- Whenever a good engineer sees a nonlinear
term in an
equation, he or she usually tries either to eliminate it (if linear
performance is necessary) or to exploit the nonlinearity; we can do the
latter
- By implementing "courteous" spectrum
sharing and interference avoidance, cognitive radios can be used to
keep SNR above the "knee" in the curve. Because returns from greater
SNR diminish rapidly above the knee, this yields the best performance
that it is practical to achieve with or without sharing
- At the same time, sharing of spectrum
(nonexclusive licensing) allows larger chunks to be allocated so as to
maximize the linear term in the equation. This maximizes the product of
the two terms, providing the greatest overall utility
- Allocating spectrum in larger chunks also
avoids waste due to imperfect filtering
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