Optimized signaling of demodulation reference signal patterns

• US 9,001,771 B2
• Filed: 08/02/2013
• Issued: 04/07/2015
• Est. Priority Date: 06/28/2010
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Jngren, George, Sorrentino, Stefano
• Primary Examiner(s): Wong, Warner
• Application Number:
  US13/957,957
• Publication Number:
  US 20130308588A1
• Time in Patent Office: 613 Days
• Field of Search: 370/252, 370310-350, 370/395.4
• US Class Current: 370/329
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• 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 72/0466 the resource being a scrambling code
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

Orthogonality in cyclic shift (CS) and orthogonal cover code (OCC) selection for DMRS in MIMO is improved by new n_DMRS to n_DMRS⁽²⁾ mapping patterns. Values in the mapping tables are arranged in sets, with minimum CS separation between the values in each set. Additionally, the semi-static n_DMRS is independently configurable for each UL component carrier (CC) in the case of cross-CC scheduling in carrier aggregation, and the PHICH allocation formula that defines the allocation of the PHICH process relative to the k^th codeword (CW) on the c^th UL CC is a function of both the CS index n_DMRS,k,c⁽²⁾ that is dynamically assigned to a certain layer of the considered CW and the semi-static CS offset n_DMRS,c⁽¹⁾ for the c^th CC.

Claims

1. A method of determining cyclic shift (CS) values associated with DeModulation Reference Signals (DMRS) for a plurality of transmission layers and allocating transmission resources, by a device in a wireless communication system employing Multiple Input Multiple Output (MIMO) operation and carrier aggregation, comprising:

receiving a semi-static cyclic shift (CS) value n_DMRS,c⁽¹⁾ associated with each component carrier (CC) in the case of cross-CC scheduling; and

allocating transmission resources for a Physical Hybrid Automatic Repeat Request (HARQ) Channel (PHICH) transmission such that an allocation for a k^th codeword on a c^th CC is a function of both a first CS value n_DMRS,k,c⁽²⁾ associated with a DeModulation Reference Signal (DMRS) for a certain layer of a codeword and the semi-static CS value n_DMRS,c⁽¹⁾ associated with the c^th CC.

2. The method of claim 1 wherein allocating transmission resources comprises determining one or more resources to be used for a PHICH transmission based on values I_PRB—

_RA<sup>lowest—

index</sup>, N_PHICH^group, I_PHICH and N_SF^PHICH, wherein N_SF^PHICH is spreading-factor size used for modulation of PHICH, I<sub>PRB—

RA</sub><sup>lowest—

index</sup> is an index associated with a lowest physical resource block (PRB) index in a particular slot of a corresponding uplink control transmission, N_PHICH^group is a number of PHICH groups and is configured by higher layers, and I_PHICH is a constant whose value depends on a time-division duplex (TDD) or frequency division duplex (FDD) configuration being used.

3. The method of claim 2, wherein determining the one or more resources comprises determining an index pair (n_PHICH^group, n_PHICH^seq) associated with a first resource, wherein n_PHICH^group comprises a PHICH group number and n_PHICH^seq comprises an orthogonal signal index within the PHICH group number, and wherein:

n_PHICH,k,c^group=(I<sub>PRB—

RA</sub><sup>lowest—

index</sup>+n_DMRS,k,c⁽²⁾+n_DMRS,c⁽¹⁾)mod N_PHICH^group+I_PHICHN_PHICH^group

n_PHICH,k,c^seq=(└

I<sub>PRB—

RA</sub><sup>lowest—

index</sup>/N_PHICH^group┘

+n_DMRS,k,c⁽²⁾+n_DMRS,c⁽¹⁾)mod 2N_SF^PHICH.

4. The method of claim 2, wherein determining the one or more resources comprises determining an index pair (n_PHICH^group, n_PHICH^seq) associated with a first resource, wherein n_PHICH^group comprises a PHICH group number and n_PHICH^seq comprises an orthogonal signal index within the PHICH group number, and wherein:

n_PHICH,k,c^group=(I<sub>PRB—

RA</sub><sup>lowest—

index</sup>+n_DMRS,k,c⁽²⁾+n_DMRS,c⁽¹⁾)mod N_PHICH^group+I_PHICHN_PHICH^group

n_PHICH,k,c^seq=(└

I_{PRB RA}<sup>lowest—

index</sup>/N_PHICH^group┘

+n_DMRS,k,c⁽²⁾)mod 2N_SF^PHICH.

5. The method of claim 2, wherein determining the one or more resources comprises determining an index pair (n_PHICH^group, n_PHICH^seq) associated with a first resource, wherein n^PHICHgroup comprises a PHICH group number and n^PHICHseq comprises an orthogonal signal index within the PHICH group number, and wherein:

n_PHICH,k,c^group=(I<sub>PRB—

RA</sub><sup>lowest—

index</sup>+n_DMRS,k,c⁽²⁾)mod N_PHICH^group+I_PHICHN_PHICH^group

n_PHICH,k,c^seq=(└

I<sub>PRB—

RA</sub><sup>lowest—

index</sup>/N_PHICH^group┘

+n_DMRS,k,c⁽²⁾+n_DMRS,k,c⁽¹⁾)mod 2N_SF^PHICH.

6. An apparatus for determining cyclic shift (CS) values associated with DeModulation Reference Signals (DMRS) for a plurality of transmission layers and allocating transmission resources in a wireless communication system employing Multiple Input Multiple Output (MIMO) operation and carrier aggregation, comprising:

a receiver operable to receive a semi-static cyclic shift (CS) value n_DMRS,c⁽¹⁾ associated with each of one or more component carriers (CCs); and

a controller operable to allocate transmission resources for a Physical Hybrid Automatic Repeat Request (HARQ) Channel (PHICH) transmission such that an allocation for a k^th codeword on a c^th CC is a function of both a first CS value n_DMRS,k,c⁽²⁾ associated with a DeModulation Reference Signal (DMRS) for a particular layer of a codeword and the semi-static CS value n_DMRS,c⁽¹⁾ associated with the c^th CC.

7. The apparatus of claim 6 wherein the controller is operable to allocate transmission resources by determining one or more resources to be used for a PHICH transmission based on values I_PRB—

_RA<sup>lowest—

index</sup>, N_PHICH^group, I_PHICH and N_SF^PHICH, wherein N_SF^PHICH is a spreading-factor size used for modulation of PHICH, I<sub>PRB—

RA</sub><sup>lowest—

index</sup> is an index associated with a lowest physical resource block (PRB) index in a particular slot of a corresponding uplink control transmission, N_PHICH^group is a number of PHICH groups and is configured by higher layers, and I_PHICH is a constant whose value depends on a time-division duplex (TDD) or frequency division duplex (FDD) configuration being used.

8. The apparatus of claim 7, wherein determining the one or more resources comprises determining an index pair (n_PHICH^group, n_PHICH^seq) associated with a first resource, wherein n_PHICH^group comprises a PHICH group number and n_PHICH^seq comprises an orthogonal signal index within the PHICH group number, and wherein:

n_PHICH,k,c^group=(I<sub>PRB—

RA</sub><sup>lowest—

index</sup>+n_DMRS,k,c⁽²⁾+n_DMRS,c⁽¹⁾)mod N_PHICH^group+I_PHICHN_PHICH^group

n_PHICH,k,c^seq=(└

<sub>PRB—

RA</sub><sup>lowest—

index</sup>/N_PHICH^group┘

+n_DMRS,k,c⁽²⁾+n_DMRS,c⁽¹⁾)mod 2N_SF^PHICH.

9. The apparatus of claim 7, wherein determining the one or more resources comprises determining an index pair (n_PHICH^group, n_PHICH^seq) associated with a first resource, wherein n_PHICH^group comprises a PHICH group number and n_PHICH^seq comprises an orthogonal signal index within the PHICH group number, and wherein:

n_PHICH,k,c^group=(I<sub>PRB—

RA</sub><sup>lowest—

index</sup>+n_DMRS,k,c⁽²⁾+n_DMRS,c⁽¹⁾)mod N_PHICH^group+I_PHICHN_PHICH^group

_PHICH,k,c^seq=(└

I_{PRB RA}<sup>lowest—

index</sup>/N_PHICH^group┘

+n_DMRS,k,c⁽²⁾)mod 2N_SF^PHICH.

10. The apparatus of claim 7, wherein determining the one or more resources comprises determining an index pair (n_PHICH^group, n_PHICH^seq) associated with a first resource, wherein n_PHICH^group comprises a PHICH group number and n_PHICH^seq comprises an orthogonal signal index within the PHICH group number, and wherein:

n_PHICH,k,c^group=(I<sub>PRB—

RA</sub><sup>lowest—

index</sup>+n_DMRS,k,c⁽²⁾)mod N_PHICH^group+I_PHICHN_PHICH^group

n_PHICH,k,c^seq=(└

I<sub>PRB—

RA</sub><sup>lowest—

index</sup>/N_PHICH^group┘

+n_DMRS,k,c+n_DMRS,c⁽¹⁾)mod 2N_SF^PHICH.