Almost blank subframe configuration in wireless networks

1. A method comprising comprising:

broadcasting first parameters identifying a first set of subframes on a primary carrier as almost blank subframes; and

transmitting to a wireless device at least one unicast control message comprising:

second parameters identifying a second set of subframes on a secondary carrier as almost blank subframes; and

at least one cross carrier scheduling parameter indicating that the primary carrier carries scheduling information for packets transmitted to the wireless device on a data channel of the secondary carrier; and

wherein, during the time the cross carrier scheduling is configured and the secondary carrier is activated, when the primary carrier enters an almost blank subframe, the secondary carrier also enters an almost blank subframe.

2. The method of claim 1 , wherein the at least one unicast control message further comprises:

a first measurement subframe allocation bitmap identifying a first plurality of measurement subframes of the secondary carrier; and

a second measurement subframe allocation bitmap identifying a second plurality of measurement subframes of the secondary carrier.

3. The method of claim 2 , further comprising receiving first channel state information (CSI) and second CSI from the wireless device, the first CSI being measured on a first plurality of OFDM subcarriers of the secondary carrier on the first plurality of measurement subframes, the second CSI being measured on a second plurality of OFDM subcarriers of the secondary carrier on the second plurality of measurement subframes.

4. The method of claim 3 , wherein the at least one unicast control message further comprises:

one or more third parameters identifying a CSI transmission resource;

one or more CSI measurement resource parameters; and

one or more fourth parameters identifying a physical uplink control channel format.

5. The method of claim 3 , further comprising transmitting a plurality of data packets to the wireless device on the secondary carrier, the plurality of data packets being encoded and modulated based, at least in part, on one of the first and second CSI.

6. The method of claim 3 , wherein:

the first plurality of measurement subframes exclude the second set of almost blank subframes on the secondary carrier; and

the second plurality of measurement subframes exclude subframes in the first plurality of measurement subframes.

7. The method of claim 1 , wherein in an almost blank subframe of the base station:

no signal is transmitted by the base station; or

signals are transmitted at an almost blank subframe power level that is substantially lower than a transmit power during a non-almost blank subframe.

8. The method of claim 1 , further comprising transmitting, in an almost blank subframe, a common reference signal only in a control region of the almost blank subframe.

9. The method of claim 1 , wherein the at least one unicast control message further comprises at least one measurement subframe parameter of a plurality neighboring carriers.

10. The method of claim 1 , wherein the at least one unicast control message further comprises:

a first measurement subframe allocation bitmap identifying a first plurality of measurement subframes of the secondary carrier, the first plurality of measurement subframes excluding the second set of almost blank subframes on the secondary carrier;

a second measurement subframe allocation bitmap identifying a second plurality of measurement subframes of the secondary carrier, the second plurality of measurement subframes excluding subframes in the first plurality of measurement subframes.

11. A method comprising:

receiving from a base station a broadcast message comprising first parameters identifying a first set of subframes on a primary carrier as almost blank subframes; and

receiving from the base station at least one unicast control message comprising:

second parameters identifying a second set of subframes on a secondary carrier as almost blank subframes; and

at least one cross carrier scheduling parameter indicating that the primary carrier carries scheduling information for packets received from the base station on a data channel of the secondary carrier; and

wherein, during the time the cross carrier scheduling is configured and the secondary carrier is activated, when the primary carrier enters an almost blank subframe, the secondary carrier also enters an almost blank subframe.

12. The method of claim 11 , wherein the at least one unicast control message further comprises:

a first measurement subframe allocation bitmap identifying a first plurality of measurement subframes of the secondary carrier; and

a second measurement subframe allocation bitmap identifying a second plurality of measurement subframes of the secondary carrier.

13. The method of claim 12 , further comprising receiving first channel state information (CSI) and second CSI, the first CSI being measured on a first plurality of OFDM subcarriers of the secondary carrier on the first plurality of measurement subframes, the second CSI being measured on a second plurality of OFDM subcarriers of the secondary carrier on the second plurality of measurement subframes.

14. The method of claim 13 , wherein the at least one unicast control message further comprises:

one or more third parameters identifying a CSI transmission resource;

one or more CSI measurement resource parameters; and

one or more fourth parameters identifying a physical uplink control channel format.

15. The method of claim 13 , further comprising receiving a plurality of data packets from the base station on the secondary carrier, the plurality of data packets being encoded and modulated based, at least in part, on one of the first and second CSI.

16. The method of claim 13 , wherein:

the first plurality of measurement subframes exclude the second set of almost blank subframes on the secondary carrier; and

the second plurality of measurement subframes exclude subframes in the first plurality of measurement subframes.

17. The method of claim 11 , wherein in an almost blank subframes of the base station:

no signal is transmitted by the base station; or

signals are transmitted by the base station at an almost blank subframe power level that is substantially lower than a transmit power during a non-almost blank subframe.

18. The method of claim 11 , wherein the instructions, when executed, further cause the wireless device to receive, in an almost blank subframe, a common reference signal only in a control region of the almost blank subframe.

19. The method of claim 11 , wherein the at least one unicast control message further comprises at least one measurement subframe parameter of a plurality neighboring carriers.

20. The method of claim 11 , wherein the at least one unicast control message further comprises:

a first measurement subframe allocation bitmap identifying a first plurality of measurement subframes of the secondary carrier, the first plurality of measurement subframes excluding the second set of almost blank subframes on the secondary carrier;

a second measurement subframe allocation bitmap identifying a second plurality of measurement subframes of the secondary carrier, the second plurality of measurement subframes excluding subframes in the first plurality of measurement subframes.