Indication of hybrid automatic repeat request feedback by synchronization signal

1. A method of controlling radio transmissions in a wireless communication network, the method comprising:

a node of the wireless communication network receiving a non-time aligned synchronization signal from a radio device;

the node determining, based on the received synchronization signal, a time alignment configuration for uplink radio transmissions from the radio device to the wireless communication network;

the node determining, based on a non-time aligned uplink radio transmission from the radio device, Hybrid Automatic Repeat Request feedback information for at least one downlink radio transmission from the wireless communication network to the radio device; wherein the non-time aligned uplink radio transmission is:

the synchronization signal which conveys the Hybrid Automatic Repeat Request feedback information; or

a non-time aligned further uplink signal, which conveys the Hybrid Automatic Repeat Request feedback information, transmitted by the radio device after the non-time aligned synchronization signal; and

the node controlling, based on the determined Hybrid Automatic Repeat Request feedback information, retransmission of the at least one downlink radio transmission.

2. The method of claim 1 , further comprising, in response to determining that the time alignment configuration of the radio device is valid, the node determining Hybrid Automatic Repeat Request feedback information for acknowledgement of at least one downlink radio transmission from the wireless communication network to the radio device based on at least one of the uplink radio transmissions from the radio device.

3. The method of claim 1 , further comprising, in response to determining that the time alignment configuration of the radio device is invalid, the node determining Hybrid Automatic Repeat Request feedback information for acknowledgement of at least one downlink radio transmission from the wireless communication network to the radio device based on the synchronization signal.

4. The method of claim 1 , further comprising:

in response to detecting a first type of the synchronization signal, the node determining the Hybrid Automatic Repeat Request feedback information as including a positive acknowledgement indicating successful reception of the at least one downlink radio transmission; and

in response to detecting a second type of the synchronization signal, the node determining the Hybrid Automatic Repeat Request feedback information as including a negative acknowledgement indicating failed reception of the at least one downlink radio transmission.

5. The method of claim 1 , further comprising:

based on the synchronization signal, the node estimating a timing of the further non-time aligned uplink signal from the radio device;

based on the estimated timing, the node receiving the further non-time aligned uplink signal; and

the node determining the Hybrid Automatic Repeat Request feedback information from the further non-time aligned uplink signal from the radio device.

6. The method of claim 1 , further comprising, in response to detecting the synchronization signal while not expecting Hybrid Automatic Repeat Request feedback information from the radio device, the node allocating uplink radio resources to the radio device and indicating the allocated uplink radio resources to the radio device.

7. A method of controlling transmissions in a wireless communication network, the method comprising:

a radio device determining Hybrid Automatic Repeat Request feedback information for at least one downlink radio transmission from the wireless communication network to the radio device;

by sending a non-time aligned uplink radio transmission, the radio device indicating the Hybrid Automatic Repeat Request feedback information to the wireless communication network; wherein the non-time aligned uplink radio transmission indicating the Hybrid Automatic Repeat Request feedback information is:

a non-time aligned synchronization signal from the radio device; or

a non-time aligned further uplink signal transmitted by the radio device after the non-time aligned synchronization signal; and

wherein the synchronization signal enables a node of the wireless communication network to determine a time alignment configuration for uplink radio transmissions from the radio device to the wireless communication network.

8. The method of claim 7 , further comprising, in response to determining that the time alignment configuration of the radio device is valid, the radio device sending Hybrid Automatic Repeat Request feedback information for acknowledgement of at least one downlink radio transmission from the wireless communication network to the radio device based on at least one of the uplink radio transmissions from the radio device.

9. The method of claim 7 , further comprising, in response to determining that the time alignment configuration of the radio device is invalid, the radio device sending Hybrid Automatic Repeat Request feedback information for acknowledgement of at least one downlink radio transmission from the wireless communication network to the radio device based on the synchronization signal.

10. The method of claim 7 , further comprising:

by sending a first type of the synchronization signal, the radio device sending the Hybrid Automatic Repeat Request feedback information as a positive acknowledgement indicating successful reception of the at least one downlink radio transmission; and

by sending a second type of the synchronization signal, the radio device sending the Hybrid Automatic Repeat Request feedback information as a negative acknowledgement indicating failed reception of the at least one downlink radio transmission.

11. The method of claim 7 , further comprising:

the radio device sending the Hybrid Automatic Repeat Request feedback information in the non-time aligned further uplink signal to the wireless communication network;

wherein the synchronization signal enables a node of the wireless communication network to estimate a timing of the non-time aligned further uplink signal and receive the further uplink signal based on the estimated timing.

12. The method of claim 7 , further comprising the radio device requesting allocation of uplink radio resources to the radio device by sending the synchronization signal while the wireless communication network does not expect Hybrid Automatic Repeat Request feedback information from the radio device.

13. A node for a wireless communication network, the node comprising:

processing circuitry;

memory containing instructions executable by the processing circuitry whereby the node is operative to:

receive a non-time aligned synchronization signal from a radio device;

determine, based on the received synchronization signal, a time alignment configuration for uplink radio transmissions from the radio device to the wireless communication network;

determine, based on a non-time aligned uplink radio transmission from the radio device, Hybrid Automatic Repeat Request feedback information for at least one downlink radio transmission from the wireless communication network to the radio device; wherein the non-time aligned uplink radio transmission is:

the synchronization signal which conveys the Hybrid Automatic Repeat Request feedback information; or

a non-time aligned further uplink signal, which conveys the Hybrid Automatic Repeat Request feedback information, transmitted by the radio device after the non-time aligned synchronization signal; and

control, based on the determined Hybrid Automatic Repeat Request feedback information, retransmission of the at least one downlink radio transmission.

14. The node of claim 13 , wherein the instructions are such that the node is operative to, in response to determining that the time alignment configuration of the radio device is valid, determine Hybrid Automatic Repeat Request feedback information for acknowledgement of at least one downlink radio transmission from the wireless communication network to the radio device based on at least one of the uplink radio transmissions from the radio device.

15. The node of claim 13 , wherein the instructions are such that the node is operative to, in response to determining that the time alignment configuration of the radio device is invalid, determine Hybrid Automatic Repeat Request feedback information for acknowledgement of at least one downlink radio transmission from the wireless communication network to the radio device based on the synchronization signal.

16. The node of claim 13 , wherein the instructions are such that the node is operative to:

in response to detecting a first type of the synchronization signal, determine the Hybrid Automatic Repeat Request feedback information as including a positive acknowledgement indicating successful reception of the at least one downlink radio transmission; and

in response to detecting a second type of the synchronization signal, determine the Hybrid Automatic Repeat Request feedback information as including a negative acknowledgement indicating failed reception of the at least one downlink radio transmission.

17. The node of claim 13 , wherein the instructions are such that the node is operative to:

based on the synchronization signal, estimate a timing of the non-time aligned further uplink signal from the radio device;

based on the estimated timing, receive the further non-time aligned uplink signal; and

determine the Hybrid Automatic Repeat Request feedback information from the non-time aligned further uplink signal from the radio device.

18. The node of claim 13 , wherein the instructions are such that the node is operative to, in response to detecting the synchronization signal while not expecting Hybrid Automatic Repeat Request feedback information from the radio device, allocate uplink radio resources to the radio device and indicating the allocated uplink radio resources to the radio device.

19. A radio device, the radio device comprising:

processing circuitry;

memory containing instructions executable by the processing circuitry whereby the radio device is operative to:

determine Hybrid Automatic Repeat Request feedback information for at least one downlink radio transmission from a wireless communication network to the radio device; and

by sending a non-time aligned uplink radio transmission, indicate the Hybrid Automatic Repeat Request feedback information to the wireless communication network; wherein the non-time aligned uplink radio transmission indicating the Hybrid Automatic Repeat Request feedback information is:

a non-time aligned synchronization signal from the radio device; or

a non-time aligned further uplink signal transmitted by the radio device after the non-time aligned synchronization signal; and

wherein the synchronization signal enables a node of the wireless communication network to determine a time alignment configuration for uplink radio transmissions from the radio device to the wireless communication network.

20. The radio device of claim 19 , wherein the instructions are such that the radio device is further operative to, in response to determining that the time alignment configuration of the radio device is valid, send Hybrid Automatic Repeat Request feedback information for acknowledgement of at least one downlink radio transmission from the wireless communication network to the radio device based on at least one of the uplink radio transmissions from the radio device.

21. The radio device of claim 19 , wherein the instructions are such that the radio device is further operative to, in response to determining that the time alignment configuration of the radio device is invalid, send Hybrid Automatic Repeat Request feedback information for acknowledgement of at least one downlink radio transmission from the wireless communication network to the radio device based on the synchronization signal.

22. The radio device of claim 19 , wherein the instructions are such that the radio device is further operative to:

by sending a first type of the synchronization signal, send the Hybrid Automatic Repeat Request feedback information as a positive acknowledgement indicating successful reception of the at least one downlink radio transmission; and

by sending a second type of the synchronization signal, send the Hybrid Automatic Repeat Request feedback information as a negative acknowledgement indicating failed reception of the at least one downlink radio transmission.

23. The radio device of claim 19 :

wherein the instructions are such that the radio device is further operative to send the Hybrid Automatic Repeat Request feedback information in the non-time aligned further uplink signal to the wireless communication network;

wherein the synchronization signal enables a node of the wireless communication network to estimate a timing of the non-time aligned further uplink signal and receive the non-time aligned further uplink signal based on the estimated timing.

24. The radio device of claim 19 , wherein the instructions are such that the radio device is further operative to request allocation of uplink radio resources to the radio device by sending the synchronization signal while the wireless communication network does not expect Hybrid Automatic Repeat Request feedback information from the radio device.

25. A non-transitory computer readable recording medium storing a computer program product for controlling radio transmissions in a wireless communication network, the computer program product comprising software instructions which, when run on processing circuitry of a node of the wireless communication network, causes the node to:

receive a non-time aligned synchronization signal from a radio device;

determine, based on the received synchronization signal, a time alignment configuration for uplink radio transmissions from the radio device to the wireless communication network;

determine, based on a non-time aligned uplink radio transmission from the radio device, Hybrid Automatic Repeat Request feedback information for at least one downlink radio transmission from the wireless communication network to the radio device; wherein the non-time aligned uplink radio transmission is:

the synchronization signal which conveys the Hybrid Automatic Repeat Request feedback information; or

a non-time aligned further uplink signal, which conveys the Hybrid Automatic Repeat Request feedback information, transmitted by the radio device after the non-time aligned synchronization signal; and

control, based on the determined Hybrid Automatic Repeat Request feedback information, retransmission of the at least one downlink radio transmission.

26. A non-transitory computer readable recording medium storing a computer program product for controlling transmissions in a wireless communication network, the computer program product comprising software instructions which, when run on processing circuitry of a radio device, causes the radio device to:

determine Hybrid Automatic Repeat Request feedback information for at least one downlink radio transmission from the wireless communication network to the radio device;

indicate, by sending a non-time aligned uplink radio transmission, the Hybrid Automatic Repeat Request feedback information to the wireless communication network; wherein the non-time aligned uplink radio transmission indicating the Hybrid Automatic Repeat Request feedback information is;

a non-time aligned synchronization signal from the radio device; or

a non-time aligned further uplink signal transmitted by the radio device after the non-time aligned synchronization signal; and

wherein the synchronization signal enables a node of the wireless communication network to determine a time alignment configuration for uplink radio transmissions from the radio device to the wireless communication network.