Optical wireless communication system
First Claim
1. A method for preventing interference between adjacent sections in an optical wireless communication system wherein a center device communicates concurrently through lines with a plurality of parent devices each disposed in one of the sections, each of said parent devices communicating with a plurality of child devices disposed in the same section as that of the parent device the method comprising the steps of:
- in a first period of a first communication cycle, said center device permitting each of said parent devices belonging to a first group of sections which do not adjoin each other to communicate with child devices disposed in the same section where each of parent devices belonging to said first group is disposed;
in a second period of said first communication cycle, said center device permitting each of said parent devices belonging to a second group of sections which do not adjoin each other and are different from those of said first group to communicate with child devices disposed in the same section in which each of parent devices belonging to said second group is disposed;
said center device executing all of said steps in each communication cycle in numerical sequence starting from said first period of said first communication cycle wherein;
in each period of each communication cycle, each parent device communicates through optical wireless links with child devices disposed in the same section where said parent device is disposed and wherein the operation of the center device to permit each parent device to communicate with the child devices in the same section thereof comprises the steps ofcollecting up-link requesting child device IDs from said each of said sections through a parent device disposed in each of the sections; and
on the basis of said up-link requesting child device IDs from said each of said sections and IDs of child devices whose up-link request have been brought over from a previous communication cycle, limiting the number of up-links in said each of said sections to an average up-link number per section and bringing over limited up-links to the next communication cycle.
1 Assignment
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Accused Products
Abstract
Interference between adjacent sections is prevented in an optical wireless communication system, in which a center device is capable of concurrently communicating through lines with a plurality of parent devices each disposed in one of the sections into which a communication area of the system is divided and each of the parent devices communicates with a plurality of child devices disposed in the same section where said parent device is disposed. The sections is grouped into some groups of sections which do not adjoin each other. Optical wireless communications are done only within one group of sections in each communication period. Some techniques for improving the effect of communication are disclosed.
22 Citations
13 Claims
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1. A method for preventing interference between adjacent sections in an optical wireless communication system wherein a center device communicates concurrently through lines with a plurality of parent devices each disposed in one of the sections, each of said parent devices communicating with a plurality of child devices disposed in the same section as that of the parent device the method comprising the steps of:
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in a first period of a first communication cycle, said center device permitting each of said parent devices belonging to a first group of sections which do not adjoin each other to communicate with child devices disposed in the same section where each of parent devices belonging to said first group is disposed; in a second period of said first communication cycle, said center device permitting each of said parent devices belonging to a second group of sections which do not adjoin each other and are different from those of said first group to communicate with child devices disposed in the same section in which each of parent devices belonging to said second group is disposed; said center device executing all of said steps in each communication cycle in numerical sequence starting from said first period of said first communication cycle wherein; in each period of each communication cycle, each parent device communicates through optical wireless links with child devices disposed in the same section where said parent device is disposed and wherein the operation of the center device to permit each parent device to communicate with the child devices in the same section thereof comprises the steps of collecting up-link requesting child device IDs from said each of said sections through a parent device disposed in each of the sections; and on the basis of said up-link requesting child device IDs from said each of said sections and IDs of child devices whose up-link request have been brought over from a previous communication cycle, limiting the number of up-links in said each of said sections to an average up-link number per section and bringing over limited up-links to the next communication cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An optical wireless communication system free from interference between adjacent sections wherein a communication area is divided into a plurality sections, comprising:
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a center device; plurality of parent devices each disposed in one of said sections, said center device communicating concurrently with said parent devices through conductive lines; and a plurality of child devices disposed in each of said sections, with each of said parent devices communicating with said plurality of child devices disposed in the same section as said parent device is disposed, wherein said center device comprises; means operative in a hist period of a first communication cycle for permitting each of said parent devices belonging to a first group of sections which do not adjoin each other to communicate with child devices disposed in the same section to which each parent devices of said first group is disposed; means operative in a second period of said first communication cycle for permitting each of said parent devices belonging to a second group of sections which do not adjoin each other and are different from those of said first group of sections, to communicate with child devices disposed in the same section to which each of the parent devices of said second group are disposed; means for executing all of said steps in said first communication cycle in numerical sequence and symmetrically advancing to subsequent communication cycles in which each period is reexecuted, in sequence with each of said plurality of parent devices comprising; means, for communicating through optical wireless links with child devices disposed in the same section in which said parent device is disposed and wherein said system includes a center device connected to each parent device for controlling the communication of each parent device to each child device in the same section as the parent device, said center device comprising; means for collecting up-link requesting child device IDs from each of said sections through a parent device disposed in said each of said sections; and means, operative on the basis of said up-link requesting child device IDs from said each of said sections and IDs of child devices whose up-link request have been brought over from a previous communication cycle, for limiting the number of up-links in said each of said sections to an average up-link number per section and bringing over limited up-links to the next communication cycle. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification