Terayon was formed in 1993 in Silicon Valley to pursue the vision of
broadband over cable developed by Zaki and Shlomo Rakib in Israel.
Analogous to Qualcomm's wireless CDMA, S-CDMA uses spread spectrum
techniques to modulate signals across a swath of available spectrum
rather than chopping them up into time slots in a narrow band as in
Time Division Multiple Access (TDMA). Just as in wireless, S-CDMA
over cable offers a shared medium system with more flexible handling
of bursty data, greater capacity, and far superior immunity to noise.
Like urban cellular environments, cable coax spectrum is fraught with
interference and noise...
Terayon always writes their prose as if there was nothing else
of importance. It's a type of marketing/spin pitch that suckers
people right in who don't do their homework.
In 1993, there were three cable modem vendors of importance: Zenith,
LANCity, and Hybrid. Hybrid was mostly focused on telephone return
and didn't care at that time with two-way cable. Zenith and
LANCity were two-way cable, but had a similar dumb head-end transverter
design. Zenith, I believe, used a simple ALOHA based protocol,
LANCity used a more advanced protocol. Spin will place both of these
technologies in the TDMA camp. These systems had several problems:
symmetrical, dumb head end transverter, and no use of Forward Error
Correction.
After 1994, every "new" vendor used an intelligent head end controller
and forward error correction. This includes Motorola, Com21, and
also Terayon. Every intelligent head-end controller with forward
error correction (FEC) has the ability to offer[s] a shared medium
system with more flexible handling of bursty data, greater capacity,
and far superior immunity to noise.
The 1993 based statement was true in 1993 and 1994. In 1995 and
beyond, that statement is inaccurate due to not mentioning the
other alternatives which are equally/more effective which were found
in Com21 and Motorola.
Mark |
