# US 7,609,681 B2 · Communication apparatus and coexistence method for enabling coexistence of communication systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,681 B2 - Document ID: US7609681B2 - Status: Granted - Kind: B2 - Application number: 11/542,153 - Filed: 2006-10-04 - Published: 2007-05-03 - Granted: 2009-10-27 - Earliest claimed: 2005-10-05 - Assignees: Panasonic Corporation - Inventors: Akio Kurobe; Go Kuroda; Koji Ikeda; Hisao Koga; Yuji Igata - Web page: https://patentgrep.com/patent/US7609681B2 ## CPC - H04L 12/66: Arrangements for connecting between networks having differing types of switching systems, e.g. gateways - H04B 3/54: Systems for transmission via power distribution lines - H04J 3/0638: {Clock or time synchronisation among nodes; Internode synchronisation (synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43)} - H04L 12/2801: {Broadband local area networks} - H04B 2203/542: using zero crossing information - H04B 2203/545: Audio/video application, e.g. interphone - H04J 3/0644: {External master-clock} - H04L 12/2803: {Home automation networks} - H04L 2012/2843: {Mains power line} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) ## Abstract In-home communication systems 110 and 130 and an access communication system 120 that are capable of co-existing. The communication systems 110 and 130 and the access communication system 120 are able to co-exist by utilizing TDM that is in synchronization with a power cycle. Further, communication system that needs to secure AV-QoS assigns transmission timing to a slave station within itself by synchronizing a beacon cycle with a cycle of a power line. ## Claims ### Claim 1 A communication apparatus for allocating a transmission band to secure a quality of service (QoS) based on a reference signal, the communication apparatus belonging to (i) one or more in-home communication systems that perform communication within a limited region or (ii) an access communication system that connects the limited region to a wide area network, at least one of the in-home communication systems and the access communication system coexisting on a same communication medium by time division, the communication apparatus comprising: a power reference point extracting section operable to extract a reference point of a commercial power supply that is supplied on a power line; a TDM coexistence control section operable to (i) receive and transmit a coexistence signal in synchronization with the extracted reference point to detect the coexistence signal and (ii) perform time division of a time division multiplexing (TDM) cycle with another communication system based on the detected coexistence signal; and a transmission timing determining section operable to synchronize, in accordance with a result of the time division of the TDM cycle, a timing of transmitting the reference signal with the reference point extracted by the power reference point extracting section. ### Claim 2 (depends on 1) The communication apparatus of claim 1, wherein the power reference point extracting section defines, as the reference point, a zero-crossing point of the commercial power supply. ### Claim 3 (depends on 1) The communication apparatus of claim 1, wherein the power reference point extracting section defines, as the reference point, a point that is phase-shifted by an integral multiple of 60 degrees from a zero-crossing point of the commercial power supply. ### Claim 4 (depends on 1) The communication apparatus of claim 1, wherein the reference signal is a beacon. ### Claim 5 A method performed by a communication apparatus for allocating a transmission band to secure a quality of service (QoS) based on a reference signal, the communication apparatus belonging to (i) one or more in-home communication systems that perform communication within a limited region or (ii) an access communication system that connects the limited region to a wide area network, at least one of the in-home communication systems and the access communication system coexisting on a same communication medium by time division, the method comprising: extracting a reference point of a commercial power supply that is supplied on a power line; receiving and transmitting a coexistence signal in synchronization with the extracted reference point to detect the coexistence signal; performing time division of a time division multiplexing (TDM) cycle with another communication system based on the detected coexistence signal; and synchronizing, in accordance with a result of the time division of the TDM cycle, a timing of transmitting the reference signal with the reference point extracted by the extracting of the reference point. ### Claim 6 An integrated circuit for use in a communication apparatus for allocating a transmission band to secure a quality of service QoS based on a reference signal, the communication apparatus belonging to (i) one or more in-home communication systems that perform communication within a limited region or (ii) an access communication system that connects the limited region to a wide area network at least one of the in-home communication systems and the access communication system coexisting on a same communication medium by time division, the integrated circuit comprising circuitry functioning as: a power reference point extracting section operable to extract a reference point of a commercial power supply that is supplied on a power line; a TDM coexistence control section operable to (i) receive and transmit a coexistence signal in synchronization with the extracted reference point to detect the coexistence signal and (ii) perform time division of a time division multiplexing (TDM) cycle with another communication system based on the detected coexistence signal; and a transmission timing determining section operable to synchronize, in accordance with a result of the time division of the TDM cycle, a timing of transmitting the reference signal with the reference point extracted by the power reference point extracting section.