Method and apparatus for path metric processing in telecommunications systems
AssigneeLucent Technologies Inc.
InventorMark Andrew Bickerstaff
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Abstract
An apparatus and a method for calculating in-place path metric addressing for a trellis processing arrangement are disclosed. An arrangement of cascaded multiplexers and stores receives a known input sequence of path metrics. The input sequence of path metrics is manipulated such that certain of the path metrics are delayed in the stores by a clock cycle, whilst the remaining path metrics are presented to the cascaded banks of multiplexers. In this manner, the input sequence of path metrics is continuously processed to produce a desired output sequence of path metrics. Advantageously, the apparatus and method of the invention may be practised on either a forward trellis or a reverse trellis.
Claims56
An apparatus for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said apparatus comprising:
- first, second and third cascaded banks of multiplexers, each bank for receiving said input sequence of path metrics, each multiplexer of said first bank receiving two of said path metrics, each multiplexer of said second bank receiving at least one of said path metrics and each multiplexer of said third bank receiving a corresponding one of said path metrics;
- a first bank of stores for receiving outputs from said first bank of multiplexers and delaying provision of said outputs to one of said second and third banks of multiplexers by a predetermined time period;
- a second bank of stores for receiving path metrics output from said third bank of multiplexers and storing said received path metrics in said desired output sequence;
- and
- a controller coupled to each of said banks to select one of a plurality of predetermined path metric patterns to be applied to the corresponding said bank of L=multiplexers within each time period, said patterns over a sequence of said time periods applying the conversion from said input sequence to said output sequence.
An apparatus for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said apparatus comprising:
- a first plurality of first multiplexers corresponding in number to half the number of said path metrics, each of said first multiplexers receiving two of said path metrics of said input sequence;
- a corresponding first plurality of first stores, each receiving an output from a corresponding one of said first multiplexers and delaying provision of said output by a predetermined time period;
- a second plurality of second multiplexers, each receiving at least one of said path metrics of said input sequence;
- a third plurality of second stores for receiving path metrics output from at least one of said second multiplexers and said first stores and forming said desired output sequence;
- and
- a controller coupled to each of said multiplexers and said first stores for selecting in a predetermined pattern a first number of said input path metrics and a second number of said input path metrics delayed via said first stores.
An apparatus for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said apparatus comprising:
- a first plurality of first multiplexers corresponding in number to half the number of said path metrics, each of said multiplexers receiving two of said path metrics of said input sequence;
- a corresponding first plurality of first stores, each receiving an output from a corresponding one of said first multiplexers and delaying provision of said output;
- a second plurality of second multiplexers, each receiving at least one of said path metrics of said input sequence;
- a third plurality of third multiplexers, corresponding in number to the number of path metrics, each of said third multiplexers configured to receive one of said path metrics of said input sequence and at least one of an output from a corresponding one of said second multiplexers and a delayed output from said first stores;
- a corresponding second plurality of second stores for receiving path metrics output from said third multiplexers and forming said desired output sequence;
- and
- a controller coupled to each of said multiplexers and said first stores for selecting in a predetermined pattern a first number of said input path metrics and a second number of said input path metrics delayed via said first stores.
An apparatus for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said apparatus comprising:
- first and second cascaded banks of multiplexers, each bank for receiving said input sequence of path metrics, each multiplexer of said first bank receiving two of said path metrics, each multiplexer of said second bank receiving at least one of said path metrics;
- a first bank of stores for receiving outputs from said first bank of multiplexers and delaying provision of said outputs by a predetermined time period;
- a second bank of stores for receiving path metrics output from at least one of said second bank of multiplexers and said first bank of stores, and storing said received path metrics in said desired output sequence;
- and
- a controller coupled to each of said banks to select one of a plurality of predetermined path metric patterns to be applied to the corresponding said bank of multiplexers within each time period, said patterns over a sequence of said time periods applying the conversion from said input sequence to said output sequence.
An apparatus for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said apparatus comprising:
- first, second and third cascaded banks of multiplexers, each bank for receiving said input sequence of path metrics, each multiplexer of said first bank receiving two of said path metrics, each multiplexer of said second bank receiving at least one of said path metrics and each multiplexer of said third bank receiving a corresponding one of said path metrics;
- a first bank of stores for receiving outputs from said first bank of multiplexers and delaying provision of said outputs to one of said second and third banks of multiplexers by a predetermined time period;
- and
- a second bank of stores for receiving path metrics output from said third bank of multiplexers and storing said received path metrics in said desired output sequence;
- wherein said banks are controlled to select one of a plurality of predetermined path metric patterns to be applied to the corresponding said bank of multiplexers within each time period, said patterns over a sequence of said time periods applying the conversion from said input sequence to said output sequence.
An apparatus for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said apparatus comprising:
- a first plurality of first multiplexers corresponding in number to half the number of said path metrics, each of said first multiplexers receiving two of said path metrics of said input sequence;
- a corresponding first plurality of first stores, each receiving an output from a corresponding one of said first multiplexers and delaying provision of said output by a predetermined time period;
- a second plurality of second multiplexers, each receiving at least one of said path metrics of said input sequence;
- and
- a third plurality of second stores for receiving path metrics output from at least one of said second multiplexers and said first stores and forming said desired output sequence;
- wherein
- each of said multiplexers and said first stores are controlled to select in a predetermined pattern a first number of said input path metrics and a second number of said input path metrics delayed via said first stores.
An apparatus for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said apparatus comprising:
- first, second and third cascaded banks of multiplexing means for multiplexing said input sequence of path metrics, each multiplexing means of said first bank receiving two of said path metrics, each multiplexing means of said second bank receiving at least one of said path metrics and each multiplexing means of said third bank receiving a corresponding one of said path metrics;
- first storage means for receiving outputs from said first bank to delay provision of said outputs by a predetermined time period;
- second storage means for receiving path metrics output from said third bank to store said received path metrics in said desired output sequence;
- and
- control means for controlling each of said banks to select one of a plurality of predetermined path metric patterns to be applied to the corresponding said bank of multiplexing means within each time period, said patterns over a sequence of said time periods applying the conversion from said input sequence to said output sequence.
An apparatus for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said apparatus comprising:
- a first plurality of first multiplexing means for multiplexing pairs of path metrics of said input sequence, said first plurality corresponding in number to half the number of said path metrics, each of said multiplexing means receiving two of said path metrics of said input sequence;
- a corresponding first plurality of first storage means for storing an output from a corresponding one of said first multiplexing means to delay said output by a predetermined time period;
- a second plurality of second multiplexing means for multiplexing said path metrics of said input sequence, each one of said multiplexing means receiving at least one of said path metrics of said input sequence;
- and
- a third plurality of second storage means for storing path metrics output from at least one of said second multiplexing means and said first storage means to form said desired output sequence;
- wherein
- each of said multiplexing means and said first storage means is controlled to select in a predetermined pattern a first number of said input path metrics and a second number of said input path metrics delayed via said first storage means.
A method for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said method comprising the steps of:
- multiplexing pairs of path metrics of said input sequence of a first time period to produce first multiplexed outputs;
- storing said first multiplexed outputs for a time period to produce first delayed multiplexed outputs;
- multiplexing one of (i) pairs of path metrics of said input sequence of said first time period and (ii) path metrics of said input sequence of a second time period and said first delayed multiplexed outputs, to produce second multiplexed outputs;
- multiplexing at least one of said second multiplexed outputs and said first delayed multiplexed outputs with path metrics of said input sequence of said second time period to produce third multiplexed outputs;
- storing said third multiplexed outputs in said desired output sequence;
- and
- controlling said multiplexing to select one of a plurality of predetermined path metric patterns to be applied within each time period, said patterns over a sequence of said time periods applying the conversion from said input sequence to said output sequence.
A method for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said method comprising the steps of:
- multiplexing pairs of path metrics of said input sequence of a first time period to produce first multiplexed outputs;
- storing said first multiplexed outputs for a time period to produce first delayed multiplexed outputs;
- multiplexing one of (i) pairs of path metrics of said input sequence of said first time period and (ii) path metrics of said input sequence of a second time period and said first delayed multiplexed outputs, to produce second multiplexed outputs;
- storing at least one of said second multiplexed outputs and said first delayed multiplexed outputs in said desired output sequence;
- wherein said multiplexing is controlled to select one of a plurality of predetermined path metric patterns to be applied within each time period, said patterns over a sequence of said time periods applying the conversion from said input sequence to said output sequence.
A method for calculating in-place path metric addressing for a trellis processing arrangement to alter a known input sequence of path metrics to form a desired output sequence of path metrics, said method comprising the steps of:
- multiplexing pairs of path metrics of said input sequence of a first time period to produce first multiplexed outputs;
- storing said first multiplexed outputs for a time period to produce first delayed multiplexed outputs;
- multiplexing first data selected from a first data set to produce second multiplexed outputs, said first data set comprising path metrics of said input sequence of said first time period, path metrics of said input sequence of a second time period, and said first delayed outputs;
- multiplexing second data selected from a second data set with path metrics of said input sequence of said second time period to produce third multiplexed outputs, said second data set comprising said second multiplexed outputs and said first delayed multiplexed outputs;
- storing said third multiplexed outputs in said desired output sequence;
- and
- controlling said multiplexing to select one of a plurality of predetermined path metric patterns to be applied within each time period, said patterns over a sequence of said time periods applying the conversion from said input sequence to said output sequence.
Dependencies are inferred from the claim text.