Power line communication apparatus, power line communication method and communication apparatus

• US 20070115973A1
• Filed: 11/09/2006
• Published: 05/24/2007
• Est. Priority Date: 11/10/2005
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Igata, Yuji, Koga, Hisao, Kodama, Nobutaka, Yasukawa, Toru, Haraguchi, Masahiko, Yokomitsu, Yasushi
• Granted Patent: US 8,537,819 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04B 2203/5408 using protocols
• CPC Class Codes: H04B 2203/5445 Local network
• CPC Class Codes: H04B 2203/5495 having measurements and testing channel
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines

Abstract

PLC modems and a PLC communication system that includes the PLC modems receive a multicast packet from a video server of a multicast group. When a MAC address table is set therein, the PLC modems and the PLC communication system convert the multicast packet into a unicast packet and transmit the converted packet to a power line. When no MAC address is set, the PLC modems and the PLC communication system transmit the multicast packet to the power line.

Claims

1. A power line communication apparatus for transmitting a packet to one power line communication apparatus through a power line, said power line communication apparatus comprising:

a receiver for receiving the packet having a first address used for multicast as a destination address;

a packet converter for converting the first address of the packet received by the receiver into a second address used for unicast;

a modulation scheme setting unit for setting a modulation scheme in accordance with a status of the power line between said power line communication apparatus and the one power line communication apparatus; and

a packet transmitter for transmitting, to the one power line communication apparatus, the packet having the second address, based on the modulation scheme set by the modulation scheme setting unit.

2. The power line communication apparatus according to claim 1, further comprising:

a memory for storing information representing a relationship between the second address and the first address, wherein

the packet converter converts the first address into the second address represented in the information.

3. The power line communication apparatus according to claim 2, further comprising:

a snooping unit for reading out a multicast MAC address of an IP device from an IGMP (Internet Group Management Protocol) packet, when the IGMP packet is transmitted from the IP device connected under the power line communication apparatus; and

a transmission/reception management controller for setting a conversion table having a source PLC MAC address of the IGMP packet as the second address, and the multicast MAC address as the first address.

4. The power line communication apparatus according to claim 3, wherein a multicast IP address and a PLC IP address are used instead of the multicast MAC address and the PLC MAC address respectively.

5. The power line communication apparatus according to claim 3, wherein the conversion table is a MAC address table on which the multicast MAC address is associated with the source PLC MAC address of the IGMP packet.

6. The power line communication apparatus according to claim 1, further comprising:

a bandwidth controller for selecting a predetermined transmission band, wherein

the bandwidth controller fixes a transmission rate and obtains the transmission band when receiving a multicast packet from a server.

7. The power line communication apparatus according to claim 6, wherein the transmission band is secured as a band of a predetermined transmission time in TDMA (time division multiple access).

8. The power line communication apparatus according to claim 6, wherein the transmission band is secured as a predetermined frequency band in FDMA (frequency division multiple access).

9. The power line communication apparatus according to claim 6, wherein the bandwidth controller releases the transmission band when receiving from an IP device an IGMP packet for leaving a multicast group.

10. The power line communication apparatus according to claim 6, wherein the bandwidth controller releases the transmission band through aging.

11. The power line communication apparatus according to claim 1, wherein the conversion information is deleted after being invalidated for a predetermined time, when receiving from an IP device an IGMP packet for leaving a multicast group.

12. The power line communication apparatus according to claim 1, further comprising:

a transmission status measuring unit for monitoring a transmission rate, wherein

a transmission band is changed when there is a difference between an actual average transmission rate and an obtained transmission rate.

13. The power line communication apparatus according to claim 1, wherein the PLC interface performs communication in diversity mode.

14. The power line communication apparatus according to claim 6, wherein the transmission band is obtained and secured when the conversion information is set to the conversion table;

and the transmission band is not secured for forwarding when no conversion information is set.

15. A power line communication method for communicating between a power line communication apparatus and one power line communication apparatus through a power line, the power line communication method comprising:

receiving a packet having a first address used for multicast as a destination address;

converting the first address of the packet into a second address used for unicast;

setting a modulation scheme in accordance with a status of the power line between the power line communication apparatus and the one power line communication apparatus; and

transmitting to the one power line communication apparatus, the packet having the second address, based on the modulation scheme.

16. A communication apparatus for transmitting data to a plurality of receiving communication apparatuses, the communication apparatus comprising:

a reception information obtaining unit for obtaining reception information indicating a reception status from each of the plurality of receiving communication apparatuses at least used for multicast communication; and

a transmission processor for determining a transmission scheme of transmitted data for multicast communication for the plurality of receiving communication apparatuses, based on the reception information obtained by the reception information obtaining unit.

17. The communication apparatus according to claim 16, wherein the transmission processor selects a transmission scheme suitable for a reception status having a worst characteristic among reception statuses indicated in the obtained reception information, as the transmission scheme for multicast communication.

18. The communication apparatus according to claim 17, wherein:

a multicarrier communication system is employed for communication with the receiving communication apparatuses; and

the transmission processor allocates the transmission scheme suitable for the reception status having the worst characteristic among the reception statuses indicated in the reception information, per subcarrier group having at least one subcarrier.

19. The communication apparatus according to claim 17, wherein the transmission processor computes a unicast transmission rate for each of the plurality of receiving communication apparatuses, when transmitting the data to the plurality of receiving communication apparatuses in a transmission scheme for unicast communication, and a multicast transmission rate, when transmitting the data in the transmission scheme for multicast communication, based on the obtained reception information;

and selects a transmission scheme having a higher rate from a lowest value of the unicast transmission rate and the multicast transmission rate, as the transmitted scheme of the transmission data for multicast communication.

20. The communication apparatus according to claim 19, wherein the transmission processor computes the transmission rate of each of the plurality of receiving communication apparatuses, based on the obtained reception information;

determines allocation of transmission bands assigned to the plurality of receiving communication apparatus, so that each of the transmission rates is greater than a predetermined rate threshold; and

computes the unicast transmission rate based on the determined allocation.