Transmission of encoded data over reliable digital communication link using enhanced error recovery mechanism

A method of transporting digital data across a reliable digital communication link comprising the steps of:

• (a) prior to processing said digital data with elements of procedure that are farthest upstream elements of procedure relative to said reliable digital communication link, subjecting unencoded digital data to a data encoding operation so as to derive encoded digital data;
• (b) subjecting said unencoded digital data to an error detection operation to derive error detection information associated with said unencoded digital data;
• (c) combining said encoded digital data and said error detection information into a composite digital data sequence;
• and
• (d) processing said composite digital data sequence in accordance with link access protocol elements of procedure and transmitting said composite digital data sequence across said reliable digital communication link.

For use with a reliable digital communication link, wherein, at a transmitter site, prior to being processed with elements of procedure that are farthest upstream elements of procedure relative to said reliable digital communication link, digital data to be transported over said reliable digital communication link is subjected to each of an error detection operation, which derives error detection information associated with said digital data, and an encoding operation, which provides encoded digital data that is combined with said error detection information into a composite digital data sequence and is processed in accordance with link access protocol elements of procedure and is transmitted over said reliable digital communication link, a method of controlling the operation of said reliable digital communication link, said method comprising the steps of:

• (a) receiving said composite digital data sequence that has been transmitted across said reliable digital communication link and processing said composite digital data sequence in accordance with elements of procedure to provide encoded digital data components of said composite data sequence;
• (b) decoding the encoded digital data component of said composite data sequence received and processed in step (a) to obtain decoded digital data;
• (c) subjecting said decoded digital data obtained in step (b) to an error detection operation so as to derive error detection information associated with said decoded digital data;
• (d) comparing the error detection information associated with said decoded digital data derived in step (c) with the error detection information component contained in said composite digital data sequence received in step (a);
• and
• (e) controllably resetting the digital data encoding operation carried out at said transmitter site, and the digital data decoding operation of step (b), in dependence upon the result of step (d) of comparing said error detection information associated with said decoded digital data derived in step (c) with said error detection information component of said composite digital data sequence in received in step (a).

A system for transporting digital data across a reliable digital communication link between a transmit site and a destination site comprising:

• at said transmit site,
• upstream of elements of procedure through which said digital data is processed that are farthest upstream elements of procedure relative to said reliable digital communication link, an error detection operator to which said digital data is applied, and which is operative to derive error detection information associated with said digital data, and a digital data encoder to which said digital data is applied and which is operative to encode said digital data;
• and
• a transmitter which is coupled to said error detection operator and said digital data encoder and which processes said composite digital data sequence in accordance with link access protocol elements of procedure and transmits a composite digital data sequence containing an encoded digital data component as encoded by said digital data encoder, and an error detection component as derived by said error detection operator;
• and
• at said destination site,
• a receiver which receives said composite digital data sequence that has been transmitted across said reliable digital communication link from said transmit site and processes said composite digital data sequence in accordance with elements of procedure to provide encoded digital data components of said composite data sequence;
• a decoder which decodes the encoded digital data component of said composite data sequence received and processed by said receiver to obtain decoded digital data;
• an error detection operator to which said decoded digital data obtained by said decoder is applied and which outputs error detection information associated with said decoded digital data;
• a comparator, which is coupled to said error detection operator and said receiver, and is operative to compare the error detection information associated with said decoded digital data with the error detection information component contained in said composite digital data sequence;
• and
• a synchronization controller which is operative to controllably reset said digital data encoder and said digital data decoder in dependence upon the output of said comparator.

For use with a reliable digital communication link, wherein, at a transmitter site, prior to being processed with elements of procedure that are farthest upstream elements of procedure relative to said reliable digital communication link, digital data to be transported over said reliable digital communication link from a source site to a destination site is subjected to each of an error detection operation, which derives error detection information associated with said digital data, and an encoding operation, which provides encoded digital data that is combined with said error detection information into a composite digital data sequence, said composite digital data sequence being processed in accordance with link access protocol elements of procedure and transmitted over said reliable digital communication link to a said destination site, an arrangement at said destination site for controlling the operation of said reliable digital communication link, said arrangement comprising:

• a receiver which receives said composite digital data sequence that has been transmitted over said reliable digital communication link to said destination site and which processes said composite digital data sequence in accordance with elements of procedure to provide encoded digital data components of said composite digital data sequence;
• a decoder which is operative to decode said encoded digital data received by said receiver and processed thereby into decoded digital data;
• an error detection operator which is operative to subject said decoded digital data to an error detection operation and thereby derive error detection information associated with said decoded digital data;
• a comparator which compares said derived error detection information associated with said decoded digital data with the error detection information component separated from said composite digital data sequence;
• and
• a synchronization controller which is operative to controllably reset the digital data encoder at said transmit site and said digital data decoder at said destination site in accordance with the output of said comparator.