I'll be more precise, In what way is CDMA more flexible than TDMA? In what way is CDMA's capacity greater than TDMA? And under what conditions is CDMA superior to TDMA regarding noise immunity? I submit the jury's come back and pronounced TDMA the better technology. Until CableLabs determines otherwise, I rest my case.
Pat, the main thesis of Gilder's first piece on TERN is that S-CDMA works better on noisy cable, allowing upstream transmission in the "lower 40" MHz, where TDMA supposedly does not work due to interference from other radio sources. I don't think Gilder made any (convincing) arguments re: why S-CDMA would be any better for upgraded plant, and others have suggested here that S-CDMA is not necessarily better in such environments. In any case, this Gilder piece is available on Terayon's site. Published last summer. To find it, go to terayon.com and look under "Press Coverage" for 2nd quarter 1999. From Terayon's site:
The thick coaxial cable used in cable systems is intuitively more capacious than the thin twisted copper pairs used for phone lines. DSL (digital subscriber line) providers must cram enough data through those little wires point-to-point over long distances, all the while limiting noisy interference with neighboring wires twisting through the same bundle. Cable modem providers, however, have their own challenges. They must find a way to make one-way cable plant accommodate two-way data streams twisting through a shared tree and branch structure spread through a neigborhood.
All along the coax path the splits and amplifiers in the lines introduce noise into the system. In the upstream direction-from home to headend-the same noise is compounded and funnelled as the branches rejoin the trunks. Furthermore in the spectrum used for upstream transmission-mostly the "lower forty" megahertz in the pipe-the coax cable itself acts as a large antenna receiving interference from nearly everything that spikes and vibrates in the area, from garage door openers to hairdryers, from CD radios to AM radio and TV harmonics.
The expensive answer to these noise problems is to upgrade the system, laboriously adding fiber and coax, moving nodes closer to homes, severing branches from each trunk, removing old cables, splits, and amplifiers, all in all reducing the number of homes sharing each node.
The cheap and effective answer is Terayons cable modem technology. Based on the same spread spectrum noise defeating principles as Qualcomms (QCOM) CDMA, Terayons modems encode the data signals and spread them across the available upstream spectrum. The wide and weak signal escapes the noise and is decoded at the other end. Any components blocking two-way traffic still must be replaced. But Terayons system will work on older, noisy, all coax systems without the expense of fiber upgrades and node splits. In addition, the spread spectrum system exploits all the bandwidth all the time, using the codes to differentiate the signals sharing the conduit. Thus, like wireless CDMA, it can gracefully accommodate bursts of data, such as a rapidly downloaded film or webfile.
On May 25th, Terayon announced that its S-CDMA (synchronous-CDMA) technology now enables Terayon modems to operate at a full 14 megabits per second in previously unused downstream cable spectrum where signal loss prevents the transmission of video channels. In order to offer broadband Internet service, cable operators with maxed out older systems no longer need either to sacrifice existing video channels or upgrade capacity.
In the early cable modem market Terayons superiority went unrewarded. Unwilling to adapt to the existing cable regime, Terayon spurned the DOCSIS (data over cable service interface specification) standard. As it is, Terayons new DOCSIS compliant modem will not be available until early next year. Cable providers with already upgraded cable, or plans for upgrades, signed long term supply agreements for hundreds of thousands of modems with Nortel/LANCity and Motorola.
But Terayon was not sidelined for long. Making a potent presentation at our 1997 Telecosm Conference, Terayon persuaded the @Home network to test and approve S-CDMA equipment for use by its affiliates. Using Terayon modems and headend equipment, Shaw Communications (SJR) in Canada became the first @Home affiliate to pass 100,000 subscribers, and North Americas most successful cable modem service as measured in penetration levels (7% of ALL homes passed-not merely served markets and over 17% penetration of some markets). At the time of choosing Terayons system, Shaw cited its superiority in cost-effective and timely deployment. Now Shaw plans to accelerate the rollout of cable modem availability to its entire system of 2.3 million homes passed within six months, becoming the first operator with 100 percent cable modem coverage.
In a breakthrough resembling Qualcomms CDMA triumph in Third Generation wireless, Terayons technology finally prevailed last November, when Terayon was asked by CableLabs to join with Broadcom (BRCM) in authoring the next generation DOCSIS 1.2 standard. Terayon will join with other standards participants offering their patents into a shared pool of intellectual property, but Terayon retains the rights to its trade secrets in implementing its technology. We will take process know-how and learning curve leadership over patent hoarding any day. Already developing a highly integrated, low cost chip based on the initial drafts of the DOCSIS 1.2 standard, Terayon should do well following the Qualcomm model, selling not only its own modems but also ICs and technical assistance.
I don't really see how this breakthrough (no-starter, as it happened) resembles QCOM's. After all, the point about QCOM is that they are patent hoarders, and are not willing to submit their IPR to a patent pool for 3G. Rather, anyone who wants to use QCOM's IP has to "pay up". That is what you do when the ball is "yours". Assistance to "partners" in implementation is something that happens after they pay the toll. I don't see how TERN's joining a patent pool is at all consistent with the kind of leverage QCOM has in its business. In its cc last week, QCOM mgmt were very clear that they will not join the pool for WCDMA. One of the reasons for the stock's rebound. |
