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To: Ramus who wrote (29431)	5/7/1999 2:09:00 PM
From: Stewart V. Nelson	Respond to of 152472

Here is the big picture tek.com Click to enlarge the picture. regards Stewart V. Nelson

To: Ramus who wrote (29431)	5/8/1999 5:48:00 PM
From: quidditch	Read Replies (1) \| Respond to of 152472

Walt, thanks for the reply. It's not that I'm dumb, just that I'm ignorant! So, I'll try to stumble through this once more, if you'll indulge me. Conceptually, I understand full well time diversity and code diversity for purposes of transmitting, and maintaining separation, of signals within given RF spectrum/channel. To articulate my question re. "TDMA survives" more precisely, if W-CDMA involves simultaneous TD and CD to maintain compatibility with legacy GSM (TD?) mode, and base station is "processing" signals on TD mode, where is the functionality of CD in this context, or is the air interface CD but TD remnant of system is at another layer of system operation (realize my question is lacking in tech specific lingo)? Gotta post this in two parts because of server limitations. Regards. Steven

To: Ramus who wrote (29431)	5/8/1999 6:04:00 PM
From: quidditch	Read Replies (2) \| Respond to of 152472

Part II: Also, as I understand the dialogue on the matched filters/aynchronous signal issue--is the asynchronicity attributable precisely to the TDMA elements (burst of power/signal as part of time division), whereas CDMA mode is at a constant (and lower) power output and does not need that kind of filtering, or has TD nothing to do with this? Also, is the relative spectrum inefficiency of W-CDMA attributable to the hybridization of TD/CD, or for other reasons? (I read carefully the first para from your response to me, quoting the ETSI UTRA W-CDMA proposal to ITU. I would assume, but don't know, that CDMA2000 also has a maximum number of orthogonal [downlink] channels available and must use a certain number of those for control channels/system management. It's the last sentence of the quoted text of the proposal whose import escapes me: <The reason why the maximum number of channels in TDD is only 50% of that in FDD is the UL/DL sharing of one 5 MHz carrier in TDD."> Does this not occur in CDMA2000?). Anyhooo, I'm trying to expand my understanding. Sorry to bother you. Thank you. (PS, do you have the medved link?) Best regards. Steven