Selective reallocation of previously allocated radio resources

1. A method of controlling radio transmission in a cellular network, the method comprising:

an access node of the cellular network sending an uplink grant to a communication device, the uplink grant indicating uplink radio resources allocated to the communication device in reoccurring time intervals;

the access node monitoring an uplink radio resource, configured before each of the reoccurring time intervals, for an indication of intention to transmit uplink data by an uplink transmission on the indicated uplink radio resources in the corresponding reoccurring time interval; and

in response to not detecting the indication and determining a need for an uplink transmission in the corresponding reoccurring time interval by a further communication device, the access node reallocating the indicated uplink radio resources in the corresponding time interval to the further communication device.

2. The method of claim 1 , further comprising the access node selecting, depending on detection of the indication, between a first mode in which monitoring of the indicated uplink radio resources in the corresponding reoccurring time interval by the access node is active and a second mode in which monitoring of the indicated uplink radio resources in the corresponding reoccurring time interval by the access node is inactive.

3. The method of claim 2 , further comprising the access node selecting the second mode in response to not detecting the indication.

4. The method of claim 2 , further comprising the access node selecting the first mode in response to detecting the indication.

5. The method of claim 1 , wherein:

the indicated uplink radio resources are allocated to a group of multiple communication devices; and

the configured uplink radio resource is shared by the communication devices of the group.

6. The method of claim 5 , further comprising the access node estimating, based on a received signal strength in the configured uplink radio resource, a number of communication devices with intention to perform an uplink transmission on the indicated radio resources in the corresponding reoccurring time interval.

7. The method of claim 6 , further comprising the access node, in response to estimated number of communication devices being larger than one, allocating new uplink radio resources in the corresponding reoccurring time interval to at least one of the communication devices of the group.

8. A method of controlling radio transmission in a cellular network, the method comprising:

a communication device receiving an uplink grant from the cellular network, the uplink grant indicating uplink radio resources allocated to the communication device in reoccurring time intervals;

in an uplink radio resource configured before each of the reoccurring time intervals, the communication device sending an indication of intention to transmit uplink data by an uplink transmission on the indicated uplink radio resources in the corresponding reoccurring time interval; and

after sending the indication, the communication device performing the uplink transmission on the indicated uplink radio resources in the corresponding reoccurring time interval.

9. The method of claim 8 , wherein:

the indicated uplink radio resources are allocated to a group of multiple communication devices; and

the configured uplink radio resource is shared by the communication devices of the group.

10. The method of claim 8 further comprising the communication device selecting, for each of the reoccurring time intervals, between:

an active mode in which the communication device performs an uplink transmission on the indicated uplink radio resources; and

an inactive mode in which the communication device performs no uplink transmission on the indicated uplink radio resources.

11. The method of claim 10 , further comprising the communication device:

for each of the reoccurring time intervals, checking whether one or more conditions for sending a buffer status report are met; and

in response to one or more of the conditions being met, selecting the active mode to send an uplink transmission comprising the buffer status report, the buffer status report indicating an amount of uplink data available for transmission by the communication device.

12. An access node for a cellular network, the node comprising:

an interface for connecting to a communication device; and

processing circuitry configured to:

send an uplink grant to the communication device via the interface, the uplink grant indicating uplink radio resources allocated to the communication device in reoccurring time intervals;

monitor an uplink radio resource, configured before each of the reoccurring time intervals, for an indication of intention to transmit uplink data by an uplink transmission on the indicated uplink radio resources in the corresponding reoccurring time interval; and

in response to not detecting the indication and determining a need for an uplink transmission in the corresponding reoccurring time interval by a further communication device, reallocate the indicated uplink radio resources in the corresponding reoccurring time interval to the further communication device.

13. The access node of claim 12 , wherein the processing circuitry is configured to select, depending on detection of the indication, between a first mode in which monitoring of the indicated uplink radio resources in the corresponding reoccurring time interval by the access node is active and a second mode in which monitoring of the indicated uplink radio resources in the corresponding reoccurring time interval by the access node is inactive.

14. The access node of claim 13 , wherein the processing circuitry is configured to select the second mode in response to not detecting the indication.

15. The access node of claim 13 , wherein the processing circuitry is configured to select the first mode in response to detecting the indication.

16. The access node of claim 12 , wherein:

the indicated uplink radio resources are allocated to a group of multiple communication devices;

the configured uplink radio resource is shared by the communication devices of the group; and

the processing circuitry is configured to estimate, based on a received signal strength in the configured uplink radio resource, a number of communication devices with intention to perform an uplink transmission on the indicated radio resources in the corresponding reoccurring time interval.

17. The access node of claim 16 , wherein the processing circuitry is configured to allocate, in response to estimated number of communication devices being larger than one, new uplink radio resources in the corresponding reoccurring time interval to at least one of the communication devices of the group.

18. A communication device, comprising:

an interface for connecting to a cellular network; and

processing circuitry configured to:

receive, via the interface, an uplink grant from the cellular network, the uplink grant indicating uplink radio resources allocated to the communication device in reoccurring time intervals;

in an uplink radio resource configured before each of the reoccurring time intervals, send an indication of intention to transmit uplink data by an uplink transmission on the indicated uplink radio resources in the corresponding reoccurring time interval; and

after sending the indication, perform the uplink transmission on the indicated uplink radio resources in the corresponding reoccurring time interval.

19. The communication device of claim 18 , wherein:

the indicated uplink radio resources are allocated to a group of multiple communication devices, and

the configured uplink radio resource is shared by the communication devices of the group.

20. The communication device of claim 18 , wherein the processing circuitry is configured to select, for each of the reoccurring time intervals, between:

an active mode in which the communication device performs an uplink transmission on the indicated uplink radio resources; and

an inactive mode in which the communication device performs no uplink transmission on the indicated uplink radio resources.