"We’ve never seen a mobile network whose capacity we couldn’t increase by 20%," says Yuval Davidor, president of Schema Corp., an Israeli company currently relocating to the San Francisco area. Schema is striving to sell its network optimization software to wireless carriers and has already won the support of Verizon. "Sometimes we get a 40% increase, and once over 50%.," he continues. "If data by itself accounts for 15% of network traffic, as many predict, then our technology alone would enable the carrier to keep pace."

Schema’s approach to hot-rodding a mobile network is complementary to any of the 3G approaches involving advanced modulation, aggressive data compression and silence suppression. At the same time, it represents an entirely different strategy. Instead of concentrating on the air interface, Schema seeks to optimize the assignment of channels within contiguous cells to provide maximum frequency reuse – in effect, re-examining the basic design tenet inherent in all cellular mobile networks.

"Most network engineers have strong backgrounds in RF and have very little understanding of how to plot channel reuse for maximum efficiency," says Davidor. "They fall back on textbook solutions which generally involve moving clusters of adjacent channels rather than allocating channels individually on a single frequency basis. Admittedly, it’s much more complicated doing it frequency by frequency, but the gains in efficiency are substantial, even with no other change in the network."

Davidor claims that Schema’s software is airlink-agnostic and frequency-agnostic, although he suggests that the benefits are greatest in CDMA networks. "But we’ve done AMPS and digital TDMA as well, and we’ve been particularly successful with networks attempting to transition from AMPS to digital, where they’ve had to divide channels between the two air interfaces. This will allow the carrier to make the best choice."

Davidor also maintains that the software allows carriers to make tradeoffs between capacity and voice quality. "They’re dependent variables, and you can gain in one area by sacrificing in another," he says.

While Schema is seeking cellular and PCS carrier customers, it is extending its software to fixed broadband wireless services – which could be a huge business opportunity as well as a much greater engineering challenge. "Fixed networks exhibit complexity that is many orders of magnitude greater," says Davidor, "but the benefits are ultimately the same."

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