Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: fmsystm!macy@cwjcc.ins.cwru.edu Newsgroups: comp.dcom.telecom Subject: Re: Cellular Phone Question Message-ID: <6282@accuvax.nwu.edu> Date: 12 Apr 90 18:10:08 GMT Sender: news@accuvax.nwu.edu Organization: F M Systems, Inc. Medina (where's that?) Ohio USA Lines: 56 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 10, Issue 248, Message 4 of 7 In article <6109@accuvax.nwu.edu> you write: X-Telecom-Digest: Volume 10, Issue 235, Message 5 of 11 >Yes there is a limit to the number of cellular channels available. >The specific limit and the method used in the detection and use of the >next available channel differs by city/system. I believe the limit of >U.S. West in the Omaha area is 10 channels. The next available >channel is marked with a tone. When no channels are available the >handset probably generates the trunk busy signal. Good grief! Does this mean US West has managed to make an IMTS system out of a cellular system? Telecommunications technology takes a giant step backwards... Seriously, this is a very basic description of IMTS (Improved Mobile Telephone Servce), which until cellular service came online, was the primary method of providing dial mobile service in the US. Cellular has 832 channels, all of them of short range, available. One half of them are available to each of the two carriers in a market. The actual number of conversations possible in a given cell area depends on a great many design and propagation factors. In the Cleveland area, the lowest capacity cell site I am aware of has a ten simultaneous call capacity. The largest can handle over one hundred (achieved by using directional antennas to subdivide the cell). A number of schemes exist (and are being developed) to maximize the capacity of cell sites in high density locations. Talk of micro-cells with 300 foot ranges (or less) is now heard. Digital cellular telephony will be introduced in the US shortly. This will further increase the capacity of cell systems, often by threefold or more. I'll leave a detailed technical description of cellular system design for traffic engineering to one of the experts ... I'm just an old pole climber myself. Yessir ... that's it ... life would be simpler if we just went back to open wire and cans ... (does anyone here remember "transpostion brackets" or frogs?) > It will be interesting to see what happens in the future as more > and users come on-line. On an IMTS it was always interesting if too many phones were put on the air ... and most cities only had two to six IMTS channels. I'll start a discussion of IMTS if anyone is interested ... I spent a few years working on these animals. Macy M. Hallock, Jr. macy@NCoast.ORG uunet!aablue!fmsystm!macy F M Systems, Inc. {uunet!backbone}!usenet.cwru.edu!ncoast!fmsystm!macy 150 Highland Drive Voice: +1 216 723-3000 Ext 251 Fax: +1 216 723-3223 Medina, Ohio 44256 USA Cleveland:273-3000 Akron:239-4994 (Dial 251 at tone) (Please note that our system name is "fmsystm" with no "e", .NOT. "fmsystem")