WIRELESS COMMUNICATION SYSTEM FOR MONITORING PHYSICAL DOWNLINK CONTROL CHANNEL

• US 20090088148A1
• Filed: 09/29/2008
• Published: 04/02/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Eun Jong, Chung, Jae Hoon, Kim, So Yeon
• Granted Patent: US 8,401,542 B2
• Time in Patent Office: Days
• US Class Current: 455/423
• CPC Class Codes: H04L 1/0029 Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling power control H04W52/04
• CPC Class Codes: H04L 1/0032 Without explicit signalling
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2666 Acquisition of further OFDM parameters, e.g. bandwidth, subcarrier spacing, or guard interval length
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information

Abstract

A method of monitoring a physical downlink control channel (PDCCH) in a wireless communication system is provided. A user equipment monitors a set of PDCCH candidates for a search space in a subframe. The search space includes a common search space monitored by all user equipments in a cell and a UE-specific search space monitored by at least one UE in the cell.

Claims

1. A method of monitoring a physical downlink control channel (PDCCH) in a wireless communication system, the method comprising:

monitoring a set of PDCCH candidates for a search space in a subframe, wherein the subframe comprises a control region for transmitting control information, the control region comprising a plurality of resource elements mapped to a plurality of control channel elements (CCEs), a CCE corresponds to a set of resource elements, and the search space that comprises a contiguous set of CCEs is classified into a common search space and a UE-specific search space, wherein the common search space is monitored by all user equipments (UEs) in a cell and the UE-specific search space is monitored by at least one UE in the cell.

2. The method of claim 1, wherein the subframe further comprises a slot that comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols in a time domain and a plurality of subcarriers in a frequency domain.

3. The method of claim 2, wherein a portion of the plurality of OFDM symbols and subcarriers in the slot makes up a resource block, the resource block comprising resource elements in the portion.

4. The method of claim 1, wherein locations for the PDCCH candidates for the search space occur every K CCEs where K is a size of a CCE aggregation level.

5. The method of claim 4, wherein a size of the search space is defined by the size of the CCE aggregation level and a number of the PDCCH candidates for the search space.

6. The method of claim 4, wherein a number of CCE aggregation levels for the common search space is smaller than a number of CCE aggregation levels for the UE-specific search space.

7. The method of claim 1, wherein a starting location of the common search space is same for all the UEs in the cell.

8. The method of claim 7, wherein the starting location of the common search space is fixed.

9. The method of claim 7, wherein the starting location of the common search space is set to zero.

10. The method of claim 1, wherein a starting location of the UE-specific search space is determined in every subframe.

11. The method of claim 1, wherein a starting location to search common control information is restricted in the common search space.

12. The method of claim 11, wherein a starting location to search first common control information and a starting location to search second common control information are restricted in the common search space.

13. The method of claim 12, wherein the starting location to search the first common control information is different from the starting location to search the second common control information.

14. The method of claim 1, wherein the common search space and the UE-specific search space overlap with each other.

15. A user equipment for monitoring a physical downlink control channel (PDCCH), the user equipment comprising:

a radio frequency (RF) unit for receiving a radio signal; and

a processor coupled with the RF unit and configured to;

monitor a common search space at each of common control channel element (CCE) aggregation levels in a subframe, wherein the subframe comprises a control region for transmitting control information, the control region comprising a plurality of resource elements mapped to a plurality of CCEs, a CCE corresponds to a set of resource elements, and the common search space comprising a contiguous set of CCEs is monitored by all user equipments (UEs) in a cell; and

monitor a UE-specific search space at each of UE-specific CCE aggregation levels in the subframe, wherein the UE-specific search space is monitored by at least one UE in the cell.

16. The user equipment of claim 15, wherein a starting location of the common search space is same for all the UEs in the cell.

17. The user equipment of claim 15, wherein a starting location of the UE-specific search space is UE-specific in the cell.

18. The user equipment of claim 15, wherein a number of the common CCE aggregation levels is smaller than a number of the UE-specific CCE aggregation levels.

19. A method of transmitting control information on a physical downlink control channel (PDCCH) in a wireless communication system, the method comprising:

configuring common control information on the PDCCH in a common search space, wherein the common search space is monitored by all UEs in a cell; and

transmitting the common control information on the PDCCH.

20. The method of claim 19, further comprising:

transmitting UE-specific control information on the PDCCH in a UE-specific search space, wherein the UE-specific search space is monitored by at least one UE which receives the UE-specific control information.