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Technology Stocks : LAST MILE TECHNOLOGIES - Let's Discuss Them Here -- Ignore unavailable to you. Want to Upgrade?

To: MikeM54321 who wrote (9753)	12/16/2000 2:29:18 PM
From: slacker711	Respond to of 12823

As you know, I'm not fully up to speed on mobile wireless. Is what you state above a fact or opinion? I am probably oversimplifying. GPRS incorporates packet-switching which will probably provide some extra data capacity....however, as far as I know, GPRS will NOT provide any extra voice capacity. If a GPRS user is simply surfing the web, they will not be taking up data channels when they are not transmitting or receiving data....so it is not like one GPRS user will knock of 6 GSM users. However, if a GPRS user is downloading or streaming, they will be taking up the entire data channel...in this case their would be a straight trade-off of 1 GPRS user for X number of GSM users (it depends on the speed). comsoc.org Each of the 200 kHz frequency channels carries eight TDMA channels by dividing each of them into eight time slots. The eight time slots in these TDMA channels form a TDMA frame. Each time slot of a TDMA frame lasts for a duration of 156.25 bit times and, if used, contains a data burst. The time slot lasts 15/26 ms = 576.9 µs; so a frame takes 4.613 ms. The recurrence of one particular time slot defines a physical channel. A GSM mobile station uses the same time slots in the uplink as in the downlink [5]. The channel allocation in GPRS is different from the original GSM. GPRS allows a single mobile station to transmit on multiple time slots of the same TDMA frame (multislot operation). This results in a very flexible channel allocation: one to eight time slots per TDMA frame can be allocated for one mobile station. Moreover, uplink and downlink are allocated separately, which efficiently supports asymmetric data traffic (e.g., Web browsing). In conventional GSM, a channel is permanently allocated for a particular user during the entire call period (whether data is transmitted or not). In contrast to this, in GPRS the channels are only allocated when data packets are sent or received, and they are released after the transmission. For bursty traffic this results in a much more efficient usage of the scarce radio resources. With this principle, multiple users can share one physical channel. The difference that CDMA provides is the extra voice capacity. It depends on how capacity constrained GSM operators are....if the current operators are anywhere near saturation in terms of voice capacity, the GPRS upgrade will only hurt their performance. In contrast, 1xrtt (the IS-95A upgrade) will provide between 1.5x to 2x the current IS-95 voice capacity....and the comment from Ericsson indicates W-CDMA will provide 9x the voice capacity of GSM. It is this extra capacity that would allow GSM operators to provide data services without impacting voice services. Here is a much better explanation of the problems with GPRS... Message 14986920 Slacker