COMMUNICATION APPARATUS AND COMMUNICATION METHOD

• US 20100195656A1
• Filed: 04/23/2009
• Published: 08/05/2010
• Est. Priority Date: 04/25/2008
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Matsushita, Yosuke, Kuroda, Go, Morita, Naoki, Homma, Hideki, Fujiwara, Yuki
• Granted Patent: US 9,008,090 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04L 49/55 Prevention, detection or correction of errors
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04W 40/30 for proactive routing
• CPC Class Codes: H04W 74/0825 with collision detection
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

There is provided a communication apparatus which, in an ad-hoc network, when receiving control packets from a plurality of terminals, can determine whether or not there is a collision among the control packets, and, based on the determination, can be prevented from continuing to be out of the network due to a collision among the control packets transmitted from the plurality of terminals. In the communication terminal, a communication section receives a control packet which periodically comes up on a communication path. When the communication apparatus receives a plurality of control packets which are defective in at least payload portions thereof within a predetermined time period, if a control section determines that source addresses included in header portions of the control packets which are defective in the payload portions thereof include a source address which is not identical to the other source addresses, the control section determines that the control packets are transmitted from a plurality of terminals and collide with each other.

Claims

1. A communication apparatus comprising:

a communication section for receiving a control packet which periodically comes up on a communication path; and

a control section for, when a plurality of control packets which are defective in at least payload portions thereof are received within a predetermined time period, if the control section determines that source addresses included in header portions of the control packets which are defective in the payload portions thereof include a source address which is not identical to the other source addresses, determining that the control packets are transmitted from a plurality of terminals and collide with each other.

2. The communication apparatus according to claim 1, wherein if the control section determines that source addresses included in header portions of the control packets which are defective in the payload portions thereof include a source address which is not identical to the other source addresses, and that the source addresses included in the header portions of the control packets which are defective are identical to an address of an original transmission source which transmits the control packets, the control section determines that the control packets are transmitted from the plurality of terminals and collide with each other.

3. The communication apparatus according to claim 1, wherein when the control packet is not received during a certain time period, the control section determines whether or not source addresses included in header portions of the plurality of control packets which are defective in the payload portions thereof include a source address which is not identical to the other source addresses.

4. The communication apparatus according to claim 1, wherein if the control section determines that the control packets are transmitted from a plurality of terminals and collide with each other, the control section instructs one of the plurality of terminals to delay a timing of transmission of the corresponding control packet.

5. The communication apparatus according to claim 4, wherein the control section gives an instruction of delaying the timing of transmission of the control packet by at least one packet.

6. The communication apparatus according to claim 1, wherein when a plurality of control packets which are defective in at least payload portions thereof are received within the predetermined time period and when the control packets are defective also in header portions thereof, the control section instructs a terminal present within a communication area of the communication apparatus to change a probability of transmission of the control packet.

7. The communication apparatus according to claim 1, wherein the control packet is transmitted by broadcast.

8. The communication apparatus according to claim 6, wherein the control packet includes a beacon signal.

9. The communication apparatus according to claim 1, wherein the communication path is a power line.

10. A communication method comprising:

a step of receiving a control packet which periodically comes up on a communication path; and

a step of, when a plurality of control packets which are defective in at least payload portions thereof are received within a predetermined time period, if the control section determines that source addresses included in header portions of the control packets which are defective in the payload portions thereof include a source address which is not identical to the other source addresses, determining that the control packets are transmitted from a plurality of terminals and collide with each other.