Channel state information compressing apparatus and method, channel state information expanding apparatus and method, computer programs, receiver, and transmitter

• US 8,638,845 B2
• Filed: 11/17/2010
• Issued: 01/28/2014
• Est. Priority Date: 12/08/2009
• Status: Active Grant

• Current Assignee: KDDI Corporation
• Original Assignee: KDDI Corporation
• Inventors: Hatakawa, Yasuyuki, Fukuhara, Tadayuki, Nagareda, Riichirou
• Primary Examiner(s): Liu, Shuwang
• Assistant Examiner(s): TAYONG, HELENE E
• Application Number:
  US12/948,323
• Publication Number:
  US 20110135021A1
• Time in Patent Office: 1,168 Days
• Field of Search: 375/240, 375/260, 375/267, 375/295, 375/316, 455/450, 370/329, 370/332, 714/776
• US Class Current: 375/240
• 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 provided in a receiver of a MIMO system in which a transmitter precodes transmitted data based on information received from the receiver, wherein the channel state information compressing apparatus comprises:

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, where the channel state information is a channel response matrix defined between a plurality of reception antennas of the receiver and a plurality of transmission antennas of the transmitter; 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 adaptive selector selects a predetermined number of frequency components in order of an amount of the electric power from the largest to the smallest,

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 the predetermined number of frequency components in order of the 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.

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

4. A channel state information compressing apparatus provided in a receiver of a MIMO system in which a transmitter precodes transmitted data based on information received from the receiver, wherein the channel state information compressing apparatus comprises:

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, where the channel state information is a channel response matrix defined between a plurality of reception antennas of the receiver and a plurality of transmission antennas of the transmitter; 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 time-to-frequency region converter performs discrete cosine transform;

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; and

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.

5. A channel state information expanding apparatus provided in a transmitter of a MIMO system in which the transmitter precodes transmitted data based on information received from a receiver, wherein the channel state information expanding apparatus comprises:

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, where the channel state information is a channel response matrix defined between a plurality of reception antennas of the receiver and a plurality of transmission antennas of the transmitter, and the compressed data includes each frequency component selected based on electric power thereof, from among the frequency region data obtained by converting a region for the channel response matrix from a time region to a frequency region, wherein a predetermined number of frequency components are selected in order of an amount of the electric power from the largest to the smallest; and

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

6. The channel state information expanding apparatus in accordance with claim 5, wherein the frequency-to-time region converter performs inverse discrete cosine transform.

7. A channel state information compressing method used in a MIMO system in which a transmitter precodes transmitted data based on information received from a receiver, wherein the channel state information compressing method comprises 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, where the channel state information is a channel response matrix defined between a plurality of reception antennas of the receiver and a plurality of transmission antennas of the transmitter;

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, wherein a predetermined number of frequency components are selected in order of an amount of the electric power from the largest to the smallest;

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

8. A channel state information expanding method used in a MIMO system in which a transmitter precodes transmitted data based on information received from a receiver, wherein the channel state information expanding method comprises 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, where the channel state information is a channel response matrix defined between a plurality of reception antennas of the receiver and a plurality of transmission antennas of the transmitter, and the compressed data includes each frequency component selected based on electric power thereof, from among the frequency region data obtained by converting a region for the channel response matrix from a time region to a frequency region, wherein a predetermined number of frequency components are selected in order of an amount of the electric power from the largest to the smallest; and

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

9. A non-transitory computer-readable storage medium that stores a program used in a MIMO system in which a transmitter precodes transmitted data based on information received from a receiver, wherein the program makes 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, where the channel state information is a channel response matrix defined between a plurality of reception antennas of the receiver and a plurality of transmission antennas of the transmitter;

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, wherein a predetermined number of frequency components are selected in order of an amount of the electric power from the largest to the smallest;

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

10. A non-transitory computer-readable storage medium that stores a program used in a MIMO system in which a transmitter precodes transmitted data based on information received from a receiver, wherein the program makes 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, where the channel state information is a channel response matrix defined between a plurality of reception antennas of the receiver and a plurality of transmission antennas of the transmitter, and the compressed data includes each frequency component selected based on electric power thereof, from among the frequency region data obtained by converting a region for the channel response matrix from a time region to a frequency region, wherein a predetermined number of frequency components are selected in order of an amount of the electric power from the largest to the smallest; and

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

11. A receiver in a MIMO system in which a transmitter precodes transmitted data based on information received from the receiver, wherein the receiver comprises:

a time-to-frequency region converter that converts a region for channel state information between the receiver and the transmitter, where the channel state information is a channel response matrix defined between a plurality of reception antennas of the receiver and a plurality of transmission antennas of the transmitter;

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 adaptive selector selects a predetermined number of frequency components in order of an amount of the electric power from the largest to the smallest; and

a sending device 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.

12. A transmitter in a MIMO system in which the transmitter precodes transmitted data based on information received from a receiver, wherein the transmitter comprises:

a receiving device that receives compressed data of frequency region data for channel state information between the transmitter and the receiver and information for identifying each frequency component which forms the compressed data, from the receiver, where the channel state information is a channel response matrix defined between a plurality of reception antennas of the receiver and a plurality of transmission antennas of the transmitter, and the compressed data includes each frequency component selected based on electric power thereof, from among the frequency region data obtained by converting a region for the channel response matrix from a time region to a frequency region, wherein a predetermined number of frequency components are selected in order of an amount of the electric power from the largest to the smallest;

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 the frequency region to the time region; and

a precoding device that precodes the transmitted data by using the channel response matrix obtained by the frequency-to-time region converter.