Whether we all agree on what a fourth-generation wireless network will do, which technologies qualify to create one, or how to pay for the expense involved in getting there, the connectivity world is on an inexorable path to 4G.

Just one day after Sprint launched the first city for Xohm, its U.S. WiMAX network, I’m in Chicago at Yankee Group’s 4G World Executive Summit. I had a chance to chat with Mark Pecen, VP of Advanced Technology at Research in Motion. Some of his thoughtful observations:

• What’s driving us to 4G?  “When I first worked on wireless in the early ‘90s, there were big holes in U.S. coverage, but no one cared. We were just glad it worked every now and then. Fast-forward a few years, soon people expected it to work everywhere except when they left the country. Now, we want it to work all the time, anywhere. There’s no shortage of user expectations to try to meet.”
  
• What are some of the core technical issues?  “Take any standard communications cable, send a signal through it, and measure it a thousand times–your results will hardly vary. Do the same thing with radio, and it’s a different story: the standard deviation across a set of measurements like that will be quite large. Radio is a hard problem. Theoretical performance in the lab for any wireless technology is dramatically higher than actual results in the field, where signal interference is the dominant factor. The challenges have been the same since Marconi starting selling radios to shipping companies: spectrum, power, mobility. We just have to continue to evolve the solutions. We’ll still be working on good power-efficient and spectrally efficient radio techniques 10 years from now.”
  
• What’s challenging from a business perspective?  “Consumers don’t understand the true cost of the devices and experiences they seek. Mobile operators have the same problem as airlines: extremely high fixed costs to run a network, and very low marginal costs to add the next user. So they develop some bad habits to get that next user onto their networks–and those are hard to break.”

He’s right on that one: subsidizing device prices to users, and requiring long-term contracts and credit checks, actually damp progress to 4G as they tie consumers to current networks. YG’s Phil Marshall published new work this week on the technology road to 4G.  What do you think the big questions about 4G are? As we plan Yankee Group’s next 4G conference, we’d love to hear from you.