| Patent application number | Description | Published |
|---|
| 20080231511 | Beacon-Assisted Precision Location of Untethered Client in Packet Networks - A novel beacon-based position location technique for efficient location discovery of untethered clients in packet networks is disclosed. The position location technique utilizes the time-difference-of-arrival (“TDOA”) of a first signal transmitted by a beacon of known location and a second signal transmitted by an untethered client. The TDOA of these two signals is measured locally by at least three non-collinear signal receivers. For each of the receivers, the TDOA is used to calculate a perceived distance to the client. A circle is then calculated for each receiver, centered on the receiver and having a radius equal to the perceived distance. At least two lines defined by points of intersection of the calculated circles are then calculated. The point of intersection of the lines represents the location of the client. To facilitate operation, the signal receivers may be arranged on vertices which define a convex polygon as viewed from above. The location system requires no time (time-of-day) synchronization of the signal receivers, and only the coarse frequency synchronization, on the order of, tens of parts-per-million (ppm). The technique even works for the case where the signal receivers are run asynchronously, provided the frequency accuracies of the signal receivers are on the order of about 50ppm or better. The technique introduces no communication overhead for the beacon, client and signal receivers. Further, the computation overhead at the signal receivers is relatively low because the location detection algorithm involves only simple algebraic operations over scalar values. | 09-25-2008 |
| 20080273460 | METHODS AND SYSTEMS FOR COMMUNICATION BETWEEN NETWORK ELEMENTS - A system for synchronizing a first network device and a second network device. The first network device comprises an interface configured to release over a communication link a first signal carrying a first data stream clocked by a first clock signal. The second network device comprises an interface configured to receive the first signal over the communication link. The second network device also comprises a clock extraction module configured to generate an extracted clock signal from the received first signal; and a data coding module configured to clock a second data stream with an output clock signal selected based on a speed of a locally generated clock signal relative to the first clock signal or the extracted clock signal, thereby to produce a second signal for transmission from the second network element to the first network element. By clocking the second data stream with the fastest available clock signal, greater link utilization can be achieved. Furthermore, synchronism between the first and second network elements reduces the incidence of sync slips, which permits a reduction in the size of inter-frame gaps and also affords the use of a clock frequencies exceeding the nominal rate, leading to even greater link utilization. | 11-06-2008 |
| 20100008351 | METHOD AND SYSTEM FOR ROUTE SYNCHRONIZATION USING TIME SYNCHRONIZATION - A system, method and apparatus synchronize protocol events in a distributed communication network. The network includes a plurality of nodes. Each node in the network includes a time source which maintains a clock signal synchronized with each other node time source in the network. An announcement of a protocol event is sent to at least one node. The announcement includes a predetermined time for implementing the protocol event. The protocol event is acted upon at the predetermined time. | 01-14-2010 |
| 20100080248 | TECHNIQUES FOR TIME TRANSFER VIA SIGNAL ENCODING - Techniques for time transfer via signal encoding are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method for time transfer via signal encoding comprising generating a time service ordered-set for inclusion in a physical coding sublayer frame of a physical layer device, generating time service data for inclusion in the physical coding sublayer frame of the physical layer device, and transmitting the physical coding sublayer frame. | 04-01-2010 |
| 20100118894 | DIFFERENTIAL TIMING TRANSFER OVER SYNCHRONOUS ETHERNET USING DIGITAL FREQUENCY GENERATORS AND CONTROL WORD SIGNALING - A method, system and master service interface transfer differential timing over a packet network. The transmitting service interface receives a service clock and is coupled to a receiving service interface through a network backplane. A primary reference clock is provided to time the network backplane. The primary reference clock and the service clock are used to synthesize a copy of the service clock connected to the transmitting service interface. A first control word containing an error differential between the service clock and the synthesized copy of the service clock is generated and transmitted through the network backplane via a packet. The first control word, together with the primary reference clock, is used to recreate the service clock for timing the receiving service interface. | 05-13-2010 |
| 20110199941 | Rate-Varying Multicast Transmission for Clock Distribution in Packet Networks - In at least some embodiments, the disclosure includes an apparatus a root node in a packet based network that multicasts a plurality of packets. The apparatus also includes an intermediary node coupled to the root node and a plurality of leaf nodes coupled to the intermediary node. The root node, the intermediary node, and the plurality of leaf nodes are arranged in a tree topology. The packets are received at the intermediary node from the root node at a data rate equal to the data rate of the leaf node having the maximum data rate. The packets are multicast from the intermediary node to each of the plurality of leaf nodes at a plurality of different data rates such that each particular one of the plurality of leaf nodes receives the packets at a data rate corresponding to the data rate for the particular one of the plurality of leaf nodes. | 08-18-2011 |
| 20110243156 | TECHNIQUES FOR TIME TRANSFER VIA SIGNAL ENCODING - Techniques for time transfer via signal encoding are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method for time transfer via signal encoding comprising generating a time service ordered-set for inclusion in a physical coding sublayer frame of a physical layer device, generating time service data for inclusion in the physical coding sublayer frame of the physical layer device, and transmitting the physical coding sublayer frame. | 10-06-2011 |
| 20110243196 | MULTIPLE REDUNDANT GNSS SYNCHRONIZATION SYSTEM - A diamine absorbent that contains heat stable salts is regenerated using an ion exchange process wherein the cation exchange resin is regenerated using sulfurous acid reflux. | 10-06-2011 |
