Control channel in a wireless communication system

• US 9,949,265 B2
• Filed: 05/06/2013
• Issued: 04/17/2018
• Est. Priority Date: 05/04/2012
• Status: Active Grant

• Current Assignee: Comcast Cable Communications LLC (Comcast Corporation)
• Original Assignee: Comcast Cable Communications LLC (Comcast Corporation)
• Inventors: Dinan, Esmael Hejazi
• Primary Examiner(s): Kassim, Khaled
• Assistant Examiner(s): BELETE, BERHANU D
• Application Number:
  US13/887,408
• Publication Number:
  US 20130294369A1
• Time in Patent Office: 1,807 Days
• Field of Search: 370329, 370224, 370260
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 72/0466 the resource being a scrambling code

Abstract

A base station receives channel state information from a wireless device. The base station transmits to the wireless device one or more data packets on a data channel employing a first precoding matrix identifier. The base station transmits one or more control packets on a control channel to the wireless device employing a second precoding matrix.

Claims

1. A method comprising:

receiving, by a base station and from a wireless device, first channel state information (CSI) comprising a first precoding matrix indicator;

determining, by the base station and based at least in part on the first precoding matrix indicator, a first precoding matrix for transmission of a downlink data channel to the wireless device;

determining, by the base station and based at least in part on the first precoding matrix indicator, a second precoding matrix for transmission of a downlink control channel to the wireless device, wherein the second precoding matrix is different from the first precoding matrix, and wherein the downlink control channel is associated with the downlink data channel;

transmitting, to the wireless device and in a subframe, the downlink data channel using the first precoding matrix and transmitting at least one first reference signal associated with the downlink data channel; and

transmitting, to the wireless device and in the subframe, the downlink control channel using the second precoding matrix and transmitting at least one second reference signal associated with the downlink control channel.

2. The method of claim 1, wherein:

the transmitting the downlink data channel comprises transmitting the downlink data channel via a first plurality of orthogonal frequency division multiplexed (OFDM) subcarriers, and

the transmitting the downlink control channel comprises transmitting the downlink control channel via a second plurality of OFDM subcarriers that is different from the first plurality of OFDM subcarriers.

3. The method of claim 2, further comprising transmitting one or more control packets to a second wireless device via a third plurality of OFDM subcarriers of the subframe.

4. The method of claim 1, wherein the transmitting the at least one second reference signal associated with the downlink control channel employs a smaller number of antenna ports than the transmitting the at least one first reference signal associated with the downlink data channel.

5. The method of claim 1, wherein the second precoding matrix employs a smaller number of multiple-input-multiple-output (MIMO) layers than the first precoding matrix.

6. The method of claim 1, wherein the second precoding matrix is a column vector.

7. The method of claim 1, wherein the at least one second reference signal associated with the downlink control channel comprises at least two orthogonal reference signals.

8. The method of claim 1, further comprising transmitting, via the downlink control channel and employing multiple user multiple-input-multiple-output (MIMO), one or more control packets.

9. The method of claim 1, wherein the second precoding matrix is a submatrix of the first precoding matrix.

10. The method of claim 1, wherein the second precoding matrix is based, at least in part, on a linear transformation on a subset of rows and columns of the first precoding matrix.

11. The method of claim 1, wherein the first CSI further comprises one or more of a channel quality indicator (CQI) or a rank indicator (RI).

12. A base station comprising:

one or more processors; and

memory storing instructions that, when executed, cause the base station to;

receive, from a wireless device, first channel state information comprising a first precoding matrix indicator;

determine, based at least in part on the first precoding matrix indicator, a second precoding matrix for transmission of a downlink control channel to the wireless device, wherein the second precoding matrix is different from a first precoding matrix indicated by the first precoding matrix indicator;

transmit, to the wireless device, in a subframe, and employing the first precoding matrix, one or more data packets via a downlink data channel and transmit at least one first reference signal associated with the downlink data channel; and

transmit, to the wireless device, in the subframe, and employing the second precoding matrix, one or more control packets via the downlink control channel and transmit at least one second reference signal associated with the downlink control channel, wherein the downlink control channel carries scheduling information for the downlink data channel.

13. The base station of claim 12, wherein the instructions, when executed, cause the base station to transmit, via the downlink control channel and employing multiple user multiple-input-multiple-output (MIMO), the one or more control packets.

14. The base station of claim 12, wherein the second precoding matrix has a smaller number of columns than the first precoding matrix.

15. The base station of claim 12, wherein the second precoding matrix employs a smaller number of multiple-input-multiple-output (MIMO) layers than the first precoding matrix.

16. The base station of claim 12, wherein the second precoding matrix is a submatrix of the first precoding matrix.

17. A method comprising:

transmitting, by a wireless device and to a base station, first channel state information (CSI) comprising a first precoding matrix indicator;

receiving, by the wireless device, at least one first demodulation reference signal corresponding to a downlink data channel that is precoded using a first precoding matrix indicated by the first precoding matrix indicator;

receiving, by the wireless device, at least one second demodulation reference signal corresponding to a downlink control channel that is associated with the downlink data channel and that is precoded using a second precoding matrix that is based, at least in part, on the first precoding matrix indicator;

receiving, by the wireless device and from the base station, in a subframe, the downlink data channel; and

receiving, by the wireless device and from the base station, in the subframe, the downlink control channel.

18. The method of claim 17, wherein:

the receiving the downlink data channel comprises receiving the downlink data channel via a first plurality of orthogonal frequency division multiplexed (OFDM) subcarriers, and

the receiving the downlink control channel comprises receiving the downlink control channel via a second plurality OFDM subcarriers that is different from the first plurality of OFDM subcarriers.

19. The method of claim 17, wherein the at least one second demodulation reference signal comprises at least two orthogonal reference signals.

20. The method of claim 17, wherein the second precoding matrix employs a smaller number of multiple-input-multiple-output (MIMO) layers than the first precoding matrix.

21. The method of claim 17, wherein the second precoding matrix is a column vector.

22. The method of claim 17, further comprising receiving one or more control packets that were transmitted employing multi-user multiple-input-multiple-output (MIMO) in the downlink control channel.

23. The method of claim 17, wherein the first CSI further comprises one or more of a channel quality indicator (CQI) or a rank indicator (RI).

24. The method of claim 17, wherein the second precoding matrix is a submatrix of the first precoding matrix.

25. A wireless device comprising:

one or more processors; and

memory storing instructions that, when executed by the one or more processors, cause the wireless device to;

transmit, by the wireless device and to a base station, first channel state information (CSI) comprising a first precoding matrix indicator;

receive, by the wireless device, at least one first demodulation reference signal corresponding to a downlink data channel that is precoded using a first precoding matrix indicated by the first precoding matrix indicator;

receive, by the wireless device, at least one second demodulation reference signal corresponding to a downlink control channel that is associated with the downlink data channel and that is precoded using a second precoding matrix that is based, at least in part, on the first precoding matrix indicator;

receive, by the wireless device and from the base station, in a subframe, the downlink data channel; and

receive, by the wireless device and from the base station, in the subframe, the downlink control channel.

26. The wireless device of claim 25, wherein the instructions that, when executed by the one or more processors, cause the wireless device to receive the downlink data channel further cause the wireless device to receive the downlink data channel via a first plurality of orthogonal frequency division multiplexed (OFDM) subcarriers;

and

wherein the instructions that, when executed by the one or more processors, cause the wireless device to receive the downlink control channel further cause the wireless device to receive the downlink control channel via a second plurality of OFDM subcarriers different from the first plurality of OFDM subcarriers.

27. The wireless device of claim 25, wherein the at least one second demodulation reference signal comprises at least two orthogonal reference signals.

28. The wireless device of claim 25, wherein the second precoding matrix employs a smaller number of multiple-input-multiple-output (MIMO) layers than the first precoding matrix.

29. The wireless device of claim 25, wherein the second precoding matrix is a column vector.

30. The wireless device of claim 25, wherein the instructions further comprise instructions that, when executed by the one or more processors, cause the wireless device to receive one or more control packets that were transmitted employing multi-user multiple-input-multiple-output (MIMO) in the downlink control channel.

31. The wireless device of claim 25, wherein the first CSI further comprises one or more of a channel quality indicator (CQI) or a rank indicator (RI).

32. The wireless device of claim 25, wherein the second precoding matrix is a submatrix of the first precoding matrix.

33. A base station comprising:

one or more processors; and

memory storing instructions that, when executed, cause the base station to;

receive, from a wireless device, first channel state information (CSI) comprising a first precoding matrix indicator;

determine, based at least in part on the first precoding matrix indicator, a first precoding matrix for transmission of a downlink data channel to the wireless device;

determine, based at least in part on the first precoding matrix indicator, a second precoding matrix for transmission of a downlink control channel to the wireless device, wherein the second precoding matrix is different from the first precoding matrix, and wherein the downlink control channel is associated with the downlink data channel;

transmit, to the wireless device and in a subframe, the downlink data channel using the first precoding matrix and transmit at least one first reference signal associated with the downlink data channel; and

transmit, to the wireless device and in the subframe, the downlink control channel using the second precoding matrix and transmit at least one second reference signal associated with the downlink control channel.

34. The base station of claim 33, wherein the instructions that, when executed, cause the base station to transmit the downlink data channel further cause the base station to transmit the downlink data channel via a first plurality of orthogonal frequency division multiplexed (OFDM) subcarriers;

and

wherein the instructions that, when executed, cause the base station to transmit the downlink control channel further cause the base station to transmit the downlink control channel via a second plurality of OFDM subcarriers, different from the first plurality of OFDM subcarriers.

35. The base station of claim 34, wherein the instructions that, when executed, cause the base station to transmit the at least one second reference signal associated with the downlink control channel further cause the base station to transmit the least one second reference signal employing a smaller number of antenna ports than the at least one first reference signal associated with the downlink data channel.

36. The base station of claim 34, wherein the memory further stores instructions that, when executed, cause the base station to transmit one or more control packets to a second wireless device via a third plurality of OFDM subcarriers of the subframe.

37. The base station of claim 33, wherein the second precoding matrix employs a smaller number of multiple-input-multiple-output (MIMO) layers than the first precoding matrix.

38. The base station of claim 33, wherein the second precoding matrix is a column vector.

39. The base station of claim 33, wherein the at least one second reference signal associated with the downlink control channel comprises at least two orthogonal reference signals.

40. The base station of claim 33, wherein the memory further stores instructions that, when executed, cause the base station to transmit one or more control packets employing multi-user multiple-input-multiple-output (MIMO) in the downlink control channel.

41. The base station of claim 33, wherein the second precoding matrix is a submatrix of the first precoding matrix.

42. The base station of claim 33, wherein the first CSI further comprises one or more of a channel quality indicator (CQI) or a rank indicator (RI).

43. A method comprising:

receiving, by a base station and from a wireless device, first channel state information (CSI) comprising a first precoding matrix indicator;

determining, by the base station and based at least in part on the first precoding matrix indicator, a first precoding matrix for transmission of a downlink data channel to the wireless device;

determining, by the base station and based at least in part on the first precoding matrix indicator, a second precoding matrix for transmission of a downlink control channel to the wireless device, wherein the downlink control channel is associated with the downlink data channel;

transmitting, by the base station, to the wireless device, in a subframe, and using the first precoding matrix, the downlink data channel, wherein the downlink data channel comprises at least one first demodulation reference signal; and

transmitting, by the base station, to the wireless device, in the subframe, and using the second precoding matrix, the downlink control channel, wherein the downlink control channel comprises at least one second demodulation reference signal.

44. The method of claim 43, wherein the first precoding matrix is different from the second precoding matrix.

45. The method of claim 44, wherein the second precoding matrix is a submatrix of the first precoding matrix.

46. The method of claim 43, wherein the at least one second demodulation reference signal comprises at least two orthogonal reference signals.

47. The method of claim 43, wherein the transmitting the downlink control channel employs a smaller number of antenna ports than the transmitting the downlink data channel.

48. The method of claim 43, wherein the at least one second demodulation reference signal comprises at least two orthogonal reference signals.