Method for synchronization in a communication network and implementing appliances
First Claim
1. Method for synchronization in a communication network comprising at least two buses interconnected by a wireless communication network, each bus being linked to the wireless communication network by a portal, the method comprising the steps of:
- determining a so-called cycle server portal comprising a reference clock that will serve as reference for the other portals;
transmitting, via each portal, a synchronization signal at a predetermined instant with respect to the start of a frame and characteristic of each portal, the frame being defined with respect to an internal clock of each portal, the synchronization signal being achieved via the insertion of a control window; and
detecting, by each portal, the control windows of other portals and selecting one of the detected windows for the synchronization of the receiver portal'"'"'s internal clock with the reference clock of the cycle server portal, the selected window corresponding to a portal whose clock is already synchronized with the reference clock of the cycle server portal.
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Accused Products
Abstract
A process for synchronization in a communications network comprising at least two buses interconnected by a wireless communications network, each bus being linked to the wireless communications network by a portal. The process comprises the steps of: determining a so-called cycle server portal whose own clock will serve as a reference for the other portals; transmitting, via each portal, a synchronization signal at a predetermined instant with respect to the start of a frame and characteristic of each portal, the frame being defined with respect to each portal'"'"'s own internal clock, the synchronization signal being achieved via the insertion of a control window; and detecting, via each portal, the control windows of other portals and selecting one of the detected windows for the synchronization of the receiver portal'"'"'s own clock with the clock of the cycle server portal, the selected window corresponding to a portal whose clock is already synchronized with that of the cycle server portal. The invention also relates to receiver and transmitter apparatuses implementing the process.
29 Citations
13 Claims
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1. Method for synchronization in a communication network comprising at least two buses interconnected by a wireless communication network, each bus being linked to the wireless communication network by a portal, the method comprising the steps of:
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determining a so-called cycle server portal comprising a reference clock that will serve as reference for the other portals;
transmitting, via each portal, a synchronization signal at a predetermined instant with respect to the start of a frame and characteristic of each portal, the frame being defined with respect to an internal clock of each portal, the synchronization signal being achieved via the insertion of a control window; and
detecting, by each portal, the control windows of other portals and selecting one of the detected windows for the synchronization of the receiver portal'"'"'s internal clock with the reference clock of the cycle server portal, the selected window corresponding to a portal whose clock is already synchronized with the reference clock of the cycle server portal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Apparatus for interfacing a cable bus and a wireless communication network, the apparatus comprising:
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means of clock recovery utilizing the cable bus, the recovery means comprising a phase locked loop for locking onto a periodic signal travelling around the cable bus and a counter for counting an own-clock absolute value, the counter being linked to a clock derived from the phase locked loop for the incrementation of the counter, the absolute value of the counter being synchronized with that of a node connected to the cable bus; and
means of periodic transmission to the wireless communication network of a control window serving as time reference for the other apparatuses connected to the wireless network, the generation of the control window being bound with the state of the counter, the control window comprising an item relating to the state of the counter at the moment of transmission of the control window.
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13. Apparatus for interfacing a cable bus and a wireless communication network, the apparatus comprising:
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means of clock recovery utilizing a signal transmitted over the wireless communication network, the recovery means comprising a phase locked loop and an own-clock register;
means for selecting one control window from among a plurality of control windows transmitted over the wireless network;
means for extracting a synchronization of the control window for feeding the phase locked loop; and
means for extracting items relating to an absolute value of a reference clock of the control window, and for updating the own-clock register.
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Specification