Master station of communication system and access control method

• US 20080117882A1
• Filed: 12/04/2007
• Published: 05/22/2008
• Est. Priority Date: 08/06/2003
• Status: Active Grant

• Current Assignee: Kensuke Yoshizawa, Shinichiro Ohmi, Tsuyoshi Yamaguchi
• Original Assignee: Kensuke Yoshizawa, Shinichiro Ohmi, Tsuyoshi Yamaguchi
• Inventors: Ohmi, Shinichiro, Yamaguchi, Tsuyoshi, Yoshizawa, Kensuke
• Granted Patent: US 7,957,342 B2
• Time in Patent Office: Days
• US Class Current: 370/336
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04W 12/08 Access security
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

A communication bandwidth is divided into a beacon period in which all master stations compete for transmission of a beacon packet, a first carrier sense multiple access (CSMA) period in which only authorized specific stations are allowed to compete for access, and a second CSMA period in which all stations are allowed to compete for access. The master stations exchange information with each other about a communication bandwidth being used in the first CSMA period, thereby calculating a communication bandwidth which can be used by each communication system in the first CSMA period, based on the information.

Claims

1. A master station used in a communication system in a system environment in which a plurality of communication systems, each of which is composed of the master station, share a same channel, the master station comprising

a communication section operable to communicate with a master station used in another communication system using a communication bandwidth of the channel,

wherein a beacon period is repeatedly set in the communication bandwidth of the channel on a periodic basis,

wherein the communication section receives a beacon packet transmitted from another master station in the beacon period, and

wherein the received beacon packet includes information representing an offset time from a start time of the beacon period, when the beacon packet is transmitted, to a transmission start time of the beacon packet.

2. The master station according to claim 1,

wherein the master station synchronizes the start time of the beacon period with the other master station based on the information included in the received beacon packet,

wherein the communication section transmits a beacon packet in the beacon period when the start time of the beacon period is synchronized with the other master station, and

wherein the beacon packet includes information representing an offset time from a start time of the beacon period, when the beacon packet is transmitted, to a transmission start time of the beacon packet.

3. A method of communication performed by a master station in a system environment in which a plurality of communication systems, each of which is composed of the master station, share a same channel,

wherein a beacon period is repeatedly set in the communication bandwidth of the channel on a periodic basis,

wherein a beacon packet transmitted from another master station in the beacon period is received, and

wherein the received beacon packet includes information representing an offset time from a start time of the beacon period, when the beacon packet is transmitted, to a transmission start time of the beacon packet.

4. The method of communication according to claim 3,

wherein synchronization of the start time of the beacon period with the other master station is performed based on the information included in the received beacon packet,

wherein a beacon packet is transmitted in the beacon period when the start time of the beacon period is synchronized with the other master station, and

wherein the beacon packet includes information representing an offset time from a start time of the beacon period, when the beacon packet is transmitted, to a transmission start time of the beacon packet.

5. A master station used in a communication system in a system environment in which a plurality of communication systems, each of which is composed of the master station, share a same channel, the master station comprising

a communication section operable to communicate with a master station used in another communication system using a communication bandwidth of the channel,

wherein the communication section receives a beacon packet transmitted from another master station in a beacon period set in a communication bandwidth of the channel, and

wherein the received beacon packet includes information representing a timer value of the other master station at a transmission start time of the beacon packet.

6. The master station according to claim 5,

wherein the master station corrects its own timer value based on the information included in the received beacon packet.

7. A method of communication performed by a master station in a system environment in which a plurality of communication systems, each of which is composed of the master station, share a same channel,

wherein a beacon packet transmitted from another master station in a beacon period set in a communication bandwidth of the channel is received, and

wherein the received beacon packet includes information representing a timer value of the other master station at a transmission start time of the beacon packet.

8. The method of communication according to claim 7, wherein a timer value of the master station is corrected based on the information included in the received beacon packet.