Method for efficient channel estimation and beamforming in FDD system by exploiting uplink-downlink correspondence

• US 9,814,037 B2
• Filed: 12/17/2013
• Issued: 11/07/2017
• Est. Priority Date: 06/28/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Xue, Feng, Li, Qinghua, Zhu, Yuan
• Primary Examiner(s): NGO, RICKY QUOC
• Assistant Examiner(s): Truong, Lan Huong
• Application Number:
  US14/109,211
• Publication Number:
  US 20150003338A1
• Time in Patent Office: 1,421 Days
• 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 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04J 11/005 of intercell interference
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 25/021 Estimation of channel covariance
• CPC Class Codes: H04L 25/0242 using matrix methods
• CPC Class Codes: H04L 25/03891 Spatial equalizers MIMO diversity systems H04B7/0413
• CPC Class Codes: H04L 5/1469 using time-sharing
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 68/04 multi-step notification using statistical or historical mobility data
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/004 : in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/006 : in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0816 : with collision avoidance
• CPC Class Codes: H04W 76/10 : Connection setup
• CPC Class Codes: H04W 76/19 : Connection re-establishment
• CPC Class Codes: H04W 76/30 : Connection release
• CPC Class Codes: H04W 8/005 : Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/045 : using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: H04W 84/18 : Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/02 : Terminal devices
• CPC Class Codes: H04W 88/06 : adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A method for selecting at least one parameter for downlink data transmission with a mobile user equipment. The method is executable by a wireless communication base station having multiple antennas configured to communicate wirelessly with the mobile user equipment. The method receives an uplink probing signal from the mobile user equipment. The method determines a plurality of angles of arrival for a corresponding plurality of paths between the mobile user equipment and the multiple antennas. The method transmits a plurality of downlink probing signals directionally toward corresponding angles of arrival in the plurality of angles of arrival. Each downlink probing signal is a virtual antenna port with respect to the mobile user equipment. The method receives channel state information. The method composes at least one of a rank indicator (RI), precoding matrix indicator (PMI), or modulating and coding scheme (MCS) for downlink data transmission to the mobile user equipment.

Claims

1. A method for selecting at least one parameter for downlink data transmission with a mobile user equipment, the method executable by a single wireless communication base station having multiple antennas configured to communicate wirelessly with the mobile user equipment, the method comprising:

receiving an uplink probing signal from the mobile user equipment;

determining, from the received uplink probing signal, a plurality of angles-of-arrival for a corresponding plurality of paths between the mobile user equipment and the multiple antennas of the single wireless communication base station, wherein each of the angles-of-arrival is associated with a corresponding one of the plurality of paths between the mobile user equipment and the single wireless communication base station, and each angle-of-arrival is determined based on projecting the received uplink probing signal towards a spatial signature of the corresponding one of the plurality of paths;

transmitting, from the multiple antennas, a plurality of downlink probing signals, each downlink probing signal being transmitted directionally toward a corresponding one of the angles-of-arrival, each downlink probing signal being a virtual antenna port with respect to the mobile user equipment, each virtual antenna port formed by a discrete Fourier transform (DFT) vector;

receiving, from the mobile user equipment, channel state information corresponding to a channel associated with one of the downlink probing signals; and

composing, in response to the received channel state information, a rank indicator (RI) and a preceding matrix indicator (PMI) for downlink data transmission to the mobile user equipment.

2. The method of claim 1, further comprising:

composing, in response to the received channel state information, a modulating and coding scheme (MCS) for downlink data transmission to the mobile user equipment, wherein each downlink probing signal appears to originate from a different location from the point of view of the mobile user equipment.

3. The method of claim 1, wherein determining, from the received uplink probing signal, a plurality of angles-of-arrival for a corresponding plurality of paths between the mobile user equipment and the multiple antennas comprises:

employing an angle-of-arrival estimation algorithm.

4. The method of claim 3, wherein the angle-of-arrival estimation algorithm:

projects the received uplink probing signal toward different spatial signatures spanning the angular space;

determines peak values from the projection; and

adopts the peak values as estimated angles-of-arrival.

5. The method of claim 1, wherein the uplink probing signal and the downlink probing signals are at different frequencies.

6. The method of claim 5, wherein determining the downlink probing signal, in response to the uplink probing signal, comprises:

determining an uplink channel vector;

multiplying the uplink channel vector by a diagonal matrix to form a product; and

adopting the product to be a downlink channel vector.

7. The method of claim 6, wherein the diagonal matrix includes, at an Mth row and column, a complex exponential factor having an exponent that varies as (M−

1) multiplied by the difference in frequency between the uplink probing signal and the downlink probing signal.

8. The method of claim 6, further comprising:

forming a complex transpose of the product; and

adopting the complex transpose as a defining vector for downlink virtual channel state information reference signal ports.

9. The method of claim 6, further comprising:

applying channel state information reference signals on top of the plurality of virtual antenna ports.

10. The method of claim 1, further comprising:

for virtual antenna ports numbering greater than four, downselecting the virtual antenna ports to a number fewer than four based on channel state information reference signal measurements.

11. A wireless communication base station having multiple antennas configured to communicate wirelessly with a mobile user equipment, the wireless communication base station including circuitry configured to:

receive an uplink probing signal from the mobile user equipment;

determine, from the received uplink probing signal, a plurality of angles-of-arrival for a corresponding plurality of paths between the mobile user equipment and the multiple antennas of the wireless communication base station, wherein each of the angles-of-arrival is associated with a corresponding one of the plurality of paths between the mobile user equipment and a single wireless communication base station, and each angle-of-arrival is determined based on projecting the received uplink probing signal towards a spatial signature of the corresponding one of the plurality of paths;

transmit, from the multiple antennas, a plurality of downlink probing signals, each downlink probing signal being transmitted directionally toward a corresponding one of the angles-of-arrival, each downlink probing signal being a virtual antenna port with respect to the mobile user equipment, each virtual antenna port formed by a discrete Fourier transform (DFT) vector;

receive, from the mobile user equipment, channel state information corresponding to a channel associated with one of the downlink probing signals; and

compose, in response to the received channel state information, a rank indicator (RI) and a precoding matrix indicator (PMI) for downlink data transmission to the mobile user equipment.

12. The wireless communication base station of claim 11, wherein the circuitry is further configured to compose, in response to the received channel state information, a modulating and coding scheme (MCS) for downlink data transmission to the mobile user equipment, wherein each downlink probing signal appears to originate from a different location from the point of view of the mobile user equipment.

13. The wireless communication base station of claim 11, wherein determining, from the received uplink probing signal, a plurality of angles-of-arrival for a corresponding plurality of paths between the mobile user equipment and the multiple antennas comprises:

employing an angle-of-arrival estimation algorithm.

14. The wireless communication base station of claim 13, wherein the angle-of-arrival estimation algorithm:

projects the received uplink probing signal toward different spatial signatures spanning the angular space;

determines peak values from the projection; and

adopts the peak values as estimated angles-of-arrival.

15. The wireless communication base station of claim 11, wherein the uplink probing signal and the downlink probing signals are at different frequencies.

16. The wireless communication base station of claim 15, wherein determining the downlink probing signal, in response to the uplink probing signal, comprises:

determining an uplink channel vector;

multiplying the uplink channel vector by a diagonal matrix to form a product; and

adopting the product to be a downlink channel vector.

17. The wireless communication base station of claim 16, wherein the circuitry is further configured to:

form a complex transpose of the product; and

adopt the complex transpose as a defining vector for downlink virtual channel state information reference signal ports.

18. The wireless communication base station of claim 16, wherein the circuitry is further configured to:

apply channel state information reference signals on top of the plurality of virtual antenna ports.

19. A method for selecting at least one parameter for downlink data transmission with a mobile user equipment, the method performed by a single wireless communication base station having multiple antennas configured to communicate wirelessly the mobile user equipment, the method comprising:

receiving an uplink probing signal from the mobile user equipment;

employing an angle-of-arrival estimation algorithm;

determining, from the angle-of-arrival estimation algorithm, a plurality of angles-of-arrival for a corresponding plurality of paths between the mobile user equipment and the multiple antennas of the single wireless communication base station, wherein each of the angles-of-arrival is associated with a corresponding one of the plurality of paths between the mobile user equipment and the single wireless communication base station, and each angle-of-arrival is determined based on projecting the received uplink probing signal towards a spatial signature of the corresponding one of the plurality of paths;

transmitting, from the multiple antennas, a plurality of downlink probing signals, each downlink probing signal being transmitted directionally toward a corresponding one of the angles-of-arrival, each downlink probing signal being a virtual antenna port with respect to the mobile user equipment, each virtual antenna port formed by a discrete Fourier transform (DFT) vector, each downlink probing signal appearing to originate from a different location from the point of view of the mobile user equipment and the uplink probing signal and the downlink probing signals having different frequencies;

receiving, from the mobile user equipment, channel state information corresponding to a channel associated with one of the plurality of downlink probing signals; and

composing, in response to the received channel state information, a rank indicator (RI) and a precoding matrix indicator (PMI) for downlink data transmission to the mobile user equipment.

20. A wireless communication base station having multiple antennas configured to communicate wirelessly with a mobile user equipment, the wireless communication base station including circuitry configured to:

receive an uplink probing signal from the mobile user equipment;

determine, from the received uplink probing signal, a plurality of angles-of-arrival for a corresponding plurality of paths between the mobile user equipment and the multiple antennas, wherein each of the plurality of angles-of-arrival is associated with a corresponding one of the plurality of paths;

transmit, from the multiple antennas, a plurality of downlink probing signals directionally toward corresponding angles-of-arrival in the plurality of angles-of-arrival, each downlink probing signal being a virtual antenna port with respect to the mobile user equipment;

receive, from the mobile user equipment, channel state information corresponding to a channel associated with one of the plurality of downlink probing signals; and

compose, in response to the received channel state information, a rank indicator (RI) and a precoding matrix indicator (PMI) for downlink data transmission to the mobile user equipment,

wherein the uplink probing signal and the downlink probing signals are at different frequencies,

wherein determining the downlink probing signal, in response to the uplink probing signal, comprises;

determining an uplink channel vector;

multiplying the uplink channel vector by a diagonal matrix to form a product;

adopting the product to be a downlink channel vector, and

wherein the diagonal matrix includes, at an Mth row and column, a complex exponential factor having an exponent that varies as (M−

1) multiplied by the difference in frequency between the uplink probing signal and the downlink probing signal.