LTE total latency is 20-50 ms, and you compare this to the marketing "air link only" 5G latency of 1 ms. It's apple and oranges ;)

FYI, the air link latency for LTE was given as 4-5 ms. FDD as it's the best here. The 5G improvement to 1ms would require features (URLLC) that nobody implemented and nobody will: too expensive for too niche markets.

The latency in a cellular network is mostly from the core network, not the radio link anymore. Event in 4G.

(telecom engineer, having worked on both 4G and 5G and recently out of the field)

Always been interested in this stuff. Where would you recommend a software/math guy learn all this stuff? My end goal is to understand the tech well enough to at least have opinions on it. How wifi works would be great as well if you're aware of any resources for that.

It's a good but hard question... Because cellular is huge.

In a professional context, nobody knows it all in details. There are specializations: core network and RAN, and inside RAN protocol stack vs PHY, and in PHY algos vs implementation, etc.

You can see all the cellular specs (they're public) from there: https://www.3gpp.org/specifications-technologies/specificati...

5G (or NR) is the series 38 at the bottom. Direct access: https://www.3gpp.org/ftp/Specs/archive/38_series

It's a lot ;) But a readable introduction is the 38.300 spec, and the latest edition for the first 5G release (R15, or "f") is this one: https://www.3gpp.org/ftp/Specs/archive/38_series/38.300/3830...

It's about as readable as it can get. The PHY part is pretty awful by comparison. If you have a PHY interest, you'll need to look for technical books as the specs are quite hermetic (but it's not my field either).

Forgot to get back to you on these.. thanks for the links!

> 5G is 1ms

I have never seen this. Where do I have to get 5G service to see these latencies?

1ms to the cell tower. Even on fiber Internet there’s still single digit ms latency to servers in the same metro area. Only T-Mobile has deployed 5G SA (standalone). ATT and Verizon use 5G NSA (non standalone) which is a 4G control channel bonded with 5G channels so it has 4G latency.

Pretty sure splitting up latency by useless endpoints is not a relevant way to do it.

if we go by useless endpoints, let's compare apples to apples. on fiber network equivalent to cell tower will be probably splitter. i guess it has sub 1ms latency

When 5G first rolled out this was absolutely not the case. Not only was it not 1ms, it was like full 1000's of ms to the point where I actively turned off 5G on my iPhone because it was so bad.

I can only speculate 5G was so saturated on the initial rollout so it led to congestion and now its stabilized. But latency isn't only affected by distance and hops - congestion matters.

Could be lots of things. I'd go with "your telco was doing something stupid" as a first guess, tbh.

This is blatantly false. I will bet many $$$ that no one in this thread has ever gotten 1ms.

If you search "5g latency", Google's AI answer says 1 ms, followed by another quote lift from Thales Group™ saying 4G was 20 ms and 5G is 1ms.

Once you scroll past the automated attempts, you start getting real info.

Actual data is in the "SpeedTest Award Report" PDF, retrieved from https://www.speedtest.net/awards/united_states/ via https://www.speedtest.net/awards/reports/2024/2024_UnitedSta....

Spoiler: 23 ms median for fastest provider, T-mobile.

Latency to where? Speedtest servers or cell towers?

I assume Speedtest servers, as they wouldn't have a way to get measurements for individual cell towers at scale.

(at least, I don't recall being able to get that sort of info from iOS APIs, nor have I ever seen data that would have required being derived that way)