CRS (common reference signal) and CSI-RS (channel state information reference signal) transmission for remote radio heads (RRHs)

• US 9,054,842 B2
• Filed: 02/13/2012
• Issued: 06/09/2015
• Est. Priority Date: 02/14/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Bhattad, Kapil, Chen, Wanshi, Gaal, Peter, Geirhofer, Stefan, Ji, Tingfang, Montojo, Juan
• Primary Examiner(s): Oveissi, David
• Application Number:
  US13/372,078
• Publication Number:
  US 20130051240A1
• Time in Patent Office: 1,212 Days
• US Class Current: 1/1
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/03866 using scrambling
• CPC Class Codes: H04L 25/0391 construction details of matrices
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

One aspect of the present disclosure provides various configurations of the macro cell and remote radio heads to allow legacy UEs to function, including mapping CRS ports to physical antenna, configuring CSI-RS transmissions and assisting the new UE in identifying remote radio heads.

Claims

1. A method of wireless communication, comprising:

selecting, at an eNodeB, a common reference signal (CRS) virtualization scheme for at least one legacy user equipment (UE) that decodes data transmissions based at least in part on channel estimates obtained from a CRS; and

transmitting, from the eNodeB to the at least one legacy UE, the CRS via at least one CRS antenna port based at least in part on the CRS virtualization scheme, the CRS transmissions using a same set of beams, a same time and frequency resource, a same CRS antenna port, and a same traffic-to-pilot (T2P) ratio as the data transmissions from the eNodeB to the at least one legacy UE when the at least one legacy UE decodes the data transmissions using a CRS based decoding scheme.

2. The method of claim 1, in which a remote radio head (RRH) has a same number of CRS antenna ports as the eNodeB.

3. The method of claim 1, in which CRS antenna ports of a remote radio head (RRH) are linearly independent from CRS antenna ports of the eNodeB.

4. The method of claim 1, further comprising selecting the CRS virtualization scheme that increases power boost of the transmitted CRS.

5. The method of claim 1, further comprising selecting the CRS virtualization scheme to improve SFBC (space frequency block code)/SFBC-FSTD (frequency shift transmit diversity) performance.

6. The method of claim 1, further comprising transmitting a signal, to the at least one legacy UE, to enable the at least one legacy UE to determine T2P ratio differences between CRS antenna ports.

7. The method of claim 1, in which the CRS transmissions use at least a different set of beams, a different time and frequency resource, a different CRS antenna port, a different traffic-to-pilot (T2P) ratio, or a combination thereof when the at least one legacy UE does not decode the data transmissions using the CRS based decoding scheme.

8. An eNodeB for wireless communication, comprising:

a memory; and

at least one processor coupled to the memory, the at least one processor being configured;

to select a common reference signal (CRS) virtualization scheme for at least one legacy user equipment (UE) that decodes data transmissions based at least in part on channel estimates obtained from a CRS; and

to transmit, to the at least one legacy UE, the CRS via at least one CRS antenna port based at least in part on the CRS virtualization scheme, the CRS transmissions using a same set of beams, a same time and frequency resource, a same CRS antenna port, and a same traffic-to-pilot (T2P) ratio as the data transmissions from the eNodeB to the at least one legacy UE when the at least one legacy UE decodes the data transmissions using a CRS based decoding scheme.

9. The eNodeB of claim 8, in which a remote radio head (RRH) has a same number of CRS antenna ports as the eNodeB.

10. The eNodeB of claim 8, in which CRS antenna ports of a remote radio head (RRH) are linearly independent from CRS antenna ports of the eNodeB.

11. The eNodeB of claim 8, in which the processor is further configured to select the CRS virtualization scheme that increases power boost of the transmitted CRS.

12. The eNodeB of claim 8, in which the processor is further configured to select the CRS virtualization scheme to improve SFBC (space frequency block code)/SFBC-FSTD (frequency shift transmit diversity) performance.

13. The eNodeB of claim 8, in which the processor is further configured to transmit a signal, to the at least one legacy UE, to enable the at least one legacy UE to determine T2P ratio differences between CRS antenna ports.

14. The eNodeB of claim 8, in which the CRS transmissions use at least a different set of beams, a different time and frequency resource, a different CRS antenna port, a different traffic-to-pilot (T2P) ratio, or a combination thereof when the at least one legacy UE does not decode the data transmissions using the CRS based decoding scheme.

15. A computer program product for wireless communication in a wireless network, comprising:

a non-transitory computer-readable medium having non-transitory program code recorded thereon, the program code comprising;

program code to select, at an eNodeB, a common reference signal (CRS) virtualization scheme for at least one legacy user equipment (UE) that decodes data transmissions based at least in part on channel estimates obtained from a CRS; and

program code to transmit, from the eNodeB to the at least one legacy UE, the CRS via at least one CRS antenna port based at least in part on the CRS virtualization scheme, the CRS transmissions using a same set of beams, a same time and frequency resource, a same CRS antenna port, and a same traffic-to-pilot (T2P) ratio as the data transmissions from the eNodeB to the at least one legacy UE when the at least one legacy UE decodes the data transmissions using a CRS based decoding scheme.

16. The computer program product of claim 15, in which the CRS transmissions use at least a different set of beams, a different time and frequency resource, a different CRS antenna port, a different traffic-to-pilot (T2P) ratio, or a combination thereof when the at least one legacy UE does not decode the data transmissions using the CRS based decoding scheme.

17. An apparatus for wireless communication, comprising:

means for selecting, at an eNodeB, a common reference signal (CRS) virtualization scheme for at least one legacy user equipment (UE) that decodes data transmissions based at least in part on channel estimates obtained from a CRS; and

means for transmitting, from the eNodeB to the at least one legacy UE, the CRS via at least one CRS antenna port based at least in part on the CRS virtualization scheme, the CRS transmissions using a same set of beams, a same time and frequency resource, a same CRS antenna port, and a same traffic-to-pilot (T2P) ratio as the data transmissions from the eNodeB to the at least one legacy UE when the at least one legacy UE decodes the data transmissions using a CRS based decoding scheme.

18. The apparatus of claim 17, in which the CRS transmissions use at least a different set of beams, a different time and frequency resource, a different CRS antenna port, a different traffic-to-pilot (T2P) ratio, or a combination thereof when the at least one legacy UE does not decode the data transmissions using the CRS based decoding scheme.