# US 2014/0153380 A1 · Data communication systems and methods for locomotive consists > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153380 A1 - Document ID: US20140153380A1 - Status: Published application - Kind: A1 - Application number: 13/690,239 - Filed: 2012-11-30 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Secure Communication Systems Inc.; Electro-Motive Diesel, Inc. - Applicants: Electro-Motive Diesel Inc.; Secure Communication Systems Inc. - Inventors: James Robert Luecke; Wayne Rudolph - Web page: https://patentgrep.com/patent/US20140153380A1 ## CPC - H04W 72/27: between access points - H04W 56/0015: {one node acting as a reference for the others} - H04W 56/0035: {detecting errors in frequency or phase} - H04W 92/20: between access points - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A method for controlling data communication among two or more of access points within a locomotive consist is disclosed. The method may include selecting, from among the two or more access points, a first access point to output a synchronization signal. The method may also include outputting the synchronization signal from the first access point to the remaining one or more access points, wherein the synchronization signal may be used to synchronize data communication among the two or more access points. ## Claims ### Claim 1 A method for controlling data communication among a plurality of access points within a locomotive consist, the method comprising: selecting, from among the plurality of access points, a first access point to output a synchronization signal; and outputting the synchronization signal from the first access point to the remaining plurality of access points, wherein the synchronization signal is used to synchronize data communication among the plurality of access points. ### Claim 2 (depends on 1) The method of claim 1, wherein the synchronization signal is used to synchronize data communication between a second access point and a third access point from among the plurality of access points, the second and third access points being different from the first access point. ### Claim 3 (depends on 1) The method of claim 1, further comprising: monitoring the synchronization signal; determining that an error has occurred with the first access point outputting the synchronization signal; and responsive to determining that the error has occurred, selecting, from among the plurality of access points, a second access point to output a failover synchronization signal. ### Claim 4 (depends on 3) The method of claim 3, further comprising: outputting the failover synchronization signal from the second access point to the remaining plurality of access points, wherein the failover synchronization signal is used to synchronize data communication among the plurality of access points. ### Claim 5 (depends on 1) The method of claim 1, further comprising: generating the synchronization signal at the first access point, wherein the synchronization signal includes a beacon signal that announces the beginning of a data communication period during which data is communicated among the plurality of access points. ### Claim 6 (depends on 1) The method of claim 1, further comprising: generating the synchronization signal at the first access point, wherein the synchronization signal includes an oscillating signal oscillating at a determined frequency. ### Claim 7 (depends on 6) The method of claim 6, further comprising: multiplexing the oscillating signal over a communication line that is communicatively connected to the plurality of access points. ### Claim 8 (depends on 1) The method of claim 1, further comprising: communicating among the plurality of access points using a frequency division multiple access communication scheme that is based on the synchronization signal. ### Claim 9 (depends on 8) The method of claim 8, wherein the first access point determines bandwidth allocation for all of the plurality of access points within the frequency division multiple access communication scheme. ### Claim 10 A system for controlling data communication in a locomotive consist comprising: a communications network; and a plurality of access points disposed within locomotives of the locomotive consist and communicatively coupled to the communications network, the plurality of access points including a first access point that is selected to output a synchronization signal and is configured to: output the synchronization signal from the first access point to the remaining plurality of access points via the communications network, wherein the synchronization signal is used to synchronize data communication among the plurality of access points. ### Claim 11 (depends on 10) The system of claim 10, wherein the synchronization signal is used to synchronize data communication between a second access point and a third access point from among the plurality of access points, the second and third access points being different from the first access point. ### Claim 12 (depends on 10) The system of claim 10, wherein a second access point among the plurality of access points is configured to: monitor the synchronization signal; determine that an error has occurred with the first access point outputting the synchronization signal; and responsive to determining that the error has occurred, generate a failover synchronization signal. ### Claim 13 (depends on 12) The system of claim 12, the second access point being further configured to output the failover synchronization signal to the remaining plurality of access points, wherein the failover synchronization signal is used to synchronize data communication among the plurality of access points. ### Claim 14 (depends on 10) The system of claim 10, the first access point being further configured to generate the synchronization signal, wherein the synchronization signal includes a beacon signal that announces the beginning of a data communication period during which data is communicated among the plurality of access points. ### Claim 15 (depends on 10) The system of claim 10, the first access point being further configured to generate the synchronization signal at the first access point, wherein the synchronization signal includes an oscillating signal oscillating at a determined frequency. ### Claim 16 (depends on 15) The system of claim 15, the first access point being further configured to multiplex the oscillating signal over a communication line that is communicatively connected to the plurality of access points. ### Claim 17 (depends on 10) The system of claim 10, wherein the plurality of access points are configured to communicate with each other using a frequency division multiple access communication scheme that is based on the synchronization signal. ### Claim 18 (depends on 17) The system of claim 17, wherein the first access point determines bandwidth allocation for all of the plurality of access points within the frequency division multiple access communication scheme. ### Claim 19 A locomotive consist comprising: a plurality of locomotives; a communications network; and a plurality of access points disposed within locomotives of the locomotive consist and communicatively coupled to the communications network, the plurality of access points including a first access point that is selected to output a synchronization signal and is configured to: output the synchronization signal from the first access point to the remaining plurality of access points via the communications network, wherein the synchronization signal is used to synchronize data communication among the plurality of access points. ### Claim 20 (depends on 19) The locomotive consist of claim 19, wherein a second access point among the plurality of access points is configured to: monitor the synchronization signal; determine that an error has occurred with the first access point outputting the synchronization signal; and responsive to determining that the error has occurred, generate a failover synchronization signal.