Wireless reception apparatus, wireless transmission apparatus, wireless communication system, wireless reception method, wireless transmission method, and wireless communication method

• US 8,145,128 B2
• Filed: 04/14/2005
• Issued: 03/27/2012
• Est. Priority Date: 04/14/2005
• Status: Expired due to Fees

• Current Assignee: Intertechnology Global LLC (IP Edge LLC)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Malik, Rahul, Tan, Pek Yew
• Primary Examiner(s): Nguyen, Simon
• Application Number:
  US11/911,335
• Publication Number:
  US 20090061786A1
• Time in Patent Office: 2,539 Days
• Field of Search: 455/67.11, 455/69, 455/101, 455/115.1, 455/226.1, 455/39, 370/328, 375/299, 375/358
• US Class Current: 455/39
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0647 Variable feedback rate
• CPC Class Codes: H04L 25/0204 of multiple channels

Abstract

The present invention relates to an apparatus and a method capable of achieving closed loop MIMO communications, using reduced feedback, without a loss in system performance. In one embodiment of the present invention, a phase-rotated right handed singular vector matrix is derived from an estimation result of a MIMO channel (steps 231 and 232). Then, a coefficient are fed back (step 235). The coefficient is associated with an element in the phase-rotated right-handed singular vector matrix.

Claims

1. A wireless reception apparatus comprising:

a calculation section that calculates a right-handed singular vector matrix from an estimation result of a multiple input multiple output (MIMO) channel;

a phase rotation section that performs phase rotation on the right-handed singular vector matrix calculated by the calculation section to generate a phase-rotated right-handed singular vector matrix, the phase rotation being performed by using a unitary matrix containing a diagonal element having a value corresponding to a point on a unit circle in a complex number plane; and

a feedback section that feeds back, to a wireless transmission apparatus, information about a coefficient in the complex number plane, the coefficient being associated with an element of the phase-rotated right-handed singular vector matrix generated by the phase rotation section.

2. The wireless reception apparatus according to claim 1, wherein the right-handed singular vector matrix has a plurality of right-handed singular vectors, and the phase rotation section eliminates a phase component of an element in each of the plurality of right handed singular vectors.

3. The wireless reception apparatus according to claim 1, wherein:

the calculation section further calculates a left-handed singular vector matrix from the estimation result; and

the phase rotation section performs phase rotation on the left-handed singular vector matrix calculated by the calculation section, and the wireless reception apparatus further comprising;

an application section that applies, to a received signal, a conjugate transposed matrix of the left-handed singular vector matrix subjected to the phase rotation by the phase rotation section, to obtain an estimate of data transmitted from the wireless transmission apparatus.

4. A wireless reception apparatus comprising:

a calculation section that calculates a right-handed singular vector matrix from an estimation result of a multiple input multiple output (MIMO) channel, the right-handed singular vector matrix having a plurality of right-handed singular vectors, each of which is assigned a corresponding reference vector in a complex number plane;

a phase rotation section that performs phase rotation on the right-handed singular vector matrix calculated by the calculation section to generate a phase-rotated right-handed singular vector matrix, the phase rotation being performed by rotating a phase component of an element in each of the plurality of right handed singular vectors to a direction of the corresponding reference vector; and

a feedback section that feeds back, to a wireless transmission apparatus, information about a coefficient in the complex number plane, the coefficient being associated with an element of the phase-rotated right-handed singular vector matrix generated by the phase rotation section.

5. The wireless reception apparatus according to claim 4, wherein:

the phase rotation section rotates the phase component of one of a plurality of elements in each of the plurality of right-handed singular vectors to the direction of the corresponding reference vector, the plurality of elements being included in a single row of the right-handed singular vector matrix.

6. The wireless reception apparatus according to claim 4, wherein the right-handed singular vector matrix has a plurality of right-handed singular vectors, and the phase rotation section eliminates a phase component of an element in each of the plurality of right handed singular vectors.

7. The wireless reception apparatus according to claim 4, wherein:

the calculation section further calculates a left-handed singular vector matrix from the estimation result; and

the phase rotation section performs phase rotation on the left-banded singular vector matrix calculated by the calculation section, and the wireless reception apparatus further comprising;

an application section that applies, to a received signal, a conjugate transposed matrix of the left-handed singular vector matrix subjected to the phase rotation by the phase rotation section, to obtain an estimate of data transmitted from the wireless transmission apparatus.

8. A wireless reception apparatus comprising:

a calculation section that calculates a right-handed singular vector matrix from an estimation result of a multiple input multiple output (MIMO) channel, the right-handed singular vector matrix having a plurality of right-handed singular vectors;

a phase rotation section that performs phase rotation on the right-handed singular vector matrix calculated by the calculation section to generate a phase-rotated right-handed singular vector matrix, the phase rotation being performed by arranging an element in each of the plurality of right-handed singular vectors on a positive real axis of a coordinate system in a complex number plane; and

a feedback section that feeds back, to a wireless transmission apparatus, information about a coefficient in the complex number plane, the coefficient being associated with an element of the phase-rotated right-handed singular vector matrix generated by the phase rotation section.

9. The wireless reception apparatus according to claim 8, wherein:

the phase rotation section arranges one of a plurality of elements in each of the plurality of right-handed singular vectors on the positive real axis, the elements being included in a single row of the right-handed singular vector matrix.

10. The wireless reception apparatus according to claim 8, wherein the right-handed singular vector matrix has a plurality of right-handed singular vectors, and the phase rotation section eliminates a phase component of an element in each of the plurality of right handed singular vectors.

11. The wireless reception apparatus according to claim 8, wherein:

the calculation section further calculates a left-handed singular vector matrix from the estimation result; and

the phase rotation section performs phase rotation on the left-handed singular vector matrix calculated by the calculation section, and the wireless reception apparatus further comprising;

an application section that applies, to a received signal, a conjugate transposed matrix of the left-handed singular vector matrix subjected to the phase rotation by the phase rotation section, to obtain an estimate of data transmitted from the wireless transmission apparatus.

12. A wireless communication system comprising a wireless reception apparatus and a wireless transmission apparatus, wherein:

the wireless reception apparatus comprises;

a calculation section that calculates a right-handed singular vector matrix from an estimation result of a multiple input multiple output (MIMO) channel;

a phase rotation section that performs phase rotation on the right-handed singular vector matrix calculated by the calculation section to generate a phase-rotated right-handed singular vector matrix, the phase rotation being performed by using a unitary matrix containing a diagonal element having a value corresponding to a point on a unit circle in a complex number plane; and

a feedback section that feeds back, to said wireless transmission apparatus, information about a coefficient in the complex number plane, the coefficient being associated with an element of the phase-rotated right-handed singular vector matrix generated by the phase rotation section, and

the wireless transmission apparatus comprises;

an acquisition section that acquires the information which is fed back from the wireless reception apparatus;

a generation section that generates a transmission filter using the information acquired by the acquisition section; and

an application section that applies the transmission filter generated by the generation section to data, to be transmitted to the wireless reception apparatus via the MIMO channel.

13. A wireless reception method comprising:

calculating a right-handed singular vector matrix from an estimation result of a multiple input multiple output (MIMO) channel;

performing phase rotation on the calculated right-handed singular vector matrix to generate a phase-rotated right-handed singular vector matrix, the phase rotation being performed by using a unitary matrix containing a diagonal element having a value corresponding to a point on a unit circle in a complex number plane; and

feeding back information about a coefficient in the complex number plane, the coefficient being associated with an element of the phase-rotated right-handed singular vector matrix generated by the phase rotation.

14. A wireless communication method comprising:

calculating a right-handed singular vector matrix from an estimation result of a multiple input multiple output (MIMO) channel;

performing phase rotation on the calculated right-handed singular vector matrix to generate a phase-rotated right-handed singular vector matrix, the phase rotation being performed by using a unitary matrix containing a diagonal element having a value corresponding to a point on a unit circle in a complex number plane;

feeding back information about a coefficient in the complex number plane, the coefficient being associated with an element of the phase-rotated right-handed singular vector matrix generated by the phase rotation;

generating a transmission filter using the fed back information; and

applying the generated transmission filter to data to be transmitted via the MIMO channel.