REFERENCE SIGNAL DESIGN AND ASSOCIATION FOR PHYSICAL DOWNLINK CONTROL CHANNELS

• US 20130188577A1
• Filed: 01/18/2013
• Published: 07/25/2013
• Est. Priority Date: 01/19/2012
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: PAPASAKELLARIOU, Aris, CHO, Joonyoung
• Granted Patent: US 9,603,125 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 1/0038 Blind format detection for detection of modulation format H04L27/0012
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 72/04 Wireless resource allocation

Abstract

A method and apparatus for designing a Reference Signal (RS) used by a User Equipment (UE) to obtain respective channel estimates for demodulating respective Physical Downlink Control CHannels (PDCCHs), for determining at a UE a number of resource blocks to include for a reception of a Physical Downlink Shared CHannel (PDSCH), for determining at a UE a RS antenna port in order to enable spatial multiplexing of Enhanced PDCCH (EPDCCH) transmissions to different UEs, and for supporting Quadrature Amplitude Modulation 16 (QAM16) modulation, in addition to Quadrature Phase Shift Keying (QPSK) modulation, for EPDCCH transmissions without increasing a number of decoding operations at a UE are provided.

Claims

1. A method for a User Equipment (UE) to receive a Physical Downlink Shared CHannel (PDSCH) conveying data information and transmitted from a base station over a Transmission Time Interval (TTI) that includes a number of symbols and over a set of Resource Blocks Groups (RBGs) wherein each RBG includes a number of Resource Blocks (RBs) and each RB includes a number of frequency Resource Elements (REs), the PDSCH reception being scheduled by a Physical Downlink Control CHannel (PDCCH) transmitted from the base station over the TTI and over a subset of RBs in a set of RBs configured to the UE by the base station for potential transmission of PDCCHs, the method comprising:

detecting, by the UE, the PDCCH over the subset of RBs to obtain the set of RBGs for PDSCH reception wherein a first RBG in the set of RBGs includes a first RB in the set of RBs; and

receiving, by the UE, the PDSCH in the first RBG wherein the first RBG includes the first RB if the first RB is not included in the subset of RBs or excludes the first RB if the first RB is included in the subset of RBs.

2. The method of claim 1, wherein the UE demodulates the data information in the first RBG by obtaining a channel estimate from interpolating Reference Signals (RS) transmitted in symbols of the TTI and in REs in a second number of RBs in the first RBG, wherein the second number of RBs includes the first RB if the first RB is not included in the subset of RBs or excludes the first RB if the first RB is included in the subset of RBs.

3. The method of claim 2, wherein the RS is transmitted in a first number of REs if the RB is used to transmit PDSCH and in a second number of REs if the RB is used to transmit PDCCH wherein the first number of REs is different than the second number of REs.

4. A method for a User Equipment (UE) to demodulate control information in a candidate Physical Downlink Control CHannel (PDCCH) using a channel estimate obtained from a Reference Signal (RS) transmitted from a first Antenna Port (AP) of a base station (first RS AP), the candidate PDCCH including one or more Control Channel Elements (CCEs) and transmitted from the base station over a Transmission Time Interval (TTI) and over a bandwidth Resource Block (RB), the method comprising:

receiving, from the base station, a Radio Network Temporary Identifier (RNTI);

computing a total number of ECCEs N_ECCE in the RB over the TTI and a first set of RS APs in the RB over the TTI, wherein the first set of RS APs includes the first RS AP and is a subset of a predetermined second set of RS APs and a total number of RS APs N_DMRS in the first set of RS APs is equal to N_ECCE;

mapping the candidate PDCCH consisting of L ECCEs having respective indexes to resource elements in the RB over the TTI; and

computing the first RS AP from a value of a function that includes as its arguments the RNTI, at least one index of the L ECCEs, L, and N_ECCE.

5. The method of claim 4, wherein the function further includes as its argument an index of the RB or an index of the TTI.

6. The method of claim 4, wherein the PDCCH transmission comprises Orthogonal Frequency Division Multiplexing (OFDM) and N_ECCE is computed by a number of OFDM symbols in the TTI that are used to transmit the PDCCH candidate or by a length of a cyclic prefix applied to a respective OFDM symbol.

7. The method of claim 6, wherein N_DMRS and N_ECCE each comprise a first value in a first TTI and a second value in a second TTI.

8. The method of claim 4, wherein for L=1 each RS AP index in the first set of RS APs is uniquely mapped to each ECCE index.

9. The method of claim 4, wherein the first RS AP is same for all indexes of the L ECCEs.

10. A User Equipment (UE) apparatus for receiving a Physical Downlink Shared CHannel (PDSCH) conveying data information and transmitted from a base station over a Transmission Time Interval (TTI) that includes a number of symbols and over a set of Resource Blocks Groups (RBGs) wherein each RBG includes a first number of Resource Blocks (RBs) and each RB includes a number of frequency Resource Elements (REs), the PDSCH reception being scheduled by a Physical Downlink Control CHannel (PDCCH) transmitted from the base station over the TTI and over a subset of RBs in a set of RBs configured to the UE apparatus by the base station for potential transmission of PDCCHs, the apparatus comprising:

a detector for detecting the PDCCH over the subset of RBs to obtain the set of RBGs for PDSCH reception wherein a first RBG in the set of RBGs includes a first RB in the set of RBs; and

a receiver for receiving the PDSCH in the first RBG wherein the first RBG includes the first RB if the first RB is not included in the subset of RBs or excludes the first RB if the first RB is included in the subset of RBs.

11. The apparatus of claim 10 further comprising a demodulator for demodulating data information in the first RBG by obtaining a channel estimate from interpolating Reference Signals (RS) transmitted in symbols of the TTI and in REs in a second number of RBs in the first RBG, wherein the second number of RBs includes the first RB if the first RB is not included in the subset of RBs or excludes the first RB if the first RB is included in the subset of RBs.

12. The apparatus of claim 11, wherein the RS is transmitted in a first number of REs if the RB is used to transmit PDSCH and in a second number of REs if the RB is used to transmit PDCCH wherein the first number of REs is different than the second number of REs.

13. A User Equipment (UE) apparatus for demodulating control information in a candidate Physical Downlink Control CHannel (PDCCH) using a channel estimate obtained from a Reference Signal (RS) transmitted from a first Antenna Port (AP) of a base station (first RS AP), the candidate PDCCH including one or more Control Channel Elements (CCEs) and transmitted from the base station over a Transmission Time Interval (TTI) and over a bandwidth Resource Block (RB), the apparatus comprising:

a receiver for receiving from the base station a Radio Network Temporary Identifier (RNTI);

a first computing unit for computing a total number of ECCEs N_ECCE in the RB over the TTI and a first set of RS APs in the RB over the TTI wherein the first set of RS APs is a subset of a predetermined second set of RS APs and a total number of RS APs N_DMRS in the first set of RS APs is equal to N_ECCE;

a mapper for mapping the candidate PDCCH consisting of L ECCEs having respective indexes to resource elements in the RB over the TTI; and

a second computing unit for computing the first RS AP from a value of a function that includes as its arguments the RNTI, at least one index of the L ECCEs, L, and N_ECCE.

14. The apparatus of claim 13, wherein the function further includes as its argument an index of the RB or an index of the TTI.

15. The apparatus of claim 13, wherein the PDCCH transmission method is the Orthogonal Frequency Division Multiplexing (OFDM) and N_ECCE is computed by a number of OFDM symbols in the TTI that are used to transmit the PDCCH candidate or by a length of a cyclic prefix applied to a respective OFDM symbol.

16. The apparatus of claim 15, wherein N_DMRS and N_ECCE each comprise a first value in a first TTI and a second value in a second TTI.

17. The apparatus of claim 13, wherein for L=1 each RS AP index in the first set of RS APs is uniquely mapped to each ECCE index.

18. The apparatus of claim 13, wherein the first RS AP is same for all indexes of the L ECCEs.