Physical Structure and Reference Signal Utilization of Enhanced Physical Downlink Control Channel for OFDM/OFDMA Systems

• US 20130286980A1
• Filed: 06/26/2013
• Published: 10/31/2013
• Est. Priority Date: 03/16/2012
• Status: Active Grant

• Current Assignee: HFI Innovation, Inc. (MediaTek, Inc.)
• Original Assignee: MediaTek, Inc.
• Inventors: Liao, Pei-Kai, Zhuang, Xiangyang, Chen, Hua-Min
• Granted Patent: US 9,277,548 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0025 Spatial division following the spatial signature of the channel
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/53 based on regulatory allocation policies
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A two-level physical structure is defined for better diversity for both distributed and localized transmission in enhanced physical downlink control channel (ePDCCH). First level is a physical unit of enhanced resource element groups (eREGs), where the group of REs is predefined for each eREG. Second level is a logical unit of enhanced control channel elements (eCCEs), where the group of eREGs is predefined or configurable by higher layer for each eCCE. For distributed transmission of ePDCCH, eCCE consists of several eREGs that are distributed in multiple non-contiguous PRBs spreading over the whole channel frequency. Downlink control information (DCI) is transmitted on a number of aggregated eCCEs according to the modulation and coding level required. The utilization reference signals of antenna ports for ePDCCH demodulation is based on the logical order of eCCEs and the aggregation level for DCI transmission.

Claims

1. A method of decoding downlink control information by a user equipment (UE) in an OFDM/OFDMA system, the method comprising:

(a) receiving a control signal from a base station to determine received physical resource blocks (PRBs) that carry the downlink control information;

(b) determining a set of candidate enhanced physical downlink control channels (ePDCCHs) within the PRBs, wherein each ePDCCH is associated with a set of enhanced control channel elements (eCCEs) for ePDCCH transmission;

(c) collecting a plurality of enhanced resource element groups (eREGs) for each eCCE, wherein each eCCE consists of a number of eREGs based on a first de-mapping rule;

(d) collecting a plurality of resource elements (REs) for each eREG, wherein each eREG consists of a number of REs based on a second de-mapping rule; and

(e) decoding the downlink control information that are mapped to the collected REs.

2. The method of claim 1, wherein the plurality of eREGs for one eCCE are distributed in a plurality of non-contiguous PRB pairs.

3. The method of claim 1, wherein the plurality of REs for one eREG are physically contiguous REs allocated for either data or reference signal transmission within a block of physically contiguous radio resources.

4. The method of claim 1, wherein the plurality of REs for one eREG are physically distributed REs excluding REs allocated for ePDCCH demodulation reference signal transmission within a block of physically contiguous radio resources.

5. The method of claim 4, wherein the ePDCCH demodulation reference signal is UE-Specific reference signal (DM-RS).

6. The method of claim 1, wherein the UE decodes the downlink control information in either single eCCE or a plurality of eCCEs.

7. The method of claim 1, wherein the control signal is from higher layer signaling.

8. A method comprising:

receiving downlink control information via an enhanced physical downlink control channel (ePDCCH) by a user equipment (UE) in an OFDM/OFDMA system, wherein the ePDCCH is associated with a set of enhanced control channel elements (eCCEs);

decoding the downlink control information with reference signals of a first specific antenna port based on a logical address of a single eCCE if the UE decodes the downlink control information utilizing the single eCCE for ePDCCH transmission; and

decoding the downlink control information with reference signals of a second specific antenna port based on a logical address of a specific eCCE among a plurality of eCCEs if the UE decodes the downlink control information utilizing the plurality of eCCEs for ePDCCH transmission.

9. The method of claim 8, wherein each eCCE consists of a plurality of enhanced resource element groups (eREGs) based on a first de-mapping rule.

10. The method of claim 9, wherein the plurality of eREGs for one eCCE are distributed in a plurality of non-contiguous PRBs.

11. The method of claim 9, wherein each eREG consists of a plurality of resource elements (REs) based on a second de-mapping rule.

12. A user equipment (UE) in an OFDM/OFDMA system, the UE comprises:

a receiver that receives a control signal from a base station to determine received physical resource blocks (PRBs) that carry the downlink control information;

a control module that determines a set of candidate enhanced physical downlink control channels (ePDCCHs) within the PRBs, wherein each ePDCCH is associated with a set of enhanced control channel elements (eCCEs) for ePDCCH transmission;

a collector module that collects a plurality of enhanced resource element groups (eREGs) for each eCCE, wherein each eCCE consists of a plurality of eREGs based on a first de-mapping rule, wherein the collector module also collects a plurality of resource elements (REs) for each eREG, wherein each eREG consists of a plurality of REs based on a second de-mapping rule; and

a decoder that decodes the downlink control information that are mapped to the collected REs.

13. The UE of claim 12, wherein the plurality of eREGs for one eCCE are distributed in a plurality of non-contiguous PRB pairs.

14. The UE of claim 12, wherein the plurality of REs for one eREG are physically contiguous REs allocated for either data or reference signal transmission within a block of physically contiguous radio resources.

15. The UE of claim 12, wherein the plurality of REs for one eREG are physically distributed REs excluding REs allocated for ePDCCH demodulation reference signal transmission within a block of physically contiguous radio resources.

16. The UE of claim 15, wherein the ePDCCH demodulation reference signal is UE-Specific reference signal (DM-RS).

17. The UE of claim 12, wherein the UE decodes the downlink control information in either single eCCE or a plurality of eCCEs.

18. The UE of claim 12, wherein the control signal is from higher layer signaling.

19. The UE of claim 12, wherein the UE decodes the downlink control information with reference signals of a specific antenna port based on a logical address of a single eCCE if the UE decodes the downlink control information utilizing the single eCCE for ePDCCH transmission.

20. The UE of claim 12, wherein the UE decodes the downlink control information with reference signals of a specific antenna port based on a logical address of a specific eCCE among a plurality of eCCEs if the UE decodes the downlink control information utilizing the plurality of eCCEs for ePDCCH transmission.