Message 5140198
Some Readware stuff on Loral. But looky what Readware writes!
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Jul 8, 1998
Good question. G* uses a variable rate vocoder. The most important resource in a satcom system is power (I think everyone agrees on that-- if not, let's say it is one of the most important.) A variable rate vocoder allows you to vary power as the voice requirements mandate. G*'s vocoder can vary from 4.8 kb to 9.6, as the voice requirements in a conversation dictate. Thus, it does not have to always operate at say 6.2, or 7.1. That way it
saves power, and by allowing up to 9.6 it has the ability to accomodate that flow for the customer. I do not know if Iridium has the same sort of vocoder. I really don't follow Iridium that closely.
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Now does anyone notice that he thinks power is a somewhat significant part of a satellite? He is saying that it is very much worth mucking about to reduce power consumption. Why would that be if there is a surplus of power on a satellite?
As suggested way back in the first 100 posts and more, of this thread, there is a shortage of power on satellites and the use of it needs to be optimized, which means it needs to be sold for the highest price. No use selling the power cheaply over Zimbabwe, China or India to have the batteries flat when the satellite gets to Japan or other high value high demand areas.
So, yes, here it comes, somehow the power needs to be rationed to the high value users. Little messages could be put on handsets saying "Sorry, your handset is having a Save-the-System half hour while we recharge the satellite batteries! We regret any temporary inconvenience" Bad luck if they just happen to be in a sinking yacht or are trying to call emergency services to a child fallen through some ice. Or trying to get prices for a $billion contract tender closing in 5 minutes. [Or Babe is on the horns of a dilemma at Mighty-Q stadium - inside joke - refer to Q.com thread about a year ago]. Write your own scenario.
We got some huffing and puffing from Readware way back then, and others, but no answer other than running the system wildly under capacity to maintain reasonable service availability so that such problems aren't too extensive. In fact it took a long time for the satellite aces to actually agree that power supplies are limited and in fact will be in short supply at times.
Which is what I was told 2 and a half years ago, when suggesting NZ would have cheap Globalstar calls since the satellites would obviously be greatly underused over the Waterworld of NZ. Not so said the Qualcomm Globalstar designer because the power would be needed for the China leg of the trip where there would be high demand and plenty of money flowing. So no discounts.
So here we are right back to where I started, with the Mighty Readware at last admitting that power is in short supply after all.
Anyone got any bright ideas for how to ration something in short supply?
Maurice |
