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Technology Stocks : Qualcomm Incorporated (QCOM) -- Ignore unavailable to you. Want to Upgrade?

To: 2brasil who wrote (25291)	3/27/1999 12:44:00 AM
From: Ruffian	Respond to of 152472

Tdma vs. Cdma> I Told You So... In light of the QCOM/ERICY news yesterday, I thought it would be helpful to give a quick review as to the difference between TDMA and CDMA. Here we go. First, TDMA. Imagine you are at a party. Then imagine a sequence of times in which first I talk, then you talk, then I talk, then you talk, etc. Thus, with this example, the talking is sequenced such that one set occurs after another, without any overlap, and everyone has a set amount of time to talk. Bear in mind that the key here is that everyone can understand everyone else because no one else speaks when someone else is speaking. Now, CDMA. Imagine everyone is still at the party, but this time I am talking in English, another is speaking in French, another is speaking in German, etc. Here, all conversations are happening at the same time (multiple users can talk at the same time, unlike the TDMA example), yet the individual that speaks English only hears the conversation in English, the French speaking individual only hears the conversation in French, etc. So what does all of this mean? What this means is that there are channels, i.e., with TDMA one user can only use a channel at a time, while with CDMA, multiple users can use the same channel at the same time. To wrap up the lesson for the day, simply substitute the words "frequencies" for languages and "channel" for party and you now understand the differences between CDMA and TDMA. Now here is a quick review as to why CDMA is triumphing: 1. Given that multiple users are able to speak at once, there is more capacity. 2. Less power is required. That is, the average power used by one person is less to send a call because that person is only using part of the spectrum. As a contrast, with TDMA, the user, given their allotted time, uses the entire spectrum. For example, with TDMA, if one minute is allotted and three seconds are used, the entire amount of power for one minute is used. 3. While CDMA involves a higher costs to set up, it has very low maintenance costs going forward given it takes less power. And that's the end of our review today....