The crucial information is up and down ticks of the ES-mini futures at the Chicago Mercantile Exchange. These lead the S&P500 (SPY) index funding in NYC (by 4 milliseconds), and the ES-mini ticks up and down about once per second. This few bits of information carries huge value since much of the world's equity market responds to it. See https://arxiv.org/abs/1302.5966
Great link, thank you. Abstract in case it piques people's interest:
"High frequency trading has led to widespread efforts to reduce information propagation delays between physically distant exchanges. Using relativistically correct millisecond-resolution tick data, we document a 3-millisecond decrease in one-way communication time between the Chicago and New York areas that has occurred from April 27th, 2010 to August 17th, 2012. We attribute the first segment of this decline to the introduction of a latency-optimized fiber optic connection in late 2010. A second phase of latency decrease can be attributed to line-of-sight microwave networks, operating primarily in the 6-11 GHz region of the spectrum, licensed during 2011 and 2012. Using publicly available information, we estimate these networks’ latencies and bandwidths. We estimate the total infrastructure and 5-year operations costs associated with these latency improvements to exceed $500 million."
It's a cool system. There's a slight disadvantage that the satellite-to-ground link is at 10-15 GHz for users, so it will go down in a heavy rainstorm, and some fraction of the time due to other atmospheric effects. Should be reasonably reliable but far from fiber, and it will be interesting to see what uptime they guarantee. Assuming this all ever actually happens.
I assume the sensitity to weather etc depends on the type of equipment you have? Couldn't a community use a huge high power and high sensitivity common receiver/transmitter station, that provides fiber to 10-1000 households? The community station could also provide some kind of limited bandwidth fallback such as DSL or LTE that just ensures peoples fiber lines limp along when the satellites can't be reached (so their juice machines don't stop working...).
I think that's true in places like (large parts of) the US where the "last mile problem" exists. However for lots of rural Africa, China, Australia there surely must also exist a "first 1000miles problem".
