Adaptive cancellation of fixed interferers
First Claim
1. An interference cancellation system for use in conjunction with a base station having a main antenna for receiving signals from a plurality of remote users, wherein at least one interference source is known, the system comprising:
- at least one directional antenna directed toward said at least one interference source, said antenna having a plurality of coplanar feeds that are located one quarter to one half wavelength apart from each other, each coplanar feed for receiving an RF signal;
means for weighting said RF signals received by said plurality of coplanar feeds to produce a cancellation signal;
first summing means for summing said weighted signals using a least mean square (LMS) algorithm; and
second summing means for summing said cancellation signal with signals received from said main antenna to produce an output signal substantially free from interference.
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Abstract
An improved base station which cancels the effects of known fixed interference sources produces a signal substantially free from the interference sources thereby increasing total channel capacity. The adaptive interference canceler system includes a main antenna for receiving signals from other communication stations and at least one directional antenna directed toward an interference source. The main and directional antennas are coupled together such that an output signal substantially free from the interference is generated.
15 Citations
7 Claims
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1. An interference cancellation system for use in conjunction with a base station having a main antenna for receiving signals from a plurality of remote users, wherein at least one interference source is known, the system comprising:
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at least one directional antenna directed toward said at least one interference source, said antenna having a plurality of coplanar feeds that are located one quarter to one half wavelength apart from each other, each coplanar feed for receiving an RF signal;
means for weighting said RF signals received by said plurality of coplanar feeds to produce a cancellation signal;
first summing means for summing said weighted signals using a least mean square (LMS) algorithm; and
second summing means for summing said cancellation signal with signals received from said main antenna to produce an output signal substantially free from interference. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for interference cancellation for use in conjunction with a base station having a main antenna for receiving signals from a plurality of remote users, wherein at least one interference source is known, comprising the steps of:
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directing at least one directional antenna toward said at least one interference source, each directional antenna having a plurality coplanar feeds that are located one quarter to one half wavelength apart from each other, each coplanar feed for receiving an RF signal; and
cancelling an interference signal generated by said at least one known interference source, wherein said cancelling step further comprises;
weighting the RF signals received by said coplanar feeds;
summing the weighted signals using a least mean square (LMS) algorithm to produce a cancellation signal;
summing the cancellation signal with signals received from the main antenna to produce an output signal substantially free from interference; and
comparing feedback from the output signal to the weighted signal until steady state is achieved.
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Specification