Interference mitigation method and apparatus for multiple collocated transceivers
First Claim
1. Apparatus for mitigating interference between a plurality of collocated radio transceivers operating through a common antenna, at least some of said transceivers having both a transmit mode and a receive mode, said apparatus comprising:
- (a) a filter bank having a plurality of filters, said filter bank being electrically coupled to said common antenna, each of said plurality of filters corresponding to one of a plurality of desired operating frequency bands;
(b) a switch matrix having a plurality of first ports electrically connected to said plurality of filters and a plurality of second ports corresponding to said plurality of transceivers, each of said plurality of second ports being capable of selective electrical interconnection with each of said plurality of first ports, whereby at least one of said plurality of second ports may be electrically interconnected with said common antenna through at least one of said plurality of filters of said filter bank, for at least one of transmission and reception in the desired frequency band to which said filter corresponds;
(c) a plurality of transmission path pairs for selective electrical interconnection of said plurality of transceivers and said plurality of corresponding second ports, at least one of said plurality of transmission path pairs including a transmitted signal transmission line and a received signal transmission path, each of said transceivers being connected to its corresponding switch matrix second port through said transmitted signal transmission line when in transmit mode and through said received signal transmission path when in receive mode; and
(d) a cancellation device, said cancellation device being electrically coupled to each of said transmitted signal transmission lines of said plurality of transmission path pairs for receipt of a transmitted signal sample from each of said plurality of transceivers that is operating in said transmit mode, said cancellation device being electrically coupled to said received signal transmission paths of said plurality of transmission path pairs for both receipt of a received signal sample and injection of an interference cancellation signal, said received signal sample having an interference portion and a non-interference portion, said cancellation device being responsive to said transmitted signal samples and said received signal sample and generating in response thereto said interference cancellation signal, said interference cancellation signal having substantially the same frequency and amplitude as said interference portion of said received signal sample, said interference cancellation signal being substantially 180°
out-of-phase with said interference portion of said received signal sample.
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Accused Products
Abstract
An apparatus and method for mitigating interference between multiple collocated radio transceivers operating through a common antenna. In a preferred form, the apparatus includes a filter bank containing bandpass filters corresponding to a number of desired operating frequency bands. Each transceiver can be selectively electrically interconnected with the common antenna through an appropriate filter. The filters attenuate out-of-band interference. An adaptive cancellation device is also provided to compare samples of the transmitted and received signals and produce an interference cancellation signal that is substantially equal in amplitude and 180° out of phase with the coherent portions of the compared transmitted and received signals.
190 Citations
12 Claims
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1. Apparatus for mitigating interference between a plurality of collocated radio transceivers operating through a common antenna, at least some of said transceivers having both a transmit mode and a receive mode, said apparatus comprising:
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(a) a filter bank having a plurality of filters, said filter bank being electrically coupled to said common antenna, each of said plurality of filters corresponding to one of a plurality of desired operating frequency bands; (b) a switch matrix having a plurality of first ports electrically connected to said plurality of filters and a plurality of second ports corresponding to said plurality of transceivers, each of said plurality of second ports being capable of selective electrical interconnection with each of said plurality of first ports, whereby at least one of said plurality of second ports may be electrically interconnected with said common antenna through at least one of said plurality of filters of said filter bank, for at least one of transmission and reception in the desired frequency band to which said filter corresponds; (c) a plurality of transmission path pairs for selective electrical interconnection of said plurality of transceivers and said plurality of corresponding second ports, at least one of said plurality of transmission path pairs including a transmitted signal transmission line and a received signal transmission path, each of said transceivers being connected to its corresponding switch matrix second port through said transmitted signal transmission line when in transmit mode and through said received signal transmission path when in receive mode; and (d) a cancellation device, said cancellation device being electrically coupled to each of said transmitted signal transmission lines of said plurality of transmission path pairs for receipt of a transmitted signal sample from each of said plurality of transceivers that is operating in said transmit mode, said cancellation device being electrically coupled to said received signal transmission paths of said plurality of transmission path pairs for both receipt of a received signal sample and injection of an interference cancellation signal, said received signal sample having an interference portion and a non-interference portion, said cancellation device being responsive to said transmitted signal samples and said received signal sample and generating in response thereto said interference cancellation signal, said interference cancellation signal having substantially the same frequency and amplitude as said interference portion of said received signal sample, said interference cancellation signal being substantially 180°
out-of-phase with said interference portion of said received signal sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for mitigating interference between N collocated radio transceivers operating through a common antenna, each of said transceivers having a transmit mode and a receive mode, said apparatus comprising:
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(a) a filter bank having a group of N tunable bandpass filters, each of said filters corresponding to one of said N transceivers, each of said filters being tuned to a desired operating frequency of its corresponding transceiver, each of said filters having a first port electrically coupled to said common antenna and having a second port; (b) a group of N transmission path pairs for selective electrical interconnection of said N transceivers and said second ports of said corresponding filters, each of said N transmission path pairs including a transmitted signal transmission line and a received signal transmission path, each of said transceivers being connected to the second port of its corresponding bandpass filter through said transmitted signal transmission line when in said transmit mode and through said received signal transmission path when in said receive mode; and (c) a cancellation device, said cancellation device being electrically coupled to each of said transmitted signal transmission lines of said N transmission path pairs for receipt of a transmitted signal sample from each of said N transceivers that is operating in said transmit mode, said cancellation device being electrically coupled to said received signal transmission paths of said N transmission path pairs for both receipt of a received signal sample and injection of an interference cancellation signal, said received signal sample having an interference portion and a non-interference portion, said cancellation device being electrically configured to compare said transmitted signal samples with said received signal sample to produce said interference cancellation signal, said interference cancellation signal having substantially the same frequency and amplitude as said interference portion of said received signal sample, said interference cancellation signal being substantially 180°
out-of-phase with said interference portion of said received signal sample.
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12. A method for mitigating interference between N collocated radio transceivers operating through a common antenna, each of said transceivers having a transmit mode and a receive mode and having an associated frequency band, said method comprising the steps of:
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(a) sampling a main output signal of each of those said N transceivers operating in transmit mode to provide sampled output signals; (b) filtering each of said main output signals through a filter corresponding to the associated frequency band of the transceiver producing each one of said main output signals to substantially prevent subsequent transmission of out-of-band interference, said filtering step being performed after said sampling step (a); (c) transmitting said main output signals through said common antenna after said step of filtering said main output signals; (d) filtering a main received signal through a filter bank having a filter set to receive in each of said associated frequency bands of those of said N transceivers operating in receive mode, said main received signal having an interference portion and a non-interference portion, the number of those of said N transceivers operating in receive mode being designated as X, said filtering of said main received signal filtering out substantially all out-of-band interference from said main received signal; (e) sampling said main received signal to provide a sampled received signal; (f) comparing said sampled output signals and said sampled received signal in a cancellation device and generating an error correction signal which is substantially identical to but is 180°
out of phase with said interference portion of said main received signal;(g) combining said main received signal and said error correction signal to produce an error-corrected received signal that is substantially free of interference; and (h) dividing said received signal X ways for distribution to said X transceivers operating in receive mode.
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Specification