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Data transmission system with automatic repeat request

  • US 4,939,731 A
  • Filed: 09/29/1988
  • Issued: 07/03/1990
  • Est. Priority Date: 12/02/1986
  • Status: Expired due to Term
First Claim
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1. In an HF radio communication system for transmitting data comprising a plurality of radio stations, each station including a transceiver with associated encoding/decoding means for transmitting/receiving data, the method comprising the steps of:

  • (A) providing each radio station with a plurality of predetermined channel frequencies for transmission which have acceptable levels of noise and interference, and providing each such channel frequency with a predetermined reserve channel frequency to which transmission may be changed;

    (B) transmitting data from a first of said radio stations on one of said predetermined channel frequencies in the form of a data packet, said packet including one or more blocks of data encoded with an error correcting code;

    (C) receiving and decoding the transmitted data packets at a second of said radio stations and correcting errors, and automatically transmitting a request to said first station for retransmitting of a data packet should it be received with more than a predetermined number of errors;

    (D) determining the error rate at said second radio station in received data packets;

    (E) transmitting a request to said first radio station from said second radio station to reduce the rate of data transmission if the error rate is greater than a predetermined amount over a predetermined time interval of data transmission; and

    (F) transmitting a request to said first radio station from said second radio station to change the channel frequency to said predetermined reserve channel frequency if said step of transmitting a request to said first radio station to reduce the rate of data trasmission does not reduce the error rate below said predetermined amount.

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