

receiving, from the infrastructure equipment, an indication that the communications device is permitted to select the default starting transmission time or any one of the starting transmission times other than the default starting transmission time from the set of permitted starting transmission times; and

selecting the default starting transmission time or any one of the starting transmission times other than the default starting transmission time.

5. The method according to claim 1 , further comprising receiving, from the infrastructure equipment, an indication that the random access procedure message should be retransmitted.

6. The method according to claim 5 , further comprising:

receiving, from the infrastructure equipment, an allocation of a second set of radio resources to be used for retransmission of the random access procedure message, the second set of radio resources being allocated by the infrastructure equipment based on the selected TBS for the transmission of the random access procedure message; and

retransmitting the random access procedure message to the infrastructure equipment in the second set of radio resources using the selected TBS, the repetition number associated with the selected TBS, and the selected starting transmission time.

7. The method according to claim 5 , further comprising:

receiving, from the infrastructure equipment, an allocation of a second set of radio resources to be used for retransmission of the random access procedure message, the second set of radio resources being large enough for the random access procedure message to be transmitted using the maximum TBS;

receiving an indication that the repetition number that should be used for the retransmission of the random access procedure message should be a repetition number associated with the maximum TBS; and

retransmitting the random access procedure message to the infrastructure equipment in the second set of radio resources using the selected TBS, the repetition number associated with the selected TBS, and the selected starting transmission time.

8. The method according to claim 5 , further comprising:

receiving, from the infrastructure equipment, an allocation of a second set of radio resources to be used for retransmission of the random access procedure message, the second set of radio resources being large enough for the random access procedure message to be transmitted using the maximum TBS;

receiving an indication of a repetition number that should be used for the retransmission of the random access procedure message; and

retransmitting the random access procedure message to the infrastructure equipment in the second set of radio resources using the selected TBS, the indicated repetition number, and the selected starting transmission time.

9. The method according to claim 5 , further comprising:

receiving, from the infrastructure equipment, an allocation of a second set of radio resources to be used for retransmission of the random access procedure message, the second set of radio resources being large enough for the random access procedure message to be transmitted using the selected TBS;

receiving an indication of a repetition number that should be used for the retransmission of the random access procedure message; and

retransmitting the random access procedure message to the infrastructure equipment in the second set of radio resources using the selected TBS, the indicated repetition number, and the selected starting transmission time.

10. The method according to claim 5 , further comprising:

receiving, from the infrastructure equipment, an allocation of a second set of radio resources to be used for retransmission of the random access procedure message;

receiving an indication that the maximum TBS should be used for the retransmission of the random access procedure message; and

retransmitting the random access procedure message to the infrastructure equipment in the second set of radio resources using the selected TBS, the repetition number associated with the selected TBS, and the selected starting transmission time.

11. The method according to claim 5 , further comprising:

receiving, from the infrastructure equipment, an allocation of a second set of radio resources to be used for retransmission of the random access procedure message;

receiving an indication that the maximum TBS should be used for the retransmission of the random access procedure message;

receiving an indication of a repetition number that should be used for the retransmission of the random access procedure message;

applying a scaling factor to the indicated repetition number to generate a scaled repetition number, the scaling factor having been applied to the repetition number associated with the selected TBS for the initial transmission of the random access procedure message; and

retransmitting the random access procedure message to the infrastructure equipment in the second set of radio resources using the selected TBS, the scaled repetition number, and the selected starting transmission time.

12. The method according to claim 5 , further comprising:

receiving, from the infrastructure equipment, an allocation of a second set of radio resources to be used for retransmission of the random access procedure message;

receiving an indication that the selected TBS should be used for the retransmission of the random access procedure message; and

retransmitting the random access procedure message to the infrastructure equipment in the second set of radio resources using the selected TBS, the repetition number associated with the selected TBS, and the selected starting transmission time.

13. The method according to claim 5 , further comprising:

receiving, from the infrastructure equipment, an allocation of a second set of radio resources to be used for retransmission of the random access procedure message;

receiving, from the infrastructure equipment, an indication that the communications should retransmit the random access procedure message using a different starting transmission time from the selected starting transmission time; and

retransmitting the random access procedure message to the infrastructure equipment in the second set of radio resources using the selected TBS, the repetition number associated with the selected TBS, and a starting transmission time from the set of one or more permitted starting transmission times associated with the selected TBS other than the selected starting transmission time for the transmission of the random access procedure message.

14. The method according to claim 5 , further comprising:

receiving, from the infrastructure equipment, an allocation of a second set of radio resources to be used for retransmission of the random access procedure message;

generating a random number;

comparing the random number with a probability threshold; and

retransmitting the random access procedure message to the infrastructure equipment in the second set of radio resources using the selected TBS, the repetition number associated with the selected TBS, and, dependent on the comparison, a starting transmission time from the set of one or more permitted starting transmission times associated with the selected TBS other than the selected starting transmission time.

15. The method according to claim 14 , wherein the probability threshold is predetermined and known to the communications device.

16. The method according to claim 14 , wherein the probability threshold is indicated to the communications device by the infrastructure equipment along with the allocation of the second set of radio resources.

17. A communications device operating in a wireless communications system that supports a random access procedure, the wireless communications system including an infrastructure equipment, the communications device comprising:

transceiver circuitry; and

controller circuitry configured in combination with the transceiver circuitry to:

receive, from the infrastructure equipment, a scheduling message comprising an indication of allocated radio resources to be used for a random access procedure message for the random access procedure;

select a transport block size (TBS) from a plurality of permitted TBS values for the transmission of the random access procedure message, wherein each permitted TBS value of the plurality of permitted TBS values is associated with a repetition number, and the repetition number is a maximum number of times that the random access procedure message can be transmitted in the allocated radio resources for the each permitted TBS value of the plurality of permitted TBS values;

determine whether the selected TBS is lower than a maximum TBS of the plurality of permitted TBS values; and

in a case that the controller circuitry determines that the selected TBS is lower than the maximum TBS:

select, based on an identifier of the communications device, a starting transmission time for starting transmission of the random access procedure message from a set of one or more permitted starting transmission times associated with the selected TBS; and

transmit the random access procedure message to the infrastructure equipment in the allocated radio resources using the selected TBS, the repetition number associated with the selected TBS, and the selected starting transmission time.