Autonomous Quasi Co-Location Status Redefinition by Receiver in Coordinated Multipoint Downlink

• US 20150349855A1
• Filed: 01/17/2014
• Published: 12/03/2015
• Est. Priority Date: 01/17/2013
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sesia, Stefania, Sorrentino, Stefano
• Granted Patent: US 9,531,448 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0665 Feed forward of transmit weights to the receiver
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04L 25/0202 Channel estimation
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

User Equipment, UE (30), in a wireless radiocommunication network (10) supporting Coordinated Multi-Point, CoMP, transmissions may autonomously adopt an assumption of the quasi co-located (QCL) status of two (or more) antenna ports that is different from the default QCL status defined or signaled by the network (10), in response to one or more estimates of certain operating parameter values. The altered QCL status assumption allows the UE (30) to correct parameter estimates more accurately, and/or to reduce complexity in the parameter estimation correction.

Claims

1-42. -42. (canceled)

43. A method of operating a User Equipment (UE) in the downlink of a wireless radiocommunication network operative to transmit signals from a plurality of transmission points, wherein two or more antenna ports are defined or signaled by the network to be quasi co-located (QCL), or to not be quasi-co-located, with respect to a given long term channel property, whereby the antenna ports are QCL if the given long term channel property may be assumed to be the same for both antenna ports by the UE, the method comprising:

ascertaining, by predefinition or signaling from the network, a default QCL status of the first and second antenna ports;

estimating one or more wireless network operating parameters;

wherein the estimating comprises estimating one or more of the signal to noise ratio (SNR) of received cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), or demodulation reference signals (DMRS);

autonomously adopting an assumption of the QCL status, different from the default QCL status, of the first and second antenna ports, in response to the one or more parameter estimates.

44. The method according to claim 43, further comprising signaling to the network that the UE is capable of autonomously adopting an assumption of the QCL status of two or more antenna ports.

45. The method according to claim 43, further comprising receiving from the network a configuration of QCL assumptions to be adopted in response to the one or more parameter estimates.

46. The method according to claim 43, further comprising receiving from the network an identification of the one or more wireless network operating parameters on which to base the autonomous adoption of QCL status assumption.

47. The method according to claim 43, wherein the QCL assumption autonomously adopted is that cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), and demodulation reference signals (DMRS) are QCL with respect to certain long term channel properties.

48. The method according to claim 43, wherein the QCL assumption autonomously adopted is that demodulation reference signals are not QCL with CRS.

49. The method according to claim 43, wherein:

estimating one or more wireless network operating parameters comprises estimating the quality of CRS;

wherein autonomously adopting a different assumption of the QCL status comprises adopting a different assumption of QCL status only if the CRS are of sufficient quality to support accurate estimation of other reference signals, or CRS are not necessary for the accurate estimation of other reference signals.

50. The method according to claim 43, wherein:

estimating one or more wireless network operating parameters comprises estimating the SNR of DMRS;

wherein the QCL assumption autonomously adopted is that CRS, CSI-RS, and DMRS are QCL with respect to certain long term channel properties.

51. A User Equipment (UE) operative in a wireless radiocommunication network transmitting signals from a plurality of transmission points, wherein two or more antenna ports are defined or signaled by the network to be quasi co-located (QCL), or to not be quasi co-located, with respect to a given long term channel property, whereby the antenna ports are QCL if the given long term channel property may be assumed to be the same for both antenna points by the UE, the UE comprising:

radio circuitry operative to receive signals from the network;

memory; and

processing circuitry operatively connected to the memory and radio circuitry, the processing circuitry operative to;

ascertain, by predefinition or signaling from the network, a default QCL status of the first and second antenna ports;

estimate one or more wireless network operating parameters by estimating one or more of the signal to noise ratio (SNR) of received cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), or demodulation reference signals (DMRS);

autonomously adopt an assumption of the QCL status, different from the default QCL status, of the first and second antenna ports, in response to the one or more parameter estimates.

52. The UE according to claim 51, wherein the processing circuitry is further operative to signal to the network that the UE is capable of autonomously adopting an assumption of the QCL status of two or more antenna ports.

53. The UE according to claim 51, wherein the radio circuitry is operative to receive from the network a configuration of QCL assumptions to be adopted in response to the one or more parameter estimates.

54. The UE according to claim 51, wherein the radio circuitry is operative to receive, from the network, an identification of the one or more wireless network operating parameters on which to base the autonomous adoption of QCL status assumption.

55. The UE according to claim 51, wherein the QCL assumption autonomously adopted is that cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), and demodulation reference signals (DMRS) are QCL with respect to certain long term channel properties.

56. The UE according to claim 51, wherein the QCL assumption autonomously adopted is that demodulation reference signals are not QCL with CRS.

57. The UE according to claim 51, wherein the processing circuitry is operative to:

estimate one or more wireless network operating parameters by estimating the quality of CRS;

autonomously adopt a different assumption of the QCL status by adopting a different assumption of QCL status only if the CRS are of sufficient quality to support accurate estimation of other reference signals, or CRS are not necessary for the accurate estimation of other reference signals.

58. The UE according to claim 51, wherein:

the processing circuitry is operative to estimate one or more wireless network operating parameters by estimating the SNR of DMRS;

the QCL assumption autonomously adopted is that CRS, CSI-RS, and DMRS are QCL with respect to certain long term channel properties.