Variable-length constrained-sequence codes

• Author / Creator

  Steadman, Andrew

• The use of variable-length codes to construct capacity approaching constrained sequence codes is examined. Constrained sequence codes are commonly used for digital storage and transmission, but have historically been implemented using block codes. A new technique is developed for constructing variable-length constrained sequence codes. These codes are based on Huffman encoding various partial extensions, a technique that is shown to be optimal in the sense that no other technique can result in a higher code rate given the same partial extension. Partial extensions are exhaustively searched in order to identify the highest rate code within a particular bound. Examples of the technique are provided for various constraints, including (d,k) and DC-free constraints. These examples are shown to have average rates within 1% of capacity for their respective constraints. Tables are also provided listing the optimal sourceword to codeword length mappings for various other constraints.

• Subjects / Keywords

  • Recording
  • Codes
  • Variable-length
  • Constraint
  • Huffman

• Graduation date

  Fall 2011

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3WS8W

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.