March 01, 2014

Perlman's Artemis pCell Wireless real time beamforming will massively boost wireless communication speed and enable wireless power revolutin

Steve Perlman's Artemis Wireless technology will offer a solution to the "spectrum crunch" problem. From a mobile consumer's standpoint, it'll just seem like the next step in evolution from 4G to 5G - much faster, more consistent speeds, and with lower latency.

New analysis is from Imran Akbars website. I believe Imran Akbar is the VP of Motorola Solutions.

The theory behind the Perlman pCell system system is referred to as "network MIMO" or "cooperative MIMO" in the literature and "coordinated beamforming" in the 3GPP LTE-A specification, and dates back to at least 2001. Artemis has taken techniques that are being proposed for upcoming 5G systems and figured out how to solve all the engineering challenges involved, years ahead of the rest of the industry.

The last slide of the presentation at Columbia says the following:

* "pCell technology is not just limited to communications"
* the "synthesis of a tiny radio-wave bubble in real time software opens up a new wave of applications"

Wireless power transmission will be the next wave of application for real time beamforming.





With Artemis:

* You could use beamforming instead of beamsteering, eliminating the cost of traditional approaches.
* The power being transmitted would be split among hundreds of antennas, each of which is individually not transmitting harmfully high levels of RF energy. At the location of the receiver constructively interferes to add up to the necessary power required, and everywhere else the radio waves just add up to noise.
* The ability to focus the radio waves to a sphere of energy just a cm in diameter means potentially that little energy will be wasted, and it's safe to use around humans (assuming the receiver itself is a cm thick).

Wireless power, though would be a total game-changer. What would the implications be?

* Consumer electronics that never need to be plugged in again - phones, tablets, laptops, televisions could all be powered wirelessly in the home and office.
* With transmission towers spaced every kilometer along major highways, electric cars would not need massive, expensive batteries. Everyone could afford a Tesla, and the demand for oil would drop.
* With transmitters on a few rooftops in a city, you could have drones and quadcopters delivering groceries and mail, again without heavy batteries that limit their flying time.
( You could an electrical grid that's a wireless mesh network, especially in developing countries, and have excess power from solar panels beamed to other locations which need it.

Perlman has filed two patents on just these ideas:
System and method for powering vehicle using radio frequency signals and feedback

Patent - US 8469122 B2 ABSTRACT

A system and method are described for powering a vehicle using radio frequency (“RF”) signals. For example, a method according to one embodiment of the invention comprises: positioning an antenna array beneath or on the road surface of a roadway, the antenna array configured to transmit RF signals responsive to RF processing logic and/or circuitry; coupling a rectenna array to a vehicle, the rectenna array configured to receive the RF signals transmitted from the antenna array and to generate power from the RF signals; providing feedback signals from the vehicle to the RF processing logic and/or circuitry, the feedback signals including channel state information (CSI) defining a current state of the channels between the antenna array and the rectenna array, the RF processing logic and/or circuitry using the channel state information to adjust the RF signal transmissions from the antenna array to improve the efficiency of the power generated by the rectenna array; and using the power generated by the rectenna array to power the vehicle.


System and method for powering an aircraft using radio frequency signals and feedback

Patent US 8307922 B2 ABSTRACT

A system and method are described for powering an aircraft using radio frequency (“RF”) signals. For example, a method according to one embodiment of the invention comprises: positioning an antenna array beneath or on the road surface of a roadway, the antenna array configured to transmit RF signals responsive to RF processing logic and/or circuitry; coupling a rectenna array to an aircraft, the rectenna array configured to receive the RF signals transmitted from the antenna array and to generate power from the RF signals; providing feedback signals from the aircraft to the RF processing logic and/or circuitry, the feedback signals including channel state information (CSI) defining a current state of the channels between the antenna array and the rectenna array, the RF processing logic and/or circuitry using the channel state information to adjust the RF signal transmissions from the antenna array to improve the efficiency of the power generated by the rectenna array; and using the power generated by the rectenna array to power the aircraft.

Artemis Beamforming steps

The detailed picture of how Artemis works is the following set of procedures:

1. Transmitter sends training signal for frequency offset estimation
2. User(s) estimate the frequency offset and sends feedback
3. Transmitter pre-compensates for frequency offset and sends precoded training signal for channel estimation
4. User(s) estimate the channel and send channel state information (CSI) to the transmitter
5. Transmitter estimates the phase offset and computes the precoded weights based on the CSI
6. Transmitter sends precoded data to user(s)
7. User(s) demodulate data

Will it work for WiFi as well? It's protocol agnostic, so it could work in unlicensed spectrum as well. The issue is that you don't have complete control over all the other transmitters, so you can't coordinate them.

Does this work for just downloading, or uploading as well? It should work for both - the uplink is just the inverse problem. In the literature the downstream transmission technique is called "joint transmission" and the upstream is called "joint detection". In case time-division duplexing is being utilized, you could even use reciprocity to help deduce the channel matrix in one direction from the other, as they tend to be correlated.

Interference cancellation allows you to use lower-frequency radio waves with better propogation characteristics (ie longer range). Until now, governments have had to limit the power output of radio antennas so as not to cause undue interference to other users of the spectrum, especially when you're using a frequency that can travel very far (amateur radio, AM, and TV white space frequencies, etc). Note that the 1 millisecond latency they refer to is the overhead of doing signal processing, not the round-trip time from the base station to the cloud server and back (which would be ~ 100 milliseconds).

pCell gets around Shannon's Law by not sharing each wireless spectrum broadcast. They form a separate wireless beam for each user.

Each pCell radio uses just a mW of power, two orders of magnitude less than usual WiFi routers (you do need a multidue of pCell radios, though, but still).

Trials in a single city with a major mobile carrier should be expected in 2014, with a larger rollout in 2015, the diffusion of innovations teaches us that the best technology doesn't always win, and adoption certainly doesn't happen overnight. Smart antennas have been around for 20 years, but have not been adopted by cell phone carriers. Mobile carriers would need to spend billions of dollars on new base station radios, a massive cloud (C-RAN ) infrastructure, and tons of backhaul fiber to upgrade their networks to support this, which could easily take years

SOURCES - Akbars.net, Google US Patents

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