Channel state information feedback

• US 9,325,469 B2
• Filed: 12/01/2014
• Issued: 04/26/2016
• Est. Priority Date: 12/05/2011
• Status: Active Grant

• Current Assignee: Comcast Cable Communications LLC (Comcast Corporation)
• Original Assignee: Ofinno Technologies, LLC (Ofinno, LLC)
• Inventors: Dinan, Esmael Hejazi
• Primary Examiner(s): Renner, Brandon
• Assistant Examiner(s): Preval, Voster
• Application Number:
  US14/556,314
• Publication Number:
  US 20150085806A1
• Time in Patent Office: 512 Days
• Field of Search: 370/329, 370/252
• US Class Current: 1/1
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

A wireless device receives a first reference signal from a first base station and estimates a first signal strength based on the received first reference signal. The wireless device receives a second reference signal from a second base station and estimates a second signal strength based on the received second reference signal. The wireless device estimates an interference value based, at least in part, on the second reference signal. The wireless device estimates a signal to interference ratio value based on the second signal strength and a total interference value. The total interference value is computed based upon the interference value or the interference value plus the first signal strength.

Claims

1. A method comprising:

a) receiving, by a wireless device, a first reference signal from a first base station on a first plurality of OFDM resources in a first subframe in a plurality of subframes, said first plurality of OFDM resources depending at least in part on a first base station identifier of said first base station;

b) estimating, by said wireless device, a first signal strength corresponding to said first base station based on said received first reference signal;

c) receiving, by said wireless device, a second reference signal from a second base station, on a second plurality of OFDM resources in said first subframe, said second plurality of OFDM resources depending at least in part on a second base station identifier of said second base station;

d) estimating, by said wireless device, a second signal strength corresponding to said second base station based on said received second reference signal;

e) estimating, by said wireless device, an interference value on said second plurality of OFDM resources based at least in part on said second reference signal; and

f) calculating, by said wireless device, a signal to interference ratio value based on said second signal strength and a total interference value, wherein;

i) if said first plurality of OFDM resources overlap with said second plurality of OFDM resources, said total interference value is computed based upon said interference value; and

ii) if said first plurality of OFDM resources do not overlap with said second plurality of OFDM resources, said total interference value is computed based upon said interference value plus said first signal strength.

2. The method of claim 1, wherein radio signals are received from said first base station at a higher power than radio signals received from said second base station.

3. The method of claim 1, wherein said second base station transmits radio signals at a higher power than said first base station.

4. The method of claims 1, wherein said first base station type is one of the following:

a) a macro base station type;

b) a pico base station type;

c) a femto base station type with open access; and

d) a femto base station type with close subscriber group access.

5. The method of claim 1, wherein said second base station type is one of the following:

a) a macro base station type;

b) a pico base station type;

c) a femto base station type with open access; and

d) a femto base station type with close subscriber group access.

6. The method of claim 1, wherein said first reference signal is one of the following:

a) a common reference signal; and

b) a channel state information reference signal.

7. The method of claim 1, wherein said second reference signal is one of the following:

a) a common reference signal; and

b) a channel state information reference signal.

8. The method of claim 1, wherein said first signal strength is represented by one of the following:

a) a short term signal strength value obtained from a most recent observation; and

b) a long term signal strength value obtained by averaging a plurality of recent observations.

9. The method of claim 1, wherein said second signal strength is represented by one of the following:

a) a short term signal strength value obtained from a most recent observation; and

b) a long term signal strength value obtained by averaging a plurality of recent observations.

10. The method of claim 1, wherein said interference value is one of the following:

a) a short term interference value obtained from a most recent observation; and

b) a long term interference value obtained by averaging a plurality of recent observations.

11. A method comprising:

a) receiving, by a wireless device, a first reference signal from a first base station on a first plurality of OFDM resources in a first subframe in a plurality of subframes, said first plurality of OFDM resources depending at least in part on a first base station identifier of said first base station;

b) estimating, by said wireless device, a first signal strength corresponding to said first base station based on said received first reference signal;

c) receiving, by said wireless device, a second reference signal from a second base station, on a second plurality of OFDM resources in said first subframe, said second plurality of OFDM resources depending at least in part on a second base station identifier of said second base station;

d) estimating, by said wireless device, a second signal strength corresponding to said second base station based on said received second reference signal;

e) estimating, by said wireless device, an interference value on said second plurality of OFDM resources based at least in part on said second reference signal; and

f) calculating, by said wireless device, a signal to interference ratio value based on said second signal strength and a total interference value, wherein;

i) if said first plurality of OFDM resources do not overlap with said second plurality of OFDM resources, said total interference value is computed based upon said interference value; and

ii) if said first plurality of OFDM resources overlap with said second plurality of OFDM resources, said total interference value is computed based upon said interference value minus said first signal strength.

12. The method of claim 11, wherein radio signals are received from said first base station at a higher power than radio signals received from said second base station.

13. The method of claim 11, wherein said second base station transmits radio signals at a higher power than said first base station.

14. The method of claim 11, wherein said first base station type is one of the following:

a) a macro base station type;

b) a pico base station type;

c) a femto base station type with open access; and

d) a femto base station type with close subscriber group access.

15. The method of claim 11, wherein said first reference signal is one of the following:

a) a common reference signal; and

b) a channel state information reference signal.

16. The method of claim 11, wherein said second reference signal is one of the following:

a) a common reference signal; and

b) a channel state information reference signal.

17. A wireless device comprising:

a) one or more communication interfaces;

b) one or more processors; and

c) memory storing instructions that, when executed, cause the wireless device to;

i) receive a first reference signal from a first base station on a first plurality of OFDM resources in a first subframe in a plurality of subframes, said first plurality of OFDM resources depending at least in part on a first base station identifier of said first base station;

ii) estimate a first signal strength corresponding to said first base station based on said received first reference signal;

iii) receive a second reference signal from a second base station, on a second plurality of OFDM resources in said first subframe, said second plurality of OFDM resources depending at least in part on a second base station identifier of said second base station;

iv) estimate a second signal strength corresponding to said second base station based on said received second reference signal;

v) estimate an interference value on said second plurality of OFDM resources based at least in part on said second reference signal; and

vi) calculate a signal to interference ratio value based on said second signal strength and a total interference value, wherein;

(1) if said first plurality of OFDM resources overlap with said second plurality of OFDM resources, said total interference value is computed based upon said interference value; and

(2) if said first plurality of OFDM resources do not overlap with said second plurality of OFDM resources, said total interference value is computed based upon said interference value plus said first signal strength.

18. The wireless device of claim 17, wherein said first signal strength is represented by one of the following:

a) a short term signal strength value obtained from a most recent observation; and

b) a long term signal strength value obtained by averaging a plurality of recent observations.

19. The wireless device of claim 17, wherein said second signal strength is represented one of the following:

a) a short term signal strength value obtained from a most recent observation; and

b) a long term signal strength value obtained by averaging a plurality of recent observations.

20. The wireless device of claim 17, wherein said interference value is one of the following:

a) a short term interference value obtained from a most recent observation; and

b) a long term interference value obtained by averaging a plurality of recent observations.