Method for retransmission using checksums for identifying lost data packets
First Claim
1. A method for retransmission of data packets, wherein the data packets are sent in data frames, each data frame comprising a checksum but lacking a unique sequence number, during a data transmission of a session between a data transmitter and a receiving device, the method comprising the steps of:
- detecting data loss in the data stream transmission;
determining checksums of at least the received data frames that are directly adjacent to and enclosing the detected data loss;
sending an identification key comprising said determined checksums to a retransmission server, whereby the sent checksums constitute a checksum sequence and said identification key is used by the server for identifying the data loss;
receiving the requested missing data, comprising at least one data frame, from the retransmission server;
interleaving the received at least one data frame in the correct place in the received data transmission before rendering the data information of the data transmission.
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Accused Products
Abstract
The present invention relates to a method for retransmission of lost data, a receiving device operating according to the invented method and a retransmission server. In the absence of a unique identifier per data packet or data frame, there is obviously a problem to directly identify a specific data packet, data block or data frame in the stream and retransmission can'"'"'t take place with current technologies. The object of the present invention is to offer a retransmission method and means for making said retransmission of missing data packets possible in the absence of a unique identifier.
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Citations
20 Claims
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1. A method for retransmission of data packets, wherein the data packets are sent in data frames, each data frame comprising a checksum but lacking a unique sequence number, during a data transmission of a session between a data transmitter and a receiving device, the method comprising the steps of:
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detecting data loss in the data stream transmission; determining checksums of at least the received data frames that are directly adjacent to and enclosing the detected data loss; sending an identification key comprising said determined checksums to a retransmission server, whereby the sent checksums constitute a checksum sequence and said identification key is used by the server for identifying the data loss; receiving the requested missing data, comprising at least one data frame, from the retransmission server; interleaving the received at least one data frame in the correct place in the received data transmission before rendering the data information of the data transmission. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A receiving device for receiving retransmission of data packets, wherein the data packets are sent in data frames, each data frame comprising a checksum but lacking a unique sequence number, during a data transmission of a session from a data transmitter to the receiving device, the receiving device comprising:
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detecting means for detecting data loss in the data stream transmission; determining means for determining the checksums of at least the received data frames that are directly adjacent to and enclosing the detected data loss; sending means for sending adapted to send an identification key comprising said determined checksums to a retransmission server, whereby the sent checksums constitute a checksum sequence and said identification key is used by the server for identifying the data loss; receiving means for receiving the requested missing data comprising at least one data frame from the retransmission server; interleaving means for interleaving said received at least one data frame in the correct place in the received data transmission before rendering the data information of the data transmission. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A retransmission server for retransmission of data packets, wherein the data packets are sent in data frames, each data frame comprising a checksum but lacking a unique sequence number, during a data transmission of a session from a data transmitter to at least one receiving device, the retransmission server comprising:
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a buffer storage; and means for storing the sent data frames in the buffer storage, wherein the retransmission server is adapted for receiving an identification key from a retransmission requesting receiving device, said identification key identifying a data loss in the sent data frames using checksums that are directly adjacent to and enclose the data loss, whereby the received checksums constitute a checksum sequence, and said identification key is used by the retransmission server for identifying a stored data frame corresponding to the data loss, the retransmission server being further adapted for sending the identified stored data frame to the requesting receiving device. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification