Representatives from companies at the core of innovation in multi-antenna signal processing (MAS) debated the economics of MAS architectures in broadband wireless access networks at WCA 2006 yesterday—a critical issue that ArrayComm Executive Chairman Martin Cooper says will determine whether or not consumers are willing to pay for broadband wireless data services.
About 90 percent of revenue garnered by today’s mobile operators is derived from voice. Cooper said he believes this is due in part to the fact that most mobile phones transmit data too slowly. But the real issue, he said, is that of cost.
“There really aren’t any [data] applications that are practical that can be done for a reasonable cost,” Cooper said. “If you look at an EVDO system and have only one subscriber, [it’s feasible for you to have] a couple of Mbits/s. But that’s not very practical. So I only look at cost.”
To make offering data services worthwhile for mobile operators, Cooper said that one must look at spectral efficiency. But, he noted, there are only so many things you can do with radio spectrum—use more of it, go up in frequency, use better coding schemes, or geographically share it. The limits for using more spectrum, increasing frequency, and using coding schemes are looming—if they haven’t already been realized—but geographical sharing is still a viable and effective option.
“It turns out that if you examine history, that almost all of the improvements in efficiency over the years have been in geographic sharing,” Cooper said. “So the solution is really going to be one common solution that optimizes a channel with geographic sharing so that the user gets the highest data rate and most robust performance at the lowest possible cost.”
Dr. Deepshikha Garg, a senior systems engineer with Kyocera Telecommunications Research Corporation, said that multiple antenna signal processing is a reality. She said that there are almost 300,000 base stations equipped with MAS in China alone, and almost 100 million subscribers.