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Algorithm for Detecting Unacceptable Bit Error Rate

IP.com Disclosure Number: IPCOM000099889D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 3 page(s) / 62K

Publishing Venue

IBM

Related People

Downes, RW: AUTHOR [+2]

Abstract

Disclosed is an algorithm for computing a lower bound on the bit error rate (BER) for data frames transmitted over switched data lines. It is assumed that these data frames include a cyclic redundancy code (CRC) checksum for detecting a burst of bits in error. It is also assumed that the frames are large enough that the probability of a single error burst affecting two frames is negligible. The total number of data bytes transmitted are not counted.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 73% of the total text.

Algorithm for Detecting Unacceptable Bit Error Rate

       Disclosed is an algorithm for computing a lower bound on
the bit error rate (BER) for data frames transmitted over switched
data lines.  It is assumed that these data frames include a cyclic
redundancy code (CRC) checksum for detecting a burst of bits in
error.  It is also assumed that the frames are large enough that the
probability of a single error burst affecting two frames is
negligible.  The total number of data bytes transmitted are not
counted.

      To obtain a lower bound for BER, first compute Mean Time
Between Frame Errors (MTBFEs) as:
MTBFE = (Current Time - Start Time)/(Frames in Error, n)

      This calculation is only performed when N errors have occurred.
 At that time, a pre-computed threshold, representing the minimum
acceptable MTBFE is compared to the computed value to determine if
line quality is acceptable. Note that the number of frames in error,
n, represents a minimal number of errors since the number of bits in
error must be greater than or equal to 1 for each frame in error. The
maximum amount of data that a line can transmit is found by multiply
ing the elapsed time by the line speed (in bits/second). Thus, the
best case BER, BER_BC, is found from
      BER_BC = 1/(MTBFE*line speed).

      In Fig. 1, the flow chart for the algorithm for monitoring
MTBFE is given.  The threshold value for MTBFE is computed from
      Threshold = 1/(maximum rated BER*line...