Power Optimal Non-contiguous Spectrum Access in Multi Front End Radio Enabled Point-to-Point Link

Abstract: 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.