  Non-contiguous spectrum chunks allow wireless links to flexibly access a wide
amount of bandwidth. Multi- Channel Multi-Radio (MC-MR) and Non-Contiguous
Orthogonal Frequency Division Multiplexing (NC-OFDM) are the two commercially
viable strategies to access non-contiguous spectrum chunks. MC-MR accesses
multiple non-contiguous chunks by activating multiple front ends which, in
turn, increases the circuit power consumption of each of the activated front
ends. NC-OFDM accesses non-contiguous spectrum chunks with a single front end
by nulling remaining subchannels but increases spectrum span which, in turn,
increases the power consumption of ADC and DAC. This work focuses on a
point-to-point link where transmitter and receiver have multiple front ends and
can employ NC-OFDM technology. We investigate optimal spectrum fragmentation in
each front end from a system power (summation of transmit power and circuit
power) perspective. We formulate a mixed integer non-linear program (MINLP) to
perform power control and scheduling, and minimize system power by providing a
greedy algorithm (O(M^3 I)) where M and I denote the number of channels and
radio front ends respectively.
