BLANK SUBFRAME UPLINK DESIGN

• US 20100135235A1
• Filed: 11/25/2009
• Published: 06/03/2010
• Est. Priority Date: 12/01/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gaal, Peter, Ji, Tingfang
• Granted Patent: US 8,879,461 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access
• CPC Class Codes: H04W 84/047 using dedicated repeater stations

Abstract

Blank subframe link design uses reduced bandwidth either explicit or derived for Closed Subscriber Group (CSG) cell interference mitigation, enabling a non-allowed User Equipment (UE) to co-exist with CSG cells on the same carrier. One could specify UL blank subframes to orthogonalize non-allowed UE and allowed UE transmissions on UL either via explicit UL blank subframe definition or derived from DL blank subframe definition. Scheduling can orthogonalize data transmissions. A femto cell temporarily reducing uplink bandwidth can mitigate uplink control channel residual interference from a non-allowed UE. A relay configures RACH occasion to coincide with non-blank UL subframes as much as possible. UE knowledge of RACH occasion is sufficient to start RACH and hand over procedure. RACH occasions with 10 ms periodicity are supported by assigning all odd/even uplink HARQ interlaces to relay. RACH occasions with 20 ms periodicity are supported by assigning any of the 1/4 UL HARQ interlaces to relay.

Claims

1. A method for interference mitigation in a wireless communication system, the method comprising:

determining a half duplex schedule of performing non-simultaneous receiving and transmitting by a relay with an access node;

determining a physical random access channel configuration having a random access channel occasion that coincides with the half duplex schedule; and

performing a random access channel procedure with the access node via the relay by using the physical random access channel configuration.

2. The method of claim 1, further comprising determining a subframe occasion with a periodicity of 10 ms.

3. The method of claim 2, further comprising assigning a selected one of odd and even Hybrid Automatic Repeat Request (HARQ) interlaces to transmit to the relay according to the half duplex schedule.

4. The method of claim 1, further comprising determining a subframe occasion with a periodicity of 20 ms.

5. The method of claim 4, further comprising assigning one of four uplink HARQ interlaces to transmit to the relay.

6. A computer program product for interference mitigation in a wireless communication system, the computer program product comprising:

at least one computer readable storage medium storing computer executable instructions that, when executed by at least one processor, implement components comprising;

a first set of codes for determining a half duplex schedule of performing non-simultaneous receiving and transmitting by a relay with an access node;

a second set of codes for determining a physical random access channel configuration having a random access channel occasion that coincides with the half duplex schedule; and

a third set of codes for performing a random access channel procedure with the access node via the relay by using the physical random access channel configuration.

7. An apparatus for interference mitigation in a wireless communication system, the apparatus comprising:

at least one processor;

at least one computer readable storage medium storing computer executable instructions that, when executed by the at least one processor, implement components comprising;

means for determining a half duplex schedule of performing non-simultaneous receiving and transmitting by a relay with an access node;

means for determining a physical random access channel configuration having a random access channel occasion that coincides with the half duplex schedule; and

means for performing a random access channel procedure with the access node via the relay by using the physical random access channel configuration.

8. An apparatus for interference mitigation in a wireless communication system, the apparatus comprising:

a computing platform for determining a half duplex schedule of performing non-simultaneous receiving and transmitting by a relay with an access node and for determining a physical random access channel configuration having a random access channel occasion that coincides with the half duplex schedule; and

a transmitter and a receiver for performing a random access channel procedure with the access node via the relay by using the physical random access channel configuration.

9. The apparatus of claim 8, wherein the computing platform is further for determining a subframe occasion with a periodicity of 10 ms.

10. The apparatus of claim 9, wherein the computing platform is further for assigning a selected one of odd and even Hybrid Automatic Repeat Request (HARQ) interlaces to transmit to the relay according to the half duplex schedule.

11. The apparatus of claim 8, wherein the computing platform is further for determining a subframe occasion with a periodicity of 20 ms.

12. The apparatus of claim 11, wherein the computing platform is further for assigning one of four uplink HARQ interlaces to transmit to the relay.

13. A method for interference mitigation in a wireless communication system, the method comprising:

scheduling a user equipment to use an uplink having a first bandwidth;

defining a band edge portion of the first bandwidth that includes an interference signal;

scheduling a reduced portion of an uplink bandwidth to the user equipment that avoids the band edge portion; and

receiving the reduced portion of the uplink bandwidth by filtering out the band edge portion.

14. The method of claim 13, further comprising mitigating interference between the user equipment that is being served and a second user equipment by,

accessing a downlink frame structure including a plurality of downlink subframes that have a portion that is blank;

and

determining an uplink frame structure including a plurality of uplink subframes that have a potion that is blank.

15. The method of claim 14, further comprising determining the uplink frame structure by accessing an explicit uplink subframe definition.

16. The method of claim 14, further comprising deriving the uplink frame structure.

17. The method of claim 13, further comprising restoring the uplink to use the first bandwidth in response to detecting an absence the interference signal.

18. The method of claim 13, further comprising:

scheduling the user equipment to transmit an uplink control channel in the uplink using the first bandwidth; and

rescheduling the user equipment to transmit the uplink control channel in the reduced portion of the uplink.

19. The method of claim 18, further comprising authenticating the user equipment on a closed subscription group cell.

20. The method of claim 19, further comprising managing the closed subscription group cell by a femto cell.

21. The method of claim 13, further comprising filtering out the band edge portion by,

analog to digital sampling of a received signal sufficient to separate the band edge portion from the reduced portion;

and

changing digital filter coefficients to attenuate the band edge portion.

22. The method of claim 13, further comprising analog filtering out the band edge portion.

23. A computer program product for interference mitigation in a wireless communication system, the computer program product comprising:

at least one computer readable storage medium storing computer executable instructions that, when executed by at least one processor, implement components comprising;

a first set of codes for scheduling a user equipment to use an uplink having a first bandwidth;

a second set of codes for defining a band edge portion of the first bandwidth that includes an interference signal;

a third set of codes for scheduling a reduced portion of an uplink bandwidth to the user equipment that avoids the band edge portion; and

a fourth set of codes for receiving the reduced portion of the uplink bandwidth by filtering out the band edge portion.

24. An apparatus for interference mitigation in a wireless communication system, the apparatus comprising:

at least one processor;

at least one computer readable storage medium storing computer executable instructions that, when executed by the at least one processor, implement components comprising;

means for scheduling a user equipment to use an uplink having a first bandwidth;

means for defining a band edge portion of the first bandwidth that includes an interference signal;

means for scheduling a reduced portion of an uplink bandwidth to the user equipment that avoids the band edge portion; and

means for receiving the reduced portion of the uplink bandwidth by filtering out the band edge portion.

25. An apparatus for interference mitigation in a wireless communication system, the apparatus comprising:

a transmitter;

a scheduler for scheduling a user equipment via the transmitter to use an uplink having a first bandwidth;

a computing platform for defining a band edge portion of the first bandwidth that includes an interference signal;

the scheduler further for scheduling a reduced portion of an uplink bandwidth via the transmitter to the user equipment that avoids the band edge portion; and

a receiver for receiving the reduced portion of the uplink bandwidth by filtering out the band edge portion.

26. The apparatus of claim 25, further comprising mitigating interference between the user equipment that is being served and a second user equipment wherein the computing platform is further for accessing a downlink frame structure including a plurality of downlink subframes that have a portion that is blank, and for determining an uplink frame structure including a plurality of uplink subframes that have a potion that is blank.

27. The apparatus of claim 26, wherein the computing platform is further for determining the uplink frame structure by accessing an explicit uplink subframe definition.

28. The apparatus of claim 26, wherein the computing platform is further for deriving the uplink frame structure.

29. The apparatus of claim 25, wherein the computing platform is further for restoring the uplink to use the first bandwidth in response to detecting an absence the interference signal.

30. The apparatus of claim 25, wherein the scheduler is further for scheduling the user equipment to transmit an uplink control channel in the uplink using the first bandwidth, and for rescheduling the user equipment to transmit the uplink control channel in the reduced portion of the uplink.

31. The apparatus of claim 30, wherein the computing platform is further for authenticating the user equipment on a closed subscription group cell.

32. The apparatus of claim 31, further comprising a femto cell for managing the closed subscription group cell.

33. The apparatus of claim 25, wherein the receiver is further for filtering out the band edge portion by,

analog to digital sampling of a received signal sufficient to separate the band edge portion from the reduced portion;

and

changing digital filter coefficients to attenuate the band edge portion.

34. The apparatus of claim 25, wherein the receiver is further for analog filtering out the band edge portion.