Orthogonal-Beam-Space Spatial Multiplexing Radio Communication System and Associated Antenna Array

Patent metadata

Field	Value
Publication number	US-2016352012-A1
Application number	US-201514725306-A
Country	US
Kind code	A1
Filing date	May 29, 2015
Priority date	May 29, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

Methods and systems for Spatial Multiplexing Mu-MIMO radio communications are provided. An antenna array is controlled to establish plural radio beams which are mutually orthogonal in terms of excitation functions and which are differently spatially directed to cover a geographic area. The beams may be arranged in angular space in a pattern of rows, with adjacent rows being offset. To facilitate same, the antenna array may include elements which are offset from neighbouring elements horizontally, vertically, or both. For each terminal, a subset of the radio beams may be selected for communication. The selection may prefer higher-power beams, where power is determined by summing contributions from eigen-channels. Subsets of radio beams may be grouped into orthogonal channels for use in servicing different sets of terminals in different geographic areas, and terminals sharing a channel may further share resources using multi-access techniques.

First claim

What is claimed is:

1 . A method for radio communication between an access point and a set of terminals located in a predetermined geographic region served by the access point, the method comprising:
controlling an array of antenna elements, associated with the access point, to establish a plurality of mutually orthogonal radio beams, each of the established plurality of radio beams corresponding to a respective one of a plurality of radiation patterns, each of the plurality of radiation patterns differing spatially from other radiation patterns in the plurality; and selecting a subset of the plurality of radio beams for use in transmitting a signal to one of the set of terminals.

2 . The method of claim 1 , wherein each of the plurality of radio beams has a respective power level, said power level corresponding to an amount of power contribution, from said one of the plurality of radio beams and relative to a total amount of power from all of the plurality of radio beams, which passes between said one of the set of terminals and the access point, and wherein selecting the subset of the plurality of radio beams comprises selecting, for membership in the subset, radio beams having higher absolute or relative values of said power levels.

3 . The method of claim 2 , wherein selecting the subset of the plurality of radio beams comprises selecting, for membership in the subset, radio beams having higher power levels relative to one or both of: a predetermined threshold power level; and relative power levels of the plurality of radio beams.

4 . The method of claim 2 , wherein selecting the subset of the plurality of radio beams comprises selecting a minimal number of radio beams having a sum total of said power levels which exceeds a predetermined threshold power level.

5 . The method of claim 4 , wherein the predetermined threshold power level is a predetermined fraction of a sum total of the power levels of all of the plurality of radio beams.

6 . The method of claim 2 , wherein the power level is derived through spectral analysis of a matrix H k ·H k H , wherein H k is a channel matrix for terminal k.

7 . The method of claim 2 , wherein the power level, for a given beam j of the plurality of radio beams and said one of the set of terminals k, corresponds to a value P k (j) satisfying:
P k ( j )=Σ i λ i k ·∥EV i ( j )∥ 2 ,

wherein i is an index of summation over eigenvalues λ i k of a system matrix H k ·H k H , wherein H k is a MIMO channel matrix for terminal k, and EV i (j) is a jth component of an ith eigenvector EV i of the matrix H k ·H k H .

8 . The method of claim 1 , further comprising defining a plurality of channels, each of the plurality of channels corresponding to a disjoint set of the plurality of radio beams, and using each of the plurality of channels for communication with different members of the set of terminals.

9 . The method of claim 8 , wherein at least one of the plurality of channels is used for communication with two or more terminals, the method further comprising sharing said at least one of the plurality of channels between the two or more terminals using a multi-access scheme.

10 . The method of claim 1 , wherein mutual orthogonality of the plurality of radio beams corresponds to satisfaction, by each pair of the plurality of radio beams, of an orthogonality condition corresponding to:

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B
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wherein i is an index of summation over a number of the antenna elements, W i A and W i B are, respectively, complex-valued excitations of an ith antenna element for production of a beam A and a beam B corresponding to the pair of the plurality of radio beams, and 8 is a predetermined threshold value which is selected to provide for a desired amount of orthogonality.

11 . The method of claim 1 , further comprising limiting beam overlap between subsets of the plurality of radio beams allocated to different members of the set of terminals.

12 . The method of claim 1 , wherein the array of antenna elements are spatially arranged according to a pattern extending in azimuthal and elevation directions, wherein the pattern includes one or both of the following:
at least two antenna elements that are adjacent in the azimuthal direction are offset in the elevation direction; and at least two antenna elements that are adjacent in the elevation direction are offset in the azimuthal direction.

13 . The method of claim 1 , further comprising configuring the plurality of radiation patterns such that a Beam Coupling Factor (BCF) for all pairs of terminals k and l of the set of terminals is below a predetermined threshold, wherein the BCF between terminals k and l is given by:
BCF( k,l )=Σ i=1 . . . M Σ j=1 . . . N [∫E i (θ, φ)· E j (θ, φ) dΩ]/[∫∥E i (θ, φ)∥·∥ E j (θ, φ)∥ dΩ],

wherein M and N are numbers of active beams for terminals k and l, E i and E j represent electric field patterns of i th and i th beams as a function of azimuth and elevation angles θ, φ and Ω is an angular variable of integration.

14 . The method of claim 1 , further comprising selecting the subset of the plurality of radio beams or another subset of the plurality of radio beams for use in receiving another signal from said one of the set of terminals or from another one of the set of terminals.

15 . A wireless communication system for radio communication between an access point and a set of terminals located in a predetermined geographic region served by the access point, the wireless communication system comprising:
an array of antenna elements associated with the access point; a beam controller configured to control the array of antenna elements to establish a plurality of mutually orthogonal radio beams, each of the plurality corresponding to one of a plurality of radiation patterns, each radiation pattern of the plurality differing spatially from other radiation patterns in the plurality; a beam selector configured to select a subset of the plurality of radio beams for use in transmitting a signal to one of the set of terminals.

16 . The system of claim 15 ,

Assignees

• Foo Senglee
• Huawei Tech Co Ltd

Inventors

• Foo Senglee

Classifications

• H01Q3/40 Primary

  with phasing matrix · CPC title

• H04B7/0452

  Multi-user MIMO systems · CPC title

• H04B7/0426

  Power distribution · CPC title

• H01Q21/065

  Patch antenna array · CPC title

• H04L25/03343

  Arrangements at the transmitter end · CPC title