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To: Joe NYC who wrote (20854)	1/5/1999 11:28:00 PM
From: Clarksterh	Respond to of 152472

Joe - Can TDMA system do sectorization? Yes, and so can analog, but they do not get as much bang for the buck because they can't just reuse all of the same frequencies. Very simplisticly(sp?) they need to split up their original frequency into at least two pieces (each with about 1/2 as much capacity) so that each sector is using a different frequency from its neighboring sectors. Thus with 6 sectors they get less than 3 times the number of users. If you want more details I'd recommend reading the cdg website, but if you have any questions feel free to ask. Clark

To: Joe NYC who wrote (20854)	1/6/1999 12:51:00 AM
From: engineer	Respond to of 152472

Yes, TDMA can do sectorization somewhat. Remember that is has a frequency reuse factor of 5 or 7, which means that they use distance to separate the frequencies, or every 7th cell site can have the same frequency. So if you had secortization, you would have to deal wtih this. I am not familiar enough with the present state of TDMA systems to coment on this, but I would see it as a very tough thing to do. Remember that CDMA has a frequency reuse factor of 1, which means that it can use the same frequency in the next cell site, so doing 6 sectored cells is just a simple code change. in fact the code changes are not code changes at all, but merely a time delay of the same code. If you delay it be say 128 codes, it looks like an entirely new cell site, since the searching code comparator in the chipsets only looks out the amount you tell it. in the commerical systems, they use code delay of 256 between cells. this equates to enough time to get about 30 miles and back in delay. enough that the strongest cell site (at 14 miles) would not see the same code delayed enough to be confused. This is all covered at www.cdg.org.