摘要:
A frame synchronization detection system which enables frame synchronization and synchronizing pulses to be provided from at least two formats of DS1 TDM signals, specifically the D4 and extended superframe Fe formats. A first search logic circuit provides an output indicating the onset of a maintenance mode of frame detection when either Fe or D4 patterns are decoded. For the D4 pattern an alternate pattern is decoded and the first search circuit enters the maintenance mode only after both alternate D4 framing patterns are decoded. A second search logic circuit enables the decoding of a subsequent sequence and detection of framing, thereby reducing the probability of false framing. A frame counter which is synchronized upon the detection of a valid framing pattern by the first search circuit continues to supply frame sync pulses until an error detector, which detects whether a predetermined ratio of invalid to valid framing bits occurs, resets the system back to the search mode.
摘要:
A method of correcting errors in a packet based communications system comprises generating m parity packets from each group of k consecutive data packets to form a code word of k data packets and m parity packets. Each parity packet is a combination of two or more data packets, and each data and parity packet includes a sequence number representative of a relative position of the packet in the code word. The method also includes examining, after transmission, the sequence number associated with each packet to determine if one or more packets from the code word is missing. If any packets are missing, the method includes identifying the one or more missing packets. The method further includes processing the data packets and the parity packets according to the combinations of data packets used to generate the parity packets, so as to recover one or more missing packets.
摘要:
A method of encapsulating TDM data into individual data packets for transmission across a packet network includes delineating the TDM data into one or more signaling multiframes, wherein each signaling multiframe includes one period of a periodic signaling pattern. The method also includes appending a header that is associated with the individual data packets to each of the signaling multiframes of TDM data. Further, a method of selecting the number of multiframes of TDM data in the data packet includes calculating the efficiency of the data packet as a function of the number of multiframes, and selecting the number of multiframes so that the efficiency of the data packet increases exponentially as a number of time-slots in the TDM data increases.
摘要:
A method of encapsulating TDM data into individual data packets for transmission across a packet network includes delineating the TDM data into one or more signaling multiframes, wherein each signaling multiframe includes one period of a periodic signaling pattern. The method also includes appending a header that is associated with the individual data packets to each of the signaling multiframes of TDM data. Further, a method of selecting the number of multiframes of TDM data in the data packet includes calculating the efficiency of the data packet as a function of the number of multiframes, and selecting the number of multiframes so that the efficiency of the data packet increases exponentially as a number of time-slots in the TDM data increases.