5 ms·

> 3. Discovery is laughed out of industry as "impractical", "academic", etc. To be fair, sometimes academic inventions are impractical given the technical land

> 3. Discovery is laughed out of industry as "impractical", "academic", etc. To be fair, sometimes academic inventions are impractical given the technical landscape du jour. They only become feasible as technology and society progresses, say 30 years. Also, your observation does not mean any invention is meaningful (and will eventually be recognized as such). I for one, learned a bunch of "impractical", "academic" nonsense too in university. But yes, I think as a whole, your 7 points observation as a whole is very much at play in the Turbo Codes case. Yes.

Yoric 4y ago
Fair enough.
jiggawatts 4y ago
The specific issue with LDPC and Turbo Codes is that they both introduce latency, and require a ton of compute to decode. If you don't care about latency and have an "unlimited" compute budget, then they're great and hence they were used very early for deep space communications. The speed-of-light delay means that there's minutes or even hours of latency anyway. And of course, the receiving station is a data centre with as much computer power available as you please. In hand-held devices running on battery with latency constraints measured in milliseconds, it's an entirely different ballgame. Suddenly, there's real engineering problems to solve, and the trade-offs aren't always worth it. Something I've told people when both 4G and 5G technologies rolled out is that these are enabled by the advances in the bleeding edge of silicon chip technology. Both rely on very heavyweight signal decoding algorithms that require dedicated "offload" circuitry almost as big as the main CPU! Some anti-5G crazies think that their hand is getting hot from the "radiation", when in fact it is the decoding chip that's getting warm from the power it has to draw from the battery! PS: This is why every new 4G/5G/6G/etc... tech always gets panned as impacting battery life. One or two silicon process shrinks later, this is not a problem. The radio power didn't change, but the decoding power did!

Yoric 4y ago

Fair enough.

jiggawatts 4y ago

The specific issue with LDPC and Turbo Codes is that they both introduce latency, and require a ton of compute to decode. If you don't care about latency and have an "unlimited" compute budget, then they're great and hence they were used very early for deep space communications. The speed-of-light delay means that there's minutes or even hours of latency anyway. And of course, the receiving station is a data centre with as much computer power available as you please. In hand-held devices running on battery with latency constraints measured in milliseconds, it's an entirely different ballgame. Suddenly, there's real engineering problems to solve, and the trade-offs aren't always worth it. Something I've told people when both 4G and 5G technologies rolled out is that these are enabled by the advances in the bleeding edge of silicon chip technology. Both rely on very heavyweight signal decoding algorithms that require dedicated "offload" circuitry almost as big as the main CPU! Some anti-5G crazies think that their hand is getting hot from the "radiation", when in fact it is the decoding chip that's getting warm from the power it has to draw from the battery! PS: This is why every new 4G/5G/6G/etc... tech always gets panned as impacting battery life. One or two silicon process shrinks later, this is not a problem. The radio power didn't change, but the decoding power did!