Hawkynt

Convolutional Code (Viterbi)

Convolutional encoder with Viterbi maximum likelihood decoder. Uses constraint length K=3, rate 1/2 with generator polynomials (7,5) octal. Widely used in digital communications including WiFi, LTE, and satellite systems.

Properties

Property	Value
Category	Error Correction
Sub-category	Convolutional Code
Security status	🎓 Educational Only
Complexity	Advanced
Inventor	Andrew Viterbi
Year	1967
Origin	🇺🇸 United States
Source	algorithms/ecc/convolutional-viterbi.js

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue	Description	Mitigation
Decoding Complexity	Viterbi decoding complexity grows exponentially with constraint length. K=7 is practical limit for software.	—
Error Propagation	Bit errors can propagate through decoder state transitions, though typically limited to 5× constraint length.	—

Documentation

• Wikipedia - Viterbi Decoder
• MIT Viterbi Tutorial
• Convolutional Encoding

References

• Viterbi’s Original Paper
• Error Correction Coding
• Princeton Lecture Notes

Test vectors

4 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — K=3 all zeros test

Field	Value
input	00000000
expected	0000000000000000

Vector 2 — K=3 single bit test

Field	Value
input	01000000
expected	0101010001010000

Vector 3 — K=3 all ones test

Field	Value
input	01010101
expected	0101000101000100

Vector 4 — K=3 alternating pattern

Field	Value
input	01000100
expected	0101010000000100

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