Hi:
QAM [Quadrature Amplitude Modulation] is superior to spread-spectrum because the former can sends more bits using less bandwidth than the later. QAM is is meant to send/receive large amounts of info while saving bandwidth. Yet so many cell phones and wireless internet routers, modems, and access points use spread spectrum. Why? It would make a lot more sense if they switch to QAM, so that wireless internet access can be faster and cell phones reception can be more efficient. Sure QAM has more RFI than spread spectrum but it definitely beats the annoying aliasing you get when using spread-spectrum.
In addition, wireless internets and cell phones should use radio frequencies that are in or close to the UHF range. UHF is the most efficient spectrum for radio communications. Last but not least, the carrier waves should be AM, not FM. FM uses too much bandwidth and cuts of many other users. AM won't do that. AM's chief drawbacks are the EMI/RFI resulting from magnetic disruptions, however this only affects analog reception. QAM is a digital modulation scheme and as such it is immune to the electromagnetic disturbances that would normally hinder analog telecommunications.
Any questions/comments welcome.
Thanks,
Radium