Radio communication device

• US 7,899,401 B2
• Filed: 06/03/2005
• Issued: 03/01/2011
• Est. Priority Date: 06/04/2004
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Hosokawa, Shuya, Shirakata, Naganori, Kimura, Tomohiro, Tanaka, Koichiro
• Primary Examiner(s): Wendell; Andrew
• Application Number:
  US11/628,039
• Publication Number:
  US 20070259623A1
• Time in Patent Office: 2,097 Days
• Field of Search: 455/39, 455/41.1, 455/41.2, 455/67.11, 455/69, 455/133, 455/150.1, 455/226.1, 455/227, 455/229, 340/10.1, 340/10.4, 340/10.52, 340/10.42
• US Class Current: 455/67.11
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion

Abstract

A radio communication device that, even if it is interfered by a radio transmission station other than a radio transmission station with which it intends to communicate, estimates a signal transmitted from the intended radio transmission station by taking into account the influence of the interference, by obtaining an estimator of “s” that denotes a column vector representing a signal transmitted from the radio transmission station, in accordance with a following expression: s=RssH^H(HRssH^H+Ruu)⁻¹r, where “Rss” denotes a covariance matrix of the column vector “s”, “r” denotes a column vector representing the signal received by the signal receiving unit, “H” denotes a matrix being the numerical sequence calculated by the first calculating unit, “Ruu” denotes a covariance matrix being the numerical sequence calculated by the second calculating unit, “^H” denotes a complex conjugate transposition, and “⁻¹” denotes an inverse matrix.

Claims

1. A radio communication device which identifies a radio transmission station as a communication partner based on a patterned signal which has a predetermined pattern and is contained in a signal transmitted from the radio transmission station, and performs a radio communication with the identified radio transmission station, the radio communication device comprising:

a plurality of antennas;

a signal receiving unit operable to receive a signal via the plurality of antennas;

a first calculating unit operable to calculate, based on the received signal, a numerical sequence that indicates a property of a signal transmission path used in a radio communication with the radio transmission station;

a second calculating unit operable to calculate, based on the received signal, a numerical sequence that indicates a property of an unnecessary signal that is a component of the received signal and that does not have the predetermined pattern; and

a transmission signal estimating unit operable to correct the received signal so as to remove the unnecessary signal from the received signal based on the numerical sequence calculated by the second calculating unit, and estimate a signal transmitted from the radio transmission station based on the corrected received signal and the numerical sequence calculated by the first calculating unit,

wherein the transmission signal estimating unit obtains an estimator “

v”

of “

s”

that denotes a column vector representing a signal transmitted from the radio transmission station, in accordance with a following expression;

v=RssH^H(HRssH^H+Ruu)<sup>−

1</sup>r,

wherein “

Rss”

denotes a covariance matrix of the column vector “

s”

, “

r”

denotes a column vector representing the signal received by the signal receiving unit, “

H”

denotes a matrix being the numerical sequence calculated by the first calculating unit, “

Ruu”

denotes a covariance matrix being the numerical sequence calculated by the second calculating unit, “

^H”

denotes a complex conjugate transposition, and “

<sup>−

1</sup>”

denotes an inverse matrix.

2. The radio communication device of claim 1, wherein

when elements of the column vector “

s”

are uncorrelated with each other and when each of the elements has an equivalent average power that is denoted as “

p”

,

the estimator “

v”

of the column vector “

s”

is obtained in accordance with a following expression;

v=H^H(HH^H+(1/p)Ruu)<sup>−

1</sup>r.

3. A radio communication device which identifies a radio transmission station as a communication partner based on a patterned signal which has a predetermined pattern and is contained in a signal transmitted from the radio transmission station, and performs a radio communication with the identified radio transmission station, the radio communication device comprising:

a plurality of antennas;

a signal receiving unit operable to receive a signal via the plurality of antennas;

a first calculating unit operable to calculate, based on the received signal, a numerical sequence that indicates a property of a signal transmission path used in a radio communication with the radio transmission station;

a second calculating unit operable to calculate, based on the received signal, a numerical sequence that indicates a property of an unnecessary signal that is a component of the received signal and that does not have the predetermined pattern;

a transmission signal estimating unit operable to correct the received signal so as to remove the unnecessary signal from the received signal based on the numerical sequence calculated by the second calculating unit, and estimate a signal transmitted from the radio transmission station based on the corrected received signal and the numerical sequence calculated by the first calculating unit; and

a reliability evaluating unit operable to calculate a residual error contained in the signal estimated by the transmission signal estimating unit based on the numerical sequence calculated by the first calculating unit and the numerical sequence calculated by the second calculating unit,

wherein the reliability evaluating unit obtains an estimator “

z[k]”

of a residual error corresponding to a k^th element of “

v”

, in accordance with a following expression;

z[k]=(W[k]H−

I_M[k])Rss(H^HW[k]^H−

I_M[k]^H)+W[k]RuuW[k]^H,

wherein “

W”

is obtained in accordance with a following expression;

W=RssH^H(HRssH^H+Ruu)<sup>−

1</sup>r,

wherein “

s”

denotes a column vector representing a signal transmitted from the radio transmission station, “

Rss”

denotes a covariance matrix of the column vector “

s”

, “

r”

denotes a column vector representing the signal received by the signal receiving unit, “

H”

denotes a matrix being the numerical sequence calculated by the first calculating unit, “

Ruu”

denotes a covariance matrix being the numerical sequence calculated by the second calculating unit, “

v”

denotes a column vector representing, by an equivalent baseband system, an estimator obtained by the transmission signal estimating unit, a dimension of the column vector “

s”

is represented as “

M×

1”

, “

^H”

denotes a complex conjugate transposition, “

<sup>−

1</sup>”

denotes an inverse matrix, and

wherein W[k] represents a row vector of a k^th row when W represents a matrix;

W[k] represents a k^th element of W when W represents a column vector;

I_M[k] represents a row vector of a k^th row in an M×

M unit matrix when M is 2 or more; and

I_M[k] represents 1 when M is 1.

4. A radio communication device which identifies a radio transmission station as a communication partner based on a patterned signal which has a redetermined pattern and is contained in a signal transmitted from the radio transmission station, and performs a radio communication with the identified radio transmission station, the radio communication device comprising:

a plurality of antennas;

a signal receiving unit operable to receive a signal via the plurality of antennas;

a first calculating unit operable to calculate, based on the received signal, a numerical sequence that indicates a property of a signal transmission path used in a radio communication with the radio transmission station;

a second calculating unit operable to calculate, based on the received signal, a numerical sequence that indicates a property of an unnecessary signal that is a component of the received signal and that does not have the predetermined pattern;

a transmission signal estimating unit operable to correct the received signal so as to remove the unnecessary signal from the received signal based on the numerical sequence calculated by the second calculating unit, and estimate a signal transmitted from the radio transmission station based on the corrected received signal and the numerical sequence calculated by the first calculating unit; and

a reliability evaluating unit operable to calculate a residual error contained in the signal estimated by the transmission signal estimating unit based on the numerical sequence calculated by the first calculating unit and the numerical sequence calculated by the second calculating unit,

wherein the reliability evaluating unit obtains an estimator “

z[k]”

of a residual error corresponding to a k^th element of “

v”

, in accordance with a following expression;

z[k]=p(W[k]H−

I_M[k])(H^HW[k]^H−

I_M[k]^H)+W[k]RuuW[k]^H,

wherein “

W”

is obtained in accordance with a following expression when elements of a transmission signal “

s”

are uncorrelated with each other and when each element has an equivalent average power that is denoted as “

p”

;

W=H^H(HH^H+(1/p)Ruu)<sup>−

1</sup>,

wherein “

s”

denotes a column vector representing a signal transmitted from the radio transmission station, “

Rss”

denotes a covariance matrix of the column vector “

s”

, “

r”

denotes a column vector representing the signal received by the signal receiving unit, “

H”

denotes a matrix being the numerical sequence calculated by the first calculating unit, “

Ruu”

denotes a covariance matrix being the numerical sequence calculated by the second calculating unit, “

v”

denotes a column vector representing, by an equivalent baseband system, an estimator obtained by the transmission signal estimating unit, a dimension of the column vector “

s”

is represented as “

M×

1”

, “

^H”

denotes a complex conjugate transposition, “

<sup>−

1</sup>”

denotes an inverse matrix, and

wherein W[k] represents a row vector of a k^th row when W represents a matrix;

W[k] represents a k^th element of W when W represents a column vector;

I_M[k] represents a row vector of a k^th row in an M×

M unit matrix when M is 2 or more; and

I_M[k] represents 1 when M is 1.