Isolation requirement mitigation for IDU-ODU interconnections in microwave systems
View Patent ↗A system and method to reduce and/or eliminate interference between an indoor unit (IDU) and an outdoor unit (ODU) in a split backhaul architecture. The interference can be present in, for example, an N-plexer in the IDU and/or the ODU. For example, interference on an outbound signal that is introduced by an inbound signal in the N-plexer can be reduced and/or eliminated by introducing a cancellation signal that is combined with the outbound signal. Further, the N-plexer can include two or more signal cancellation modules configured such that the output of a first signal cancellation module is connected to both a common pathway and the input of the second signal cancellation module. The input of the first signal cancellation module and the output of the second signal cancellation module can be configured as the Tx and Rx pathways of the IDU and/or ODU with respect to the common pathway.
1. A communication device, comprising:
an intermediate frequency (IF)-to-radio frequency (RF) module configured to generate a cancelation signal and a second signal;
a combiner configured to combine the cancelation signal with an input signal to generate a combined signal; and
an N-plexer configured to receive the combined signal and the second signal, and to generate a third signal by combining the combined signal and a portion of the second signal such that the cancelation signal included in the combined signal at least partially cancels out the portion of the second signal.
2. The communication device of claim 1 , wherein the third signal substantially corresponds to the input signal.
3. The communication device of claim 1 , wherein the N-plexer is configured such that the portion of the second signal interferes with the combined signal.
4. The communication device of claim 1 , wherein a phase of the cancelation signal is substantially opposite of a phase of the portion of the second signal.
5. The communication device of claim 4 , wherein the cancelation signal is 180° out of phase of the portion of the second signal.
6. The communication device of claim 4 , wherein an amplitude of the cancelation signal is substantially equal to an amplitude of the portion of the second signal.
7. The communication device of claim 1 , wherein the portion of the second signal is a non-isolated portion of the second signal with respect to the combined signal.
8. The communication device of claim 1 , wherein the IF-to-RF module includes a filter module configured to generate the cancelation signal.
9. The communication device of claim 8 , wherein the filter module is configured to filter a received RF signal to generate the cancelation signal.
10. The communication device of claim 8 , wherein the filter module is configured to generate the cancelation signal by adaptively processing the third signal.
11. The communication device of claim 10 , wherein the adaptive processing of the third signal includes least-mean-squares (LMS) processing of the third signal.
12. A communication device, comprising:
an intermediate frequency (IF)-to-radio frequency (RF) module including:
an digital signal processor (DSP) configured to generate a first signal; and
a filter module configured to generate a cancelation signal based on the first signal;
a combiner configured to combine an analog version of the cancelation signal with an input signal received by the combiner to generate a combined signal; and
an N-plexer configured to receive the combined signal from the combiner and a second signal from the IF-to-RF module, and to generate a third signal based on the combined signal and a portion of the second signal not isolated from the combined signal by the N-plexer, wherein the analog version of the cancelation signal included in the combined signal substantially cancels out the portion of the second signal not isolated from the combined signal.