Adaptive Scheduling for Half-Duplex Wireless Terminals

• US 20090135748A1
• Filed: 10/21/2008
• Published: 05/28/2009
• Est. Priority Date: 11/16/2007
• Status: Active Grant

• Current Assignee: Optis Wireless Technology, LLC (Brevet Capital)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Camp, Williams O., Lindoff, Bengt, Mattisson, Sven
• Granted Patent: US 8,155,032 B2
• Time in Patent Office: Days
• US Class Current: 370/296
• CPC Class Codes: H04W 72/51 based on terminal or device properties
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

Adaptation is introduced into allocation of uplink and downlink subframes in wireless communication systems that support full-duplex and half-duplex mobile terminals, thus reducing interference between mobile terminals. In an exemplary method for allocating uplink and downlink timeslots in a wireless communication system supporting full-duplex and half-duplex mobile terminals, a base station determines that a mobile terminal is capable of only half-duplex operation and allocates one or more uplink subframes and one or more downlink subframes to the first mobile terminal, for each of a plurality of frames, so that none of the allocated uplink subframes overlaps in time with an allocated downlink subframe. The allocation of uplink subframes and downlink subframes is varied between consecutive ones in at least a first series of frames according to a pre-determined pattern. In some embodiments, the method further includes transmitting an allocation message to the first mobile terminal, designating the pre-determined pattern.

Claims

1. A method of allocating uplink and downlink timeslots in a wireless communication system supporting full-duplex and half-duplex mobile terminals, the method comprising:

determining that a first mobile terminal is capable of only half-duplex operation;

for each of a plurality of frames comprising two or more subframes that are independently allocable to one or more mobile terminals, allocating one or more uplink subframes and one or more downlink subframes to the first mobile terminal so that none of the allocated uplink subframes overlaps in time with any of the allocated downlink subframes; and

varying the allocation of uplink subframes and downlink subframes to the first mobile terminal between consecutive ones in at least a first series of frames according to a first pre-determined pattern.

2. The method of claim 1, further comprising transmitting to the first mobile terminal an allocation message designating the first pre-determined pattern.

3. The method of claim 2, wherein the allocation message designates one of a plurality of pre-determined patterns.

4. The method of claim 2, wherein the allocation message further indicates a starting position in the first pre-determined pattern.

5. The method of claim 2, further comprising transmitting to the first mobile terminal a second allocation message designating a second pre-determined pattern, and thereafter varying the allocation of uplink subframes and downlink subframes to the first mobile terminal between consecutive ones of a second series of frames according to the second pre-determined pattern.

6. The method of claim 5, further comprising receiving a status message from a second mobile terminal indicating excessive interference to a received signal at the second mobile terminal, wherein transmitting the second allocation message to the first mobile terminal is responsive to receiving the status message.

7. The method of claim 5, further comprising determining that interference at a second mobile terminal from the first mobile terminal is likely or has occurred, based on received signal quality reports, and transmitting the second allocation message responsive to said determining.

8. The method of claim 2, wherein the allocated one or more uplink subframes or the allocated one or more downlink subframes, but not both, remain fixed between consecutive ones of the first series of frames, according to the first pre-determined pattern.

9. The method of claim 1, further comprising, for each frame, allocating one or more uplink subframes and one or more downlink subframes to a second mobile terminal on a non-varying schedule.

10. The method of claim 9, wherein at least one of the uplink subframes allocated to the second mobile terminal overlaps in time with at least one of the downlink subframes allocated to the second mobile terminal.

11. A method of allocating uplink and downlink timeslots in a wireless communication system supporting full-duplex and half-duplex mobile terminals, the method comprising:

for each frame in a first series of frames, assigning a first fixed allotment of one or more uplink subframes and one or more downlink subframes to a first mobile terminal;

detecting that excessive interference in at least one of the allocated downlink subframes is likely or has occurred; and

responsive to said detecting, assigning a second fixed allotment of uplink and downlink subframes to the first mobile terminal for use in a second series of frames, wherein at least one allotted downlink subframe differs from the first fixed allotment.

12. The method of claim 11, wherein detecting that excessive interference in at least one of the allocated downlink subframes is likely or has occurred comprises receiving a message from the first mobile terminal indicating that excessive interference has occurred.

13. The method of claim 11, wherein detecting that excessive interference in at least one of the allocated downlink subframes is likely or has occurred is based on received signal quality reports from the first mobile terminal.

14. The method of claim 11, wherein detecting that excessive interference in at least one of the allocated downlink subframes is likely or has occurred comprises predicting that interference to the first mobile terminal from a second mobile terminal is likely by comparing one or more of scheduling information for the first and second mobile terminals, time alignment values for the first and second mobile terminals, and signal quality reports from the first mobile terminals.

15. The method of claim 11, further comprising transmitting first and second allocation messages to the first mobile terminal, the first and second allocation messages designating the first and second fixed allotments, respectively.

16. A base station for use in a wireless communication system supporting full-duplex and half-duplex mobile terminals, the base station comprising a control unit configured to:

determine that a first mobile terminal is capable of only half-duplex operation;

for each of a plurality of frames comprising two or more subframes that are independently allocable to one or more mobile terminals, allocate one or more uplink subframes and one or more downlink subframes to the first mobile terminal so that none of the allocated uplink subframes overlaps in time with any of the allocated downlink subframes; and

vary the allocation of uplink subframes and downlink subframes to the first mobile terminal between consecutive ones in a first series of frames according to a first pre-determined pattern.

17. The base station of claim 16, wherein the control unit is further configured to transmit to the first mobile terminal, via a base station transceiver section, an allocation message designating the first pre-determined pattern.

18. The base station of claim 17, wherein the allocation message designates one of a plurality of pre-determined patterns.

19. The base station of claim 17, wherein the allocation message further indicates a starting position in the first pre-determined pattern.

20. The base station of claim 17, wherein the control unit is further configured to transmit a second allocation message designating a second pre-determined pattern, and to thereafter vary the allocation of uplink subframes and downlink subframes to the first mobile terminal between consecutive ones of a second series of frames according to the second pre-determined pattern.

21. The base station of claim 20, wherein the control unit is configured to transmit the second allocation message responsive to receiving a status message from a second mobile terminal indicating excessive interference to a received signal at the second mobile terminal.

22. The base station of claim 20, wherein the control unit is further configured to determine that interference at a second mobile terminal from a second mobile terminal is likely or has occurred, based on received signal quality reports, and to transmit the second allocation message responsive to the determination that interference is likely or has occurred.

23. The base station of claim 16, wherein the control unit is further configured to allocate, for each frame, one or more uplink subframes and one or more downlink subframes to a second mobile terminal on a non-varying schedule.

24. The base station of claim 23, wherein at least one of the uplink subframes allocated to the second mobile terminal overlaps in time with at least one of the downlink subframes allocated to the second mobile terminal.

25. A base station for use in a wireless communication system supporting full-duplex and half-duplex mobile terminals, the base station comprising a control unit configured to:

for each frame in a first series of frames, assign a first fixed allotment of one or more uplink subframes and one or more downlink subframes to the first mobile terminal;

detect that excessive interference in at least one of the allocated downlink subframes is likely or has occurred; and

responsive to said detection, assign a second fixed allotment of uplink and downlink subframes to the first mobile terminal for use in a second series of frames, wherein at least one allotted downlink subframe differs from the first fixed allotment.

26. The base station of claim 25, wherein the control unit is configured to detect that excessive interference in at least one of the allocated downlink subframes is likely or has occurred by receiving a message from the first mobile terminal indicating that excessive interference has occurred.

27. The base station of claim 25, wherein the control unit is configured to detect that excessive interference in at least one of the allocated downlink subframes is likely or has occurred based on received signal quality reports from the first mobile terminal.

28. The base station of claim 25, wherein the control unit is configured to detect that excessive interference in at least one of the allocated downlink subframes is likely or has occurred by predicting that interference to the first mobile terminal from a second mobile terminal is likely by comparing one or more of scheduling information for the first and second mobile terminals, time alignment values for the first and second mobile terminals, and signal quality reports from the first mobile terminals.

29. The base station of claim 25, further comprising transmitting first and second allocation messages to the mobile terminal, the first and second allocation messages designating the first and second fixed allotments, respectively.

30. A method for controlling a half-duplex mobile terminal for use in a wireless communication system supporting full-duplex and half-duplex mobile terminals, the method comprising:

receiving a first allocation message from a serving base station, the first allocation message designating an allotment of uplink and downlink subframes within each of one or more frames; and

switching a transceiver section of the mobile terminal to a receive mode for each of the allotted downlink subframes and to a transmit mode for one or more of the allotted uplink subframes.

31. The method of claim 30, wherein the allocation message designates a first pre-determined pattern for varying the allotment of uplink and downlink subframes between consecutive ones in a first series of frames, and wherein switching the transceiver section comprises switching the transceiver section between the receive and transmit modes according to the first pre-determined pattern.

32. The method of claim 30, further comprising:

detecting excessive interference in one or more of the allotted downlink subframes;

transmitting a status message to the serving base station, the status message indicating that excessive interference was detected;

receiving a second allocation message from the serving base station; and

switching the transceiver section according to the second allocation message.

33. A mobile terminal for use in a wireless communication system supporting full-duplex and half-duplex mobile terminals, the mobile terminal comprising a half-duplex transceiver section and a control section configured to:

receive a first allocation message from a serving base station, the first allocation message designating an allotment of uplink and downlink subframes within each of one or more frames; and

switch the transceiver section to a receive mode for each of the allotted downlink subframes and to a transmit mode for one or more of the allotted uplink subframes.

34. The mobile terminal of claim 33, wherein the allocation message designates a first pre-determined pattern for varying the allotment of uplink and downlink subframes between consecutive ones in a first series of frames, and wherein the control section is configured to switch the transceiver section between the receive and transmit modes according to the first pre-determined pattern.

35. The mobile terminal of claim 33, wherein the control section is further configured to:

detect excessive interference in one or more of the allotted downlink subframes;

transmit a status message to the serving base station, via the transceiver section, the status message indicating that excessive interference was detected;

receive a second allocation message from the serving base station; and

switch the transceiver section according to the second allocation message.