and NOMA are used to help reach UEs out of coverage due to severe blockage at mmWave band. Without loss of generality, IoT UE 1 and IoT UE 2 are selected, where UE 1 is in the beamforming coverage area while there is a severe blockage between BS and UE 2 SO that a direct transmission link between the MBS and UE 2 is difficult to establish. Thus BS can communicate to UE 2 through relays. In this chapter we assume D2D relaying mode is used SO that the relay can communication with a UE in close proximity and we assume the relay is capable of rechargeable functionality. So the power consumed for relaying comes directly from electromagnetic waves, which can relieve the concern on limited battery life for typical IoT devices. With NOMA and relay, complete transmission cycle consists of two phases. In the first phase, the BS sends a composite signal to UE 1 and a selected relay device simultaneously by applying NOMA. After receiving the signal, the relay device splits the signal into two parts. One part is for information decoding and the other part is for energy harvesting. In the second phase, the BS sends another message to UE 1 while the relay device sends the decoded message to UE 2 by using the harvested energy in phase 1. Denote the channel between BS and UE 1, BS and relay device, relay device and UE 2, as h'1' h'BR' and N'R2' respectively. Frequency flat quasi-static block fading model is used here, SO the channel does not change during the two transmission phases while the chan- nel changes from cycle to cycle. Additionally, him where hi is modeled as Rayleigh fading with ~ CN 0,1), = {B1, BR, R2} [47]. a0 is antenna-specific gain for the BS and ao = 1 when i = R2. An illustration of the system model is in Figure 4.6. In the following, the transmission process for each cycle is illustrated. 4.2.2.1 Phase 1 Transmission In this phase, the BS sends the superimposed message to both UE 1 and the relay. The message is given as X = V21PBSX1 + VA2PBSX2, where 21 and M2 are power allocation factors for UE 1 and the re