Energy-Efficient Random Access for Machine- to-Machine (M2M) Communications

In this paper, an average consumed energy for a unit data transmission in analyzed in frequency-agile cognitive radios. The average energy consumed by a random access protocol operated in a channel using a whole system bandwidth is compared with that operated in frequency-separated channels, which results in an energy saving ratio. The energy saving ratio quantitatively evaluates an energy saving effect by separating one whole bandwidth into more than one channel with a smaller bandwidth. Finally, it is shown that the frequency-separated channel can save energy of machine-to-machine communicating nodes using the random access protocol, so the battery life can be extended.