Implementing reduced-state viterbi detectors
AssigneeHitachi, Ltd.
InventorsRunsheng He, Joao R. Cruz
Life of this patent
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Abstract
A method of design and an implementation system for reduced-state Viterbi detectors for intersymbol interference channels are provided. The method uses a complement states grouping technique that comprises the steps of finding the state distances between complement states; forming the reduced-state trellis by grouping the complement states with state distance no less than the minimum free distance; and by keeping the complement states with state distance less than minimum free distance unchanged. The resultant reduced-state Viterbi detector has negligible performance loss compared to the full-state Viterbi detector while the complexity is reduced by a factor of about two.
Claims56
A method for reducing the number of states of a Viterbi detector for decoding a discrete time intersymbol interference channel, the method comprising the steps of:
- determining a state distance for a pair of complement states of the discrete channel;
- forming a superstate of a reduced-state trellis from the pair of complement states if the state distance of the pair of complement states satisfies a predetermined criterion;
- and
- keeping each state of the pair of complement states if the state distance for the pair of complement states does not satisfy the predetermined criterion.
A system for data transfer between a user and a receiver comprising:
- a channel encoder for encoding a data string to produce an encoded data string;
- a discrete time channel coupled to the channel encoder for transferring the encoded data string;
- a reduced-state detector coupled to the discrete time channel, wherein the reduced-state detector utilizes a complement states grouping technique to reduce the number of states in the detector and decodes an output of the discrete time channel to generate the encoded data string;
- and
- a channel decoder coupled to the reduced-state detector for recovering the data string from the encoded data string;
- wherein the reduced-state detector groups a pair of complement states to form a superstate if the pair of complement states have a state distance satisfying a predetermined criterion.
A system for data transfer between a user and a receiver comprising:
- a channel encoder for encoding a data string to produce an encoded data string;
- a discrete time channel coupled to the channel encoder for transferring the encoded data string;
- a reduced-state detector coupled to the discrete time channel, wherein the reduced-state detector utilizes a complement states grouping technique to reduce the number of states in the detector and decodes an output of the discrete time channel to generate the encoded data string;
- and
- a channel decoder coupled to the reduced-state detector for recovering the data string from the encoded data string;
- wherein the reduced-state detector comprises:
- at least two ACS units;
- and
- a selection unit coupled to one of the at least two ACS units;
- and wherein the selection unit eliminates a branch of a reduced-state trellis if a noiseless channel output associated with a branch has a different sign from the output of the discrete time channel.
In a discrete system having a plurality of states, a method for producing a reduced state trellis for the discrete system comprising the steps of:
- determining a state distance for each pair of a plurality of pairs of complement states;
- forming a superstate from a pair of complement states of the plurality of pairs of complement states when the state distance of the pair satisfies a predetermined criterion;
- and
- keeping each state of a second pair of the plurality of pairs of complement states when the state distance of the second pair does not satisfy the predetermined criterion, thereby forming the reduced state trellis for the discrete system.
In a discrete system having a plurality of states, a method for producing a reduced state trellis for the discrete system comprising the steps of:
- forming a superstate from a first pair of a plurality of pairs of complement states when a state distance of the first pair satisfies a predetermined criterion;
- and
- keeping each state of a second pair of the plurality of pairs of complement states when a state distance of the second pair does not satisfy the predetermined criterion, thereby reducing the complexity of a maximum likelihood trellis to produce the reduced state trellis for the discrete system.
Dependencies are inferred from the claim text.