Fig. 7From: Energy efficiency and sum rate tradeoffs for massive MIMO systems with underlaid device-to-device communicationsEE [Mbit/Joule]: a as a function of the D2D user density λ d for a fixed ratio \(\frac {T_{c}}{U_{c}}= 5\) with the number of CUEs U c ∈{1,14}; b as a function of the number of CUEs U c with the D2D user density λ d ∈{10−6,10−4} for a fixed ratio \(\frac {T_{c}}{U_{c}}= 5\) Back to article page