A Robust Nonlinear RLS Type Adaptive Filter for Second-Order-Intermodulation Distortion Cancellation in FDD LTE and 5G Direct Conversion Transceivers
Autor: | Andreas Gebhard, Matthias Wagner, Mario Huemer, Harald Pretl, Thomas Paireder, Christina Auer, Christian Motz, Oliver Lang, Ram Sunil Kanumalli, Michael Lunglmayr |
---|---|
Rok vydání: | 2019 |
Předmět: |
Signal Processing (eess.SP)
Radiation Computer science Bandwidth (signal processing) Transmitter 020206 networking & telecommunications 02 engineering and technology Stopband Filter (signal processing) Condensed Matter Physics Adaptive filter Duplexer FOS: Electrical engineering electronic engineering information engineering 0202 electrical engineering electronic engineering information engineering Electronic engineering Baseband Electrical Engineering and Systems Science - Signal Processing Electrical and Electronic Engineering Computer Science::Information Theory Intermodulation |
Zdroj: | IEEE Transactions on Microwave Theory and Techniques. 67:1946-1961 |
ISSN: | 1557-9670 0018-9480 |
Popis: | Transceivers operating in frequency division duplex experience a transmitter leakage (TxL) signal into the receiver due to the limited duplexer stopband isolation. This TxL signal in combination with the second-order nonlinearity of the receive mixer may lead to a baseband (BB) second-order intermodulation distortion (IMD2) with twice the transmit signal bandwidth. In direct conversion receivers, this nonlinear IMD2 interference may cause a severe signal-to-interference-plus-noise ratio degradation of the wanted receive signal. This contribution presents a nonlinear Wiener model recursive-least-squares (RLS) type adaptive filter for the cancellation of the IMD2 interference in the digital BB. The included channel-select filter and dc-notch filter at the output of the proposed adaptive filter ensure that the provided IMD2 replica includes the receiver front-end filtering. A second, robust version of the nonlinear recursive-least-squares (RLS) algorithm is derived which provides numerical stability for highly correlated input signals that arise in, e.g., Long-Term Evolution (LTE)-Advanced intra-band multi-cluster transmission scenarios. The performance of the proposed algorithms is evaluated by numerical simulations and by measurement data. |
Databáze: | OpenAIRE |
Externí odkaz: |