SPGDCM@CMSA.BERKELEY.EDU.UUCP (05/27/87)
MSG:FROM: SPGDCM --UCBCMSA TO: NETWORK --NETWORK 05/26/87 17:36:44 To: NETWORK --NETWORK Network Address From: Doug Mosher <SPGDCM at UCBCMSA> Title: MVS/Tandem Systems Manager (415)642-5823 Office: Evans 257, Univ. of California, Berkeley, CA 94720 Subject: cellular inquiry To: telecom@buit1.bu.edu I do not yet understand enough about the cellular technology, and perhaps the answers are relatively simple and of interest to others as well as me. (If not, the moderator may wish to divert the discussion). Clearly a customer can rent a cellular phone, and register for service in a particular area; then they can both send and receive calls. The technology somehow recognizes and notes the user's location as they drive about, and knows in what cell to ring them if an outsider calls them. The questions: 1. How is the location-recognition accomplished? Does one's currently inactive cellular phone burp regularly and its address get re-noted? Does that drain your battery? If it's really off are callers told something different from "ring...ring...ring...no answer"? 2. Over how large an area does this typically work? 3. If an owner drives from SF, normal location, to New York, and tries to call out, what happens? 4. If while they are in New York, someone in SF, their home, calls them, what happens? 5. Can you register as a visitor in a distant area, electronically or by calling in or however? Does this enable anyone else to call you from long distance? Must they know, essentially, where you went and when you're there? Thanks, Doug [ cellular inquiry
keithh@rosevax.rosemount.COM (Keith Holmquist) (05/28/87)
> Subject: cellular inquiry > > To: telecom@buit1.bu.edu > > I do not yet understand enough about the cellular technology, and perhaps the > answers are relatively simple and of interest to others as well as me. > (If not, the moderator may wish to divert the discussion). > > Clearly a customer can rent a cellular phone, and register for service in a > particular area; then they can both send and receive calls. > > The technology somehow recognizes and notes the user's location as they drive > about, and knows in what cell to ring them if an outsider calls them. First my background in cellular was as a design engineer for both mobile units and base station, primarily designed the brain sections along with signal and audio processing. It`s been 2 years since I`ve worked on it so some of my answers may be out dated but I`ll try not to lead you astray. > > The questions: > > 1. How is the location-recognition accomplished? Does one's currently inactive > cellular phone burp regularly and its address get re-noted? Does that drain > your battery? If it's really off are callers told something different from > "ring...ring...ring...no answer"? The systems do not know where a particular subscriber is at any time. As a mobile unit cruises the streets It locks on to a dedicated channel called the control channel. As travel progresses the mobile periodical scans all the avaible control channels and continually looks for the stronges signal. When a call is initiated all the control channels in a given system ( i.e. not all the systems in the country) transmit the request. The mobil whose being called then responds on it present control channel a voice channel is then assigned for the remainder of the call. I'm not clear on what you mean by "burp". How a non responding mobile unit would be delt with is really up to the individual systems. I am unaware of any regulations in that area, the systems I worked on responded with a recorded messge similar to "The mobil unit you are requesting is unavailable at this time" or something equelly as dry and tasteless. > > 2. Over how large an area does this typically work? It works over an entire system in any one geographical area. > > 3. If an owner drives from SF, normal location, to New York, and tries to cal > out, what happens? Typically the way this is being handled is the call is intercepted and the caller is given the option to place the call by credit card. It is entirely possible for the system to decide if this caller is registered with It in another city but would reqiure a nation wide network from cellular system to cellular system. I have not read any articles saying this is reality yet. It was all just a dream 3 years ago. > > 4. If while they are in New York, someone in SF, their home, calls them, what > happens? I believe presently that the caller from SF get the message you are unavailable. There are provisions in the protocol for a mobil to register whenever it roams from its preferred system and from that point it is up to the base systems to determine if the subscriber is valid or not. Again a nation wide network is needed. see above response > /------------\ > 5. Can you register as a visitor in a distant area, electronically or by > calling in or however? Does this enable anyone else to call you from long > distance? Must they know, essentially, where you went and when you're there? Now an editorial comment: The cellular concept is a good one but due to pressures to not allow it to become a monoply it may never reach it's full potential. If one uses the as an example the Bell system, I think you would agree that the nation wide/ world wide coverage was made easier by allowing one large operating system the privealage to design and implement the entire system. Could you imagine the confusion of having Dick and Jane Telephone on the west coas and Ted and Alice on the East. Cellular is presently in that state although a few large operators seem to be positioning themselves for more complete coverage. Just thought I comment. The end An opinionated source Keith > > [ cellular response]