CHANNEL STATE INFORMATION COMPRESSING APPARATUS AND METHOD, CHANNEL STATE INFORMATION EXPANDING APPARATUS AND METHOD, COMPUTER PROGRAMS, RECEIVER, AND TRANSMITTER

• US 20110135021A1
• Filed: 11/17/2010
• Published: 06/09/2011
• Est. Priority Date: 12/08/2009
• Status: Active Grant

• Current Assignee: KDDI Corporation
• Original Assignee: KDDI Corporation
• Inventors: Fukuhara, Tadayuki, Nagareda, Riichirou, HATAKAWA, Yasuyuki
• Granted Patent: US 8,638,845 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04B 17/327 Received signal code power [RSCP]
• CPC Class Codes: H04L 1/0029 Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling power control H04W52/04
• CPC Class Codes: H04L 1/0693 Partial feedback, e.g. partial channel state information [CSI]

Abstract

A channel state information compressing apparatus includes a time-to-frequency region converter that converts a region for channel state information which indicates a state of each communication channel from a time region to a frequency region; and an adaptive selector that selects each frequency component to be included in compressed data based on electric power of the frequency component from among frequency region data obtained by the time-to-frequency region converter. The channel state information compressing apparatus outputs the compressed data consisting of each selected frequency component, and information for identifying each frequency component which forms the compressed data.

Claims

1. A channel state information compressing apparatus comprising:

a time-to-frequency region converter that converts a region for channel state information which indicates a state of each communication channel from a time region to a frequency region; and

an adaptive selector that selects each frequency component to be included in compressed data based on electric power of the frequency component from among frequency region data obtained by the time-to-frequency region converter, wherein

the channel state information compressing apparatus outputs the compressed data consisting of each selected frequency component, and information for identifying each frequency component which forms the compressed data.

2. The channel state information compressing apparatus in accordance with claim 1, wherein the adaptive selector selects a predetermined number of frequency components in order of an amount of the electric power from the largest to the smallest.

3. The channel state information compressing apparatus in accordance with claim 1, wherein the adaptive selector selects a predetermined number of frequency components in order of an amount of the electric power from the largest to the smallest until the total amount of the electric power of the frequency components to be included in the compressed data reaches a predetermined value.

4. The channel state information compressing apparatus in accordance with claim 1, wherein the time-to-frequency region converter performs discrete cosine transform.

5. The channel state information compressing apparatus in accordance with claim 1, wherein:

the time-to-frequency region converter performs discrete cosine transform; and

the adaptive selector selects a predetermined number of frequency components in order of frequency of each frequency component from the lowest to the highest until the total amount of the electric power of the frequency components to be included in the compressed data reaches a predetermined value.

6. A channel state information expanding apparatus comprising:

an information compensator that complements compressed data of frequency region data for channel state information which indicates a state of each communication channel, with each missing frequency component based on information for identifying each frequency component which forms the compressed data; and

a frequency-to-time region converter that converts a region of the frequency region data complemented by the information compensator from a frequency region to a time region.

7. The channel state information expanding apparatus in accordance with claim 6, wherein the frequency-to-time region converter performs inverse discrete cosine transform.

8. A channel state information compressing method comprising the steps of:

converting a region for channel state information which indicates a state of each communication channel from a time region to a frequency region;

selecting each frequency component to be included in compressed data based on electric power of the frequency component from among frequency region data obtained by the converting step;

outputting the compressed data consisting of each selected frequency component, and information for identifying each frequency component which forms the compressed data.

9. A channel state information expanding method comprising the steps of:

complementing compressed data of frequency region data for channel state information which indicates a state of each communication channel, with each missing frequency component based on information for identifying each frequency component which forms the compressed data; and

converting a region of the complemented frequency region data from a frequency region to a time region.

10. A computer program for making a computer execute the steps of:

converting a region for channel state information which indicates a state of each communication channel from a time region to a frequency region;

selecting each frequency component to be included in compressed data based on electric power of the frequency component from among frequency region data obtained by the converting step;

outputting the compressed data consisting of each selected frequency component, and information for identifying each frequency component which forms the compressed data.

11. A computer program for making a computer execute the steps of:

complementing compressed data of frequency region data for channel state information which indicates a state of each communication channel, with each missing frequency component based on information for identifying each frequency component which forms the compressed data; and

converting a region of the complemented frequency region data from a frequency region to a time region.

12. A receiver in a MIMO system, comprising:

a time-to-frequency region converter that converts a region for channel state information between the receiver and a transmitter in the MIMO system;

an adaptive selector that selects each frequency component to be included in compressed data based on electric power of the frequency component from among frequency region data obtained by the time-to-frequency region converter; and

a sending unit that sends the transmitter the compressed data consisting of each selected frequency component, and information for identifying each frequency component which forms the compressed data.

13. A transmitter in a MIMO system, comprising:

a receiving unit that receives compressed data of frequency region data for channel state information between the transmitter and a receiver in the MIMO system and information for identifying each frequency component which forms the compressed data, from the receiver;

an information compensator that complements the compressed data with each missing frequency component based on the information for identifying each frequency component which forms the compressed data;

a frequency-to-time region converter that converts a region of the frequency region data complemented by the information compensator from a frequency region to a time region; and

a precoding unit that precodes data to be transmitted in the MIMO system by using channel state information obtained by the frequency-to-time region converter.