Blank subframe uplink design

• US 9,125,217 B2
• Filed: 09/18/2014
• Issued: 09/01/2015
• Est. Priority Date: 12/01/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gaal, Peter, Ji, Tingfang
• Primary Examiner(s): Patel, Jay P
• Application Number:
  US14/490,191
• Publication Number:
  US 20150003399A1
• Time in Patent Office: 348 Days
• US Class Current: 1/1
• 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 ¼ UL HARQ interlaces to relay.

Claims

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

advertising an uplink bandwidth;

identifying that a band edge portion of the uplink bandwidth includes an interfering signal of an interfering user equipment (UE);

scheduling a served UE to use a reduced uplink bandwidth that avoids the band edge portion based on the identifying;

receiving a transmission from the served UE in the reduced uplink bandwidth; and

filtering out the band edge portion.

2. The method of claim 1, further comprising scheduling the served UE to use the advertised uplink bandwidth in response to detecting an absence of the interfering signal.

3. The method of claim 1, wherein scheduling the served UE to use the reduced uplink bandwidth comprises scheduling the served UE to transmit the uplink control channel closer to the center of the advertised bandwidth.

4. The method of claim 1, further comprising determining there are no uplink (UL) blank subframes defined, wherein the UL blank subframes are subframes to orthogonalize transmissions on a UL by interfering UEs and served UEs.

5. The method of claim 4, wherein the determining comprises:

accessing a downlink frame structure, the downlink frame structure being capable of identifying a plurality of downlink subframes that have a blank portion; and

determining an uplink frame structure based on the downlink frame structure.

6. The method of claim 4, wherein the determining comprises accessing an explicit uplink subframe definition.

7. The method of claim 4, wherein the determining comprises deriving the uplink subframe definition.

8. The method of claim 1, further comprising authenticating the served UE on a closed subscription group cell.

9. The method of claim 1, wherein the filtering comprises:

performing 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.

10. The method of claim 1, wherein the filtering comprises analog filtering.

11. A non-transitory computer readable medium comprising code for causing at least one processor to:

advertise an uplink bandwidth;

identify that a band edge portion of the uplink bandwidth includes an interfering signal of an interfering user equipment (UE);

schedule a served UE to use a reduced uplink bandwidth that avoids the band edge portion based on the identifying;

receive a transmission from the served UE in the reduced uplink bandwidth; and

filter out the band edge portion.

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

means for advertising an uplink bandwidth;

means for identifying that a band edge portion of the uplink bandwidth includes an interfering signal of an interfering user equipment (UE);

means for scheduling a served UE to use a reduced uplink bandwidth that avoids the band edge portion based on the identifying;

means for receiving a transmission from the served UE in the reduced uplink bandwidth; and

means for filtering out the band edge portion.

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

a transmitter;

a scheduler for scheduling a served user equipment (UE) via the transmitter to use an uplink having an uplink bandwidth in a frame;

a computing platform for;

advertising the uplink bandwidth;

identifying that a band edge portion of the uplink bandwidth includes an interfering signal of an interfering UE;

the scheduler further for scheduling the served UE to use a reduced uplink bandwidth that avoids the band edge portion based on the identifying; and

a receiver for;

receiving a transmission from the served UE in the reduced uplink bandwidth, and

filtering out the band edge portion.

14. The apparatus of claim 13, wherein the scheduler is further for scheduling the served UE to use the advertised uplink bandwidth in response to detecting an absence of the interfering signal.

15. The apparatus of claim 13, wherein the scheduling the served UE to use the reduced uplink bandwidth comprises scheduling the served UE to transmit the uplink control channel closer to the center of the advertised bandwidth.

16. The apparatus of claim 13, wherein the computing platform is further for determining there are no uplink (UL) blank subframes defined, wherein the UL blank subframes are subframes to orthogonalize transmissions on a UL by interfering UEs and served UEs.

17. The apparatus of claim 16, wherein the determining comprises:

accessing a downlink frame structure, the downlink frame structure being capable of identifying a plurality of downlink subframes that have a blank portion; and

determining an uplink frame structure based on the downlink frame structure.

18. The apparatus of claim 16, wherein the determining comprises accessing an explicit uplink subframe definition.

19. The apparatus of claim 16, wherein the determining comprises deriving the uplink subframe definition.

20. The apparatus of claim 13, wherein the computing platform is further for authenticating the served UE on a closed subscription group cell.

21. The apparatus of claim 13, wherein the filtering comprises,

performing 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 apparatus of claim 13, wherein the filtering comprises analog filtering.