Adaptive controller for linearization of transmitter with impairments
US7333557B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 2002 |
| Grant date | Feb 19, 2008 |
| Priority date | — |
| Expiry date | Jul 2, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/368
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An adaptive controller for linearization of transmitters using predistortion of the input signal has reduced sensitivity to impairments such as gain variation, phase noise or modulation/demodulation frequency instability by linearizing an adaptively normalized gain provided through a separate estimation and cancellation of linear gain variations. Values of a nonlinear and a linear gain blocks, cascaded with the linearized transmitter and called respectively a predistortion block and a gain regulation block, are independently adjusted by two different adaptive controllers. In one embodiment, four banks of real gain elements compose the predistortion block and realize an arbitrary step-wise approximation of a generalized 2×2 transmit gain matrix of nonlinear functions. In a further embodiment cancellation of a DC level bias multi-channel impairment is provided by an adaptively adjusted signal adder inserted in the transmit chain between the predistortion block and the linearized transmitter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.