I can only speak to it conceptually because I haven't studied it specifically: I think anything you overlay that adds much code dependency such that it leads to lower data rates and latency won't fly. But if it has the major advantages of OFDM I see no reason why something like that can't work. OFDM is just the base upon which the structure of an advanced system might evolve because it offers the granularity and multiple signal capability that lends itself extremely well to use with other emerging technologies. The use of OFDM in 802.11a WLAN helps it to deliver higher data rates and handle signal reflections but it is still a straight stick implementation that doesn't layer on the other technologies, such as spatial signal processing techniques.
One area that I am developing more interest in is software defined radio. I thought this was about 3-5 years into the future until recently. Because DSPs have grown more capable, flash and other memories cheaper, core logic designs and software MAC layers developed, and new process technologies, including silicon on insulator are now reaching mass merchant chip status, this may propel forward soon. AMD, Intel, UMC and other high volume manufacturers will begin using SOI by mid year for production of the next versions of uPs. The process technologies and equipment developed for the huge processor market can in turn be used to advantage for communications chips to deliver higher clock rates, lower power, and improvements in performance, such as higher input sensitivities. SOI is ideal for many high volume wireless applications, including software defined radios. Part of the reason for AMD and Intel going to it is to enable them to further reduce circuit geometries below 0.13 micron, increase power densities while decreasing total power consumption, etc. It will make the use of a general purpose DSP combined with core logic areas, such as Viterbi, to implement software radio designs that can interchangeably use various modes of operation, similar to multi-mode cellular phones. 3DSP is one company that has developed SDR. They are offering 802.11a & 802.11b capability now and plan to add 802.16 capability when that is ratified for sub 10 GHz spectrum. I don't see any companies to invest in directly in SDR yet. |
