WIRELESS RECEPTION APPARATUS, WIRELESS TRANSMISSION APPARATUS, WIRELESS COMMUNICATION SYSTEM, WIRELESS RECEPTION METHOD, WIRELESS TRANSMISSION METHOD, AND WIRELESS COMMUNICATION METHOD

• US 20090061786A1
• Filed: 04/14/2005
• Published: 03/05/2009
• Est. Priority Date: 04/14/2005
• Status: Active Grant

• Current Assignee: Intertechnology Global LLC (IP Edge LLC)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Malik, Rahul, Tan, Pek Yew
• Granted Patent: US 8,145,128 B2
• Time in Patent Office: Days
• US Class Current: 455/69
• 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 derivation section that derives a phase-rotated right-handed singular vector matrix from an estimation result of a MIMO (Multiple Input Multiple Output) channel; and

a feedback section that feeds back, to a wireless transmission apparatus, a coefficient associated with an element of the phase-rotated right-handed singular vector matrix derived by said derivation section.

2. The wireless reception apparatus according to claim 1, wherein said derivation section comprises:

a calculation section that calculates a right-handed singular vector matrix from the estimation result; and

a phase rotation section that performs phase rotation on the right-handed singular vector matrix calculated by said calculation section to generate the phase-rotated right-handed singular vector matrix.

3. The wireless reception apparatus according to claim 2, wherein said phase rotation section determines a unitary matrix containing a diagonal element having a value corresponding to a point on a unit circle in a complex number plane, and performs phase rotation using the determined unitary matrix.

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

5. The wireless reception apparatus according to claim 2, wherein the right-handed singular vector matrix has a plurality of right-handed singular vectors, each of which is assigned a corresponding reference vector in a complex number plane, and

said phase rotation section rotates a phase component of an element in each of the plurality of right handed singular vectors to a direction of the corresponding reference vector.

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

said phase rotation section rotates a 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.

7. The wireless reception apparatus according to claim 2, wherein the right-handed singular vector matrix has a plurality of right-handed singular vectors, and

said phase rotation section arranges 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.

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

said phase rotation section arranges one of the 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.

9. The wireless reception apparatus according to claim 2, wherein said calculation section further calculates a left-handed singular vector matrix from the estimation result, said phase rotation section performs phase rotation on the left-handed singular vector matrix calculated by said calculation section, and the apparatus further comprising:

an application section that applies a conjugate transposed matrix of the left-handed singular vector matrix subjected to phase rotation by said phase rotation section to a received signal;

to obtain an estimate of data transmitted from said wireless transmission apparatus.

10. The wireless reception apparatus according to claim 2, further comprising:

a selection signal generation section that generates a selection signal based on which said transmission apparatus is allowed to obtain a valid solution from a plurality of solutions for a transmission filter to be applied to data to be transmitted by said wireless transmission apparatus, and

said feedback section feeds back the selection signal generated by said selection signal generation section to said wireless transmission apparatus.

11. A wireless transmission apparatus comprising:

an acquisition section that acquires a coefficient which is fed back from a wireless reception apparatus;

a generation section that generates a transmission filter by substituting the coefficient acquired by said acquisition section in a predetermined relation; and

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

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

said wireless reception apparatus comprises;

a derivation section that derives a phase-rotated right-handed singular vector matrix from an estimation result of a MIMO channel; and

a feedback section that feeds back, to said wireless transmission apparatus, a coefficient associated with an element of the phase-rotated right-handed singular vector matrix derived by said derivation section, and said wireless transmission apparatus comprises;

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

a generation section that generates a transmission filter by substituting the coefficient acquired by said acquisition section in a predetermined relation; and

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

13. A wireless reception method comprising:

a derivation step of deriving a phase-rotated right-handed singular vector matrix from an estimation result of a MIMO channel; and

a feedback step of feeding back a coefficient associated with an element of the phase-rotated right-handed singular vector matrix derived in said derivation step.

14. A wireless transmission method comprising:

an acquisition step of acquiring a fed-back coefficient;

a generation step of generating a transmission filter by substituting the fed-back coefficient acquired in said acquisition step in a predetermined relation; and

an application step of applying the transmission filter generated in said generation step to data to be transmitted via a MIMO channel.

15. A wireless communication method comprising:

a derivation step of deriving a phase-rotated right-handed singular vector matrix from an estimation result of a MIMO channel;

a feedback step of feeding back a coefficient associated with an element of the phase-rotated right-handed singular vector matrix derived in said derivation step;

a generation step of generating a transmission filter by substituting the coefficient fed back in the feedback step in a predetermined relation; and

an application step of applying the transmission filter to data to be transmitted via the MIMO channel.