US 6,553,541 B1 · Reduced-complexity sequence detection

Abstract

Reduction of the complexity of a Viterbi-type sequence detector is disclosed. It was based on elimination of less probably taken branches in the trellis. The method is applied to the design of the E2PR4 channel with 8/9 rate sliding block trellis code. Coding, by itself eliminates two states by coding constraints, and the disclosed method reduces the number of required ACS units from 14 to 11, while reducing their complexity as well. For the implementation of E2PR4 detection, 4 4-way, 3 3-way, 3 2-way and one 1-way ACSs are needed. System simulations show no BER performance drop at common SNRs when compared with a full 16-state E2PR4 implementation in magnetic disk drives.

Claims4

Dependent claims

A method of Viterbi detection, comprising:

(a) classify input samples into classes corresponding to sample values;
(b) for each of said classes, eliminate at least one possible target sample value;
(c) sort sequences of m+2 samples into sets according to the class of each member of the sequence where m is a positive integer, an m-step trellis is being used, the m+2 samples correspond to the m current samples, the immediately prior sample, and the next sample, and the number of said sets equals Cm+2 where C is the number of classes from step (a)
(d) use a number of add-compare-select units equal to the maximum number of m-step trellis input states or output states for any of said sets;
and
(e) switch state metric outputs and inputs among said add-compare-select units whereby less than all possible state metrics are maintained.

3 more elements

Dependencies are inferred from the claim text.

Reduced-complexity sequence detection

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Reduced-complexity sequence detection

Life of this patent

Abstract

Claims4