Nokia takes on WiMAX challenge with I-HSPA

Sprint's decision to go with Mobile WiMAX as its new broadband wireless technology has sent some shudders down the spines of a few vendor execs. Sprint may have just made WiMAX a viable technology for mobile operators, threatening the primacy of the 3G technologies the industry has embraced for the last half decade.

WiMAX's main advantage is its efficiency in data delivery — achieving a cost-per-bit ratio far lower than what 3G technologies deliver today. In fact, while Mobile WiMAX is expected to go commercial next year, the 3G Long-Term Evolution (LTE) and EV-DO Revision C solutions that can feasibly compete with it won't be out of the laboratories until at least 2008 or 2009, and then commercially deployed only years afterward. That would appear to leave vendors without a 3G response to Mobile WiMAX for the time being, which should be cause for concern for equipment-makers with billions of investment dollars sunk into CDMA and UMTS technologies. But Nokia Networks believes it has a solution for the interim, one that doesn't require divergence from 3G migration paths while still delivering a broadband wireless answer to the question of WiMAX.

Nokia is repositioning a little-known technology it announced last year as a more palatable offering for GSM carriers weighing an alternative to WiMAX. Called Internet-high-speed packet access (I-HSPA), the technology is essentially the data aspects of UMTS stripped down to its core. The technology uses both the high-speed downlink and uplink packet access (HSDPA and HSUPA) optimization technologies to create a big efficient data pipe, but it does away with UMTS's voice component technology entirely. In doing so, it eliminates the need for a radio network controller and signaling gateway service node (SGSN) and GPRS gateway service node (GGSN). In effect, the UMTS Node B dumps a direct IP signal onto the Internet backbone, just like a WiMAX base station.

I-HSPA still isn't a replacement for WiMAX, not providing the bit-per-hertz efficiency of the OFDMA technology, but it's not intended to be, said Mark Slater, Nokia's vice president of area sales and marketing for North America. Nokia, in fact, is straddling both sides of the fence, building a WiMAX portfolio in parallel with its strong UMTS portfolio. Slater said Nokia wants to sell WiMAX gear as an alternative mobile data network technology, but it also realizes that not every mobile operator will be in the same position as Sprint — with a completely unused and isolated swathe of spectrum over which it cannot deploy a frequency division duplexing technology like CDMA or UMTS.

“The question is, what's the most economic way to deploy a broadband network?” Slater asked. “Are you starting from a GSM/EDGE network or are you starting with a clean sheet of paper?”

For a mobile carrier, WiMAX will be ideal for a greenfield deployment where new spectrum and restrictions on said spectrum suit WiMAX's duplexing scheme and demands for an entirely new network. But most carriers don't have that kind of spectrum, nor the inclination to spend billions on a new broadband network, Slater said. What Nokia — and eventually other vendors as they optimize their UMTS gear for data only — can offer, Slater said, is a technology that delivers peak data rates of 10.7 Mb/s that integrates into current UMTS networks and transmits to the same UMTS devices and handsets, but collapses the network, thus slicing off significant capex and backhaul costs. And, Slater said, Nokia can deliver it with the advent of HSUPA in 2007, the same timeframe for the commercial deployment of WiMAX.