Wireless radio system optimization by persistent spectrum analysis
Apparatuses and methods for simultaneously operating as a wireless radio and monitoring the local frequency spectrum. For example, described herein are wireless radio devices that use a secondary receiver to monitor frequencies within the operating band and prevent or avoid interferers, including in particular half-IF interferers. The systems, devices, and methods described herein may adjust the intermediate frequency in a superheterodyne receiver to select an intermediate frequency that minimizes interference. In particular, described herein are apparatuses and methods that use a second receiver which is independent of the first receiver and may be connected to the same receiving antenna to monitor the geographically local frequency spectrum and may detect spurious interferers, allowing the primary receiver to adjust the intermediate frequency and avoid spurious interferes.
1. A wireless radio device configured to select among a plurality of intermediate frequencies to minimize interference, the device comprising:
one or more antennas;
a first receiver coupled to the one or more antennas and configured to receive a radio-frequency (RF) signal;
a second receiver coupled to the one or more antennas, the second receiver configured as a spectrum analyzer to monitor a frequency spectrum and to detect spurious interferers;
a mixer configured to generate a first intermediate frequency signal from the RF signal by mixing the RF signal with a local oscillation signal having a local oscillation frequency; and
one or more controllers configured to switch the first intermediate frequency to a second intermediate frequency if an interference in the RF signal exceeds a frequency threshold, wherein the one or more controllers is configured to process an RF signal received from the second receiver while switching the first intermediate frequency to the second intermediate frequency to prevent an interruption in data traffic during the switching.
2. The device of claim 1 , further comprising a transmitter or transceiver configured to transmit RF signals.
3. The device of claim 2 , wherein the one or more antennas includes at least a receiving antenna for receiving the RF signal and a transmitting antenna for transmitting the RF signals.
4. The device of claim 2 , wherein the received RF signal and transmitted RF signals are received and transmitted by the same antenna.
5. The device of claim 1 , wherein the mixer is configured to initially set the intermediate frequency to a first intermediate frequency.
6. The device of claim 1 , wherein the one or more controllers is configured to switch the second intermediate frequency back to the first intermediate frequency if the interference in the RF signal exceeds a second frequency threshold.
7. The device of claim 1 , wherein the one or more controllers is configured to determine if the interference in the RF signal at a first predetermined frequency exceeds the frequency threshold.
8. The device of claim 7 , wherein the one or more controllers is configured to switch the second intermediate frequency back to the first intermediate frequency if an interference in the RF signal at a second predetermined frequency exceeds the interference in the RF signal at the first predetermined frequency.
9. The device of claim 7 , wherein the first predetermined frequency is one-half of the first intermediate frequency.
10. The device of claim 7 , wherein the one or more controllers is configured to determine if the interference in the RF signal at the first predetermined frequency exceeds the frequency threshold by comparing an error rate at the first predetermined frequency with the frequency threshold.
11. The device of claim 1 , wherein the one or more controllers is configured to determine if the interference in the RF signal exceeds the frequency threshold.
12. The device of claim 1 , further comprising a spectrum processor configured to transmit spectrum information and geographic location information to a remote spectrum analysis unit.
13. The device of claim 12 , wherein the mixer is configured to operate in a channel corresponding to the first intermediate frequency signal based on information received from the remote spectrum analysis unit.
14. The device of claim 1 , wherein the spectrum analyzer is configured to scan through channels of an operating band of the wireless radio device.
15. The device of claim 1 , wherein the spectrum analyzer is configured to scan through a band that is larger than an operating band of the wireless radio device to bracketing the operating band on one or both sides.
16. A method selecting among a plurality of intermediate frequencies of a wireless radio device to minimize interference, the method comprising:
receiving, using a first receiver, a radio-frequency (RF) signal;
monitoring, using a second receiver configured as a spectrum analyzer, a frequency spectrum to detect spurious interferers;
generating a first intermediate frequency signal from the RF signal by mixing the RF signal with a local oscillation signal having a local oscillation frequency;
switching the first intermediate frequency to a second intermediate frequency if an interference in the RF signal exceeds a frequency threshold; and
processing an RF signal received from the second receiver while switching the first intermediate frequency to the second intermediate frequency to prevent an interruption in data traffic during the switching.
17. The method of claim 16 , further comprising transmitting RF signals, wherein the received RF signal is received by a receiving antenna, and the transmitted RF signals are transmitted by a transmitting antenna.
18. The method of claim 16 , further comprising transmitting RF signals, wherein the received RF signal and the transmitted RF signals are received and transmitted by the same antenna.
19. The method of claim 16 , determining if the interference in the RF signal exceeds the frequency threshold comprises determining if the interference in the RF at a first predetermined frequency exceeds the frequency threshold.
20. The method of claim 19 , further comprising switching the second intermediate frequency back to the first intermediate frequency if an interference in the RF signal at a second predetermined frequency exceeds the interference in the RF signal at the first predetermined frequency.