Granting resources to a wireless device

1. A method performed by a network node, the method comprising:

transmitting, to a wireless device operating with a short Transmission Time Interval (sTTI), a first control information message comprising a grant of resources for a downlink channel; and

transmitting, to the wireless device based on a parameter of the first control information message, a second control information message in a device-specific search space (USS) or in a common search space (CSS);

wherein the first control information message defines a frequency band for sTTI operation in an uplink and/or downlink shared channel; and

wherein the second control information message is comprised in the defined frequency band.

2. The method of claim 1 , wherein the first control information message is transmitted in the CSS and/or in a physical downlink control channel (PDCCH).

3. The method of claim 1 , wherein:

the parameter is an aggregation level of a search space of the first control information message; and

the aggregation level is used by the wireless device for decoding of the second control information message.

4. The method of claim 1 , further comprising providing, to the wireless device in a radio resource control message, an indication defining which PDCCH candidates to use in the USS.

5. The method of claim 1 , wherein:

the first control information message has an aggregation level of CCEs used for all control messages within the CSS; and/or

a highest supported aggregation level of CCEs is used for all messages within the CSS; and/or

the USS has an aggregation level of CCEs equal to, or smaller than, an aggregation level of CCEs for the CSS; and/or

less than all available physical downlink control channel candidates are defined by starting positions of CCEs for each available aggregation level of CCEs in the USS; and/or

a common aggregation level of CCEs is used for all control information messages within the USS; and/or

a same aggregation level of CCEs as the first control information message, or a highest supported aggregation level of CCEs, is used for the second control information message.

6. The method of claim 5 , wherein the less than all available control channel candidates are defined by a subset of all available control channel candidates.

7. The method of claim 5 , wherein:

the less than all available control channel candidates are defined by a first occurring half of control channel candidates of all available control channel candidates; and/or

the less than all available control channel candidates are defined by every second occurring control channel candidate of all available control channel candidates for each possible aggregation level of CCEs; and/or

the second control information message has an aggregation level of CCEs and less than all available control channel candidates are defined by every second occurring control channel candidates of all available control channel candidates for the aggregation level of CCEs.

8. A method performed by a wireless device operating with a short Transmission Time Interval (sTTI), the method comprising:

receiving a first control information message comprising a grant of resources for a downlink channel; and

decoding, based on a parameter of the first control information message, a second control information message in a device-specific search space (USS) or in a common search space (CSS);

wherein the first control information message defines a frequency band for sTTI operation in an uplink and/or downlink shared channel; and

wherein the second control information message is comprised in the defined frequency band.

9. The method of claim 8 , wherein the first control information message is received in the CSS and/or in a physical downlink control channel.

10. The method of claim 8 , wherein:

the parameter is an aggregation level of a search space of the first control information message; and

the aggregation level is used by the wireless device for decoding of the second control information message.

11. The method of claim 8 , further comprising obtaining, from a network node and in a radio resource control message, an indication defining which physical downlink control channel candidates to use in the USS.

12. The method of claim 8 , further comprising:

searching, based on the first control information message, for only one format of the second control information message in the USS; and/or

finding a slow grant by decoding less than all CSS available to the wireless device in a physical downlink control channel.

13. The method of claim 8 , further comprising finding the first control information message by searching for the first control information message in the CSS for only one aggregation level of Control Channel Elements (CCEs).

14. The method of claim 8 , wherein:

the first control information message has an aggregation level of CCEs used for all control messages within the CSS; and/or

a highest supported aggregation level of CCEs is used for all messages within the CSS; and/or

the USS has an aggregation level of CCEs equal to, or smaller than, an aggregation level of CCEs for the CSS; and/or

less than all available physical downlink control channel candidates are defined by starting positions of CCEs for each available aggregation level of CCEs in the USS; and/or

a common aggregation level of CCEs is used for all control information messages within the USS; and/or

a same aggregation level of CCEs as the first control information message, or a highest supported aggregation level of CCEs, is used for the second control information message.

15. The method of claim 14 , wherein the less than all available control channel candidates are defined by a subset of all available control channel candidates.

16. The method of claim 14 , wherein:

the less than all available control channel candidates are defined by a first occurring half of control channel candidates of all available control channel candidates; and/or

the less than all available control channel candidates are defined by every second occurring control channel candidate of all available control channel candidates for each possible aggregation level of CCEs; and/or

the second control information message has an aggregation level of CCEs and less than all available control channel candidates are defined by every second occurring control channel candidates of all available control channel candidates for the aggregation level of CCEs.

17. A network node comprising:

processing circuitry configured to cause the network node to:

transmit, to a wireless device operating with a short Transmission Time Interval (sTTI), a first control information message comprising a grant of resources for a downlink channel; and

transmit, to the wireless device, based on a parameter of the first control information message, a second control information message in a device-specific search space (USS) or in a common search space (CSS);

wherein the first control information message defines a frequency band for sTTI operation in an uplink and/or downlink shared channel; and

wherein the second control information message is comprised in the defined frequency band.

18. A wireless device configured to operate with a short Transmission Time Interval (sTTI), the wireless device comprising:

processing circuitry configured to cause the wireless device to:

receive a first control information message comprising a grant of resources for a downlink channel; and

decode, based on a parameter of the first control information message, a second control information message in a device-specific search space (USS) or in a common search space (CSS);

wherein the first control information message defines a frequency band for sTTI operation in an uplink and/or downlink shared channel; and

wherein the second control information message is comprised in the defined frequency band.