COMMUNICATION SYSTEM AND COMMUNICATION METHOD

• US 20140369236A1
• Filed: 09/02/2014
• Published: 12/18/2014
• Est. Priority Date: 03/05/2012
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: KAWASUMI, Hiroaki, KOHARAGI, Takahiro, KOBAYASHI, Katsumi, KONDO, Taiji, ITO, Takao, NAKAJIMA, Kobun, KUROSAWA, Satoshi, MATSUBARA, Shigemasa, SHIROKURA, Yoshihiko
• Granted Patent: US 9,525,614 B2
• Time in Patent Office: Days
• US Class Current: 370/254
• 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

the nodes each include

a link quality evaluating unit configured to perform 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,

an upstream route constructing unit configured to construct an upstream route based on the route evaluation by the link quality evaluating unit,

a communicating unit configured to perform upstream communication toward the specific node on a regular basis with a predetermined frequency, and

a downstream route constructing unit configured to construct a downstream route from the specific node based on a route in the upstream communication toward the specific node.

2. The communication system according to claim 1, wherein the specific node includes a reactive route constructing unit that constructs a route using a route request frame when downstream communication through the downstream route constructed by the downstream route constructing unit 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;

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.