# Cooperative SWIPT MIMO-NOMA for Reliable THz 6G Communications

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## Abstract

**:**

## 1. Introduction

- (1)
- We propose a reliable transmission with a non-LOS (NLoS) line of THz communications to overcome THz coverage shortage for open areas or any location where IRS cannot be deployed, in addition to using a simplified cost-effective DF relaying instead of IRS.
- (2)
- We design a system with low power consumption, complexity, and cost by integrating THz, NOMA, MIMO, cooperative networking, and EH (SWIPT) techniques, improving SE, EE, and other metrics compared to the state of the art.
- (3)
- We develop a path-selection mechanism for the potential NOMA-based far users to enhance the system performance and reliability.
- (4)
- Given the flexible structure, we recommend exploiting an existing user in the cell for relaying and not dedicating a fixed device, achieving a synergic coexistence with the expected mobile 6G infrastructure.
- (5)
- To enhance the SIC procedure, we suggest two-user clustering to prevent propagating errors, complications, and spectral deficiencies due to the burden of the additional operations.
- (6)
- We manage the performance and scalability of the spectral and energy efficient upgradeable system, using adjustable parameters and the simplest modulation scheme; hence, this system can be upgraded on the basis of the planner’s preferences.

## 2. Background

## 3. Related Works

## 4. System Model Design

## 5. Implementation

- (1)
- Transmit power, frequency, distance, and BW can be adjusted.
- (2)
- Targeted rates are 1 Gbps for the FU and 3 Gbps for the NU.
- (3)
- A power of −30 to 30 dBm is dedicated to cover a wider area if the FU goes farther. Hence, transmit power can be reduced.
- (4)
- We set a relatively high path-loss exponent η = 4; hence, it can be reduced. The absorption coefficient can be found in [27]. The simulations were implemented using ${\mathrm{MATLAB}}^{\circledR}$.

## 6. Simulation Results

#### 6.1. System Validity Analysis

#### 6.2. System Simulation

#### 6.2.1. Achievable Users’ Rates versus Transmit Power

#### 6.2.2. OP versus Transmit Power

#### 6.2.3. Achievable Sum Rates versus Transmit Power

## 7. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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Notation | Parameters | Value |
---|---|---|

f | Frequency | 311.04 GHz |

BW | Bandwidth | 12.96 GHz |

P | Transmission power | 30 dBm |

d | Transmission distance | Phase 1 = 20 m |

Phase 2 = 30 m | ||

αn | NU power coefficient | 0.25 of total power |

αf | FU power coefficient | 0.75 of total power |

G | Antenna gain | 25 dB |

eta | Path loss exponent | 4 |

Target data rate | 3, 1 Gbps for NU, FU |

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**MDPI and ACS Style**

Oleiwi, H.W.; Saeed, N.; Al-Raweshidy, H. Cooperative SWIPT MIMO-NOMA for Reliable THz 6G Communications. *Network* **2022**, *2*, 257-269.
https://doi.org/10.3390/network2020017

**AMA Style**

Oleiwi HW, Saeed N, Al-Raweshidy H. Cooperative SWIPT MIMO-NOMA for Reliable THz 6G Communications. *Network*. 2022; 2(2):257-269.
https://doi.org/10.3390/network2020017

**Chicago/Turabian Style**

Oleiwi, Haider W., Nagham Saeed, and Hamed Al-Raweshidy. 2022. "Cooperative SWIPT MIMO-NOMA for Reliable THz 6G Communications" *Network* 2, no. 2: 257-269.
https://doi.org/10.3390/network2020017