Abstract
The application of digital predistortion in base band signal is an extended method of amplifier linearization to reduce the Adjacent Channel Interference (ACI) in those systems in which a varying envelope modulation scheme like OFDM and MQAM is used. Digital baseband predistortion is a highly cost-effective way to linearize Power amplifiers (PAs), but most existing architectures assume that the PA has a memoryless nonlinearity. For wider bandwidth applications such as wideband code-division multiple access (WCDMA), wideband orthogonal frequency-division multiplexing (W-OFDM) and worldwide interoperability for microwave access (WiMAX), PA memory effects can no longer be ignored. In this paper a novel technique for compensating such effects is proposed. This technique is a combination of two techniques, memory polynomial predistortion and the gain based predistorter method. This method is compared with the other technique, memory polynomial method and validated using a Mini-Circuit power amplifier and QPSK signal with 1 MHz bandwidth. Simulations and results show improvement in ACLR reduction and EVM with applying this method.
| Original language | English |
|---|---|
| Pages (from-to) | 129-135 |
| Number of pages | 7 |
| Journal | Journal of Electrical Engineering |
| Volume | 60 |
| Issue number | 3 |
| Publication status | Published - 2009 |
| Externally published | Yes |
Keywords
- ACLR
- Digital predistortion
- Memory effects
- Power amplifier
- WCDMA