To: Raymond who wrote (6576 ) 12/17/1997 4:25:00 PM From: Walter Liu Respond to of 152472
"Halfrate is beeing delivered now for the European market." Congratulations! I was told in September 1994 that one year later half rate would be a standard feature without voice degradation. I am just sick of these European comapnies critizing CDMA One just because they don't have it. The latest claim is that the promises and claims are delivered late or at a discount. Well, look at the mirror and improve GSM. Let's wait for the voice quality test result: full rate vs. half rate. The jury is still out. Remeber Narrow band TDMA? "Where was that promised and by whom?" When GSM was comparing CDMA and often it points to ETDMA being the capacity gain that will catch up with CDMA. You can say it is not a promise, but ETDMA is always thought as the capacity savior of GSM. "What I know that is not part of the GSM-standard." You are right it is not. But when the European vendors propose contract bids, they always points it will be a future add-on feature that gains capacity. It was in 1995 when rumor starts in GSM community that it will be only another year before the techonology is mature. Well here we are, delayed again at best. "They have frequency hopping as a feature but no dynamic channel allocation." As you know the control channel BCCH carrier can not hop. You need at least two GSM traffic carriers to have frequency diversity, which is the reason for frequency hopping. In fact, you need three hoppable traffic carriers to fully obtain the diversity gain. To do that, US PCS carrier will have to use all of their 30 Mhz bandwidth, assuming they want a quality 7-21 reuse pattern. A lot of work to get a 3 dB gain. Don't you think the CDMA approach of frequency diversity, interference reduction is much more nature than slow frequency hopping? "You mentioned that GSM was "extremely narrowband".If GSM wasn't to narrow it wouldn't be any reason to develop a 3:rd generation system would it?" I think GSM is very good for TDMA approach. It is the way that the European vendors sell it that bugs me: When they sell GSM product, they don't mention GSM is narrow band compares to CDMA One When they sell WCDMA, they point it out CDMA One is narrow band. Does this approach very self serving? I think it is, but I am not sure it works for people who understand the truth.