UPLINK MULTI-TTI SCHEDULING IN TDD SYSTEM

• US 20150264662A1
• Filed: 03/14/2014
• Published: 09/17/2015
• Est. Priority Date: 03/14/2014
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sahlin, Henrik, Frenne, Mattias, Furuskog, Johan, Parkvall, Stefan, Zhang, Qiang
• Granted Patent: US 9,942,881 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

Systems and methods are disclosed for transmission and reception of an uplink grant during a gap created in radio resources assigned by a previous multiple Transmit Time Interval (multi-TTI) uplink grant in a system operating according to a Time Division Duplexing (TDD) scheme. In one embodiment, a method of operation of a radio network node in a cellular communications network is provided. The method includes transmitting a first uplink grant that assigns radio resources for a multi-TTI uplink transmission, and transmitting a second uplink grant during a gap in the radio resources assigned by the first uplink grant. In one embodiment, by utilizing the gap to transmit the second uplink grant, uplink radio resources assigned for uplink transmission can be maximized, which is particularly beneficial in high uplink traffic conditions.

Claims

1. A method of operation of a radio network node operating according to a Time Division Duplexing, TDD, scheme in a cellular communications network, comprising:

transmitting a first uplink grant that assigns first radio resources for a first multiple transmit time interval uplink transmission; and

transmitting a second uplink grant during a gap in the first radio resources assigned for the first multiple transmit time interval uplink transmission.

2. The method of claim 1 wherein the first radio resources comprise a set of consecutive subframes, and the gap comprises a gap subframe within the set of consecutive subframes.

3. The method of claim 1 wherein the gap is a time domain gap, and a position of the gap is a position relative to an end of the first radio resources assigned for the first multiple transmit time interval uplink transmission by the first uplink grant.

4. The method of claim 3 wherein an amount of time between the gap and the end of the first radio resources is greater than or equal to an uplink scheduling delay.

5. The method of claim 4 wherein the uplink scheduling delay is greater than zero.

6. The method of claim 1 wherein the gap is a time domain gap, and a position of the gap is defined by a cellular communications network standard.

7. The method of claim 1 further comprising signaling a position of the gap to one or more wireless devices.

8. The method of claim 1 wherein a position of the gap is semi-statically configured.

9. The method of claim 1 wherein a position of the gap is semi-statically configured individually for a wireless device.

10. The method of claim 1 wherein a position of the gap is semi-statically configured for a plurality of wireless devices.

11. The method of claim 1 further comprising signaling a position of the gap to one or more wireless devices via Radio Resource Control, RRC, signaling.

12. The method of claim 1 further comprising dynamically configuring the gap.

13. The method of claim 12 wherein dynamically configuring the gap comprises providing a position of the gap in the first uplink grant.

14. The method of claim 12 wherein dynamically configuring the gap comprises providing an indication of the gap in the first uplink grant.

15. The method of claim 1 further comprising:

prior to transmitting the second uplink grant during the gap, determining whether the gap is to be used;

wherein transmitting the second uplink grant comprises transmitting the second uplink grant during the gap in response to determining that the gap is to be used.

16. The method of claim 15 wherein determining whether the gap is to be used comprises determining that the gap is to be used if a number of transmit time intervals assigned in the first uplink grant is greater than a predefined threshold.

17. The method of claim 16 wherein the predefined threshold is greater than or equal to an uplink scheduling delay.

18. The method of claim 15 wherein the gap is a time domain gap, a position of the gap is a predefined position relative to an end of the first radio resources assigned for the first multiple transmit time interval uplink transmission by the first uplink grant, and determining whether the gap is to be used comprises determining that the gap is not to be used if the position of the gap is prior to a start of the first radio resources assigned by the first uplink grant.

19. The method of claim 15 wherein determining whether the gap is to be used comprises determining that the gap is to be used if an uplink traffic level of a corresponding cell served by the radio network node is greater than a predefined threshold.

20. The method of claim 15 wherein determining whether the gap is to be used comprises determining that the gap is to be used if an uplink traffic level of a corresponding cell served by the radio network node is greater than a first predefined threshold and a downlink traffic level of the corresponding cell served by the radio network node is less than a second predefined threshold.

21. The method of claim 15 wherein determining whether the gap is to be used comprises determining that the gap is not to be used if a fixed downlink subframe that can be used to provide the second uplink grant occurs within the first radio resources assigned for the first multiple transmit time interval uplink transmission.

22. The method of claim 1 wherein a plurality of subframes spanned by the first radio resources assigned for the first multiple transmit time interval uplink transmission are the same subframes as those spanned by radio resources assigned for multiple transmit time interval uplink transmissions by a plurality of wireless devices, and the gap is the same gap as that configured for the plurality of wireless devices.

23. A radio network node operating according to a Time Division Duplexing, TDD, scheme in a cellular communications network, comprising:

a transceiver;

a processor associated with the transceiver; and

a memory containing instructions executable by the processor whereby the radio network node is operative to;

transmit, via the transceiver, a first uplink grant that assigns first radio resources for a first multiple transmit time interval uplink transmission; and

transmit, via the transceiver, a second uplink grant during a gap in the first radio resources assigned for the first multiple transmit time interval uplink transmission.

24. A method of operation of a wireless device operating according to a Time Division Duplexing, TDD, scheme in a cellular communications network, comprising:

receiving a first uplink grant from a radio network node that assigns first radio resources for a first multiple transmit time interval uplink transmission; and

listening for a second uplink grant from the radio network node during a gap in the first radio resources assigned for the first multiple transmit time interval uplink transmission.

25. The method of claim 24 wherein the first radio resources comprise a set of consecutive subframes, and the gap comprises a gap subframe within the set of consecutive subframes.

26. The method of claim 24 further comprising:

performing a first portion of the first multiple transmit time interval uplink transmission prior to the gap; and

performing a remaining portion of the first multiple transmit time interval uplink transmission after the gap.

27. The method of claim 24 wherein the gap is a time domain gap, and a position of the gap is a position relative to an end of the first radio resources assigned for the first multiple transmit time interval uplink transmission by the first uplink grant.

28. The method of claim 27 wherein an amount of time between the gap and the end of the first radio resources is greater than or equal to an uplink scheduling delay.

29. The method of claim 28 wherein the uplink scheduling delay is greater than zero.

30. The method of claim 24 wherein the gap is a time domain gap, and a position of the gap is defined by a cellular communications network standard.

31. The method of claim 24 further comprising receiving signaling comprising an indication of a position of the gap from the radio network node.

32. The method of claim 24 wherein a position of the gap is semi-statically configured.

33. The method of claim 24 wherein a position of the gap is semi-statically configured individually for the wireless device.

34. The method of claim 24 wherein a position of the gap is semi-statically configured for a plurality of wireless devices including the wireless device.

35. The method of claim 24 further comprising receiving Radio Resource Control, RRC, signaling comprising an indication of a position of the gap from the radio network node.

36. The method of claim 24 further comprising receiving a dynamic configuration of the gap.

37. The method of claim 36 wherein receiving the dynamic configuration of the gap comprises receiving a position of the gap in the first uplink grant.

38. The method of claim 36 wherein receiving the dynamic configuration of the gap comprises receiving an indication of the gap in the first uplink grant.

39. The method of claim 24 further comprising:

prior to listening for a second uplink grant during the gap, determining whether the gap is to be used;

wherein listening for a second uplink grant comprises listening for a second uplink grant during the gap in response to determining that the gap is to be used.

40. The method of claim 39 wherein determining whether the gap is to be used comprises determining that the gap is to be used if a number of transmit time intervals assigned in the first uplink grant is greater than a predefined threshold.

41. The method of claim 40 wherein the predefined threshold is greater than or equal to an uplink scheduling delay.

42. The method of claim 39 wherein the gap is a time domain gap, a position of the gap is a predefined position relative to an end of the first radio resources assigned for the first multiple transmit time interval uplink transmission by the first uplink grant, and determining whether the gap is to be used comprises determining that the gap is not to be used if the position of the gap is prior to a start of the first radio resources assigned by the first uplink grant.

43. The method of claim 39 wherein determining whether the gap is to be used comprises determining that the gap is not to be used if a fixed downlink subframe that can be used to receive the second uplink grant occurs within the first radio resources assigned for the first multiple transmit time interval uplink transmission.

44. A wireless device operating according to a Time Division Duplexing, TDD, scheme in a cellular communications network, comprising:

a transceiver;

a processor associated with the transceiver; and

a memory containing instructions executable by the processor, whereby the wireless device is operative to;

receive, via the transceiver, a first uplink grant from a radio network node that assigns first radio resources for a first multiple transmit time interval uplink transmission; and

listen, via the transceiver, for a second uplink grant from the radio network node during a gap in the first radio resources assigned for the first multiple transmit time interval uplink transmission.