MULTI-CARRIER COMMUNICATION APPARATUS, POWER LINE COMMUNICATION CIRCUIT, AND MULTI-CARRIER COMMUNICATION METHOD

• US 20080013637A1
• Filed: 04/03/2007
• Published: 01/17/2008
• Est. Priority Date: 04/03/2006
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: ICHIHARA, Fumio, YUKIZANE, Ryota, OISHI, Mutsuhiko, KOGA, Hisao, KODAMA, Nobutaka
• Granted Patent: US 7,912,139 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04B 2203/5416 by adding signals to the wave form of the power source
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

Abstract

Provided is a multi-carrier communication apparatus, power line communication circuit, and multi-carrier communication method capable of decreasing omission of carrier detection even when a plurality of communication apparatuses are simultaneously transmitting signals at the state of time discord. Digital signals transmitted from a digital signal-processing unit 1 are converted into analog signals by an analog circuit unit 2 and then transmitted from a pair of lines 61 and 62 via a communication transformer 3. The digital signal-processing unit 1 has a frequency carrier detecting unit 10 which detects the existence of a carrier on the basis of a frequency characteristic of the received signal and the frequency carrier detecting unit 10 detects the carrier by taking correlation between sub-carriers adjacent to each other at every other interval.

Claims

1. A multi-carrier communication apparatus which receives a multi-carrier signal from one multi-carrier communication apparatuses via a transmission line, the multi-carrier communication apparatus comprising:

a complex signal-transformer which transforms a time-domain signal received via the transmission line into at least three complex signals, each of the three complex signals being corresponding to frequency different from each other;

a phase difference-calculator which calculates a phase difference between a pair of the complex signals among the at least three complex signals, the pair of the complex signals being not adjacent to each other on a frequency domain; and

a multi-carrier signal-determining unit which determines, on the basis of the phase difference, whether the time-domain signal is the multi-carrier signal.

2. The multi-carrier communication apparatus according to claim 1, further comprising a phase difference distribution-generator which generates distribution of the phase difference on the complex coordinates,

wherein the phase difference-calculator calculates a plurality of phase differences;

the phase difference distribution-generator generates the distribution of the plurality of phase differences; and

the multi-carrier signal-determining unit determines, on the basis of the distribution of the plurality of phase differences, whether the time-domain signal is the multi-carrier signal.

3. The multi-carrier communication apparatus according to claim 1, wherein the phase difference-calculator calculates the phase difference between the pair of the complex signals, the pair of the complex signals being adjacent to each other at one interval.

4. The multi-carrier communication apparatus according to claim 1, wherein the multi-carrier signal is a frame including a preamble and a synchronization word.

5. The multi-carrier communication apparatus according to claim 4, wherein at least one of the preamble and the synchronization word has a predetermined constant value on the frequency domain.

6. The multi-carrier communication apparatus according to claim 1, wherein the multi-carrier signal has a predetermined constant value on the frequency domain.

7. The multi-carrier communication apparatus according to claim 1, wherein the transmission line is a power line.

8. The multi-carrier communication apparatus according to claim 7, further comprising:

a coupler separating a communication signal from an alternating voltage of the power line;

a filter block which is connected to the coupler and to which the communication signal separated by the coupler is inputted; and

an AD converter connected to the filter block and converting the communication signal passed through the filter block into a digital signal, wherein the filter block includes,

a plurality of high-pass filters having mutually different cutoff frequencies,

a plurality of low-pass filters having mutually different cutoff frequencies, and

a selector selecting at least one high-pass filter and at least one low-pass filter from the plurality of high-pass and low-pass filters so that the communication signal separated by the coupler passes through the selected filters.

9. The multi-carrier communication apparatus according to claim 8, wherein the selector includes,

input switches selectively connecting to each input terminal of the plurality of high-pass filters and the plurality of low-pass filters;

output switches selectively connecting to each output terminal of the plurality of high-pass filters and the plurality of low-pass filters; and

bypass lines being selectively connected to the input switches and the output switches and bypassing each of the plurality of high-pass filters and the plurality of low-pass filters,

wherein the plurality of high-pass filters and the plurality of low-pass filters are selectively connected in series through the input switches and the output switches between the coupler and the AD converter.

10. The multi-carrier communication apparatus according to claim 8, wherein the selector has

input switches selectively connected to each input terminal of the high-pass filters excluding the high-pass filter with the lowest cutoff frequency among the plurality of high-pass filters and the low-pass filters excluding the low-pass filter with the highest cutoff frequency;

output switches selectively connected to each output terminals of the high-pass filters excluding the high-pass filter with the lowest cutoff frequency among the plurality of high-pass filters and the low-pass filters excluding the low-pass filter with the highest cutoff frequency; and

bypass lines for bypassing each of the high-pass filters excluding the high-pass filter with the lowest cutoff frequency among the plurality of high-pass filters and the low-pass filters excluding the low-pass filter with the highest cutoff frequency among the plurality of low-pass filters when the input switches and the output switches are selectively connected,

wherein the high-pass filter with the lowest cutoff frequency among the plurality of the high-pass filters and the low-pass filter with the highest cutoff frequency among the plurality of low-pass filters are directly connected between the coupler and the AD converter in series; and

the high-pass filter excluding the high-pass filter with the lowest cutoff frequency among the plurality of high-pass filters and the low-pass filter excluding the high-pass filter with the highest cutoff frequency among the plurality of low-pass filters are selectively connected via the input switches and the output switches between the coupler and the AD converter in series.

11. The multi-carrier communication apparatus according to claim 8, wherein the selector has

input switches of the high-pass filter selectively connected to input terminals of the plurality of high-pass filters;

output switches of the high-pass filter selectively connected to input terminals of the plurality of high-pass filters;

input switches of the low-pass filter selectively connected to input terminals of the plurality of low-pass filters; and

output switches of the low-pass filter selectively connected to input terminals of the plurality of low-pass filters,

wherein any one of the plurality of high-pass filters and any one of the plurality of low-pass filters are connected via the input switches and the output switches between the coupler and the AD converter in series.

12. The multi-carrier communication apparatus according to claim 8, wherein the selector has

input switches selectively connected to input terminals of the high-pass filters excluding the high-pass filter with the lowest cutoff frequency among the plurality of high-pass filters, input terminals of the low-pass filters excluding the low-pass filter with the highest cutoff frequency among the plurality of low-pass filters, and bypass lines;

and

output switches selectively connected to output terminals of the high-pass filters excluding the high-pass filter with the lowest cutoff frequency among the plurality of high-pass filters, output terminals of the low-pass filters excluding the low-pass filter with the highest cutoff frequency among the plurality of low-pass filters, and the bypass lines,

wherein the high-pass filter with the lowest cutoff frequency among the plurality of high-pass filters and the low-pass filter with the highest cutoff frequency among the plurality of low-pass filters are directly connected between the coupler and the AD converter; and

the high-pass filter excluding the high-pass filter with the lowest cutoff frequency among the plurality of high-pass filters and the low-pass filter excluding the low-pass filter with the highest cutoff frequency among the plurality of low-pass filters are selectively connected via the input switches and the output switches between the coupler and the AD converter in series.

13. The multi-carrier communication apparatus according to claim 8, wherein the selector has output terminals of the high-pass filters excluding the high-pass filter with the lowest cutoff frequency among the plurality of high-pass filters;

output terminals of the low-pass filters excluding the low-pass filter with the highest cutoff frequency among the plurality of low-pass filters; and

output switches selectively connected to bypass lines,

wherein the high-pass filter with the lowest cutoff frequency among the plurality of high-pass filters and the low-pass filter with the highest cutoff frequency among the plurality of low-pass filters are connected to the coupler in series and are connected to the input terminals of the high-pass filters excluding the high-pass filter with the lowest cutoff frequency among the plurality of the high-pass filters, input terminals of the low-pass filters excluding the low-pass filter with the highest cutoff frequency among the plurality of the low-pass filters, and the bypass lines; and

the output switches are connected to the AD converter.

14. A multi-carrier communication apparatus which receives a multi-carrier signal from one multi-carrier communication apparatuses via a transmission line, the multi-carrier communication apparatus comprising:

a complex signal-transformer which transforms a time domain signal received via the transmission line into a first complex signal corresponding to a first frequency, a second complex signal corresponding to a second frequency, and a third complex signal corresponding to a third complex signal, where the third frequency is higher than the second frequency and the second frequency is higher than the first frequency, and the first complex signal has a first phase and the third complex signal has a third phase;

a phase difference-calculator which calculates a phase difference between the first phase and the third phase; and

a multi-carrier signal-determining unit which determines, on the basis of the phase difference, whether the time signal is the multi-carrier signal.

15. A power line communication circuit which performs communication by using a power line, comprising:

a coupler separating a communication signal from an alternating voltage of the power line;

a filter block which is connected to the coupler and to which the communication signal separated by the coupler is inputted;

an AD converter which is connected to the filter block and converts the communication signal passed through the filter block into a digital signal,

wherein the filter block has a plurality of high-pass filters having mutually different cutoff frequencies, a plurality of low-pass filters having mutually different cutoff frequencies, a selector passing the communication signal separated by the coupler, selecting at least one high-pass filter and one low-pass filter among the plurality of high-pass filters and the plurality of low-pass filters.

16. A multi-carrier communication method of receiving a multi-carrier signal from one multi-carrier communication apparatuses via a transmission line, the method comprising the steps of:

transforming a time domain signal received via the transmission line into three or more complex signals, each of the three complex signals being corresponding to frequency different from each other;

calculating a phase difference between a pair of the complex signals, the pair of the complex signals being not adjacent to each other on a frequency domain; and

determining, on the basis of the phase difference, whether the time domain signals is the multi-carrier signal.