Method and apparatus for soft symbol processing in a communication receiver
US8934581B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 2012 |
| Grant date | Jan 13, 2015 |
| Priority date | — |
| Expiry date | Jun 1, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/38
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
In one aspect, the present invention improves Turbo equalization and/or soft interference cancellation processing in communication receivers by providing an efficient and accurate technique to compute the second moment of a received symbol, e.g., an interfering symbol, as a function of the expected bit values of only those bits in the symbol that are magnitude-controlling bits according to a defined modulation constellation. Advantageously, the expected bit values in at least one embodiment are computed using a LUT that maps bit LLRs to corresponding hyperbolic tangent function values. Further, the expected symbol value is computed as a linear function of terms comprising the expected bit values and the soft symbol variance is efficiently computed from the second moment and the expected symbol value squared. This simplified processing reduces receiver complexity, particularly in the context of modulation constellations having non-constant magnitudes, and thus saves power and/or improves design economics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.