4 ms·

Alphabet’s Project Taara laser tech beamed 700TB of data across nearly 5km

23 points by anxrn 5y ago

nharada 5y ago
Why use this instead of line-of-sight microwave links? Increased bandwidth at the expense of range?
- notdonspaulding 5y ago
  Microwave links (including point-to-point "line-of-sight" links) transmit a cigar-shaped cone of signal which raises the noise floor for all receivers within earshot of a given frequency at a given location. The absolute physical dimensions of the cone of signal are dictated by the specific frequency being transmitted, the size and shape of the antenna, and the distance from the transmitter. This makes interference (including self-interference) one of the bigger challenges to colocating many links in the same geographical area. One of the promises of millimeter-wave radios (radios which operate at frequencies from 18Ghz-100+Ghz) is that they are less prone to interference because they operate at such high frequencies. Presumably, one of the bigger reasons to use free space optics is that it results in an almost total elimination of interference. No interference means no coordination is necessary between operators. No coordination between operators means no licensing/regulations are necessary for maximizing use of the available spectrum. Non-regulated or lightly-regulated technologies can have much broader adoption in the marketplace. Lots of good reasons to pursue something like this.
mchusma 5y ago
Very cool. I'd like to better understand the difference between this and other line of sight transmission stuff. I assume bandwidth and latency, but not sure the orders of magnitude.
genpfault 5y ago
> In 20 days, Project Taara lead Baris Erkmen says the link transmitted nearly 700TB of data 700 TiB / 20 days ~= 3.56 Gbps 700 TB / 20 days ~= 3.24 Gbps
mmmBacon 5y ago
Aoptix was a company that did much than this more years ago. Founded in 2000 and despite 16 years and $150M raised, they could not find much of a market. The Aoptix system could transmit 4x this Google system, had further reach, and achieved 5 nines reliability. https://www.lightreading.com/mobile/backhaul/exclusive-its-lights-out-for-aoptix/d/d-id/720915 https://www.lightreading.com/mobile/backhaul/exclusive-its-l... https://www.lightreading.com/mobile/backhaul/aoptix-rejoins-the-backhaul-bandwagon/d/d-id/708036 https://www.lightreading.com/mobile/backhaul/aoptix-rejoins-... The main problem with wireless optical backhaul is the high cost. It cannot compete with RF wireless.
rasz 5y ago
20 years ago, fully open source design, 10Mbit https://en.wikipedia.org/wiki/RONJA https://en.wikipedia.org/wiki/RONJA
rapjr9 5y ago
What happens on a foggy day?

23 points by anxrn 5y ago

nharada 5y ago

Why use this instead of line-of-sight microwave links? Increased bandwidth at the expense of range?

notdonspaulding 5y ago
Microwave links (including point-to-point "line-of-sight" links) transmit a cigar-shaped cone of signal which raises the noise floor for all receivers within earshot of a given frequency at a given location. The absolute physical dimensions of the cone of signal are dictated by the specific frequency being transmitted, the size and shape of the antenna, and the distance from the transmitter. This makes interference (including self-interference) one of the bigger challenges to colocating many links in the same geographical area. One of the promises of millimeter-wave radios (radios which operate at frequencies from 18Ghz-100+Ghz) is that they are less prone to interference because they operate at such high frequencies. Presumably, one of the bigger reasons to use free space optics is that it results in an almost total elimination of interference. No interference means no coordination is necessary between operators. No coordination between operators means no licensing/regulations are necessary for maximizing use of the available spectrum. Non-regulated or lightly-regulated technologies can have much broader adoption in the marketplace. Lots of good reasons to pursue something like this.

mchusma 5y ago

Very cool. I'd like to better understand the difference between this and other line of sight transmission stuff. I assume bandwidth and latency, but not sure the orders of magnitude.

genpfault 5y ago

> In 20 days, Project Taara lead Baris Erkmen says the link transmitted nearly 700TB of data 700 TiB / 20 days ~= 3.56 Gbps 700 TB / 20 days ~= 3.24 Gbps

mmmBacon 5y ago

Aoptix was a company that did much than this more years ago. Founded in 2000 and despite 16 years and $150M raised, they could not find much of a market. The Aoptix system could transmit 4x this Google system, had further reach, and achieved 5 nines reliability. https://www.lightreading.com/mobile/backhaul/exclusive-its-lights-out-for-aoptix/d/d-id/720915 https://www.lightreading.com/mobile/backhaul/exclusive-its-l... https://www.lightreading.com/mobile/backhaul/aoptix-rejoins-the-backhaul-bandwagon/d/d-id/708036 https://www.lightreading.com/mobile/backhaul/aoptix-rejoins-... The main problem with wireless optical backhaul is the high cost. It cannot compete with RF wireless.

rasz 5y ago

20 years ago, fully open source design, 10Mbit https://en.wikipedia.org/wiki/RONJA https://en.wikipedia.org/wiki/RONJA

rapjr9 5y ago

What happens on a foggy day?