Systems and methods for implementing a distributed antenna system in a radio frequency integrated circuit
View Patent ↗A remote antenna unit includes an uplink integrated circuit (IC) and a downlink IC. The uplink IC includes an uplink synthesizer that provides an uplink oscillating signal; an uplink mixer stage that mixes an uplink radio frequency signal with the uplink oscillating signal to produce an uplink intermediate frequency signal; and an uplink control interface that receives uplink commands that control the frequency of the uplink oscillating signal. The downlink IC includes a downlink synthesizer that provides a downlink oscillating signal; a downlink mixer stage that mixes the downlink intermediate frequency signal with a downlink oscillating signal to produce a down link radio frequency signal; a downlink control interface that receives downlink commands that control the frequency of the downlink oscillating signal. The antenna unit also includes a clock that provides a reference frequency to the uplink and downlink synthesizers.
1. A remote antenna unit in a distributed antenna system, the antenna unit comprising:
an uplink integrated circuit, wherein the uplink integrated circuit receives a radio frequency signal, the uplink integrated circuit comprising:
an uplink synthesizer configured to provide an uplink oscillating signal in at least one frequency;
an uplink mixer stage coupled to the uplink synthesizer, the uplink mixer stage configured to mix the uplink radio frequency signal with the uplink oscillating signal to produce an uplink intermediate frequency signal; and
an uplink control interface configured to receive uplink commands that control the frequency of the uplink oscillating signal;
the antenna unit further comprising a downlink integrated circuit that is electrically isolated from the uplink integrated circuit, wherein the downlink integrated circuit receives a downlink intermediate frequency signal, the downlink integrated circuit comprising:
a downlink synthesizer configured to provide a downlink oscillating signal in at least one frequency;
a downlink mixer stage coupled to the downlink synthesizer, the downlink mixer stage configured to mix the downlink intermediate frequency signal with the downlink oscillating signal to produce a down link radio frequency signal;
a downlink control interface configured to receive downlink commands that control the frequency of the downlink oscillating signal; and
at least one clock configured to provide at least one reference frequency to the uplink synthesizer and the downlink synthesizer.
2. The remote antenna unit of claim 1 , wherein the uplink mixer stage comprises:
an uplink radio frequency variable gain attenuator, wherein the gain of the uplink radio frequency variable gain attenuator is set by the uplink commands;
an uplink mixer configured to mix the uplink radio frequency signal with the uplink oscillating signal to produce an uplink intermediate frequency signal; and
an uplink intermediate frequency variable gain attenuator, wherein the gain of the uplink intermediate frequency variable gain attenuator is set by the uplink commands.
3. The remote antenna unit of claim 2 , wherein the uplink mixer performs both low-side mixing and high-side mixing.
4. The remote antenna unit of claim 1 , wherein the uplink synthesizer comprises:
a synthesizer switchable voltage controlled oscillator configured to respond to the uplink commands by providing the uplink oscillating signal, wherein the uplink commands set the frequency of the uplink oscillating signal; and
a synthesizer phase lock loop configured to adjust the phase of the uplink oscillating signal.
5. The remote antenna unit of claim 1 , wherein the uplink control interface disables the uplink synthesizer in response to an uplink command, whereupon the uplink mixer receives the uplink oscillating signal from a device located off of the uplink integrated circuit.
6. The remote antenna unit of claim 1 , wherein the uplink integrated circuit further comprises an uplink intermediate frequency amplifier configured to amplify the uplink intermediate frequency signal.
7. The remote antenna unit of claim 1 , wherein the uplink integrated circuit further comprises an uplink radio frequency variable voltage attenuator configured to attenuate the uplink radio frequency signal in response to an uplink command received over the uplink control interface.
8. The remote antenna unit of claim 1 , wherein the uplink integrated circuit further comprises an uplink low noise amplifier configured to amplify the uplink radio frequency signal while limiting noise introduced into the uplink radio frequency signal.
9. The remote antenna unit of claim 1 , wherein the uplink integrated circuit further comprises an uplink power detector configured to detect the power of the uplink intermediate frequency signal before the uplink intermediate frequency signal is transmitted to upstream devices.
10. The remote antenna unit of claim 1 , wherein the uplink integrated circuit further includes fault detection components configured to detect a fault in the uplink path through the remote antenna unit, wherein the fault detection components generate a tone for fault detection.
11. The remote antenna unit of claim 10 , wherein the fault detection components comprise:
a fault detection switchable voltage controlled oscillator configured to respond to an uplink command by providing a fault detection oscillating signal, wherein the uplink commands set the frequency of the fault detection oscillating signal; and
a fault detection phase lock loop configured to adjust the phase of the fault detection oscillating signal; and
a fault detection mixer configured to mix the fault detection oscillating signal with the uplink oscillating signal to generate a fault detection tone.
12. The remote antenna unit of claim 1 , wherein the downlink mixer stage comprises:
a downlink intermediate frequency variable gain attenuator configured to attenuate the downlink intermediate frequency signal, wherein the gain of the downlink intermediate frequency variable gain attenuator is set by the downlink commands;
a downlink mixer configured to mix the downlink radio frequency signal with the downlink oscillating signal to produce a downlink intermediate frequency signal; and
a downlink radio frequency variable gain attenuator configured to attenuate the downlink radio frequency signal, wherein the gain of the downlink radio frequency variable gain attenuator is set by the downlink commands.
13. The remote antenna unit of claim 12 , wherein the downlink mixer performs both low-side mixing and high-side mixing.
14. The remote antenna unit of claim 1 , wherein the downlink synthesizer comprises:
a downlink switchable voltage controlled oscillator configured to respond to the downlink commands by providing the downlink oscillating signal, wherein the downlink commands set the frequency of the downlink oscillating signal; and
a synthesizer phase lock loop configured to adjust the phase of the uplink oscillating signal.
15. The remote antenna unit of claim 1 , wherein the downlink control interface disables the downlink synthesizer in response to the downlink commands, whereupon the downlink mixer stage receives the downlink oscillating signal from a device located off of the downlink integrated circuit.
16. The remote antenna unit of claim 1 , wherein the downlink integrated circuit further comprises a downlink intermediate frequency amplifier configured to amplify the downlink intermediate frequency signal.
17. The remote antenna unit of claim 1 , wherein the downlink integrated circuit further comprises a downlink radio frequency amplifier configured to amplify the downlink radio frequency signal.
18. The remote antenna unit of claim 1 , wherein the downlink integrated circuit further comprises a downlink power detector configured to detect the power of the downlink radio frequency signal before the downlink radio frequency signal is transmitted to an antenna for transmission.
19. The remote antenna unit of claim 1 , further comprising a microcontroller configured to issue uplink commands to the uplink integrated circuit and downlink commands to the downlink integrated circuit.
20. The remote antenna unit of claim 1 , wherein the remote antenna unit includes uplink supporting circuitry configured to support the operation of the uplink integrated circuit, wherein the uplink supporting circuitry comprises:
an uplink intermediate frequency filter configured to filter the uplink intermediate frequency signal;
a balun configured to balance the uplink radio frequency signal;
an uplink radio frequency filter configured to filter the uplink radio frequency signal; and
an uplink synthesizer low pass filter configured to filter a reference frequency for the uplink synthesizer.
21. The remote antenna unit of claim 1 , wherein the remote antenna unit includes downlink supporting circuitry configured to support the operation of the downlink integrated circuit, wherein the downlink supporting circuitry comprises:
a downlink intermediate frequency filter configured to filter the downlink intermediate frequency signal;
a downlink radio frequency filter configured to filter the downlink radio frequency signal; and
a downlink synthesizer low pass filter configured to filter a reference frequency for the downlink synthesizer.
22. A method for consolidating multiple components of a remote antenna unit onto integrated circuits, the method comprising:
forming an uplink integrated circuit, wherein the uplink integrated circuit receives an uplink radio frequency signal and mixes the uplink radio frequency signal into an uplink intermediate frequency signal, wherein the uplink radio frequency signal has a frequency in one of a plurality of uplink frequency bands; and
forming a downlink integrated circuit that is electrically isolated from the uplink integrated circuit, wherein the downlink integrated circuit receives a downlink intermediate frequency signal and mixes the downlink intermediate frequency signal into a downlink radio frequency signal, wherein the downlink radio frequency signal has a frequency in one of a plurality of downlink frequency bands.
23. The method of claim 22 , further comprising providing filtering and attenuation to support the operation of the uplink integrated circuit and the downlink integrated circuit.
24. The method of claim 22 , further comprising providing a reference frequency source to transmit at least one reference frequency to the downlink integrated circuit and the uplink integrated circuit.
25. The method of claim 22 , further comprising providing a microcontroller configured to transmit downlink commands to the downlink integrated circuit and uplink commands to the uplink integrated circuit.
26. The method of claim 22 , wherein the uplink integrated circuit and the downlink integrated circuit are formed using a silicon germanium process.
27. A distributed antenna system, the system comprising:
at least one hub unit configured to communicate with a base station;
a plurality of remote antenna units communicatively coupled to the at least one hub and configured to communicatively couple signals between the at least one hub and a plurality of wireless terminals, a remote antenna unit in the plurality of remote antenna units comprising:
an uplink integrated circuit, wherein the uplink integrated circuit receives a radio frequency signal, the uplink integrated circuit comprising:
an uplink synthesizer configured to provide an uplink oscillating signal in at least one frequency;
an uplink mixer stage coupled to the uplink synthesizer, the uplink mixer stage configured to mix the radio frequency signal with the uplink oscillating signal to produce an uplink intermediate frequency signal; and
an uplink control interface configured to receive uplink commands that control the frequency of the uplink oscillating signal;
the remote antenna unit also comprising a downlink integrated circuit that is electrically isolated from the uplink integrated circuit, wherein the downlink integrated circuit receives a downlink intermediate frequency signal, the downlink integrated circuit comprising:
a downlink synthesizer configured to provide a downlink oscillating signal in at least one frequency;
a downlink mixer stage coupled to the downlink synthesizer, the downlink mixer stage configured to mix the downlink intermediate frequency signal with the downlink oscillating signal to produce a down link radio frequency signal;
a downlink control interface configured to receive downlink commands that control the frequency of the downlink oscillating signal.
28. The distributed antenna system of claim 27 , wherein the uplink synthesizer, and the uplink mixer stage are located in the integrated circuit such that uplink synthesizer is electrically isolated from the uplink mixer stage.
29. The distributed antenna system of claim 27 , wherein the downlink synthesizer, and the downlink mixer stage are located in the integrated circuit such that uplink synthesizer is electrically isolated from the uplink mixer stage.
30. The distributed antenna system of claim 27 , wherein the uplink mixer stage comprises:
an uplink radio frequency variable gain attenuator, wherein the gain of the uplink radio frequency variable gain attenuator is set by the uplink commands;
an uplink mixer configured to mix the uplink radio frequency signal with the uplink oscillating signal to produce an uplink intermediate frequency signal; and
an uplink intermediate frequency variable gain attenuator, wherein the gain of the uplink intermediate frequency variable gain attenuator is set by the uplink commands.
31. The distributed antenna system of claim 27 , wherein the uplink synthesizer comprises:
a synthesizer switchable voltage controlled oscillator configured to respond to the uplink commands by providing the uplink oscillating signal, wherein the uplink commands set the frequency of the uplink oscillating signal; and
a synthesizer phase lock loop configured to adjust the phase of the uplink oscillating signal.
32. The distributed antenna system of claim 27 , wherein the uplink control interface disables the uplink synthesizer in response to an uplink command, whereupon the uplink mixer receives the uplink oscillating signal from a device located off of the uplink integrated circuit.
33. The distributed antenna system of claim 27 , wherein the uplink integrated circuit further comprises an uplink power detector configured to detect the power of the uplink intermediate frequency signal before the uplink intermediate frequency signal is transmitted to upstream devices.
34. The distributed antenna system of claim 27 , wherein the uplink integrated circuit further includes fault detection components configured to detect a fault in the uplink path through the remote antenna unit, wherein the fault detection components generate a tone for fault detection.
35. The distributed antenna system of claim 34 , wherein the fault detection components comprise:
a fault detection switchable voltage controlled oscillator configured to respond to an uplink command by providing a fault detection oscillating signal, wherein the uplink commands set the frequency of the fault detection oscillating signal; and
a fault detection phase lock loop configured to adjust the phase of the fault detection oscillating signal; and
a fault detection mixer configured to mix the fault detection oscillating signal with the uplink oscillating signal to generate a fault detection tone.
36. The distributed antenna system of claim 27 , wherein the downlink mixer stage comprises:
a downlink intermediate frequency variable gain attenuator configured to attenuate the downlink intermediate frequency signal, wherein the gain of the downlink intermediate frequency variable gain attenuator is set by the downlink commands;
a downlink mixer configured to mix the downlink radio frequency signal with the downlink oscillating signal to produce a downlink intermediate frequency signal; and
a downlink radio frequency variable gain attenuator configured to attenuate the downlink radio frequency signal, wherein the gain of the downlink radio frequency variable gain attenuator is set by the downlink commands.
37. The distributed antenna system of claim 27 , wherein the downlink synthesizer comprises:
a downlink switchable voltage controlled oscillator configured to respond to the downlink commands by providing the downlink oscillating signal, wherein the downlink commands set the frequency of the downlink oscillating signal; and
a synthesizer phase lock loop configured to adjust the phase of the uplink oscillating signal.
38. The distributed antenna system of claim 27 , wherein the downlink control interface disables the downlink synthesizer in response to the downlink commands, whereupon the downlink mixer stage receives the downlink oscillating signal from a device located off of the downlink integrated circuit.
39. The distributed antenna system of claim 27 , wherein the downlink integrated circuit further comprises a downlink power detector configured to detect the power of the downlink radio frequency signal before the downlink radio frequency signal is transmitted to an antenna for transmission.
40. The distributed antenna system of claim 27 , further comprising a microcontroller configured to issue uplink commands to the uplink integrated circuit and downlink commands to the downlink integrated circuit.