Random access for NR

1. A method comprising:

first determining that there are no uplink resources available for transmitting a scheduling request;

initiating a timer in response to the first determination;

if said timer expires, on expiry of said timer, initiating a random access procedure on the uplink;

second determining that there are uplink resources available for transmitting the scheduling request subsequent to initiating said timer and prior to expiry of said timer; and

transmitting the scheduling request on the uplink resources available in response to the second determination.

2. A method as claimed in claim 1 , wherein the second determining comprises:

receiving an allocation of resources for an uplink channel.

3. A method as claimed in claim 1 , further comprising:

on expiry of said timer, cancelling said scheduling request.

4. A method as claimed in claim 1 , further comprising:

if said timer expires, on expiry of said timer, cancelling all scheduling requests that are currently pending.

5. A method as claimed in claim 1 , further comprising:

prior to initiating said timer, receiving from a network apparatus configuration information for setting the length of the timer; and

setting the length of the timer in response using the configuration information.

6. A method as claimed in claim 1 , further comprising:

configuring the timer to apply to a single logical channel or logical channel group.

7. A method as claimed in claim 1 , further comprising configured said timer to expire at a next opportunity for transmitting a random access preamble to a network apparatus.

8. A method as claimed in claim 1 , further comprising configuring said timer to expire on a next random access channel subframe to occur subsequent to initiation of said timer that is associated with one of: a serving beam; a beam having the best quality; a candidate beam; and/or a beam group.

9. A method as claimed in claim 1 , further comprising:

initiating a time-alignment timer, wherein expiry of the time-alignment timer indicates that the network apparatus is no longer synchronised on the uplink with an apparatus initiating the timer-alignment timer;

on expiry of said timer, determining whether the time-alignment timer has expired; and

only performing said initiating of a random access procedure when it is determined that the time-alignment timer has not expired.

10. A method as claimed in claim 1 , further comprising:

initiating a timer in respect of each scheduling request to be transmitted; and

on the first expiry of one of said timers, resetting the remainder of said timers and initiating random access procedures.

11. A method as claimed in claim 1 , further comprising configuring said timer in dependence on a window of time within which a user apparatus is configured to expect a network to assign uplink resources for transmitting a scheduling request.

12. A method as claimed in claim 2 , comprising:

pausing said timer at the value of the timer when the resource allocation is received.

13. A method as claimed in claim 12 , further comprising:

resuming the count of the timer from the paused value of the timer when the scheduling request is transmitted in the allocated resources.

14. A method as claimed in claim 12 , further comprising:

restarting the count of the timer from an initial value of the timer when the scheduling request is transmitted in the allocated resources.

15. A method as claimed in claim 12 , further comprising:

restarting and/or resuming the count of the timer when the scheduling request is transmitted; or

restarting and/or resuming the count of the timer a predetermined time after transmitting the scheduling request.

16. A method comprising:

determining, by a network apparatus, a timer value for delaying an initiation of a random access procedure at a user apparatus; and

signaling, by the network apparatus, the timer value to the user apparatus; wherein the random access procedure is delayed based on the timer value when the user apparatus determines that there are no uplink resources available for transmitting a scheduling request.

17. A method as claimed in claim 16 , wherein the determining is made aperiodically in dependence on network conditions within a preceding time period.

18. An apparatus comprising:

at least one processor; and

at least one memory comprising code that, when executed on said at least one processor, causes the apparatus to;

first determine that there are no uplink resources available for transmitting a scheduling request;

initiate a timer in response to said first determination;

initiate a random access procedure on the uplink on expiry of said timer;

second determine that there are uplink resources available for transmitting the scheduling request subsequent to initiating said timer and prior to expiry of said timer; and

transmit the scheduling request on the uplink resources available in response to the second determination.

19. An apparatus comprising:

at least one processor; and

at least one processor; and

at least one memory comprising code that, when executed on said at least one processor, causes the apparatus to perform:

determine a timer value for delaying an initiation of a random access procedure at a user apparatus;

signal the timer value to the user apparatus; and

delay the random access procedure when the user apparatus determines that there are no uplink resources available for transmitting a scheduling request.

20. Non-transitory computer readable media comprising program instructions that, when executed on at least one processor, causes the method of claim 1 to be performed.

21. Non-transitory computer readable media comprising program instructions that, when executed on at least one processor, causes the method of claim 16 to be performed.