Data length compensating device for compensating lost cells in packet data composed of a plurality of cells
First Claim
1. A data length compensating device compensating a length of packet data composed of a plurality of packets, each including a plurality of cells, which have sequence numbers, the data length compensating device comprising:
- an input terminal for receiving a plurality of the packets of the packet data;
a first buffer memory for holding a plurality of cells included in the received packets;
lost cell detector for detecting lost cells to be included in the received packets and outputting the number of the lost cells;
compensating controller, operatively connected to the lost cell detecting means, for judging a cell lost mode, which indicates where the lost cells are to be located at the heading of a packet, within a packet or over succeeding packets of the received packet data, based on the number of the lost cells sent from the lost cell detector and deciding positions of the lost cells to be compensated to the received packet data in correspondence with the judged cell lost mode;
a second buffer memory, operatively connected to the compensating controller and the first buffer memory, for storing the decided number of the lost cells and the positions to be compensated; and
inserting circuit, operatively connected to the first and second buffer memories, for inserting dummy cells to the plurality of cells output from the first buffer memory, based on the number of the lost cells and the positions to be compensated, output from the second buffer memory to restore the length of the packet data.
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Accused Products
Abstract
A packet data is formed of a plurality of ATM cells. When cells of the packet data are lost, especially if the packet data is an image or picture signal including synchronous signals, it becomes difficult to reproduce the image or picture on a receiving terminal. A data length compensating device compensates the lost cell. In order to deal with the lost cells lying over between two packets, a data length compensating device includes a lost cell detecting circuit which detects a lost cell to be included in the data according to the sequence number of the plurality of cells, compensation control circuit which outputs compensation information including the number of lost cells to be compensated, and inserting circuit inserts dummy data corresponding to the lost cells to be compensated based on the compensation information.
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Citations
11 Claims
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1. A data length compensating device compensating a length of packet data composed of a plurality of packets, each including a plurality of cells, which have sequence numbers, the data length compensating device comprising:
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an input terminal for receiving a plurality of the packets of the packet data; a first buffer memory for holding a plurality of cells included in the received packets; lost cell detector for detecting lost cells to be included in the received packets and outputting the number of the lost cells; compensating controller, operatively connected to the lost cell detecting means, for judging a cell lost mode, which indicates where the lost cells are to be located at the heading of a packet, within a packet or over succeeding packets of the received packet data, based on the number of the lost cells sent from the lost cell detector and deciding positions of the lost cells to be compensated to the received packet data in correspondence with the judged cell lost mode; a second buffer memory, operatively connected to the compensating controller and the first buffer memory, for storing the decided number of the lost cells and the positions to be compensated; and inserting circuit, operatively connected to the first and second buffer memories, for inserting dummy cells to the plurality of cells output from the first buffer memory, based on the number of the lost cells and the positions to be compensated, output from the second buffer memory to restore the length of the packet data. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A data length compensating device for compensating a length of packet data composed of a plurality of packets, each including a plurality of cells, which have sequence numbers, the data length compensating device comprising:
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lost cell detector for detecting lost cells to be included in the packet data according to the sequence numbers of the plurality of cells; compensation controller for judging a cell lost mode, which indicates where the lost cells are to be located at the heading of a packet, within a packet or over succeeding packets of the packet data, based on the number of the lost cells and outputting compensation information including the number and positions of the lost cells to be compensated; and inserting circuit for inserting dummy cells in the positions of the lost cells based on the compensation information. - View Dependent Claims (9, 10)
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11. A data length compensating method for compensating a length of packet data composed of a plurality of packets, each including a plurality of cells, comprising the steps of:
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receiving the plurality of packets, each including a plurality of cells; detecting lost cells from the received plurality of packets; deciding the number of the lost cells; judging a cell lost mode based on the number of the lost cells; deciding positions of the lost cells to be compensated in correspondence with the cell lost mode; and inserting dummy cells to the packet data, based on the number of the cells and the positions to be compensated, to restore a length of the packet data.
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Specification