Methods and Apparatuses to Cancel Transmitter Self-Interference Leakage

Principal Investigator: Jacques Rudell

The steadily increasing demand for low cost, high speed data for wireless applications has caused researchers to focus on high speed, low band radios. One such high-speed technique is frequency dependent duplexing (FDD), in which the receiver and transmitter operate at different frequencies, a method which allows for high speed, but also results in non-negligible transmitter leakage because the transmitter and receiver share the same antenna. Items such as surface acoustic wave filters (SAW) are used to suppress transmitter leakage, but these filters are band specific. Additional filters add bulk and increase cost and power consumption, and active cancellation as a solution often leads to noise in the system.

UW investigators propose several methods and apparatuses to cancel transmitter self-interference leakage. These methods include the designs for a multiport transceiver which contains a port for receiving incoming signals and another to mix in a cancellation signal, a process which can cancel the leakage signal from the incoming signal. These components, combined with other elements, form a tunable cancellation circuit in which the amplitude and phase may be modulated.


• These components can help alleviate some of the problems associated with FDD by allowing for high speed and reduced leakage. 

• These components will have direct contributions to many fields that utilize wireless technologies, from smart phones to a variety of backhaul products. 

• Since this cancellation circuit is tunable, this invention can be applied across a variety of platforms. 


• The resultant cancellation circuit is tunable, allowing for more precise modulation of the system. 

• This method reduces the need for an external SAW filter.

For more info, contact: Ryan Buckmaster

  • swap_vertical_circlelibrary_booksReferences (1)
    1. Sherif H. Abdelhalem, Prasad S. Gudem, Lawrence E. Larson (July 19, 2012), A tunable differential duplexer in 90nm CMOS, IEEE
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