Method and apparatus for a data-dependent noise predictive viterbi

A system for fabricating a detector for decoding an encoded sequence of data values to be received by the detector over a plurality of time increments, the method comprising:

• means for determining, based on a number of stages of an encoder which produces the encoded sequence of data values, a plurality of possible states of the encoder as a function of a plurality of possible input values which may be received by the encoder;
• means for determining a metric for each possible transition from each of the plurality of the possible states at a first time increment of the plurality of time increments to each of the plurality of possible states at a next subsequent time increment of the plurality of time increments based on each possible data value of the encoded sequence of data values which may be received at the next subsequent time increment;
• means for determining a first least number of binary digits capable of representing a first maximum value of the determined metrics;
• means for determining a maximum difference between a first accumulation of a first consecutive subset of the determined metrics and a second accumulation of a second consecutive subset of the determined metrics, the second consecutive subset being inclusive of the first consecutive subset;
• means for determining a second least number of binary digits capable of representing a maximum accumulation of any consecutive subset of the determined metrics, the second least number of binary digits being the sum of the first least number of binary digits plus a third least number of binary digits;
• and
• means for minimizing the third least number of binary digits such that the third least number of binary digits is less than a fourth least number of binary digits determined based on the number of stages of the encoder.

A detector for decoding an encoded sequence of data values to be received by the detector over a plurality of time increments, the encoded sequence of data having been encoded by an encoder having a number of stages and thereby a plurality of possible states of the encoder as a function of the possible input values which may be received by the encoder, the detector comprising:

• a memory for storing a plurality of state metric values, the memory including a first number of bits for each of a plurality of metric values, wherein the first number of bits is a sum of a first least number of binary digits capable of representing a first maximum value of the metric values determined for each possible transition from each of the plurality of the possible states at a first time increment of the plurality of time increments to each of the plurality of possible states at a next subsequent time increment of the plurality of time increments based on each possible data value of the encoded sequence of data values which may be received at the next subsequent time increment and a second least number of binary digits computed based on a maximum difference between a first accumulation of a first consecutive subset of the determined metric values and a second accumulation of a second consecutive subset of the determined metric values, the second consecutive subset being inclusive of the first consecutive subset, the first maximum value and the first least number of binary digits, the first number of bits capable of representing a maximum accumulation of any consecutive subset of the determined metrics.

An apparatus for architecting a detector operative to decode an encoded sequence of data values to be received by the detector over a plurality of time increments, the apparatus comprising:

• a state calculator operative to determine, based on a number of stages of an encoder which produces the encoded sequence of data values, a plurality of possible states of the encoder as a fiction of a plurality of possible input values which may be received by the encoder;
• a metric calculator coupled with the state calculator and operative to calculate a metric for each possible transition from each of the plurality of the possible states at a first time increment of the plurality of time increments to each of the plurality of possible states at a next subsequent time increment of the plurality of time increments based on each possible data value of the encoded sequence of data values which may be received at the next subsequent time increment;
• a first binary placeholder calculator coupled with the metric calculator and operative to calculate a first least number of binary digits capable of representing a first maximum value of the determined metrics;
• a difference calculator coupled with the metric calculator and operative to calculate a maximum difference between a first accumulation of a first consecutive subset of the determined metrics and a second accumulation of a second consecutive subset of the determined metrics, the second consecutive subset being inclusive of the first consecutive subset;
• a second binary placeholder calculator coupled with the metric calculator and operative to calculate a second least number of binary digits capable of representing a maximum accumulation of any consecutive subset of the determined metrics, the second least number of binary digits being the sum of the first least number of binary digits plus a third least number of binary digits;
• and
• a third binary placeholder calculator coupled with the first binary placeholder calculator, the difference calculator and the second binary placeholder calculator and operative to calculate the third least number of binary digits based on the maximum difference, the first maximum value and the first least number of binary digits.

A system for allocating resource requirements for a detector operative to decode an encoded sequence of data values to be received by the detector over a plurality of time increments, the encoded sequence of data having been encoded by an encoder having a number of stages and thereby a plurality of possible states of the encoder as a function of the possible input values which may be received by the encoder, the system comprising:

• a memory allocator operative to allocate a minimum amount of memory for storing a plurality of state metric values, the minimum amount of memory being sufficient to store a first number of bits for each of a plurality of metric values, wherein the first number of bits is a sum of a first least number of binary digits capable of representing a first maximum value of the metric values determined for each possible transition from each of the plurality of the possible states at a first time increment of the plurality of time increments to each of the plurality of possible states at a next subsequent time increment of the plurality of time increments based on each possible data value of the encoded sequence of data values which may be received at the next subsequent time increment and a second least number of binary digits computed based on a maximum difference between a first accumulation of a first consecutive subset of the determined metric values and a second accumulation of a second consecutive subset of the determined metric values, the second consecutive subset being inclusive of the first consecutive subset, the first maximum value and the first least number of binary digits, the first number of bits capable of representing a maximum accumulation of any consecutive subset of the determined metrics.