To: CommSatMan who wrote (3974 ) 4/20/1999 7:06:00 AM From: Maurice Winn Read Replies (2) | Respond to of 29987
*CDMA power control* Good point CommSatMan! Tens of milliseconds are bad for power control for Globalstar compared with terrestrial systems. This delay would be cut with Constellation2 being at a third the altitude, which will improve handset performance by speeding up power control and I suppose reducing dropped calls due to encroaching obstacles - even standing still in the open, obstacles will encroach as a satellite zooms behind a tree. It would also reduce signal strength needed so save a bit of fuel [but secretly hoping that with methanol fuel cells in handsets, this will become irrelevant as standby times become infinite, needing just a topup from a handy can of MeOH]. Not wanting to get onto fuel consumption again. You said: "One other point, there are a lot of advantages to CDMA in terrestrial systems. Not all of these advantages can be realized when you take that system in to space. For example, power control in a terrestrial system is based on a few microseconds of time passing between the user and the base station, while in space this is in the tens of milliseconds. Response times and power control do impact capacity and that is one of the reasons I think the G* capacity values are overstated. Taking this to the next level, lower capacity means higher prices and while I do not think G* costs are as high as Iridium's, I am not as wildly optimistic about their ability to sell cheap minutes and make a profit as some." I agree, some people are wildly optimistic, but I prefer to be conservative and assume no less than 5c per minute while making a profit if things really come to the crunch with competition for Constellation2. I bet ICO, Iridium and whatsitsname can't match that. Maurice