 overall minimum transmit power of the CBS, M = 15, Rmin = 1 bit/s/Hz, PB = 8 Watts. Bounded CSI error model, SNR = 0,5 Bounded CSI error model, SNR = 1.5 Maximum tolerable interference of PUs (dB) Figure 5.6 Average maximum EH power under different interferences tolerated by the PUs, M = 10. Pn.p allows for a larger transmission power, leading to the increase of the harvested energy. When the channel conditions are better, less power is required for satisfying the data rate requirements. Hence more power can be reserved for EH. This also explains that when the required SNR is low, a high EH power can be achieved. 5 Robust Beamforming in NOMA Cognitive Radio Networks: Bounded CSI NOMA bounded CSI error model OMA bounded CSI error model Perfect CSI Minimum required SNR of SUs Figure 5.7 Average maximum EH power VS. the minimum SNR required by the SUs, M = 10. The impact of minimum SNRs required by the SUs is illustrated in Figure 5.7. The number of CBS antennas is M = 10 and the interference threshold P n,p is set to -24 dBm. We also list the results for the OMA cases. As expected, we can see that the maximum EH power decreases significantly when the SNR grows. This is because more power has to be used for information detection, which leaves less power for energy harvesting. Figure 5.8 shows the average total EH power VS. the number of SUs. It can be observed that the total EH power grows, when the number of SUs increases, since more nodes participate NOMA bounded CSI error model, M = 10 NOMA bounded CSI error model, M = 15 The number of SUs Figure 5.8 Average total EH power VS. the number of SUs for Pn,p = -24 dBm, min = 1 bit/s/Hz. 5.6 Summary in the harvesting process. Additionally, we can see that when the number of antennas is higher, more EH power can be achieved. This is because more antennas give a higher system DoF; therefore, less power is sufficient for information detection. 5.6 Summary In this chapter, we considered MISO-NOMA CR-aided SWIPT under the bounded CSI esti- mation error model. A non-linear 