Impact of shadowing in D2D communication

Device-to-device (D2D) communication is expected to increase the coverage probability by coexisting along with the conventional cellular systems in 5G technology. As the user equipments are often held closer to the human body, D2D links experience shadowing modelled by the amp;#954;-amp;#956; shadowed fading model. Though the cellular links do not experience amp;#954;-amp;#956; shadowed fading, the same is assumed here as it generalizes many popular fading distributions such as Rayleigh, Rician, Nakagami, amp;#954;-amp;#956;, amp;#951;-amp;#956;, Hoyt etc. Thus the above assumption makes the results obtained here generic. We show that by neglecting shadowing in the D2D link, coverage probability of D2D user is over-estimated at low SIR thresholds and under-estimated at high SIR thresholds. Though cellular links are interfered with by the D2D links, we observe that there is negligible impact on cellular coverage probability due to any change of fading parameters in the D2D links. Also, when all the links are Rayleigh faded, the D2D distance below which D2D mode is preferred to cellular mode of communication is obtained analytically.