Apparatus and method for interference mitigation

A method of mitigating interference between a first radio operating in a wide frequency band and a second radio operating in a narrow frequency band within the wide frequency band, said method comprising:

• creating by the first radio, a transmitter notch of decreased transmit power centered at a selected frequency in the wide frequency band, said selected frequency having a position in the wide frequency band that is fixed in relation to a wideband carrier frequency of a transmitted signal, said creating step including:
• creating the notch by a high-pass filter at base band in the first radio's wideband transmitter;
• and
• up-converting the signal to RF utilizing an LO frequency such that the resulting notch frequency Fnotch coincides with the second radio's narrowband carrier frequency;
• and
• adjusting the wideband carrier frequency so that the frequency of the transmitter notch is aligned with the second radio's narrowband carrier frequency.

A method of mitigating interference between a first radio operating in a wide frequency band and a second radio operating in a narrow frequency band within the wide frequency band, said method comprising:

• creating by the first radio, a transmitter notch of decreased transmit power centered at a selected frequency in the wide frequency band, said selected frequency having a position in the wide frequency band that is fixed in relation to a wideband carrier frequency;
• adjusting the wideband carrier frequency so that the frequency of the transmitter notch is aligned with the second radio's narrowband carrier frequency;
• and
• creating by the first radio, a receiver notch of decreased receiver gain at a selected frequency in the first radio's wideband receiver, wherein the frequency of the receiver notch is aligned with the frequency of the first radio's transmitter notch, thereby reducing interference that transmissions by the second radio cause for the first radio, wherein the step of creating a receiver notch of decreased receiver gain includes selecting a local oscillator (LO) frequency such that when the second radio's narrow frequency band is down-converted from radio frequency (RF) to intermediate frequency (IF), the second radio's down-converted signal is aligned with the frequency of the receiver notch.

An apparatus in a wideband radio transceiver for mitigating interference between a wideband radio operating in a wide frequency band in a single-carrier radio system and a narrowband radio operating in a narrow frequency band within the wide frequency band, said apparatus comprising:

• a fixed high-Q filter at an intermediate frequency (IF) stage of the wideband radio's wideband transmitter for creating a transmitter notch of decreased transmit power centered at a selected notch frequency in the wide frequency band, said selected notch frequency having a position in the wide frequency band that is fixed in relation to a wideband carrier frequency of a transmitted signal;
• an up-converter for up-converting the signal to RF utilizing an LO frequency such that the resulting notch frequency Fnotch coincides with the narrowband radio's narrowband carrier frequency;
• and
• means for adjusting the wideband carrier frequency so that the frequency of the transmitter notch is aligned with the narrowband radio's narrowband carrier frequency;
• wherein the wide frequency band is still processed as a single band after the notch is created therein.