It really isn't. It'd be trivial to allow mobile data to always supplement wifi data. There are apps that do this already ([1] and [2]), and some phones have the option as well (either stock or as a ROM). The problem are cellular data caps, nobody wants to blow their caps by using cellular when they could be using wifi only. There is no way for wifi to know when you're about to lose coverage, or have spotty coverage; the only way around it is to always have the mobile antenna connected to towers so it can take over. But that costs money, many mobile phone companies even disable these options on their phones to reduce congestion in their towers ([3], though it may be out of date now).
One day we might solve this problem, if we're ever able to pressure phone companies into reinvesting into their infrastructure instead of their investors.
I get that this exists, but it literally never seems to trigger for me. The situation GP brings up happens constantly despite this feature being enabled.
I think the problem is that by the time your phone knows WiFi is non-viable (e.g. it's sent, retried, timed out), you've probably screwed whatever connection you were hoping to make.
Short of hammering the AP with test transmissions (oh no, battery life) when the connection starts to get below a certain level, not sure how it could solve this before the user attempts to do something.
I think the onus is on devs to implement it. So far, the only app I've found with robust reconnect is XiiaLive Pro (a music-streaming app). I use it daily for streaming radio stations and I often forget to disable WIFI when I leave the house, so by the time I'm down the block, the music usually cuts off for 1-2 seconds before the app realizes WIFI is gone. Amazingly, it auto-retries using the 3g/4g connection. I've used 10s of music streaming apps, and ALL of them required a manual stop/start after WIFI signal is gone.
I have that enabled and the setting states that ~70MB have been downloaded in this way, but I don't know over which period and it also never does "feel" like it's working.
I disabled it after my phone freaked out one day and kept re-downloading the same few hundred iTunes songs over and over, blowing past my data cap and costing me $30 in overages, all while it was asleep on my desk (albeit mysteriously very warm).
There are also consequences to your battery for utilizing cellular data instead of/in addition to WiFi. I'm an atypical user in that I don't really care about cellular data costs, but it annoys me when my battery begins dropping at a visible rate and my phone becomes toasty warm.
I considered that, but thought the impact would be inconsequential. If you want to save battery life you'd turn one or both antennas off (or GPS, vibrations, screen brightness, etc.). Maybe running both would be too much for the battery though, I don't know.
My phone lasts nearly 24 hours on a charge, I wouldn't mind it last considerably less (18 hours for example) if I used both antennas though.
I don't know how regular web-browsing / app use from the phone with two antennas would affect it, but I frequently use my phone as a WiFi hotspot for a laptop, and that's rather battery intensive.
You are only scratching the surface. The real problem is not for mobile to take over, we can do it, but when to consider wifi down. It is all fun and games if your wireless network is connected to good fiber, but it is not always the case. Internet uplink may be high RTT or flaky itself, it may be low speed and someone started torrent client and video call, it may as well be the very same mobile broadband with "unlimited throttled home" plan, wifi AP can be connected to gateway over multiple wireless hops, etc.. Platform always has to question "is it problem with remote end or uplink? is uplink 2 better than uplink 1?"
Network switch comes with non-zero cost that all connections must be treated reset and have to be reestablished, so even if the platform monitors quality of all uplinks, we still need some uplink stickiness to avoid constant switching between uplinks in places with spotty coverage or flaky uplinks. I'm not saying current status quo is the best, but currently we cannot have it work perfectly.
It's be good if at the TCP level you could send multiple request packets across different connections on mobile and have whoever got back first was chosen for a while as the default. You have to admit currently this is very clunky.
I would also add that specifically for things like Uber it'd be good to set very low network timeouts for Wifi and allow certain apps to suggest to the device they'd like to switch.
True, however when you're leaving the building, the most common case ought to be that you stop being able to ping the upstream router. Easy for the phone to find out, since single-hop ICMP doesn't need a long timeout.
There are other possible failure modes, of course, but fixing the common case has value.
Now I'm not too experienced, so correct me if I'm wrong, but isn't a signal strength reading part of the wireless protocol? If your signal strength takes a consistent dive over a small period of time (as you walk out of the building) you could engage the cellular connection to at least supplement the pope wireless connection.
Or how about if some x% of packets were lost/failed checksum you revert to cellular?
Both of these would likely require changes to the wireless drivers but they don't seem too unachievable.
Sure, but that's assuming you can detect the weak signal, boot up the cellular antenna, negotiate a new connection to the nearest towers (after discovering them) and connect to the internet.
I'm making a bit of an assumption here, but I think if Apple or Google could detect spotty wifi quickly enough to boot up the cellular antenna, they would be. I think the issue is more that by the time the phone can tell there is a problem there isn't enough time to bring up the cellular antenna and connect before service is interrupted.
I can't say I know much about cellular networks either, but in my opinion having the cellular antenna connected to the network at all times would greatly simplify the handoff when wifi gets spotty. The ability to use both to download/upload is just icing on the proverbial cake.
I'm not sure how it works exactly, but Google's own cellular company, Google Fi, promotes the fact that they use WiFi when available, even for phone calls, but can switch quickly to cell when needed. Phone calls are not interrupted when switching. I especially like this setup because my cellular reception is poor at work, but I can use my employer's WiFi to receive calls and data. Phone call clarity is better on WiFi than cellular but sometimes there is a bit of lag that reminds me of calling overseas using geosynchronous satellite connections in the 90's.
Great prices also. Since I'm almost always using WiFi, the $20 a month for global unlimited text and phone calls with a $10/gig data rate means I only spend about $25 a month for my smartphone service. You can only use a subset of Google phones, but I find my Nexus 5x fits my needs. I also always get Android updates right away, if I want to install them.
Google's Project Fi wireless service prefers WiFi whenever it can right out of the box. That coupled with rock bottom prices & the ability to hop onto whichever network you like make it the best mobile provider around imo [just a user, no affiliation]
Can you elaborate? I just did a cursory Google and it's not clear to me why this is true.
They're $10/gb flat with refunds for unused GB. At what usage levels do you think they're 'some of the highest rates in the industry?'
I use <3 gb/MO, mainly because the mobile <-> WiFi switching is so seamless, and I've never paid more than $50/mo off contract. The UX is also top tier, which i couldn't say about Straight Talk (my last provider).
I'll buy that they're not the cheapest, but which plan offers substantially cheaper?
One day we might solve this problem, if we're ever able to pressure phone companies into reinvesting into their infrastructure instead of their investors.
[1]: http://speedify.com/mobile-vpn
[2]: https://play.google.com/store/apps/details?id=it.opbyte.supe...
[3]: http://forums.androidcentral.com/samsung-galaxy-s5/402722-ho...