Johnny works for Google. At least the last time we exchanged email. Dude is seriously smart. Wish I had kept more in touch, maybe I'd have scored a free Kinect.
It's only serendipitous if you can find it. Regions with lots of tall buildings with good LOS to each other is serendipitous. Regions where LOS is limited is not so serendipitous.
This is called handwaving. The issue here is dependent on the existing backhaul topology. Daisy chain is probably worst because of the number of hops increasing your latency but that's what many 2G and 3G backhaul networks were doing. Hub and spoke would be best (and probably closest tot their microwave topology) but few deployments are this way. Mesh would be next best or perhaps Tiered.
If you have a lot of tall buildings like SF or NY great. If you are in suburbia probably not so great. It depends on the latency requirements for p-cell to work and the average and worst case latency for the backhaul topology you have to work with.
If you are deploying in suburbia then you can't place your transcievers anywhere because there are few sites with good LOS with each other or the central hub. You ARE limited to the existing towers because that's where the backhaul is. If you are deploying to a region where they ripped out the older daisy chain topology and replaced it with a topology with sufficiently low latency to let pcell work then that's fine.
Some markets will be in a more favorable state for massive MIMO deployment. Others won't.
Transmitting a bearing and range estimate vs just signal and bearing isn't going to greatly reduce your latency requirements to the central servers doing the calculations for beam forming and traffic encoding. As only one tower you can't get more than bearing and range estimate.
The scaling requirements are not so important for the servers. The scaling requirements are important with relation to the number of antennas to service users.
Yes, the geolocation feature is very useful and could provide more position data to the server. As is it the iPhones are most likely using existing LTE features to return signal strength data. As far as doing more processing on the device it still depends on how fast that data gets back to the central server. Again, you're limited by backhaul and its latency unless you're not moving that much.
Everybody hopes stuff like this works. The theory behind it seems reasonably well understood, it's just the engineering challenges have been significant for deployment. It looks like they may be years ahead of other folks working in this domain in terms of deployable technology/software. If so great. If not then we'll get pretty much the same thing when 5G technology deploys.
Here's the deal though...they're dealing with incumbents without a huge interest in disruption. Something he points out himself. It requires someone like Apple or Google with billions to fund such disruption if the incumbents balk because telcom CAPEX would run even Apple's warchest dry in short order. TMobile or (brrrr...Sprint...yuck) might make a good partner and they're most likely to jump on board.
Maybe. Lets first be clear on three points:
Okay so where I come from is a background in writing software for network gear in a past life and knowing some folks that do SDR. I haven't talked to any of them so my opinion is that of a layperson.
I looked at the literature surrounding coordinated multipoint/cooperative MIMO. My guess is their technique is along these lines given their patent filings and the musings of folks on forums more knowledgable than I.
IF so then backhaul latency is potentially critical to be able to beamform sufficiently quickly to adapt to both movement and changing environmental factors. You need updated channel state information (CSI) very quickly to coordinate multiple antennas sending signal to converge on the device and create a local maxima (aka virtual cell). Do it wrong and that 1 cm virtual cell is in the wrong place. They obviously do it very well...at least in the confines of an auditorium.
Read these and see if you come to the same conclusions I came to regarding backhaul requirements:
"In the case of deployment of remote radio units connected to a centralized baseband processing unit via Ethernet or fiber links, COMP backhaul requirements should also be no obstacle."
That's the caveat. They assume 0.1-20 μs delay because of direct connection via fiber or 150 μs/hop from microwave. Backhaul latency in real towers to that central server is often much higher than this. 10ms round trip for LTE but much higher for 2G and 3G towers.
Something DOCOMO attempts to mitigate using clustering:
"We investigate coordinated multipoint (CoMP) multiuser multiple-input-and-multiple-output (multiuser-MIMO) downlink transmissions over mobile access networks yielding different backhaul constraints. The larger number of base stations (BSs) participating in CoMP, the higher user throughput can be expected if there is no constraint in mobile backhaul networks. Limited capacity and latency in mobile backhaul networks impose constraints on the number of BSs that can actually participate in CoMP. We propose a CoMP system architecture with multiple clustering steps that that takes into account these backhaul constraints and enables to avoid selecting BSs which do not have enough backhaul network capability."
What the actual requirements of p-cell is unknown. Maybe this is a non-issue.
AKA tree. Hub and Spoke with branches with other hub and spokes.
"We investigate coordinated multipoint (CoMP)
multiuser multiple-input-and-multiple-output (multiuser-MIMO)
downlink transmissions over mobile access networks yielding
different backhaul constraints. The larger number of base
stations (BSs) participating in CoMP, the higher user throughput
can be expected if there is no constraint in mobile backhaul
networks. Limited capacity and latency in mobile backhaul
networks impose constraints on the number of BSs that can
actually participate in CoMP. We propose a CoMP system
architecture with multiple clustering steps that that takes into
account these backhaul constraints and enables to avoid selecting
BSs which do not have enough backhaul network capability."