Physical Downlink Control Channel Design for NR Systems

• US 20180279135A1
• Filed: 03/21/2018
• Published: 09/27/2018
• Est. Priority Date: 03/22/2017
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Hwang, Chien-Hwa, Li, Chien-Chang, Liao, Yi-Ju, Liao, Pei-Kai, Yang, Weidong
• Granted Patent: US 10,757,581 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04L 1/1861 Physical mapping arrangements for ACK signaling see also H04L5/0053
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• 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: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04W 16/28 using beam steering
• 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 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02

Abstract

A new design for physical downlink control channel (PDCCH) is proposed for the next generation 5G new radio systems. A UE receives the configuration of a default control resource set (CORESET) in MIB/SIB from its serving base station. The default CORESET contains both common search space and UE-specific search space for candidate PDCCH transmission. A PDCCH in a default CORESET is mapped to physical resource in a distributed or localized manner. Specifically, various REG-to-CCE mapping rules are proposed to improve frequency diversity gain, or frequency selectivity gain, or to reduce latency of PDCCH processing. Further, to facilitate analog beamforming in mmWave systems, the default CORESET is transmitted in a synchronization signal (SS) block associated with a corresponding analog beam direction.

Claims

1. A method comprising:

receiving a control signal from a base station by a user equipment (UE) to determine a set of received physical resource blocks (PRBs) and a set of OFDM symbols that carry downlink control information;

determining a set of candidate physical downlink control channels (PDCCHs) within the set of PRBs, wherein each PDCCH is associated with a set of control channel elements (CCEs) for PDCCH transmission;

collecting a plurality of resource element groups (REGs) for each CCE, wherein each CCE comprises a number of REGs based on an REG-to-CCE mapping, and wherein each REG is indexed by a frequency first or by a time first REG indexing manner; and

decoding the downlink control information that are mapped to the collected REGs.

2. The method of claim 1, wherein the UE receives configuration of a default control resource set (CORESET) that comprises the set of PRBs in frequency domain and the set of OFDM symbols in time domain.

3. The method of claim 2, wherein a PDCCH in the default CORESET is mapped to the plurality of REGs in a distributed or a localized manner.

4. The method of claim 2, wherein the default CORESET contains both a common search space and a UE-specific search space for PDCCH transmission.

5. The method of claim 2, wherein the UE receives an additional CORESET over a higher layer signaling after the UE obtains a UE ID from the base station.

6. The method of claim 1, wherein the UE receives reference signal (RS) configuration from the base station, and wherein physical resources of RS is self-contained within physical resources of REG.

7. A user equipment (UE), comprising:

a radio frequency (RF) receiver that receives a control signal from a base station by to determine a set of received physical resource blocks (PRBs) and a set of OFDM symbols that carry downlink control information;

a control circuit that determines a set of candidate physical downlink control channels (PDCCHs) within the set of PRBs, wherein each PDCCH is associated with a set of control channel elements (CCEs) for PDCCH transmission;

a collection circuit that collects a plurality of resource element groups (REGs) for each CCE, wherein each CCE comprises a number of REGs based on an REG-to-CCE mapping, and wherein each REG is indexed by a frequency first or by a time first REG indexing manner; and

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

8. The UE of claim 7, wherein the UE receives configuration of a default control resource set (CORESET) that comprises the set of PRBs in frequency domain and the set of OFDM symbols in time domain.

9. The UE of claim 8, wherein a PDCCH in the default CORESET is mapped to the plurality of REGs in a distributed or a localized manner.

10. The UE of claim 8, wherein the default CORESET contains both a common search space and a UE-specific search space for PDCCH transmission.

11. The UE of claim 8, wherein the UE receives an additional CORESET over a higher layer signaling after the UE obtains a UE ID from the base station.

12. The UE of claim 7, wherein the UE receives reference signal (RS) configuration from the base station, and wherein physical resources of RS is self-contained within physical resources of REG.

13. A method comprising:

receiving one or more synchronization signal blocks (SS Blocks) from a base station by a user equipment (UE), wherein each SS block is associated with a corresponding analog beam direction;

obtaining a default control resource set (CORESET) in an SS block and determining a corresponding UE-favored analog beam direction, wherein the default CORESET comprises a set of physical resource blocks (PRBs), a set of OFDM symbols, a numerology, a periodicity, and reference signal (RS) configuration;

obtaining a physical random-access channel (PRACH) resource associated with the default CORESET; and

performing an access procedure over the obtained PRACH resource.

14. The method of claim 13, wherein the default CORESET contains both a command search space and a UE-specific search space for physical downlink control channel (PDCCH) transmission.

15. The method of claim 14, wherein the UE receives a broadcast or multicast PDCCH transmitted in the default CORESET of all analog beam directions.

16. The method of claim 14, wherein the UE receives an additional CORESET over a higher layer signaling after the UE obtains a UE ID from the base station.

17. The method of claim 16, wherein the UE receives a unicast PDCCH transmitted in the additional CORESET using the UE-favored analog beam direction.

18. The method of claim 16, wherein each PDCCH is associated with a set of control channel elements (CCEs), and wherein the additional CORESET and the default CORESET contain an integer multiple number of CCEs in the frequency domain.

19. A user equipment (UE) comprising:

a radio frequency (RF) receiver that receives one or more synchronization signal blocks (SS Blocks) from a base station, wherein each SS block is associated with a corresponding analog beam direction;

a control circuit that obtains a default control resource set (CORESET) in an SS block and determining a corresponding UE-favored analog beam direction, wherein the default CORESET comprises a set of physical resource blocks (PRBs), a set of OFDM symbols, a numerology, a periodicity, and reference signal (RS) configuration; and

a channel access handling circuit that obtains a physical random-access channel (PRACH) resource associated with the default CORESET and performs an access procedure over the obtained PRACH resource.

20. The UE of claim 19, wherein the default CORESET contains both a command search space and a UE-specific search space for physical downlink control channel (PDCCH) transmission.

21. The UE of claim 20, wherein the UE receives a broadcast or multicast PDCCH transmitted in the default CORESET of all analog beam directions.

22. The UE of claim 20, wherein the UE receives an additional CORESET over a higher layer signaling after the UE obtains a UE ID from the base station.

23. The UE of claim 22, wherein the UE receives a unicast PDCCH transmitted in the additional CORESET using the UE-favored analog beam direction.

24. The UE of claim 22, wherein each PDCCH is associated with a set of control channel elements (CCEs), and wherein the additional CORESET and the default CORESET contain an integer multiple number of CCEs in the frequency domain.