BlueSkyWaves has been around a very long time. Check his alias on RB, he was one of the original posters who bolstered my IDCC views. (BTW, I had both of you membermarked ;)
Here's an old BSW post:
By: BlueSkyWaves 20 Mar 2000, 04:16 AM EST Msg. 5723 of 119947 (This msg. is a reply to 5627 by slife79425.) Jump to msg. # There has always been something screwy about the tendency, especially by the more rabid Qualcommers, to do the following:
a) to judge the quality of IDC's TDMA patents by the pre-Markman Motorola case even though some of IDC's key TDMA patents have been validated in Sweden and Germany and by the addition of 8 new licensees in 1998 and 1999.
b) to judge the quality of IDC's CDMA patents by its lack of success in narrowband IS-95 CDMAOne when IDC was always after broadband CDMA and never even tried to compete against Qualcomm in 2G.
Anyway, below is a 1997 article that describes IDC's B-CDMA approach. This is just one independent way of confirming many of Corpgold's points about the quality of IDC's CDMA patents. Since this 1997 article, IDC has accomplished many things including the developments covered by its NDA with Nokia which are based on real world trials in different parts of the world. By comparison, QCOM cleared the way for narrowband IS95 CDMA with its 1994 cross-licensing agreement with IDC and 5 other companies BUT it wasn't until 1997 or 1998 that QCOM finally started to deliver on its promises in narrowband CDMA and even then not completely so its lead in CDMA technology is by no means as formidable or as insurmountable as they would have you believe.
In 1994, InterDigital Corp. (King of Prussia, Pa.), succeeded in convincing Siemens to enter a technology and marketing alliance to develop a wideband version of CDMA that InterDigital has patented, known as B-CDMA(TM) (Broadband CDMA), a proprietary technology. A year later, Korea's Samsung Corp., a heavy investor in narrowband CDMA, joined the Siemens-InterDigital alliance. The triumvirate intends to develop B-CDMA first for wireless local loop (under the product names CDMA-Link and True-Link), then for cellular and PCS applications.
"There is ... the need for providing advanced telecom services via radio or wireless format, including bandwidth on demand, digital data services, ISDN and multimedia that can't be provided by narrowband technologies," says Gary Lomp, vice president and general manager of InterDigital's B-CDMA division. "From a radio transmission point of view, narrowband CDMA offers no advantages over AMPS or GSM, and cannot provide the broadband services, enhanced radio connectivity or the reliability that B-CDMA can provide."
Lomp cites research comparing inherent radio propagation and performance characteristics of wideband CDMA vs. IS-95. The intrinsic advantages of wideband CDMA are basically two-fold:
* Those associated with the use of a broader RF bandwidth to support a single multiple access channel rather than a set of sub-bands which fill the RF spectrum collectively, and
* Those derived from implementation advantages related to spread-spectrum CDMA research. "There is an intrinsic advantage to using [B-CDMA]--namely, inherent capabilities, such as the ability to provide [multimedia] voice and data services, and also the inherent resistance to radio propagation impediments, such as fading and multipath," Lomp says.
'STREET-SMART' CDMA? Wideband CDMA works better than narrowband in crowded urban and suburban areas where traffic is heavy and transmissions can be blocked by large buildings and skyscrapers, Lomp says. "Key aspects of B-CDMA technology are an optimized power control system [critical to any CDMA system] and an optimized multipath processing scheme," Lomp explains. "Normally, an echo or ghost wreaks havoc with digital communication, but broadband signals enable the resolution of multipath components, and subsequent optimum processing of those components helps eliminate signal fading. In addition, we have perfected synchronization algorithms, which are key to successful implementation of multipath processing." The result: a stronger signal with less fade and attenuation. More digital information flowing flexibly through a wide pipe is also a broadband characteristic. "With broadband CDMA, information (i.e., multiple simultaneous voice conversations or data transmissions) is being spread over a complete channel, and all the users use the same channel," explains Mark Lemmo, an InterDigital senior vice president. Like narrowband CDMA, the technology takes advantage of "voice quiet" periods to let users share spectrum, each conversation tagged by a unique code. But a wider pipe means "you can pass more information through that channel," Lemmo says. "Beyond voice requirements, you have data for Internet access, ISDN and compressed video. So you can now have users that have ISDN systems and also pick up the phone and have voice."
Power balancing and efficient spectrum usage are other benefits. The developing Siemens/InterDigital product, for example, CDMA-Link, allows digital operation in 7, 10, 10.5, 14 and 15 MHz bands. By contrast, Brian Kiernan, an InterDigital senior vice president, says IS-95 is based on 1.25 MHz bandwidth only (which is still, relatively speaking, "broadband" as compared to GSM). IS-95 was designed to fit available spectrum in the domestic market.
"The original band was 20 MHz wide, and FCC added 2.5 MHz at each end to make it 25," Kiernan says. "In each of those 2.5 MHz chunks, you've got to have an A and B operator, so IS-95 was specified at 1.25 MHz to be sold to an operator for use in the cellular band."
IS-95 is too narrowband to deliver high-capacity benefits, and power control and update rates are a problem in narrowband systems, according to InterDigital. "To obtain capacity, you have to deal with the fact that CDMA is a self-interfering system--and power levels have to be adjusted to make sure that all the codes somehow get through," Lemmo says.
In the B-CDMA system, however, it's easier to extract coding and signal information, Lemmo suggests. For example, in a mobile PCS application, as opposed to a fixed local loop, "power level control is a dynamic event; it's happening all the time," he says. "The difference is that in broadband CDMA, we update the power level more rapidly--64,000 times per second as opposed to 800 times per second for narrowband [CDMA]."
In crowded metropolitan areas, the power update rate effects performance. "Frequency selective fading does happen in a channel," Lemmo says. One type of fading is sharp (quick attenuations in the channel) and typically in/around the 1 to 2 MHz range, he notes. "But since B-CDMA is broader band, say in the 10 to 15 MHz range, an attenuation of 1 to 2 MHz doesn't knock out the transmission." By contrast, "a frequency selective fade in a narrowband system covers the entire channel; therefore, to continue communications, the power controls must be rapidly updated. But 800 times a second is not fast enough. Our implementation has a much higher level of updates to optimize control," he says.
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