METHOD AND APPARATUS FOR CONTROL CHANNEL TRANSMISSION AND RECEPTION

• US 20130044664A1
• Filed: 08/08/2012
• Published: 02/21/2013
• Est. Priority Date: 08/15/2011
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility LLC (Lenovo Group Ltd.)
• Inventors: Nory, Ravikiran, Krishnamurthy, Sandeep H., Love, Robert T., Nangia, Vijay, Nimbalker, Ajit, Sayana, Krishna Kamal, Zhuang, Xiangyang
• Granted Patent: US 9,252,918 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end

Abstract

A communication system is provided wherein a user equipment (UE) receives control information from a wireless network. The UE monitors control channel candidates using common reference signals (CRS) and monitors enhanced control channel candidates using demodulation reference signals (DMRS) when the UE is configured in a first transmission mode, such as transmission mode 9, for receiving a downlink shared traffic channel based on DMRS. The UE monitors control channel candidates only using CRS when the UE is configured in a second transmission mode, such as any of transmission modes 1-6, for receiving a downlink shared traffic channel based on CRS. The UE then receives downlink control information (DCI) in a subframe in one of the monitored control channel candidates or enhanced control channel candidates in the subframe.

Claims

1. A method in a user equipment (UE) for receiving control information, the method comprising:

monitoring control channel candidates using common reference signals (CRS) and monitoring enhanced control channel candidates using demodulation reference signals (DMRS) when the UE is configured in a first transmission mode for receiving a downlink shared traffic channel based on DMRS;

monitoring control channel candidates only using CRS when the UE is configured in a second transmission mode for receiving a downlink shared traffic channel based on CRS; and

receiving downlink control information (DCI) in a subframe in one of the monitored control channel candidates or enhanced control channel candidates in the subframe.

2. The method of claim 1, wherein the first transmission mode is transmission mode 9.

3. The method of claim 1, wherein the second transmission mode is one of transmission modes 1, 2, 3, 4, 5, and 6.

4. The method of claim 1, wherein monitoring control channel candidates using CRS further comprises monitoring Physical Downlink Control Channel (PDCCH) candidates, wherein monitoring enhanced control channel candidates using DMRS further comprises monitoring Enhanced Physical Downlink Control Channel (EPDCCH) candidates, and wherein the downlink shared traffic channel is a Physical Downlink Shared Channel (PDSCH).

5. The method of claim 4, wherein the PDCCH candidates are monitored in a first set of time symbols in the subframe and the EPDCCH candidates are monitored in a second set of time symbols in the subframe, wherein the first and second set of time symbols are distinct.

6. The method of claim 4, wherein monitoring the PDCCH candidates comprises:

monitoring a set of PDCCH candidates in the subframe;

wherein the set of PDCCH candidates is determined based on whether both PDCCH candidates and EPDCCH candidates are monitored in the subframe or, only PDCCH candidates are monitored in the subframe;

7. The method of claim 4, wherein monitoring the PDCCH candidates comprises:

monitoring a first number of PDCCH candidates in the subframe when both PDCCH candidates and EPDCCH candidates are monitored in the subframe;

monitoring a second number of PDCCH candidates in the subframe when only PDCCH candidates are monitored in the subframe;

wherein the first number is smaller than the second number.

8. The method of claim 4, wherein monitoring the PDCCH candidates comprises:

monitoring a set of PDCCH candidates in the subframe;

monitoring the set of PDCCH candidates for a first set of DCI formats when both PDCCH candidates and EPDCCH candidates are monitored in the subframe; and

monitoring the set of PDCCH candidates for a second set of DCI formats when only PDCCH candidates are monitored in the subframe.

9. The method of claim 8, wherein a size of the first set of DCI formats is smaller than a size of the second set of DCI formats.

10. The method of claim 4, wherein monitoring the EPDCCH candidates comprises:

monitoring a set of EPDCCH candidates in the subframe;

monitoring a first subset of the set of EPDCCH candidates at a first set of aggregation levels in a first slot of the subframe; and

monitoring a second subset of the set of EPDCCH candidates at a second set of aggregation levels in a second slot of the subframe, wherein the second set of aggregation levels is different from the first set of aggregation levels.

11. The method of claim 4, wherein monitoring the EPDCCH candidates comprises:

monitoring a set of EPDCCH candidates in the subframe using a set of aggregation levels;

wherein the set of aggregation levels is determined based on one or more of a subframe type of the subframe, a channel state information (CSI) reference signal configuration, a Physical Control Format Indicator Channel (PCFICH) value signaled in the subframes.

12. The method of claim 11, wherein the subframe type comprises one of a normal subframe type and a Multicast-Broadcast Single-Frequency Network (MBSFN) subframe type.

13. A method in a user equipment (UE) for receiving control information, the method comprising:

receiving a subframe;

determining if enhanced control channel candidates using demodulation reference signals (DMRS) are monitored in the subframe;

monitoring, in the subframe, a set control channel candidates using common reference signals (CRS); and

receiving, in the subframe, downlink control information (DCI) in a control channel candidate within the set of control channel candidates;

wherein the set control channel candidates is based on whether enhanced control channel candidates using demodulation reference signals (DMRS) are monitored in the subframe.

14. The method in claim 13, wherein monitoring the set of control channel candidates using CRS comprises monitoring a set of Physical Downlink Control Channel (PDCCH) candidates and, monitoring enhanced control channel candidates using DMRS further comprises monitoring Enhanced Physical Downlink Control Channel (EPDCCH) candidates.

15. The method in claim 14, further comprising:

monitoring a first number of PDCCH candidates in the subframe when both PDCCH candidates and EPDCCH candidates are monitored in the subframe;

monitoring a second number of PDCCH candidates in the subframe when only PDCCH candidates are monitored in the subframe;

wherein the first number is smaller than the second number.

16. A method in a user equipment for receiving control information, the method comprising:

monitoring enhanced control channel candidates at a first set of aggregation levels in a first subframe;

monitoring enhanced control channel candidates at a second set of aggregation levels in a second subframe, wherein the second set of aggregation levels is different from the first set of aggregation levels;

determining the first set of aggregation levels and second set of aggregation levels based on one or more of a subframe type of the subframes, a channel state information (CSI) reference signal configuration in the subframes, and a Physical Control Format Indicator Channel (PCFICH) value signaled in the subframes; and

receiving control information in at least one of the monitored enhanced control channel candidates.

17. The method of claim 16, wherein the enhanced control channel is an Enhanced PDCCH.

18. The method of claim 16, wherein the subframe type comprises one of a normal subframe and a Multicast-Broadcast Single-Frequency Network (MBSFN) subframe.

19. A user equipment capable of receiving control information, the user equipment comprising:

a wireless transceiver; and

a signal processing unit coupled to the transceiver and that is configured to monitor control channel candidates using common reference signals (CRS) and monitor enhanced control channel candidates using demodulation reference signals (DMRS) when the UE is configured in a first transmission mode for receiving a downlink shared traffic channel based on DMRS, monitor control channel candidates only using CRS when the UE is configured in a second transmission mode for receiving a downlink shared traffic channel based on CRS, and receive downlink control information (DCI) in a subframe in one of the monitored control channel candidates or enhanced control channel candidates in the subframe.

20. The user equipment of claim 19, wherein the first transmission mode is transmission mode 9.

21. The user equipment of claim 19, wherein the second transmission mode is one of transmission modes 1, 2, 3, 4, 5, and 6.

22. The user equipment of claim 19, wherein the signal processing unit is configured to monitor control channel candidates using CRS by monitoring Physical Downlink Control Channel (PDCCH) candidates, wherein monitoring enhanced control channel candidates using DMRS further comprises monitoring Enhanced Physical Downlink Control Channel (EPDCCH) candidates, and wherein the downlink shared traffic channel is a Physical Downlink Shared Channel (PDSCH).

23. The user equipment of claim 22, wherein the PDCCH candidates are monitored in a first set of time symbols in the subframe and the EPDCCH candidates are monitored in a second set of time symbols in the subframe, wherein the first and second set of time symbols are distinct.

24. The user equipment of claim 22, wherein the signal processing unit is configured to monitor the PDCCH candidates by monitoring a set of PDCCH candidates in the subframe, wherein the set of PDCCH candidates is determined based on whether both PDCCH candidates and EPDCCH candidates are monitored in the subframe or, only PDCCH candidates are monitored in the subframe;

25. The user equipment of claim 22, wherein the signal processing unit is configured to monitor the PDCCH candidates by monitoring a first number of PDCCH candidates in the subframe when both PDCCH candidates and EPDCCH candidates are monitored in the subframe and monitoring a second number of PDCCH candidates in the subframe when only PDCCH candidates are monitored in the subframe, wherein the first number is smaller than the second number.

26. The user equipment of claim 22, wherein the signal processing unit is configured to monitor the PDCCH candidates by monitoring a set of PDCCH candidates in the subframe, monitoring the set of PDCCH candidates for a first set of DCI formats when both PDCCH candidates and EPDCCH candidates are monitored in the subframe, and monitoring the set of PDCCH candidates for a second set of DCI formats when only PDCCH candidates are monitored in the subframe.

27. The user equipment of claim 26, wherein a size of the first set of DCI formats is smaller than a size of the second set of DCI formats.

28. The user equipment of claim 22, wherein the signal processing unit is configured to monitor the EPDCCH candidates by monitoring a set of EPDCCH candidates in the subframe, monitoring a first subset of the set of EPDCCH candidates at a first set of aggregation levels in a first slot of the subframe, and monitoring a second subset of the set of EPDCCH candidates at a second set of aggregation levels in a second slot of the subframe, wherein the second set of aggregation levels is different from the first set of aggregation levels.

29. The user equipment of claim 22, wherein the signal processing unit is configured to monitor the EPDCCH candidates by monitoring a set of EPDCCH candidates in the subframe using a set of aggregation levels, wherein the set of aggregation levels is determined based on one or more of a subframe type of the subframe, a channel state information (CSI) reference signal configuration, a Physical Control Format Indicator Channel (PCFICH) value signaled in the subframes.

30. The user equipment of claim 29, wherein the subframe type comprises one of a normal subframe type and a Multicast-Broadcast Single-Frequency Network (MBSFN) subframe type.

31. A user equipment capable of receiving control information, the user equipment comprising:

a wireless transceiver; and

a signal processing unit coupled to the transceiver and that is configured to receive a subframe, determine if enhanced control channel candidates using demodulation reference signals (DMRS) are monitored in the subframe, monitor, in the subframe, a set control channel candidates using common reference signals (CRS), and receive, in the subframe, downlink control information (DCI) in a control channel candidate within the set of control channel candidates, wherein the set control channel candidates is based on whether enhanced control channel candidates using demodulation reference signals (DMRS) are monitored in the subframe.

32. The user equipment in claim 31, wherein the signal processing unit is configured to monitor the set of control channel candidates using CRS by monitoring a set of Physical Downlink Control Channel (PDCCH) candidates and, monitoring enhanced control channel candidates using DMRS further comprises monitoring Enhanced Physical Downlink Control Channel (EPDCCH) candidates.

33. The user equipment in claim 32, wherein the signal processing unit is configured monitor a first number of PDCCH candidates in the subframe when both PDCCH candidates and EPDCCH candidates are monitored in the subframe and monitor a second number of PDCCH candidates in the subframe when only PDCCH candidates are monitored in the subframe, wherein the first number is smaller than the second number.

34. A user equipment capable of receiving control information, the user equipment comprising:

a wireless transceiver; and

a signal processing unit coupled to the transceiver and that is configured to, monitor enhanced control channel candidates at a first set of aggregation levels in a first subframe, monitor enhanced control channel candidates at a second set of aggregation levels in a second subframe, wherein the second set of aggregation levels is different from the first set of aggregation levels, determine the first set of aggregation levels and second set of aggregation levels based on one or more of a subframe type of the subframes, a channel state information (CSI) reference signal configuration in the subframes, and a Physical Control Format Indicator Channel (PCFICH) value signaled in the subframes, and receive control information in at least one of the monitored enhanced control channel candidates.

35. The user equipment of claim 34, wherein the enhanced control channel is an Enhanced PDCCH.

36. The user equipment of claim 34, wherein the subframe type comprises one of a normal subframe and a Multicast-Broadcast Single-Frequency Network (MBSFN) subframe.

37. A method in a user equipment (UE) for receiving control information, the method comprising:

monitoring a set of control channel candidates in a subframe, the set of control channel candidates comprising one or more control channel candidate types, the control channel candidate types including common reference signals (CRS)-based control channel candidate, and demodulation reference signals (DMRS)-based control channel candidate;

determining a set of CRS-based control channel candidates in the monitored set of control channel candidates based on a number of control channel candidate types monitored;

receiving downlink control information (DCI) in a control channel candidate within the monitored set of control channel candidates including the determined set of CRS-based control channel candidates in the subframe.

38. The method in claim 37, further comprising:

receiving downlink control information (DCI) in a control channel candidate within the determined set of CRS-based control channel candidates in the subframe.

39. The method in claim 37, further comprising:

determining the number of control channel candidate types monitored based on a transmission mode configured for the UE.