Communication system and communication method

• US 9,525,614 B2
• Filed: 09/02/2014
• Issued: 12/20/2016
• Est. Priority Date: 03/05/2012
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kondo, Taiji, Ito, Takao, Kawasumi, Hiroaki, Koharagi, Takahiro, Kobayashi, Katsumi, Nakajima, Kobun, Kurosawa, Satoshi, Matsubara, Shigemasa, Shirokura, Yoshihiko
• Primary Examiner(s): WILLIAMS, JENEE LAUREN
• Application Number:
  US14/474,690
• Publication Number:
  US 20140369236A1
• Time in Patent Office: 840 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04W 40/12 based on transmission quality or channel quality
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 84/22 with access to wired networks

Abstract

A communication system includes: a specific node; and a plurality of nodes that are installed at fixed positions and perform ad hoc wireless communication with the specific node. The nodes each include a link quality evaluating unit, an upstream route constructing unit, a communicating unit, and a downstream route constructing unit. The link quality evaluating unit performs route evaluation using a hello frame based only on a track record of reception of the hello frame in order to perform upstream communication toward the specific node to form a network. The upstream route constructing unit constructs an upstream route based on the route evaluation. The communicating unit performs upstream communication toward the specific node on a regular basis with a predetermined frequency. The downstream route constructing unit constructs a downstream route from the specific node based on a route in the upstream communication toward the specific node.

Claims

1. A communication system comprising:

a specific node; and

a plurality of nodes configured to be installed at fixed positions and perform ad hoc wireless communication with the specific node, wherein

each of the nodes include first processer that executes a first process including;

performing route evaluation using a hello frame based only on a track record of reception of the hello frame in order to perform upstream communication toward the specific node to form a network,

constructing an upstream route based on the route evaluation,

performing upstream communication toward the specific node on a regular basis with a predetermined frequency, and

constructing a downstream route from the specific node based on a route in the upstream communication toward the specific node, and

the specific node includes a second processor that executes a second process including;

updating the downstream route based on a track record of the most recent transfers, which is updated in response to a route diversion of frames transferred on the regular basis in the upstream communication from each of the plurality of nodes to the specific node; and

preferentially reusing the downstream route constructed based on the track record of the most recent transfers.

2. The communication system according to claim 1, wherein the second process further includes constructing a route using a route request frame when downstream communication through the downstream route constructed in the first process is failed.

3. A communication method for a plurality of nodes included in a communication system including a specific node, and a plurality of nodes that are installed at fixed positions and perform ad hoc wireless communication with the specific node, the communication method comprising:

performing route evaluation using a hello frame based only on a track record of reception of the hello frame in order to perform upstream communication toward the specific node to form a network and constructing an upstream route, by each of the plurality of nodes;

performing upstream communication toward the specific node on a regular basis with a predetermined frequency, by each of the plurality of nodes;

constructing a downstream route from the specific node based on a route in the upstream communication toward the specific node, by each of the plurality of nodes;

updating the downstream route based on a track record of the most recent transfers, which is updated in response to a route diversion of frames transferred on the regular basis in the upstream communication from the each of the plurality of nodes to the specific node, by the specific node; and

preferentially reusing the downstream route constructed based on the track record of the most recent transfers, by the specific node.