Ultra-low-power millimeter-wave to baseband receiver module for scalable massive MIMO
Aspects of the subject disclosure may include, for example, receiving, by a first radio module at a first location, a wireless MIMO signal, to obtain a first received RF signal. The wireless MIMO signal includes information originating at a remote MIMO transmitter and conveyed via a wireless channel. An envelope of the first received RF signal is detected by the first radio module without requiring a local oscillator, to obtain a first baseband signal. The first baseband signal may be filtered and/or amplified, after which it is compared to a reference value to obtain a first digital signal that is provided to a digital processor. The digital processor also obtains a second digital signal from a second radio module receiving the wireless MIMO signal at a second location and determines an estimate of the information originating at the remote MIMO transmitter according to the first and second digital signals. Other embodiments are disclosed.
1. A receiver device, comprising:
an antenna element comprising an antenna terminal, wherein the antenna element is adapted to provide a received radio frequency (RF) signal at the antenna terminal responsive to illumination of the antenna element by a spatially diverse RF signal transmitted from a multiple input multiple output (MIMO) transmitter operating within a millimeter wave spectrum, wherein a baseband signal is impressed upon the spatially diverse RF signal by the MIMO transmitter according to amplitude modulation;
a non-linear energy detector communicatively coupled to the antenna terminal, wherein the non-linear energy detector is adapted to detect the baseband signal directly from the received RF signal without using a local oscillator; and
an analog-to-digital converter (ADC) communicatively coupled to the antenna terminal, wherein the ADC is adapted to generate a digital signal according to the detected baseband signal.
2. The receiver device of claim 1 , wherein the non-linear energy detector comprises a current-voltage (I-V) characteristic curve, the detected baseband signal determined according to the I-V characteristic curve.
3. The receiver device of claim 2 , wherein the non-linear energy detector comprises a diode.
4. The receiver device of claim 1 , wherein the ADC comprises a comparator adapted to compare the detected baseband signal to a reference value to obtain a comparison result, and wherein the digital signal is obtained according to the comparison result.
5. The receiver device of claim 4 , wherein the reference value comprises a threshold voltage, the digital signal being obtained according to a comparison of the detected baseband signal.
6. The receiver device of claim 1 , wherein the receiver device is a passive device operating without requiring energy beyond that obtained via the illumination of the antenna element by the spatially diverse RF signal.
7. The receiver device of claim 1 , further comprising a low noise amplifier (LNA) communicatively coupled between the antenna terminal and the non-linear energy detector, wherein the LNA is operated in saturation.
8. The receiver device of claim 1 , further comprising an antenna coupler communicatively coupled between the antenna terminal and the non-linear energy detector.
9. The receiver device of claim 8 , wherein the antenna coupler is adapted to prevent coupling of direct current (DC) energy between the antenna terminal and the non-linear energy detector.
10. A multiple input multiple output (MIMO) radio, comprising:
a plurality of radio modules, each adapted to provide a respective 1-bit output signal responsive to a wireless MIMO signal received by the plurality of radio modules via a wireless channel, each radio module comprising:
a respective antenna element comprising a respective antenna terminal, wherein the respective antenna element is adapted to provide a respective received RF signal at the respective antenna terminal responsive to the wireless MIMO signal received via the wireless channel;
a respective envelope detector communicatively coupled to the respective antenna terminal, wherein the respective envelope detector is adapted to detect information modulated onto the wireless MIMO signal prior to transmission via the wireless channel, to obtain a respective detected baseband signal; and
a respective analog-to-digital converter (ADC) communicatively coupled to the respective envelope detector, wherein the respective ADC is adapted to generate a respective digital signal according to the respective detected baseband signal; and
a digital processor communicatively coupled to the plurality of radio modules and adapted to determine an estimate of the information modulated onto the wireless MIMO signal prior to transmission according to the respective digital signal of each of the plurality of radio modules.
11. The MIMO radio of claim 10 , wherein a dimension of the respective envelope detector and the respective ADC is no larger than a maximum dimension of the respective antenna element, such that a size of each radio module is determined according to the maximum dimension of the respective antenna element.
12. The MIMO radio of claim 10 , wherein the respective envelope detector comprises a semiconductor junction configured to detect the information modulated onto the wireless MIMO signal when operating in a nonlinear region.
13. The MIMO radio of claim 10 , wherein each radio module further comprises a respective low noise amplifier (LNA) configured to operate in a nonlinear region.
14. The MIMO radio of claim 13 , wherein each respective LNA is configured to operate in saturation.
15. A method, comprising:
receiving, by a first radio module and at a first location, a wireless multiple input multiple output (MIMO) signal, to obtain a first received radio frequency (RF) signal, the wireless MIMO signal comprising information originating at a remote MIMO transmitter and conveyed to the first radio module via a wireless channel;
detecting, by the first radio module and without requiring a local oscillator, an envelope of the first received RF signal to obtain a first detected baseband signal;
comparing, by the first radio module, the first detected baseband signal to a reference value to obtain a first digital signal according to the first detected baseband signal; and
providing, by the first radio module, the first digital signal to a digital processor, the digital processor also obtaining a second digital signal from a second radio module receiving the wireless MIMO signal at a second location, the digital processor determining an estimate of the information originating at the remote MIMO transmitter according to the first and second digital signals.
16. The method of claim 15 , wherein the detecting of the envelope of the first received RF signal further comprises rectifying, via a semiconductor junction, the first received RF signal.
17. The method of claim 15 , further comprising conditioning, by the first radio module, the first detected baseband signal to obtain a first conditioned baseband signal.
18. The method of claim 15 , wherein the estimate of the information originating at the remote MIMO transmitter is based on a combination of the first digital signal and the second digital signal.
19. The method of claim 15 , wherein the wireless MIMO signal comprises a carrier wave component operating in a millimeter wave spectrum.
20. The method of claim 19 , wherein the first received RF signal comprises an amplitude modulated signal according to the information impressed upon the carrier wave component according to on-off-keying applied by the remote MIMO transmitter.