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Microcap & Penny Stocks : Globalstar Telecommunications Limited GSAT -- Ignore unavailable to you. Want to Upgrade?

To: djane who wrote (4224)	4/27/1999 11:30:00 AM
From: djane	Read Replies (1) \| Respond to of 29987

G* capacity response (via g* yahoo thread) Top>Business and Finance>Stocks>Services>Communications Services>GSTRF (Globalstar Telecommunications Ltd) Capacity question response..Part I by: AR2BW (50/M/Orlando, FL) 5769 of 5771 First off, I'm not a G* designer or insider so any opinions I have on G* technical issues are based on public information and only my own technical background. So take anything I say with a grain of salt. G* capacity appears to be subject to many factors and limits that play into to total possible capacity of the system. 1. The satellites are said to have 16 beams available in the antenna system. This would imply that a 16 fold space diversity is possible. i.e. up to 16 signals with the same frequency & code pair set can use the satellite at the same time. This aspect magnifies the spectrum use. Of course, this aspect of the system would work best if the subscribers were uniformly distributed under the satellite's footprint allowing an even spread of the load within the beams but it rarely will be. 2. Each beam is said to have 13 channels (sub-bands). I take this to mean that they allow up to 13 frequencies within the allocated spectrum. Each channel has 128 CDMA codes. It it here that I'm not clear on the design relationships built into G* but I suspect that these are used in the CDMA frequency chip and code scheme to spread information of each call over the band. 3. Taking into account both (1) and (2) the total combination of "information bins" for signals available would appear to be 1613128 = 26,624. However, the stated instantaneous voice capacity of each satellite is 2800 curcuits so they are using a number of these bins for each signal (4-8?) + some orderwire channels within the system for its operation. 4. Each user can, of course, be in contact with multiple satellites (2?). This aspect effectively means that a user is actually will reduce the number of available sat channels by that factor. Given the average number of satellites in view of a gateway (5?) this would mean that the gateway would effectively see something like 28005/2 = 7000 unique curcuits. to be continued.. Capacity..Part II by: AR2BW (50/M/Orlando, FL) 5770 of 5771 5. The Gateways are also a limiting factor in that while 2800 curcuits might be coming in from each satellite (x the number in view/user reuse) the gateway may not have, or need, the identical number of output trunk line curcuits to service the maximum traffic. In fact it is not economically a good idea to do so. I suspect that they will size the output trunks to some mulitple of the mean expected load to mimimize their reoccuring costs until the traffic increases and justifies more ground curcuits. The gateways will most likely be the limiting factor rather than the satellites. 6. I have also heard reports that the software in the gateways will have a limitation on the number of subscriber IDs available (250,000?) in area. This, of course, might be easily increased with upgrades/more gateways. How does all this play into overall capacity? Beats the sht out of me. The major driving function in the entire question appears to be the global geographic distribution of users. If they are all bunched up in Europe and North Amercia around specific cities, the usage efficiency will be lower than if we get a more uniform distribution over the earth. A second generation LEO system can do several things to increase capacity: More Sats on orbit (i.e. more raw curcuits), more CDMA codes, more beams, etc. And, of course, more gateways. A second generation system that also used Medium Earth Orbit (MEO) (or/and GEO) sats in its architecture along with the LEO could service known fixed site/roaminguser concentrations with higher capacity (VSAT like) and lower the cost for those users. This would off-load the LEO system for the more fluid mobile/roaming subscribers. I expect that that will be a hallmark of G2 in fact as various city MSA roaming areas come on-line and prove demand. All of this does not require more spectrum although, if more could be obtained from regulators, that would help. More spectrum would in fact impact existing G phones so I expect that new specturm will = new service categories. In the meantime, I'll use the 1B/month number put out by the company and we can compare that with the real useage rates next year. Without more detailed data, I can't do better than that. AR2BW Posted: 04/27/99, 10:00AM EDT as a reply to: Msg 5769 by AR2BW