08175535 is referenced by 187 patents and cites 35 patents.

Active transmitter leakage cancellation techniques are disclosed, for reducing transmitter leakage in a frequency-duplexing radio transceiver. Reducing transmitter leakage to the receiver path of a duplex transceiver eases the linearity requirements for low-noise amplifier and mixer circuits, potentially reducing transceiver cost as well as complexity. In an exemplary method, a radio-frequency (RF) cancellation signal is generated from a transmitter signal, and the RF cancellation signal is combined with a received RF signal to obtain a combined RF signal comprising a residual transmitter leakage component. The residual transmitter leakage component of the combined RF signal is converted, using, e.g., a frequency mixer, to obtain a down-converted signal at baseband or at an intermediate frequency. A magnitude of the residual transmitter leakage component is detected from the down-converted signal, and used to adjust the phase or amplitude of the RF cancellation signal, or both, to reduce the residual transmitter leakage component.

Title
Active cancellation of transmitter leakage in a wireless transceiver
Application Number
12/38487
Publication Number
8175535 (B2)
Application Date
February 27, 2008
Publication Date
May 8, 2012
Inventor
Fenghao Mu
Hjärup
SE
Agent
Coats & Bennett P L L C
Assignee
Telefonaktiebolaget LM Ericsson
SE
IPC
H04B 1/10
H04B 17/00
H04B 1/00
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