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Bell Labs Researcher Discusses the Realities of 5G
- nimish 8y ago4G->5G is the equivalent to upgrading from gigabit to 10 gigabit ethernet yet everyone is treating it like some kind of insane technology. I have yet to see what exactly the hype is about.
- johnm1019 8y agoI mostly agree but I want to nitpick. One of the areas I've heard should be improving with 5G is latency. On 4G we're talking O(10ms)? which on 5G, so says the marketing, should be O(1ms). If this is true, it will make a noticeable impact on the responsiveness of web driven apps (aka almost all apps) as well as video/audio chat liveness. Was this oversold to me (highly probable)?
- Tharkun 8y agoLatency is the sum of its parts. It doesn't matter if the latency from the cell tower to your phone is 1ms or 10ms if the rest of the trip takes 100ms. It's nice to keep some of the latency down, but it's not going to magically enable 1ms transatlantic communication.
- staplers 8y ago100ms is generally referred to as instantaneous in regards to user experience. For example: A 10ms video refresh rate would be 100fps.. the average movie is 24fps.
- penagwin 8y agoThat depends on what the user did, in video games a 100ms delay would be terrible, however in that situation the user is inputing highly timed inputs and is focused on the output. But in general for web browsing, 100ms would be unnoticeable yeah.
- dharma1 8y agoReducing latency between the tower and your phone by 9ms won't make a big difference to the overall experience of web apps. But I think real world 4G latency is more like 40-50ms? In addition to mobile network latency you have to add a few more things - depending on how far you are from the data centre serving the web app you're looking at ~20ms-300ms additional network latency, plus however long the server takes to process your request, regardless of 4G or 5G. Check out https://www.cloudping.info/ https://www.cloudping.info/ for some ping times to AWS datacentres around the world
- johnm1019 8y agoFYI O(10ms) means anything from 10-99ms.
- femto 8y agoLatency is an active research area and a driver for updating wireless networks. You won't see the results in the current 5G roll outs, which concentrate on eMBB, but the research is feeding into the future URLLC (Ultra-Reliable Low-Latency Communications), which is a 5G protocol aimed at machine-to-machine communications. Beyond URLLC are protocols aimed at replacing wires in "serious" industrial control systems: things like real time control of grid switchgear and heavy machinery, so you might not see it on your phone. Latencies of the order of microseconds have been demonstrated in recent years and the stretch goal is about 200ns.
- deathanatos 8y ago> O(10ms)? […] so says the marketing https://i.imgur.com/Dg4Jit5.png https://i.imgur.com/Dg4Jit5.png That's my RTT ping to 8.8.8.8 as I travelled south on CalTrain from SF last week, on T~mobile's network. Now, this is on an old phone that is only capable of HSPA+. However, the actual performance on the whole is still nowhere near any theoretical limits, or even limits of HSPA+.
- saidajigumi 8y agoJust that: faster speeds, except it'll be far spottier than a 1Gib -> 10Gib ethernet upgrade due to a collection of issues that will make it hard to get full 5G speeds on a regular basis. I'd take 4G LTE as implemented in much of urban Japan over hypothetical 5G any day. I witnessed nigh-instant web page load times with my phone reporting zero bars in the Tokyo subway once. Over a period of weeks, I can't recall having anything less than a "pretty darn good" level of service, no matter what the signal was reported as. In the US, I find that two bars is slow and sketchy, while one bar (still @ 4G LTE reported service!) is often a "forget about it" level of service. I.e. I'd take service consistency over theoretical-max-speed any time. On that basis, I suspect the signal consistency challenges 5G faces will make it a very frustrating service for many real-world users.
- jessriedel 8y agoIt sounds like you're mostly frustrated with the fact that the bars on your phone are lying to you, which is true but sorta separate.
- saidajigumi 8y agoNo, the bars are peripheral – it's that I want that phenomenal quality of service I experienced while traveling. Bars notwithstanding, I simply always had good service. I didn't have to care about the bars. I'd rather have that kind of ubiquitous and reliable 4G LTE than a few areas of hyper-fast yet finicky 5G.
- wyldfire 8y agoThe indicator "bars" usually show RSSI which doesn't necessarily map to throughput. Or rather, it's closer to a normalized metric for the (mobile+network infra)'s capability, but not an absolute metric like a speedometer.
- ngcc_hk 8y agoAny measurement tool for iOS? I guess we cannot use Speedtest day the day, just have an idea ... Also is signal strength important as some 4g router do report it but they are bigger
- jessriedel 8y agoIf you just mean that major Telecom companies are hyping this in their advertisements, well duh. But for technical folks, I've only heard them raving about the techniques being used being insane, and they indeed seem pretty fantastic to me. That this is only (!) increasing bandwidth and lowering latency by an order of magnitude is true, but less important. Similar things can be said about the insane techniques that have been used to increase processor power each order of magnitude.
- Nokinside 8y agoPeople seem to have strong opinion that this is the case even though they are most likely wrong. Just some changes: * You will have your own 5G home router micro cells. Factories will have their own 5G networks in unallocate bandwidth. Like Wi-fi but lower latency and better services. * High quality low latency streaming means that gaming consoles will disappear from homes. You can stream games either from servers or from edge servers. You can have "tactile internet" with 5G latency. Enough to stream games. * Very low power gadgets in your home will use 5G.
- mcguire 8y agoOf course, once you leave your home....
- jdhn 8y ago>You can stream games either from servers or from edge servers Can't wait for the rise of GaaS (gaming as a service) and the associated monthly subscription fees.
- nimish 8y agoWhy? I have wifi. It's low enough latency. What better services would I have using 5g vs WiFi as a layer 2? Nothing about 5g is _unique_ to 5g except that it's controlled by telcos.
- Nokinside 8y ago5G is less controlled by telcos than 4G. You can run local networks without buying it from telcos.
- nimish 8y agoBut I can already do that with WiFi? I'm really not seeing the advantage unless somehow there's going to be a lot of 5G gear in unlicensed bands that's somehow mystically better than WiFi.
- XnoiVeX 8y agoThat is gross over-simplification IMHO.
- kirrent 8y agoThis is a great interview! I have to say, learning about the requirement for multiple antenna modules in a smartphone, each with impressive phased arrays, the massive investment that's going to be required in microcells, and the myriad of other engineering issues to be overcome, properly put in context how ludicrous AT&T's badging of 4G technologies as 5Ge is. https://arstechnica.com/information-technology/2019/01/att-defends-misleading-5g-network-icons-on-4g-phones/ https://arstechnica.com/information-technology/2019/01/att-d...
- post_break 8y agoWhat I don't understand is if we get faster speeds, will we still see data buckets stay the same? I mean what's the point of a faster network if you're still capped at 2,5,10GB. And will qualcomm be the only game in town thanks to patents? My iPhone Xs feels like a bicycle in terms of data speed, while my Galaxy S8 is 2-3 times faster.
- kevin_thibedeau 8y agoThe point is to service more users per cell at the same effective data rate. Premium plans may enjoy prioritization and a larger bandwidth allocation similar to how cable ISPs have segmented their service tiers.
- tzs 8y ago> I mean what's the point of a faster network if you're still capped at 2,5,10GB. For those (a large majority, I suspect) whose actual data usage is determine by factors that have little to do with the network, the point of a faster network is less time waiting. For example, I'm going to take about the same number of photos on my phone if I'm on a fast network as I will if I'm on a slow network. The fast network, though, will mean less waiting to transfer the photos to my desktop for editing or for sharing. A good way to see this is to go the other way. Suppose you have a 10 GB cap. Would you object if your network were slowed down to dial-up modem speed (56 kb/sec)? That's more than enough to transfer 10 GB/month, so what's the point of anything faster if you have a 10 GB cap?
- kylec 8y agoI get what you're saying, but the faster your connection speed is the easier it is to inadvertently use more data. With my carrier if you hit the monthly limit they throttle you to 128Kbps, which is basically unusable. However, they offer a plan that's capped to 3Mbps all the time, which is fast enough for virtually everything I need and makes it much harder to hit the monthly data cap. I actually prefer always getting 3Mbps any time I want to use my phone compared to the more expensive plan which might get 30-50Mbps... until you hit your cap and you're throttled to 128Kbps. (But, as you'd imagine, if I'm A-OK with 3Mbps, I have a hard time seeing what benefit 5G brings me.)
- superkuh 8y agoGreat interview. At the start Dave kind of conflates 5G with millimeter wave 5G. The big difference between LTE networks and 5G networks is not the frequency ranges used, low band 5G is perfectly feasible. The big difference is the linear increase in information capacity per antenna in MIMO (multiple in multiple out, many send many receive antenna) verses the logarithmic increase per antenna with single antenna to single antenna links. (while power his held constant) If you want to learn more this is a great intro to channel capacity with MIMO, http://complextoreal.com/wp-content/uploads/2013/01/mimo.pdf http://complextoreal.com/wp-content/uploads/2013/01/mimo.pdf
- freyir 8y agoJust to be clear, MIMO is not a new feature in 5G. LTE has MIMO. Old Wi-Fi routers from 10 years ago had MIMO. 5G is upping the number of antennas per base station. Theoretically, this allows a linear increase in capacity, but linear scaling is not always achievable in practice. The advantage of the higher frequency bands is the larger bandwidths available there. Conventional cellular bands typically have 5, 10, or 20 MHz bandwidth, sometimes 100 MHz. 5G's millimeter-wave bands support bandwidths up to 400 MHz. Information rate scales linearly with bandwidth. That said, there are many practical challenges to operating in the millimeter wave bands that might limit real-world performance.
- ksec 8y ago>MIMO is not a new feature in 5G Or Specifically Massive-MIMO, which is as you said upping the Antennas per base Station. LTE Massive MIMO actually already works in 3GPP Rel 13 for FDD, and Rel 7/ 8 for TDD. However 5G were specially designed with M-MIMO in mind, which brings higher efficiency than using in on LTE.
- edoo 8y agoIf you've ever seriously played with wifi tech you very well know the higher the frequency the less penetration you get. In an indoor environment the difference between 800Mhz and 2.7Ghz can be astounding. 5G at 90Ghz is only going to work at certain line of sight distances. If you ever hear anyone talking about terahertz speeds you can almost be guaranteed that would be happening with very specifically located devices or within the confines of an integrated circuit.
- Spooky23 8y agoIn my city, they are dropping poles with 5G radios all over the place, as close as every 150-300 yards. It’s a land rush as the city cannot do anything to stop them, the poles get dropped in all sorts of awkward places. My understanding is that repeaters will be mounted on streetlights as well. Those radios aren’t for phones, they are for fixed wireless with antennas attached to your home. 5G is the cable killer, and eventually the WiFi killer.
- chrisco255 8y agoWhat city is this and why can't the city do anything to stop them?
- wbl 8y agoBecause of federal preemption. Thankfully NIMBYs dont have the power to block communications improvements.
- Spooky23 8y agoAlbany, NY. The FCC is choosing to let the telecoms do whatever. It’s wasteful as they do things like block crosswalks with additional poles (to avoid renting from the electric utility) and place the poles in less attractive spots to reduce cost.
- learc83 8y agoYou still need to run fiber to the radios, and at a couple hundred yards apart, you're going to be running fiber down almost every single street. If the goal is fixed installation, you could have just ran it a few feet more directly to the house. >and eventually the WiFi killer. How is this going to work? The radios you're talking about are very high frequency, so they require line of site.
- leoh 8y agoIt's hard for me to understand why anyone is excited about 5G when most carriers aren't running full bandwidth 4G and have significant data caps. Although 5G may be fast in some markets, 5G on the whole just seems so pointless for consumers.
- jjoonathan 8y agoIf new bandwidth / more bandwidth means new market entrants / more market entrants, it'll be great! I am sure that legions of lobbyists, politicians, and businessmen are working diligently as we speak to make sure that doesn't happen, but I want to believe.
- gruez 8y ago>If new bandwidth / more bandwidth means new market entrants / more market entrants, it'll be great! I doubt it. No one is going to build another network of cell towers just because new bandwidth is available
- jjoonathan 8y agoIf they can compete with cable internet they sure will.
- rayiner 8y agoNotwithstanding this supposed lobbying, we have four nationwide 4G networks—more competition than we have in putatively lobbying free markets like social media, search engines, and cell phone and tablet operating systems. The biggest roadblock to 5G is not lobbyists, but rather NIMBYs complaining about how small cells will clutter up the neighborhood.
- slededit 8y agoTo be fair, a little effort in aesthetics goes a long way.
- jjoonathan 8y ago
- freyir 8y agoEvery 5 years or so, there is a rally to make millimeter-wave communications a thing. Every time it fails. Maybe there's enough money and effort his time around to make it happen, but I wouldn't bet on it myself.
- PunksATawnyFill 8y agoThat’s just a bunch of bullet points. LAME.