I have been attending the Google Mobile Summit for past two days. I'll share some of the exciting projects that Google is doing as well as my personal take away from them.

Project Loon: LTE by ... Baloons!

In a nutshell, this project wants to send a bunch of balloons to the stratosphere to act as LTE cellular towers.

Personally, I feel like the most exciting and interesting part is to navigate the balloons by putting them up and down and leveraging the natural wind in stratosphere to move the balloons to designated area. I can imagine a lot of interesting research challenges there. In particular, I'm told that right now they need to obtain the wind direction data and prediction from third-party providers in order to plan the trajectory of the balloon. Instead, one might be able to learn the wind direction in an online fashion by dispatching balloons to different layers in the stratosphere for a short period of time. This may work because the wind directions in the stratosphere only change very slowly (in order of several hours), so such wind direction measurements can be usefully even performed very infrequently.

Physical Web: Cyberphysical Stuff

The essence of this project is to put a BLE beacon device in every physical "things" that we may want to interact with, such as parking meters, movie posters, etc. Theses beacons contain a short URL that will direct people various web interfaces.

At first glance, the idea is very similar to QR codes, or NFC tags. And indeed, I think they are quite similar: a way to link physical beings to the cyber world. I was not quite convinced why BLE beacons are better than NFC tags in any meaningful ways. Maybe BLE is more pervasive? And NFC are usually absent in high-end smartphones with metal back lids? I am not quite sure I buy these arguments...

Project Fi: AT&T, Verizon, Sprint, or... Google?

This is probably the most interesting project in this summit. Basically Google wants to serve as a "virtual cellular provider" that unifies different physical providers (such as Sprint, AT&T) and choose whichever is better for you behind the scene. Most of all, it's cheap! $20/month base rate and $10/GB data rate, as simple as that. And they even refund you for unused data packages! How cool is that! Unfortunately, as of now you do need an invitation to join, and a latest Nexus phone (Nexus 5X, 6P and 6).

From research perspective, this project also touches several know hard problems, most notably wireless handover, both between providers, and between Wifi and LTE. The later may be simpler of the two, since the device can simultaneously connect to Wifi and LTE to assess which one is better. However, since the device only have one cellular radio, it can only connect to one LTE provider at a time. Crowdsourcing may come in handy to determine the LTE quality based on locations, etc.

Project Soli: Ant Radar

They use 60GHz technologies to pack a tiny radar into wearable devices to enable touch less interaction. The demo is quite cool. I am always skeptical of such RF sensing stuff, now is Google is at it, maybe they can make it actually work...

Project Iris: "Smart" Contact Lenses

OK, now Google tries to mess up with your contact lenses :-) Basically, they developed this tiny tiny sensing system that can actually be embedded in the contact lenses. The lenses now measures the glucose level in the tears for early diabetes detection. It is amazing they may managed to pack so many stuff (sensors, battery, antenna) in such small form factor. My only concern is that...do the lenses heat up?