Enhanced PHICH Transmission for LTE-Advanced

• US 20160105266A1
• Filed: 12/14/2015
• Published: 04/14/2016
• Est. Priority Date: 03/06/2012
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Heo, Youn Hyoung, Gao, Shiwei, Xu, Hua, Blankenship, Yufei Wu, Jia, Yongkang
• Granted Patent: US 9,998,268 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0038 Blind format detection for detection of modulation format H04L27/0012
• CPC Class Codes: H04L 1/1829 Arrangements specially adapted for the receiver end
• CPC Class Codes: H04L 1/1858 Transmission or retransmission of more than one copy of acknowledgement message
• CPC Class Codes: H04L 1/1861 Physical mapping arrangements for ACK signaling see also H04L5/0053
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• 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 5/0037 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: H04L 5/0094 Indication of how sub-channels of the path are allocated

Abstract

A method is provided for communication in a wireless telecommunication system. The method comprises generating a sequence of signals of an enhanced physical HARQ (hybrid automatic repeat request) indicator channel (E-PHICH). The method further comprises mapping the sequence of signals of the E-PHICH to a first set of resource elements, wherein the first set of resource elements is multiplexed with a second set of resource elements over a set of virtual resource blocks, and wherein the second set of resource elements carries at least one of an enhanced physical downlink control channel (E-PDCCH) and a physical downlink shared channel (PDSCH).

Claims

1. A method for communication in a wireless telecommunication system, the method comprising:

monitoring, by a user equipment (UE), both a physical hybrid automatic repeat request (HARQ) indicator channel (PHICH) and an enhanced PHICH (E-PHICH) transmitted by a network element; and

determining, by the UE, whether the PHICH or the E-PHICH is being used to assign resources.

2. The method of claim 1, further comprising:

receiving, by the UE, at least one parameter from the network element, the at least one parameter specifying a number of PHICH groups and a number of E-PHICH groups;

calculating, by the UE, a PHICH group index based on the at least one parameter;

comparing, by the UE, the number of PHICH groups with the number of E-PHICH groups; and

determining, by the UE, that the E-PHICH is being used to assign resources if the number of PHICH groups is greater than or equal to the number of E-PHICH groups.

3. The method of claim 1, further comprising determining, by the UE, whether the PHICH or the E-PHICH is being used depending on whether a physical uplink shared channel (PUSCH) physical resource block (PRB) index and a demodulation reference signal (DMRS) value satisfy certain criteria.

5. The method of claim 1, further comprising monitoring, by the UE, both the PHICH and the E-PHICH in a downlink subframe.

6. The method of claim 1, further comprising monitoring, by the UE, the E-PHICH in a downlink subframe where the PHICH is not monitored.

7. The method of claim 1, further comprising receiving, by the UE, UE-specific radio resource control (RRC) signaling from the network element that directs the UE to receive an acknowledgement/negative acknowledgement (ACK/NACK) only via the E-PHICH, wherein the UE-specific RRC signaling carries resource allocation information for the E-PHICH, and wherein the UE-specific RRC signaling triggers the UE to receive a downlink control channel via an enhanced physical downlink control channel (E-PDCCH).

8. The method of claim 1, further comprising:

receiving, by the UE, UE-specific RRC signaling from the network element that directs the UE to stop monitoring the E-PHICH; and

monitoring, by the UE, only the PHICH in response to receiving the UE-specific RRC signaling.

4. The method of 1, further comprising determining, by the UE, whether the PHICH or the E-PHICH is being used based on a number of PHICH groups and a number of E-PHICH groups, wherein the number of PHICH groups is indicated in a physical broadcast channel (PBCH), and wherein the number of E-PHICH groups is indicated via one of higher layer signaling or in unused bits within the PBCH.

9. A user equipment (UE) comprising:

at least one memory device; and

a processor configured to execute instructions stored on the at least one memory device such that when executed, the UE;

monitors both a physical hybrid automatic repeat request (HARQ) indicator channel (PHICH) and an enhanced PHICH (E-PHICH) transmitted by a network element; and

determines whether the PHICH or the E-PHICH is being used to assign resources.

10. The UE of claim 9, wherein the UE determines whether the PHICH or the E-PHICH is being used based at least on a physical uplink shared channel (PUSCH) physical resource block (PRB) index.

11. The UE of claim 10, wherein all PHICH and E-PHICH resources are jointly mapped to the PUSCH PRB index.

14. The UE of claim 9, wherein, when the UE is configured to decode the E-PHICH, the UE derives an E-PHICH group number and a sequence index using the following formula:

n_E-PHICH^group=(I_{PRB_RA}^lowest_index+n_DMRS)mod N_E-PHICH^group+I_PHICHN_E-PHICH^group

n_E-PHICH^seq=(└

I_{PRB_RA}^lowest_index/N_E-PHICH^group┘

+n_DMRS)mod 2N_E-SF^PHICH.

15. The UE of claim 9, wherein the UE monitors a downlink acknowledgement/negative acknowledgement (ACK/NACK) response only via the PHICH in a legacy control region when the UE initially attaches to the network element.

16. The UE of claim 9, wherein a resource set of the E-PHICH in a subframe relates to a variable sent to a plurality of UEs by the network element.

17. The UE of claim 16, wherein a first value of the variable indicates that the resource set resides in a first slot of a subframe only, and a second value of the variable indicates that the resource set spans a first slot and a second slot of a subframe.

18. The UE of claim 9, wherein the PHICH is used to carry a HARQ-ACK response when a related uplink downlink control information (DCI) grant is transmitted on a physical downlink control channel (PDCCH), and the E-PHICH is used to carry the HARQ-ACK response when a related uplink DCI grant is transmitted on an enhanced PDCCH (E-PDCCH).

19. The UE of claim 9, wherein a resource set of the E-PHICH is defined independently of a resource set of the PHICH.

20. The UE of claim 9, wherein:

when a first component carrier that has a legacy control region on a downlink channel is associated with a second component carrier that has no legacy control region, a HARQ-ACK response is transmitted to the UE only via the PHICH in the legacy control region of the first component carrier when the UE initially attaches to the network element;

when the network element adds the second component carrier to the UE as a secondary cell, the UE starts to receive HARQ-ACK responses related to uplink data transmission on the second component carrier via a downlink channel of the second component carrier, wherein the network element configures the E-PHICH on the second component carrier before the second component carrier is added as a secondary cell; and

when the network element removes the second component carrier from the UE'"'"'s secondary cell list, the UE switches to receiving HARQ-ACK response uplink data transmission on the second component carrier via a downlink channel of the first component carrier.

12. The UE of 9, wherein the PHICH is used when an uplink downlink control information (DCI) grant is transmitted on a physical downlink control channel (PDCCH), and wherein the E-PHICH is used when the uplink DCI is transmitted on an enhanced PDCCH (E-PDCCH).

13. The UE of claim 12, wherein:

when the uplink DCI grant is transmitted on the PDCCH, the UE calculates a PHICH group index using the following formula;

n_PHICH^group=(I_{PRB_RA}^lowest_index+n_DMRS)mod N_PHICH^group+I_PHICHN_E-PHICH^group; and

n_PHICH^seq=(└

I_{PRB_RA}^lowest_index/N_PHICH^group┘

+n_DMRS)mod 2N_SF^PHICH

when the uplink DCI grant is transmitted on the E-PDCCH, the UE calculates the PHICH group index using the following formula;

n_E-PHICH^group=(I_{PRB_RA}^lowest_index+n_DMRS)mod N_E-PHICH^group+I_PHICHN_E-PHICH^group

n_E-PHICH^seq=(└

I_{PRB_RA}^lowest_index/N_E-PHICH^group┘

+n_DMRS)mod 2N_SF^PHICH.