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Comment by jdietrich | Hacker News Reader

>But compared to how we use our phones today, what new items will be be able to do with 5G that we can't do with current 4G/LTE?

5G has the potential to provide throughput and latency that is comparable to a fixed broadband connection. In reasonably competitive markets (i.e. not the US), that's A Big Deal. Latency is a particularly acute issue in many applications; 4G generally adds about 50ms in the best case scenario, but 5G can easily provide sub-millisecond latency. Imagine a near-future where it simply doesn't matter whether you're on WiFi or cellular, because they both provide the same experience.

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You say that it provides sub-millisecond latency.

-- Keep in mind that I know nothing of nothing.--

--- Is the sub-millisecond from repeater to repeater or from origin to final destination that's [n] repeaters away? Won't each repeater introduce its own latency?

What causes the 4G's >50ms response time?

One thing is that 4G is generally centrally broken out to the internet.

So let's say you're in Scotland, the packet would enter the mobile operator's network, then go to London, where they've bridged the network to the internet.

So there's an extra there and back again.

The same applies with roaming too, so in that case there is even more latency.

But why should that change with 5G? Couldn't operators already now route traffic to the internet in more locations?

5G isn't just the radio network. It's a rearchitecture of the core network as well.

For example you can have a 5G core over LTE.

But the article is only about the radio network. 5G over LTE wouldn't bring the problems discussed in the article.

5G non stand alone can provide this due to the new core network. But we are still at the mercy of the speed of light. A round trip of 1 millisecond translates to about 150 km (95 miles) of distance between you and your resource. And that is without any signal processing at the receiving end and in the air to fiber interface.

But the sub millisecond latency is only for local communication, isn't it? Which is most likely not available for most applications that phones use.

From my current location, it's a 13ms round-trip to the nearest Google server via a good fixed broadband connection; over 4G, that would be ~63ms because of the latency overhead of the cellular connection. That's a substantial difference for a lot of real-time applications.

I do not deny that 4G has worse latency, but 5G will not provide sub millisecond round trip latency for regular internet based applications. Sub millisecond latencies are due to local communication which can replace DSRC/802.11p in car2car communication and similar applications.

Your 4G results also seem quite bad, my personal test right now was more around 18ms broadband vs 31ms LTE. Google scholar results (https://scholar.google.de/scholar?hl=de&as_sdt=0%2C5&q=LTE+l...) I looked into seemed to suggest LTE is capable of ~20ms latency results, while (http://wirelessone.news/10-r/1007-lte-latency-today-9-ms-dow...) suggests that LTE-A (3gpp release 13) is capable of 14ms latency.

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