Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: "Christopher J. Pikus" Newsgroups: comp.dcom.telecom Subject: Re: BAD Digital Cellular Standard Under Development Message-ID: <8289@accuvax.nwu.edu> Date: 25 May 90 21:45:01 GMT Sender: news@accuvax.nwu.edu Organization: Megatek Corporation, San Diego, Ca. Lines: 53 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 386, Message 6 of 7 From article <8244@accuvax.nwu.edu>, by gnu@toad.com (John Gilmore): > I heard rumors of a digital cellular telephone standard among DSP > folks, and tracked them down. > The draft standard is called "IS 54" and its project number is 2215. > The standard makes no provision for data traffic and no provision for > encryption, even though it is digital end-to-end. The engineers I've > The only ones who win from IS 54 are the cellular carriers (who expand > their customer base without deploying more cells) and the phone makers > (who make people buy another phone as they crowd more early adopters > into fewer analog channels). And guess who's writing this standard? An alternate path being explored is a joint project between Pac Bell Cellular in Los Angeles and Qualcomm in San Diego. I had an opportunity to view a technology demonstration last novenber. They are using something called CDMA (Code Division Multiple Access) that uses a technique similar to sattelite communications (Qualcomms expertise). All transmitters use the same frequency with no time division; each one running with output power down at the noise floor. Each phone convolves their voice data with a special 32 bit number which a digital modem at the other end searches for. Thus each phone is secure from each other (different keys); the others look like noise to each phone. As for datacomm, the data bandwidth is flexible, you pay for what you need, (with tradeoff in quality/datarate). i.e. 8/16 kbs for voice and 64 kbs for data. The bandwidth limitation is soft since as the channel hits capacity, the b.e.r. will slowly climb. At the technology demonstration, Pac Bell was saying that if they alloc'd 10% of their service (42 channels) to this digital, they could increase capacity by a factor of 2-3 FOR THE WHOLE SERVICE. The people at Qualcomm were saying that a phone could be built that swings both ways; current technology analog and this digital service with the addition of a few DSP chips. It appears that Pac Bell doesn't have time to wait for a standards commitee and decided that an early deployment of a superior system will create a de-facto standard. Regards, Christopher J. Pikus, Megatek Corp. INTERNET: cjp@megatek.uucp San Diego, CA UUCP: ...!uunet!megatek!cjp