Method and apparatus for power line communication

a technology of transmission line and communication method, applied in the direction of transmission line, transmission monitoring, line-transmission details, etc., can solve the problems of not always achieving maximum communication efficiency, disturb communication, etc., and achieve high throughput and high precision

Inactive Publication Date: 2008-04-10
YOSHIDA SHIGEO +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0009] Therefore, an object of the present invention is to provide a communication apparatus in which a transmission line is estimated in a distributed manner by a simple scheduling, so that the characteristics of the transmission line are estimated and evaluated with a high precision and thus data can be sent and received at a high throughput without affecting other streams, and a transmission line estimation method performed by the communication apparatus.
[0014] As described above, according to the present invention, a transmission line is estimated in a distributed manner by a simple scheduling, so that the characteristics of the transmission line are estimated and evaluated with a high precision and thus data can be sent and received at a high throughput without affecting other streams.

Problems solved by technology

However, in an environment in which the characteristics of the transmission line vary periodically, the communication parameters selected when estimating the transmission line often do not suit for the characteristics of the transmission line when sending data if a timing of sending data is not synchronized with the periodical variation of the characteristics of the transmission line.
Thus, in the above-described conventional method, the maximum communication efficiency is not always obtained even when the transmission line is estimated.
However, in the conventional method shown in FIG. 12, there is the problem that the transmission line is estimated continuously, and thus requests to estimate the transmission line and their response messages occupy the transmission line and disturb communications of stream data, audio data, or other data that is supposed to be sent.
As a result, when the band is guaranteed, for example, with time sharing, not only is scheduling for transmission line estimation complicated, but also arises a case in which a scheduling condition cannot be satisfied.

Method used

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  • Method and apparatus for power line communication

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first embodiment

[0028]FIG. 1 is a diagram showing a configuration example of a communication network system using a communication apparatus 1 according to a first embodiment of the present invention. In FIG. 1, in the communication network system of the present invention, a plurality of communication apparatuses 1 are connected to each other via a transmission line 2. The transmission line 2 may be either wired or wireless. This embodiment will be described using, as an example, the communication network system in which one of the plurality of communication apparatuses 1 is a master unit, and this master unit periodically transmits a beacon so as to control the communications of the other communication apparatuses 1 (slave units).

[0029] The communication apparatus 1 is provided with a communication control portion 11, a transmission line estimation portion 12, and a communication parameter determination portion 13. The communication control portion 11 deals with most of the communication processes...

second embodiment

[0048] The first embodiment described above is a technique assuming that the variation cycle of the characteristics of the transmission line is known in advance. Then, in a second embodiment below, a technique will be described in which an optimal beacon period can be set automatically even when the variation cycle of the characteristics of the transmission line is not known in advance.

[0049] For example, a case will be described in which the communication apparatus 1 can set both of a beacon period T1 (FIG. 9) when the variation cycle L of the characteristics of the transmission line , which is synchronized with a commercial power supply frequency of 60 Hz, is 8.333 msec and when the integers n=3 and m=17, and a beacon period T2 (FIG. 10) when the variation cycle L of the characteristics of the transmission line, which is synchronized with a commercial power supply frequency of 50 Hz, is 10 msec and when the variables n=3 and m=17. In this case, the communication apparatus 1 estim...

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Abstract

The variation cycle L of the characteristics of a transmission line is divided into a plurality of sections (n sections), a procedure is repeated in which transmission line estimation is performed for only one section among n sections in one beacon period, and thus transmission line estimation is performed for all of the n sections. The beacon period T is set based on (T=L×m / n), where n is an integer that is 2 or larger, and m is an integer that is n or larger and whose greatest common measure with n is 1.

Description

[0001] This is a Continuation of Ser. No. 10 / 573,774, filed Mar. 28, 2006, now Pat. No. 7,298,706, which is the National Stage of International Application No. PCT / JP2005 / 015499.TECHNICAL FIELD [0002] The present invention relates to a communication apparatus and a transmission line estimation method. More specifically, the present invention relates to a communication apparatus sending and receiving data based on the characteristics of a transmission line between apparatuses without lowering the throughput, and a transmission line estimation method (channel estimation) performed by the communication apparatus, by which the characteristics of the transmission line are estimated and evaluated with a high precision. BACKGROUND ART [0003] In a communication method by which communication parameters such as a subcarrier and a modulation method used for transmission and reception are determined based on estimation on the characteristics of a transmission line, it is important to precisely ...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): H04B17/00
CPCH04B2203/5495H04B3/542H04B3/54
InventorYOSHIDA, SHIGEOOHMI, SHINICHIROYASUKAWA, TOHRUYAMAGUCHI, TSUYOSHI
OwnerYOSHIDA SHIGEO