Apparatus and method for communicating digital data using trellis coding with punctured convolutional codes
US5396518A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 5, 1993 |
| Grant date | Mar 7, 1995 |
| Priority date | — |
| Expiry date | May 5, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/3427
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Punctured binary convolutional codes are used in a trellis coded modulation scheme to achieve spectral efficiencies as high as those of multi-dimensional codes, using simple hardware. A base rate 1/2 binary convolutional code is punctured to rate n/k. The output of the punctured encoder is mapped to a four-way partition of a 2.sup.N point two-dimensional QAM constellation. The four-way partition consists of a two-way partition in both the I and Q dimensions. The two-way partitions of each dimension are used to transmit the two level output of the rate n/k binary convolutional coder. (N-2) "uncoded" bits are transmitted by selecting the unique constellation point in a partition group. The code has an average throughput of (N-2)+2n/k bits per symbol. The invention is also applicable to trellis coded amplitude modulation schemes based on 2.sup.N possible amplitude levels provided along a one-dimensional constellation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.