Transmit signal cancellation in wireless receivers
AssigneeEngim, Inc.
InventorSam Tiller
Life of this patent
Estimating the term…
Abstract
An interference canceling method and apparatus reduces the level of signal impinging on a wireless receiver due to the transmitted signal from the same transceiver. A signal sampler, such as directional coupler samples a portion of the transmitted signal. The gain and phase of the sampled signal are adjusted to create an equi-amplitude signal that is 180 degrees out of phase with the unwanted coupled transmit signal. The combination of the gain-phase adjusted signal with the received signal effectively cancels the unwanted transmit signal. Once configured, the interference canceller can continue to operate without further adjustment. Adjustments can be made periodically, however, when necessary to accommodate for changes such as environmental changes.
Claims32
A wireless network transceiver system comprising:
- an RF transceiver including an RF transmit path and an RF receive path;
- a sampler obtaining a sample of a transmit signal from the RF transmit path;
- a gain-phase gain-phase adjuster circuit that adjusts the transmit signal sample from the sampler and supplies the adjusted transmit signal sample to the RF receive path;
- a gain-phase controller adjusting the gain-phase adjuster circuit to minimize at a calibration frequency effects of the transmit signal cross-coupling to the RF receive path.
A method for canceling receiver interference within a transceiver having a transmitter coupled to a transmit antenna through transmit path and a receiver coupled to a receive antenna through receive path, the interference resulting from coupling of a local transmit signal at the receiver, the method comprising:
- calibrating gain and phase offsets;
- receiving an intended signal;
- coupling a sample of a transmit signal having an amplitude and a phase;
- adjusting the gain of the sampled transmit using the gain offset;
- adjusting the phase of the transmit signal sample using the phase offset;
- and
- combining the gain-phase adjusted transmit signal sample with the received intended signal.
An interference cancellation system for reducing interference at a local receiver by reducing unintentional coupling of a local transmit signal to the local receiver, the system comprising:
- a controller generating a control input;
- a first sampler sampling a transmit signal having an amplitude and a phase;
- a gain-phase adjusting circuit coupled to the controller and the sampler, the gain-phase adjusting circuit receiving the transmit signal sample and adjusting the gain-phase adjuster circuit, and further adjusting the gain and phase of the transmit signal sample in response to adjusting the gain-phase adjuster circuit;
- and
- a combiner coupled between the gain-phase adjuster and the receiver, the combiner receiving the gain-phase adjusted transmit signal sample and receiving an intended received signal, the combiner forming an adjusted received signal by combining the two received signals.
An interference cancellation system for reducing interference at a local receiver by reducing unintentional coupling of a local transmit signal to the local receiver, the system comprising:
- means for calibrating gain and phase offsets;
- means for receiving an intended signal;
- means for coupling a sample of a transmit signal having an amplitude and a phase;
- means for adjusting the gain of the sampled transmit using the gain offset;
- means for adjusting the phase of the transmit signal sample using the phase offset;
- and
- means for combining the gain-phase adjusted transmit signal sample with the received intended signal.
Dependencies are inferred from the claim text.