Performance Evaluation of Cooperative OMA and NOMA Systems in 6G Deployment Scenarios

Optimization of the energy efficiency, fairness, and rates of the system is a vital part of communication systems. Multiple access techniques have a huge potential to enhance such performance parameters. This paper studies the performance of NOMA and OMA systems in a singular cell environment, where the cellular users are distributed randomly, and cooperative relays are considered for better system reliability. The relay nodes forward the signals to the cell-edge users. This paper considers a practical scenario where all the relay equipment is distributed with non-uniform battery power levels. The performance of OMA and NOMA schemes is compared based on the key performance indicators: sum rate, fairness, and energy efficiency. The fairness factor determines fairness in the allocation of resources to all the system’s users. The performance of the two schemes is assessed in three deployment scenarios: urban, suburban, and rural scenarios. Through numerical results, it is proved that the performance of the NOMA dominates the OMA scheme.


Introduction
Over the last decade, revolutionary growth in wireless communication networks has been seen. The fifth-generation (5G) wireless communication systems back numerous rising verticals, including machine-to-machine (M2M) communications, enhanced mobile broadband, and applications such as high-speed entertainment and multimedia, virtual and augmented reality (VAR), etc. However, the 5th generation wireless mobile communication network may not be fully capable of meeting the up-surging demands of data traffic, spectral efficiency, massive connectivity, and capacity while providing fairness amongst the users. Therefore, researchers have shifted their interest in developing the 6G of the wireless communication network. 6G explores the THz communication band, which ranges from 0.1 THz to 10 THz. Researchers are analyzing communication in the THz band, as it has huge unexplored bandwidth, and it is expected to provide an edge over the bequest networks. Moreover, the short wavelengths of the THz wavelet huge spatial multiplexing deliver an amazingly exact output in sensing, spectroscopy, imaging, and numerous more 6G applications. Further, multiple access techniques can play a huge role in fulfilling such demands. To increase spectral efficiency, the non-orthogonal multiple access (NOMA) technique has attracted considerable attention [1][2][3]. The conventional orthogonal multiple access (OMA) techniques allocate orthogonal resources exclusively to a single user. Therefore, OMA does not hold for the required spectral efficiency to sustain 6G requirements. Time-division multiple access (TDMA), frequency division multiple Table 1. Comparative analysis of this paper with existing works.

Ref. No.
Algorithm Description Parameters Optimized Scenario Type of Network [13] To study OMA, cooperative NOMA, and NOMA schemes and propose a scheme that maintains QoS for both near and far users.
Spectral Efficiency, Sum Rate, Energy Efficiency Downlink Two users [14] According to CSI and the state of the buffer designed, the transmit power at each user to control inter-user interference and switch between the NOMA and OMA Throughput, Outage probability, Delay Uplink Two users [15] To enhance the sum rate by OMA and NOMA according to relay serving capabilities. Propose a buffer aided system to improve the outage probability.
Throughput, Outage probability, Delay Downlink Two users [12] To enhance the energy efficiency, a NOMA network with a cooperative relay system is analyzed Energy Efficiency Downlink Two users [16] Analysis of the sum rate of MIMO-OMA and MIMO-NOMA systems Sum rate Downlink Two users [18,19] OMA and NOMA performance evaluation in the MIMO system Capacity Downlink Multi-user [24] OMA and NOMA latency evaluation with short-packet communications Effective capacity Downlink Two-user

Contributions
Conforming to the survey of the literature, the performance of NOMA has not been thoroughly evaluated in different multi-user 6G wireless communication deployment scenarios. Therefore, we have analyzed the performance of NOMA technology using the THz channel in 6G urban, suburban and rural deployment scenarios. The users in the urban scenario are densely populated in a small space. The users in the rural area are sparsely distributed in a comparatively larger area. The users are semi-sparse in the suburban scenario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, considering different powers of user devices, in a 6G system using the THz channel is missing in the literature.
In previous works [26] we have proposed an adaptive NOMA scheme by considering different power levels of relay equipment employing the radio frequency (RF) channel in 5G scenario.
In this paper, we consider different power levels of user equipment and study the performance comparison of the OMA and NOMA systems in terms of different key performance parameters, such as achievable rates, energy efficiency, and fairness, presented for 6G urban, suburban and rural deployment scenarios. The simulation depicts the NOMA scheme as superior to the OMA scheme in terms of key performance parameters, including average energy efficiency, fairness factor, and average sum rate. This paper is organized as follows: In Section 2, the design of the considered system is described. Section 3 presents the rate, fairness, and energy efficiency analysis of the considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the paper. Table 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, the performance of NOMA has not b thoroughly evaluated in different multi-user 6G wireless communication deployment narios. Therefore, we have analyzed the performance of NOMA technology using the T channel in 6G urban, suburban and rural deployment scenarios. The users in the ur scenario are densely populated in a small space. The users in the rural area are spars distributed in a comparatively larger area. The users are semi-sparse in the suburban nario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, considering diffe powers of user devices, in a 6G system using the THz channel is missing in the literature.
In previous works [26] we have proposed an adaptive NOMA scheme by consider different power levels of relay equipment employing the radio frequency (RF) channel in scenario.
In this paper, we consider different power levels of user equipment and study performance comparison of the OMA and NOMA systems in terms of different key p formance parameters, such as achievable rates, energy efficiency, and fairness, presen for 6G urban, suburban and rural deployment scenarios. The simulation depicts NOMA scheme as superior to the OMA scheme in terms of key performance paramet including average energy efficiency, fairness factor, and average sum rate. This paper is organized as follows: In Section 2, the design of the considered sys is described. Section 3 presents the rate, fairness, and energy efficiency analysis of considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the paper. ble 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, the performance of NOMA has not b thoroughly evaluated in different multi-user 6G wireless communication deployment narios. Therefore, we have analyzed the performance of NOMA technology using the T channel in 6G urban, suburban and rural deployment scenarios. The users in the ur scenario are densely populated in a small space. The users in the rural area are spar distributed in a comparatively larger area. The users are semi-sparse in the suburban nario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, considering diffe powers of user devices, in a 6G system using the THz channel is missing in the literature.
In previous works [26] we have proposed an adaptive NOMA scheme by conside different power levels of relay equipment employing the radio frequency (RF) channel in scenario.
In this paper, we consider different power levels of user equipment and study performance comparison of the OMA and NOMA systems in terms of different key formance parameters, such as achievable rates, energy efficiency, and fairness, presen for 6G urban, suburban and rural deployment scenarios. The simulation depicts NOMA scheme as superior to the OMA scheme in terms of key performance paramet including average energy efficiency, fairness factor, and average sum rate. This paper is organized as follows: In Section 2, the design of the considered sys is described. Section 3 presents the rate, fairness, and energy efficiency analysis of considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the paper. ble 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, the performance of NOMA has not been thoroughly evaluated in different multi-user 6G wireless communication deployment scenarios. Therefore, we have analyzed the performance of NOMA technology using the THz channel in 6G urban, suburban and rural deployment scenarios. The users in the urban scenario are densely populated in a small space. The users in the rural area are sparsely distributed in a comparatively larger area. The users are semi-sparse in the suburban scenario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, considering different powers of user devices, in a 6G system using the THz channel is missing in the literature.
In previous works [26] we have proposed an adaptive NOMA scheme by considering different power levels of relay equipment employing the radio frequency (RF) channel in 5G scenario.
In this paper, we consider different power levels of user equipment and study the performance comparison of the OMA and NOMA systems in terms of different key performance parameters, such as achievable rates, energy efficiency, and fairness, presented for 6G urban, suburban and rural deployment scenarios. The simulation depicts the NOMA scheme as superior to the OMA scheme in terms of key performance parameters, including average energy efficiency, fairness factor, and average sum rate. This paper is organized as follows: In Section 2, the design of the considered system is described. Section 3 presents the rate, fairness, and energy efficiency analysis of the considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the paper. Table 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, the performance of NOMA has not been thoroughly evaluated in different multi-user 6G wireless communication deployment scenarios. Therefore, we have analyzed the performance of NOMA technology using the THz channel in 6G urban, suburban and rural deployment scenarios. The users in the urban scenario are densely populated in a small space. The users in the rural area are sparsely distributed in a comparatively larger area. The users are semi-sparse in the suburban scenario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, considering different powers of user devices, in a 6G system using the THz channel is missing in the literature.
In previous works [26] we have proposed an adaptive NOMA scheme by considering different power levels of relay equipment employing the radio frequency (RF) channel in 5G scenario.
In this paper, we consider different power levels of user equipment and study the performance comparison of the OMA and NOMA systems in terms of different key performance parameters, such as achievable rates, energy efficiency, and fairness, presented for 6G urban, suburban and rural deployment scenarios. The simulation depicts the NOMA scheme as superior to the OMA scheme in terms of key performance parameters, including average energy efficiency, fairness factor, and average sum rate. This paper is organized as follows: In Section 2, the design of the considered system is described. Section 3 presents the rate, fairness, and energy efficiency analysis of the considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the paper. Table 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, the performance of NOMA has not be thoroughly evaluated in different multi-user 6G wireless communication deployment sc narios. Therefore, we have analyzed the performance of NOMA technology using the TH channel in 6G urban, suburban and rural deployment scenarios. The users in the urb scenario are densely populated in a small space. The users in the rural area are sparse distributed in a comparatively larger area. The users are semi-sparse in the suburban sc nario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, considering differe powers of user devices, in a 6G system using the THz channel is missing in the literature.
In previous works [26] we have proposed an adaptive NOMA scheme by consideri different power levels of relay equipment employing the radio frequency (RF) channel in 5 scenario.
In this paper, we consider different power levels of user equipment and study t performance comparison of the OMA and NOMA systems in terms of different key p formance parameters, such as achievable rates, energy efficiency, and fairness, present for 6G urban, suburban and rural deployment scenarios. The simulation depicts t NOMA scheme as superior to the OMA scheme in terms of key performance paramete including average energy efficiency, fairness factor, and average sum rate. This paper is organized as follows: In Section 2, the design of the considered syste is described. Section 3 presents the rate, fairness, and energy efficiency analysis of t considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the paper. T ble 2 presents the numerous notations used in the paper.   The signal forwarded by c n ble 2 presents the numerous notations used in the paper.

System Design
Consider a downlink scenario employing cooperative NOMA in a cell system, with randomly scattered users, with one common BS. Figure 1 shows the scenario of the single-cell

System Design
Consider a downlink scenario employing cooperative NOMA in a cell system, with randomly scattered users, with one common BS. Figure 1 shows the scenario of the single-cell  The system has relays and cell-edge users. The set of relays is denoted as Ƈ = { , , . . . , }, and the cell-edge users set is represented as Ğ = { , , … , }. It is pre sumed that each user equipment (UE) has a different battery level modeling for the prac tical scenario. The battery of the relay, , where ∈ Ƈ, is denoted as Ƥ .). A Ray leigh fading scenario is considered where the BS superimposed the signals of the cell edge user or sends it to . In the cooperative NOMA system, the BS and the relay are assumed to have achieved absolute channel state information (CSI At a time, forward the signal to maximum cell-edge users, and its set is denoted by Ğ = { , , … , } such that Ğ ⊂ Ğ and Ğ " .
The signal transmitted by the BS for cell-edge users to is given as:

System Design
Consider a downlink scenario employing cooperative NOMA in a cell system, with N randomly scattered users, with one common BS. Figure 1 shows the scenario of the single-cell.

System Design
Consider a downlink scenario employing cooperative NOMA in a cell system, with randomly scattered users, with one common BS. Figure 1 shows the scenario of the single-cell.  The system has relays and cell-edge users. The set of relays is denoted as Ƈ = { , , . . . , }, and the cell-edge users set is represented as Ğ = { , , … , }. It is presumed that each user equipment (UE) has a different battery level modeling for the practical scenario. The battery of the relay, , where ∈ Ƈ, is denoted as Ƥ .). A Rayleigh fading scenario is considered where the BS superimposed the signals of the celledge user or sends it to . In the cooperative NOMA system, the BS and the relay are assumed to have achieved absolute channel state information (CSI At a time, forwards the signal to maximum cell-edge users, and its set is denoted by Ğ = { , , … , }, such that Ğ ⊂ Ğ and Ğ " .
The signal transmitted by the BS for cell-edge users to is given as: where ѵ denotes the modulated symbol for the cell-edge user. Here, ƥ denotes the signal allocated power to the respective cell-edge user, such that ∑ ƥ ≤ ƥ ,

Contributions
Conforming to the survey of the literature, the performance of NOMA has not be thoroughly evaluated in different multi-user 6G wireless communication deployment sc narios. Therefore, we have analyzed the performance of NOMA technology using the TH channel in 6G urban, suburban and rural deployment scenarios. The users in the urb scenario are densely populated in a small space. The users in the rural area are sparse distributed in a comparatively larger area. The users are semi-sparse in the suburban sc nario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, considering differe powers of user devices, in a 6G system using the THz channel is missing in the literature.
In previous works [26] we have proposed an adaptive NOMA scheme by consideri different power levels of relay equipment employing the radio frequency (RF) channel in scenario.
In this paper, we consider different power levels of user equipment and study t performance comparison of the OMA and NOMA systems in terms of different key p formance parameters, such as achievable rates, energy efficiency, and fairness, present for 6G urban, suburban and rural deployment scenarios. The simulation depicts t NOMA scheme as superior to the OMA scheme in terms of key performance paramete including average energy efficiency, fairness factor, and average sum rate. This paper is organized as follows: In Section 2, the design of the considered syste is described. Section 3 presents the rate, fairness, and energy efficiency analysis of t considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the paper. T ble 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey o thoroughly evaluated in differen narios. Therefore, we have analy channel in 6G urban, suburban scenario are densely populated distributed in a comparatively la nario in a comparatively modera Further, the performance ch powers of user devices, in a 6G sy In previous works [26] we h different power levels of relay equ scenario.
In this paper, we consider performance comparison of the formance parameters, such as ac for 6G urban, suburban and ru NOMA scheme as superior to th including average energy efficie This paper is organized as f is described. Section 3 presents considered system. The conclud Section 4 demonstrates the ble 2 presents the numerous not

Contributions
Conforming thoroughly evalu narios. Therefore channel in 6G ur scenario are dens distributed in a co nario in a compar Further, the powers of user de In previous w different power le scenario.
In this pape performance com formance parame for 6G urban, su NOMA scheme a including averag This paper is is described. Sect considered system Section 4 dem ble 2 presents the Table 2. Notations.

Notation
Descri A Rayleigh fading scenario is considered where the BS superimposed the signals of the M cell-edge user or sends it to c n . In the cooperative NOMA system, the BS and the relay are assumed to have achieved absolute channel state information (CSI At a time, c n forwards the signal to maximum M cell-edge users, and its set is denoted byG M = {g 1 , g 2 , . . . , g M }, such thatG M ⊂G andG M "E). The signal transmitted by the BS for M cell-edge users to c n is given as:     Sum rate of ce max , where the maximum transmission power of the BS for c n is denoted by considered system. The concluded Section 4 demonstrates the re ble 2 presents the numerous notati Sum rate of cell-edge use max , and the power allocation coefficient is denoted by a m , which is defined in set = { , , . . . , }, and the cell-edge users set is represented as Ğ = { , , … , }. It is presumed that each user equipment (UE) has a different battery level modeling for the practical scenario. The battery of the relay, , where ∈ Ƈ, is denoted as Ƥ .). A Rayleigh fading scenario is considered where the BS superimposed the signals of the celledge user or sends it to . In the cooperative NOMA system, the BS and the relay are assumed to have achieved absolute channel state information (CSI At a time, forwards the signal to maximum cell-edge users, and its set is denoted by Ğ = { , , … , }, such that Ğ ⊂ Ğ and Ğ " .
The signal transmitted by the BS for cell-edge users to is given as: where ѵ denotes the modulated symbol for the cell-edge user. Here, ƥ denotes the signal allocated power to the respective cell-edge user, such that ∑ ƥ ≤ ƥ , where the maximum transmission power of the BS for is denoted by ƥ , and the power allocation coefficient is denoted by , which is defined in set Ά = { , , … , }. The signal received at is given as: i.e., Here, the channel between BS and is signified by ℎ , . The ~ (0, ) represents the complex additive white Gaussian noise (AWGN) vector with mean zero and variance in the BS-relay link. The |ℎ , | represents the gain of the THz channel [27] between , and BS is represented as: where L is the path loss of the THz signal. Ɵ and €() respectively are antenna gain and array steering vector. From [27] The signal received at c n is given as: Section 4 demonstrates the results of simulations. Section 5 co ble 2 presents the numerous notations used in the paper.
i.e., This paper is organized as follows: In Section 2, the design of the con is described. Section 3 presents the rate, fairness, and energy efficiency considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 conclude ble 2 presents the numerous notations used in the paper.
a m performance comparison of the OMA and NOMA sy formance parameters, such as achievable rates, energ for 6G urban, suburban and rural deployment sce NOMA scheme as superior to the OMA scheme in te including average energy efficiency, fairness factor, a This paper is organized as follows: In Section 2, is described. Section 3 presents the rate, fairness, an considered system. The concluded results are finally Section 4 demonstrates the results of simulation ble 2 presents the numerous notations used in the pa including average energy efficiency, fairness factor This paper is organized as follows: In Section 2 is described. Section 3 presents the rate, fairness, considered system. The concluded results are finall Section 4 demonstrates the results of simulatio ble 2 presents the numerous notations used in the p Here, the channel between BS and c n is signified by h b,n . The n n~C N (0, σ 2 ) represents the complex additive white Gaussian noise (AWGN) vector with mean zero and variance σ 2 in the BS-relay link. The h b,n 2 represents the gain of the THz channel [27] between c n , and BS is represented as: where L is the path loss of the THz signal. θ and €(ω) respectively are antenna gain and array steering vector. From [27] After receiving the signal from BS, c n forwards the superimposed signal to M cell-edge users, and it is given as: different power levels of relay equipment employing the radio frequenc scenario.
In this paper, we consider different power levels of user equip performance comparison of the OMA and NOMA systems in terms o formance parameters, such as achievable rates, energy efficiency, and for 6G urban, suburban and rural deployment scenarios. The sim NOMA scheme as superior to the OMA scheme in terms of key perfo including average energy efficiency, fairness factor, and average sum This paper is organized as follows: In Section 2, the design of the is described. Section 3 presents the rate, fairness, and energy efficie considered system. The concluded results are finally shown in Section Section 4 demonstrates the results of simulations. Section 5 conc ble 2 presents the numerous notations used in the paper. √ w m channel in 6G urban, suburban and rural deploym scenario are densely populated in a small space. T distributed in a comparatively larger area. The use nario in a comparatively moderate area. Further, the performance characterization of O powers of user devices, in a 6G system using the TH In previous works [26] we have proposed an a different power levels of relay equipment employin scenario.
In this paper, we consider different power le performance comparison of the OMA and NOMA formance parameters, such as achievable rates, en for 6G urban, suburban and rural deployment NOMA scheme as superior to the OMA scheme in including average energy efficiency, fairness facto This paper is organized as follows: In Section is described. Section 3 presents the rate, fairness considered system. The concluded results are fina Section 4 demonstrates the results of simulati ble 2 presents the numerous notations used in the Sum rate of cell-edge users, for the signal tra n distributed in a comparatively larger area. The use nario in a comparatively moderate area. Further, the performance characterization of O powers of user devices, in a 6G system using the TH In previous works [26] we have proposed an different power levels of relay equipment employin scenario.
In this paper, we consider different power l performance comparison of the OMA and NOMA formance parameters, such as achievable rates, en for 6G urban, suburban and rural deployment NOMA scheme as superior to the OMA scheme in including average energy efficiency, fairness facto This paper is organized as follows: In Section is described. Section 3 presents the rate, fairness considered system. The concluded results are fina Section 4 demonstrates the results of simulat ble 2 presents the numerous notations used in the Here, the respective cell-edge user is allocated a power coefficient depicted as w m narios. Theref channel in 6G scenario are d distributed in nario in a com Further, t powers of user In previo different powe scenario.
In this pa performance c formance para for 6G urban NOMA schem including ave This pap is described. considered sy Section 4 ble 2 presents Table 2. Notati thoroughly evaluated in different multi-user 6G wireless communication de narios. Therefore, we have analyzed the performance of NOMA technology channel in 6G urban, suburban and rural deployment scenarios. The users scenario are densely populated in a small space. The users in the rural are distributed in a comparatively larger area. The users are semi-sparse in the nario in a comparatively moderate area. Further, the performance characterization of OMA and NOMA, consid powers of user devices, in a 6G system using the THz channel is missing in the In previous works [26] we have proposed an adaptive NOMA scheme b different power levels of relay equipment employing the radio frequency (RF) scenario.
In this paper, we consider different power levels of user equipment a performance comparison of the OMA and NOMA systems in terms of diff formance parameters, such as achievable rates, energy efficiency, and fairn for 6G urban, suburban and rural deployment scenarios. The simulatio NOMA scheme as superior to the OMA scheme in terms of key performanc including average energy efficiency, fairness factor, and average sum rate.
This paper is organized as follows: In Section 2, the design of the cons is described. Section 3 presents the rate, fairness, and energy efficiency a considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes ble 2 presents the numerous notations used in the paper. thoroughly evaluated in different multi-user 6G wireless communicati narios. Therefore, we have analyzed the performance of NOMA techno channel in 6G urban, suburban and rural deployment scenarios. The scenario are densely populated in a small space. The users in the rur distributed in a comparatively larger area. The users are semi-sparse i nario in a comparatively moderate area. Further, the performance characterization of OMA and NOMA, c powers of user devices, in a 6G system using the THz channel is missing In previous works [26] we have proposed an adaptive NOMA sch different power levels of relay equipment employing the radio frequenc scenario.
In this paper, we consider different power levels of user equipm performance comparison of the OMA and NOMA systems in terms o formance parameters, such as achievable rates, energy efficiency, and for 6G urban, suburban and rural deployment scenarios. The sim NOMA scheme as superior to the OMA scheme in terms of key perfo including average energy efficiency, fairness factor, and average sum This paper is organized as follows: In Section 2, the design of the is described. Section 3 presents the rate, fairness, and energy efficie considered system. The concluded results are finally shown in Section Section 4 demonstrates the results of simulations. Section 5 conc ble 2 presents the numerous notations used in the paper. . The maximum power of c n is denoted as thoroughly evalua narios. Therefore, w channel in 6G urb scenario are dense distributed in a co nario in a compara Further, the p powers of user dev In previous w different power lev scenario.
In this paper, performance comp formance paramet for 6G urban, sub NOMA scheme as including average This paper is is described. Secti considered system Section 4 dem ble 2 presents the n n(max) . The power allocation coefficient, allotted by c n for M cell-edge users is defined in set w = {w 1 , w 2, . . . , w M }.
The signal received at m th -edge user is given as: scenario are densely populated in a small space. The users in the r distributed in a comparatively larger area. The users are semi-spars nario in a comparatively moderate area. Further, the performance characterization of OMA and NOMA powers of user devices, in a 6G system using the THz channel is missin In previous works [26] we have proposed an adaptive NOMA s different power levels of relay equipment employing the radio freque scenario.
In this paper, we consider different power levels of user equi performance comparison of the OMA and NOMA systems in term formance parameters, such as achievable rates, energy efficiency, an for 6G urban, suburban and rural deployment scenarios. The si NOMA scheme as superior to the OMA scheme in terms of key per including average energy efficiency, fairness factor, and average su This paper is organized as follows: In Section 2, the design of t is described. Section 3 presents the rate, fairness, and energy effi considered system. The concluded results are finally shown in Secti Section 4 demonstrates the results of simulations. Section 5 con ble 2 presents the numerous notations used in the paper. channel in 6G urban, suburban and rural deployment sc scenario are densely populated in a small space. The use distributed in a comparatively larger area. The users are s nario in a comparatively moderate area. Further, the performance characterization of OMA an powers of user devices, in a 6G system using the THz chann In previous works [26] we have proposed an adaptiv different power levels of relay equipment employing the ra scenario.
In this paper, we consider different power levels of performance comparison of the OMA and NOMA system formance parameters, such as achievable rates, energy ef for 6G urban, suburban and rural deployment scenari NOMA scheme as superior to the OMA scheme in terms including average energy efficiency, fairness factor, and a This paper is organized as follows: In Section 2, the is described. Section 3 presents the rate, fairness, and e considered system. The concluded results are finally show Section 4 demonstrates the results of simulations. Se ble 2 presents the numerous notations used in the paper.
i.e., thoroughly evaluated in different multi-user 6G wireless communication de narios. Therefore, we have analyzed the performance of NOMA technology channel in 6G urban, suburban and rural deployment scenarios. The user scenario are densely populated in a small space. The users in the rural are distributed in a comparatively larger area. The users are semi-sparse in the nario in a comparatively moderate area. Further, the performance characterization of OMA and NOMA, consid powers of user devices, in a 6G system using the THz channel is missing in the In previous works [26] we have proposed an adaptive NOMA scheme different power levels of relay equipment employing the radio frequency (RF) scenario.
In this paper, we consider different power levels of user equipment performance comparison of the OMA and NOMA systems in terms of diff formance parameters, such as achievable rates, energy efficiency, and fairn for 6G urban, suburban and rural deployment scenarios. The simulatio NOMA scheme as superior to the OMA scheme in terms of key performan including average energy efficiency, fairness factor, and average sum rate.
This paper is organized as follows: In Section 2, the design of the cons is described. Section 3 presents the rate, fairness, and energy efficiency a considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes ble 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, th thoroughly evaluated in different multi-user 6G w narios. Therefore, we have analyzed the performan channel in 6G urban, suburban and rural deploym scenario are densely populated in a small space. T distributed in a comparatively larger area. The use nario in a comparatively moderate area.
Further, the performance characterization of O powers of user devices, in a 6G system using the TH In previous works [26] we have proposed an a different power levels of relay equipment employin scenario.
In this paper, we consider different power le performance comparison of the OMA and NOMA formance parameters, such as achievable rates, en for 6G urban, suburban and rural deployment NOMA scheme as superior to the OMA scheme in including average energy efficiency, fairness facto This paper is organized as follows: In Section is described. Section 3 presents the rate, fairness considered system. The concluded results are fina Section 4 demonstrates the results of simulati ble 2 presents the numerous notations used in the

Contributions
Conforming to the survey of the literature, th thoroughly evaluated in different multi-user 6G w narios. Therefore, we have analyzed the performan channel in 6G urban, suburban and rural deploy scenario are densely populated in a small space. distributed in a comparatively larger area. The us nario in a comparatively moderate area.
Further, the performance characterization of O powers of user devices, in a 6G system using the TH In previous works [26] we have proposed an different power levels of relay equipment employin scenario.
In this paper, we consider different power l performance comparison of the OMA and NOMA formance parameters, such as achievable rates, en for 6G urban, suburban and rural deployment NOMA scheme as superior to the OMA scheme in including average energy efficiency, fairness facto This paper is organized as follows: In Section is described. Section 3 presents the rate, fairness considered system. The concluded results are fina Section 4 demonstrates the results of simulat ble 2 presents the numerous notations used in the where the channel and AWGN are represented by h m,k and n m~C N (0, σ m 2 )), AWGN with zero mean and variance σ m 2 , respectively, in the link between c n and g m . The channel gain between c n and g m is denoted as |h n,m | 2 ; the g m users can decode the message by employing SIC. Therefore, the signal-to-interference noise-ratio (SINR) at g m , in a coordinated relay transmission, is given as:

Contributions
Conforming to the survey of the literature, the p thoroughly evaluated in different multi-user 6G wire narios. Therefore, we have analyzed the performance channel in 6G urban, suburban and rural deployme scenario are densely populated in a small space. The distributed in a comparatively larger area. The users nario in a comparatively moderate area.
Further, the performance characterization of OM powers of user devices, in a 6G system using the THz c In previous works [26] we have proposed an ada different power levels of relay equipment employing th scenario.
In this paper, we consider different power leve performance comparison of the OMA and NOMA sy formance parameters, such as achievable rates, energ for 6G urban, suburban and rural deployment sce NOMA scheme as superior to the OMA scheme in te including average energy efficiency, fairness factor, a This paper is organized as follows: In Section 2, is described. Section 3 presents the rate, fairness, a considered system. The concluded results are finally Section 4 demonstrates the results of simulation ble 2 presents the numerous notations used in the pa

Contributions
Conforming to the survey of the literature, thoroughly evaluated in different multi-user 6G narios. Therefore, we have analyzed the perform channel in 6G urban, suburban and rural deplo scenario are densely populated in a small space distributed in a comparatively larger area. The u nario in a comparatively moderate area.
Further, the performance characterization o powers of user devices, in a 6G system using the T In previous works [26] we have proposed a different power levels of relay equipment employ scenario.
In this paper, we consider different power performance comparison of the OMA and NOM formance parameters, such as achievable rates, for 6G urban, suburban and rural deploymen NOMA scheme as superior to the OMA scheme including average energy efficiency, fairness fac This paper is organized as follows: In Secti is described. Section 3 presents the rate, fairne considered system. The concluded results are fin Section 4 demonstrates the results of simul ble 2 presents the numerous notations used in th

Contributions
Conforming to the survey of the literature, th thoroughly evaluated in different multi-user 6G w narios. Therefore, we have analyzed the performan channel in 6G urban, suburban and rural deploy scenario are densely populated in a small space. T distributed in a comparatively larger area. The use nario in a comparatively moderate area.
Further, the performance characterization of O powers of user devices, in a 6G system using the TH In previous works [26] we have proposed an a different power levels of relay equipment employin scenario.
In this paper, we consider different power le performance comparison of the OMA and NOMA formance parameters, such as achievable rates, en for 6G urban, suburban and rural deployment NOMA scheme as superior to the OMA scheme in including average energy efficiency, fairness facto This paper is organized as follows: In Section is described. Section 3 presents the rate, fairness considered system. The concluded results are fina Section 4 demonstrates the results of simulati ble 2 presents the numerous notations used in the

Contributions
Conforming to the survey of the literature, the performance thoroughly evaluated in different multi-user 6G wireless commun narios. Therefore, we have analyzed the performance of NOMA te channel in 6G urban, suburban and rural deployment scenarios. scenario are densely populated in a small space. The users in the distributed in a comparatively larger area. The users are semi-spa nario in a comparatively moderate area.
Further, the performance characterization of OMA and NOM powers of user devices, in a 6G system using the THz channel is mis In previous works [26] we have proposed an adaptive NOMA different power levels of relay equipment employing the radio frequ scenario.
In this paper, we consider different power levels of user eq performance comparison of the OMA and NOMA systems in ter formance parameters, such as achievable rates, energy efficiency, for 6G urban, suburban and rural deployment scenarios. The NOMA scheme as superior to the OMA scheme in terms of key p including average energy efficiency, fairness factor, and average s This paper is organized as follows: In Section 2, the design o is described. Section 3 presents the rate, fairness, and energy ef considered system. The concluded results are finally shown in Sec Section 4 demonstrates the results of simulations. Section 5 c ble 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, the p thoroughly evaluated in different multi-user 6G wirele narios. Therefore, we have analyzed the performance o channel in 6G urban, suburban and rural deploymen scenario are densely populated in a small space. The distributed in a comparatively larger area. The users a nario in a comparatively moderate area.
Further, the performance characterization of OMA powers of user devices, in a 6G system using the THz ch In previous works [26] we have proposed an adap different power levels of relay equipment employing th scenario.
In this paper, we consider different power level performance comparison of the OMA and NOMA sy formance parameters, such as achievable rates, energy for 6G urban, suburban and rural deployment scen NOMA scheme as superior to the OMA scheme in ter including average energy efficiency, fairness factor, an This paper is organized as follows: In Section 2, t is described. Section 3 presents the rate, fairness, an considered system. The concluded results are finally s Section 4 demonstrates the results of simulations ble 2 presents the numerous notations used in the pap

Contributions
Conforming to the survey of the litera thoroughly evaluated in different multi-use narios. Therefore, we have analyzed the pe channel in 6G urban, suburban and rural scenario are densely populated in a small distributed in a comparatively larger area. nario in a comparatively moderate area.
Further, the performance characterizat powers of user devices, in a 6G system using In previous works [26] we have propo different power levels of relay equipment em scenario.
In this paper, we consider different p performance comparison of the OMA and formance parameters, such as achievable r for 6G urban, suburban and rural deplo NOMA scheme as superior to the OMA sc including average energy efficiency, fairne This paper is organized as follows: In is described. Section 3 presents the rate, f considered system. The concluded results Section 4 demonstrates the results of s ble 2 presents the numerous notations used Here, due to the superimposed signal of the users with weak channel gains, the inter-NOMA interference is represented as I 1 n,m . If c k is transmitting the signal to g m , in the same time slot as c n , then I 2 n,m is the interference encountered by g m due to the signals with higher product factors of the channel gain and the relay power, than its own. Therefore, g m encounters interference from c k if is described. Section 3 pr considered system. The co Section 4 demonstrat ble 2 presents the numero

System Analysis
The computation of signal-to-interference noise-ratio (SINR) at g m is described in Equation (8); the computation sum rate and fairness factor are described in this section. After that, energy efficiency has also been elaborated, and the problem of energy efficiency is formulated.

Sum Rate
The achievable data rate [27] at the receiver of g m is defined based on SINR as: R n,m = log 2 (1 + SI NR n,m ) bps/Hz.
Based on the data rate, the sum rate for M cell-edge users is computed as:

Fairness Factor
In a multi-user scenario, where multiple cell-edge users demand resources in the same relay, in such a case, the resources are allocated to the user's good channel gains. Therefore, cell-edge users with poor channel gains cannot achieve desirable data rates. Hence, the QoS of the system gets degraded. The fairness factor is an important parameter in determining whether the resources are allocated efficiently to all the users. Unlike OMA, NOMA ensures fairness amongst the users with its power allocation strategies. The fairness factor [28] for N cell-edge users described by Jains' Fairness, is given as:

System Design
Consider a downlink scenario employing cooperative NOMA in a c randomly scattered users, with one common BS. Figure 1 shows the scena  where ∈ Ƈ, is denot leigh fading scenario is considered where the BS superimposed the sig edge user or sends it to . In the cooperative NOMA system, the B assumed to have achieved absolute channel state information (CSI At a the signal to maximum cell-edge users, and its set is denoted by Ğ such that Ğ ⊂ Ğ and Ğ " .
The signal transmitted by the BS for cell-edge users to is g The

System Design
Consider a downlink scenario employing cooperative NOMA in a cell system, with randomly scattered users, with one common BS. Figure 1 shows the scenario of the single-cell. It is presumed that each user equipment (UE) has a different battery level modeling for the practical scenario. The battery of the relay, , where ∈ Ƈ, is denoted as Ƥ .). A Rayleigh fading scenario is considered where the BS superimposed the signals of the celledge user or sends it to . In the cooperative NOMA system, the BS and the relay are assumed to have achieved absolute channel state information (CSI At a time, forwards N ∈ 1 N , 1 , where 1 N denotes the least fairness, and 1 denotes the maximum fairness. The high fairness factor implies that the users receive identical services, which is a crucial requirement for good QoS in communication networks.

Energy Efficiency
Energy efficiency optimization is an important goal of the 5G communication system. The calculation of the energy efficiency of the cooperative NOMA [26,27] system is given in terms of data rate and the total power consumption for achieving the data rate. The energy efficiency achieved after the signal is received at g m and is given as: 22,3986 Power consumption of for signal transmission BS power consumption for sending a signal to Ȅ Energy Efficiency of Ƒ Fairness factor of cell-edge users

System Design
Consider a downlink scenario employing cooper randomly scattered users, with one common BS. Figur where, P n,m = w m

Contributions
Conforming to the survey of the literature, the performance of NOMA has n thoroughly evaluated in different multi-user 6G wireless communication deploym narios. Therefore, we have analyzed the performance of NOMA technology using channel in 6G urban, suburban and rural deployment scenarios. The users in th scenario are densely populated in a small space. The users in the rural area are distributed in a comparatively larger area. The users are semi-sparse in the subur nario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, considering powers of user devices, in a 6G system using the THz channel is missing in the litera In previous works [26] we have proposed an adaptive NOMA scheme by con different power levels of relay equipment employing the radio frequency (RF) chann scenario.
In this paper, we consider different power levels of user equipment and st performance comparison of the OMA and NOMA systems in terms of different formance parameters, such as achievable rates, energy efficiency, and fairness, pr for 6G urban, suburban and rural deployment scenarios. The simulation dep NOMA scheme as superior to the OMA scheme in terms of key performance para including average energy efficiency, fairness factor, and average sum rate. This paper is organized as follows: In Section 2, the design of the considered is described. Section 3 presents the rate, fairness, and energy efficiency analysi considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the pa ble 2 presents the numerous notations used in the paper. Sum rate of cell-edge users, for the signal transmitted by n , denotes the power utilization of c n , for sending the message to g m . The interference of the signal for g m at the relay will be due to the superimposed signals. The achieved system's energy efficiency after M cell-edge users receives the signal is given as

Performance Analysis
The simulations are carried out to evaluate the performance of OMA and NOMA schemes in a multi-user scenario. The system is analyzed in three deployment scenarios, which are urban, suburban, and rural scenarios. The NOMA system deployed in the urban, suburban, and rural scenarios is labeled as U-NOMA, S-NOMA, and R-NOMA, respectively. The OMA system deployed in urban, suburban, and rural scenarios is labeled as U-OMA, S-OMA, and R-OMA. The numerical parameters used for implementing the scenario are depicted in Table 3. nario in a comparatively moderate area. Further, the performance characterization of OMA and NOMA, considering powers of user devices, in a 6G system using the THz channel is missing in the liter In previous works [26] we have proposed an adaptive NOMA scheme by co different power levels of relay equipment employing the radio frequency (RF) cha scenario.
In this paper, we consider different power levels of user equipment and performance comparison of the OMA and NOMA systems in terms of differen formance parameters, such as achievable rates, energy efficiency, and fairness, for 6G urban, suburban and rural deployment scenarios. The simulation d NOMA scheme as superior to the OMA scheme in terms of key performance pa including average energy efficiency, fairness factor, and average sum rate.
This paper is organized as follows: In Section 2, the design of the consider is described. Section 3 presents the rate, fairness, and energy efficiency analy considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the p ble 2 presents the numerous notations used in the paper.

dBm
Distance between BS and relay in an urban scenario 300 to 400 m

Contributions
Conforming to the survey of the literature, the performance of NOMA has thoroughly evaluated in different multi-user 6G wireless communication deploy narios. Therefore, we have analyzed the performance of NOMA technology usin channel in 6G urban, suburban and rural deployment scenarios. The users in scenario are densely populated in a small space. The users in the rural area ar distributed in a comparatively larger area. The users are semi-sparse in the subu nario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, considering powers of user devices, in a 6G system using the THz channel is missing in the liter In previous works [26] we have proposed an adaptive NOMA scheme by co different power levels of relay equipment employing the radio frequency (RF) cha scenario.
In this paper, we consider different power levels of user equipment and performance comparison of the OMA and NOMA systems in terms of differen formance parameters, such as achievable rates, energy efficiency, and fairness, for 6G urban, suburban and rural deployment scenarios. The simulation d NOMA scheme as superior to the OMA scheme in terms of key performance pa including average energy efficiency, fairness factor, and average sum rate.
This paper is organized as follows: In Section 2, the design of the considere is described. Section 3 presents the rate, fairness, and energy efficiency analy considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the p ble 2 presents the numerous notations used in the paper. −40 to 10 dBm Path loss of THz, L 20 log 10 4π λ c + 10z( f )d log 10 e dB [25] The numerical results compare the two schemes in terms of average sum rate, average fairness factor, and average energy efficiency. A single-cell, BS-centered system is considered in three deployment scenarios; urban, suburban, and rural. The Z users in the considered system are taken from 150 to 450. All the users are randomly distributed in the cell, generating a variable count of both edge-users and relays. At maximum, respective relays simultaneously transmit the signal to M cell-edge users.
The data rate achieved at g m in the NOMA system is given as log 2 (1 + w m

Contributions
Conforming to the survey of the literature, the performance of NO thoroughly evaluated in different multi-user 6G wireless communication narios. Therefore, we have analyzed the performance of NOMA technolo channel in 6G urban, suburban and rural deployment scenarios. The u scenario are densely populated in a small space. The users in the rural distributed in a comparatively larger area. The users are semi-sparse in nario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, con powers of user devices, in a 6G system using the THz channel is missing in In previous works [26] we have proposed an adaptive NOMA schem different power levels of relay equipment employing the radio frequency ( scenario.
In this paper, we consider different power levels of user equipme performance comparison of the OMA and NOMA systems in terms of formance parameters, such as achievable rates, energy efficiency, and fa for 6G urban, suburban and rural deployment scenarios. The simul NOMA scheme as superior to the OMA scheme in terms of key perform including average energy efficiency, fairness factor, and average sum ra This paper is organized as follows: In Section 2, the design of the c is described. Section 3 presents the rate, fairness, and energy efficienc considered system. The concluded results are finally shown in Section 4 Section 4 demonstrates the results of simulations. Section 5 conclud ble 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, the performance of NOMA has not b thoroughly evaluated in different multi-user 6G wireless communication deployment narios. Therefore, we have analyzed the performance of NOMA technology using the channel in 6G urban, suburban and rural deployment scenarios. The users in the ur scenario are densely populated in a small space. The users in the rural area are spar distributed in a comparatively larger area. The users are semi-sparse in the suburban nario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, considering diffe powers of user devices, in a 6G system using the THz channel is missing in the literature In previous works [26] we have proposed an adaptive NOMA scheme by conside different power levels of relay equipment employing the radio frequency (RF) channel in scenario.
In this paper, we consider different power levels of user equipment and study performance comparison of the OMA and NOMA systems in terms of different key formance parameters, such as achievable rates, energy efficiency, and fairness, prese for 6G urban, suburban and rural deployment scenarios. The simulation depicts NOMA scheme as superior to the OMA scheme in terms of key performance parame including average energy efficiency, fairness factor, and average sum rate.
This paper is organized as follows: In Section 2, the design of the considered sys is described. Section 3 presents the rate, fairness, and energy efficiency analysis of considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 concludes the paper ble 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, the performanc thoroughly evaluated in different multi-user 6G wireless commu narios. Therefore, we have analyzed the performance of NOMA channel in 6G urban, suburban and rural deployment scenario scenario are densely populated in a small space. The users in t distributed in a comparatively larger area. The users are semi-sp nario in a comparatively moderate area.
Further, the performance characterization of OMA and NO powers of user devices, in a 6G system using the THz channel is m In previous works [26] we have proposed an adaptive NOM different power levels of relay equipment employing the radio fre scenario.
In this paper, we consider different power levels of user e performance comparison of the OMA and NOMA systems in te formance parameters, such as achievable rates, energy efficienc for 6G urban, suburban and rural deployment scenarios. Th NOMA scheme as superior to the OMA scheme in terms of key including average energy efficiency, fairness factor, and average This paper is organized as follows: In Section 2, the design is described. Section 3 presents the rate, fairness, and energy considered system. The concluded results are finally shown in S Section 4 demonstrates the results of simulations. Section 5 ble 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, the performance of NOM thoroughly evaluated in different multi-user 6G wireless communication narios. Therefore, we have analyzed the performance of NOMA technolog channel in 6G urban, suburban and rural deployment scenarios. The us scenario are densely populated in a small space. The users in the rural a distributed in a comparatively larger area. The users are semi-sparse in th nario in a comparatively moderate area.
Further, the performance characterization of OMA and NOMA, cons powers of user devices, in a 6G system using the THz channel is missing in t In previous works [26] we have proposed an adaptive NOMA schem different power levels of relay equipment employing the radio frequency (R scenario.
In this paper, we consider different power levels of user equipmen performance comparison of the OMA and NOMA systems in terms of d formance parameters, such as achievable rates, energy efficiency, and fai for 6G urban, suburban and rural deployment scenarios. The simula NOMA scheme as superior to the OMA scheme in terms of key performa including average energy efficiency, fairness factor, and average sum rat This paper is organized as follows: In Section 2, the design of the co is described. Section 3 presents the rate, fairness, and energy efficiency considered system. The concluded results are finally shown in Section 4. Section 4 demonstrates the results of simulations. Section 5 conclud ble 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, the performa thoroughly evaluated in different multi-user 6G wireless com narios. Therefore, we have analyzed the performance of NOM channel in 6G urban, suburban and rural deployment scena scenario are densely populated in a small space. The users i distributed in a comparatively larger area. The users are sem nario in a comparatively moderate area.
Further, the performance characterization of OMA and N powers of user devices, in a 6G system using the THz channel is In previous works [26] we have proposed an adaptive NO different power levels of relay equipment employing the radio scenario.
In this paper, we consider different power levels of use performance comparison of the OMA and NOMA systems i formance parameters, such as achievable rates, energy efficie for 6G urban, suburban and rural deployment scenarios. NOMA scheme as superior to the OMA scheme in terms of k including average energy efficiency, fairness factor, and aver This paper is organized as follows: In Section 2, the desi is described. Section 3 presents the rate, fairness, and energ considered system. The concluded results are finally shown i Section 4 demonstrates the results of simulations. Sectio ble 2 presents the numerous notations used in the paper.

Contributions
Conforming to the survey of the literature, th thoroughly evaluated in different multi-user 6G w narios. Therefore, we have analyzed the performan channel in 6G urban, suburban and rural deploy scenario are densely populated in a small space. distributed in a comparatively larger area. The use nario in a comparatively moderate area.
Further, the performance characterization of O powers of user devices, in a 6G system using the TH In previous works [26] we have proposed an different power levels of relay equipment employin scenario.
In this paper, we consider different power l performance comparison of the OMA and NOMA formance parameters, such as achievable rates, en for 6G urban, suburban and rural deployment NOMA scheme as superior to the OMA scheme in including average energy efficiency, fairness facto This paper is organized as follows: In Section is described. Section 3 presents the rate, fairness considered system. The concluded results are fina Section 4 demonstrates the results of simulat ble 2 presents the numerous notations used in the

Contributions
Conforming to the survey of the liter thoroughly evaluated in different multi-us narios. Therefore, we have analyzed the pe channel in 6G urban, suburban and rural scenario are densely populated in a small distributed in a comparatively larger area nario in a comparatively moderate area.
Further, the performance characteriza powers of user devices, in a 6G system usin In previous works [26] we have propo different power levels of relay equipment e scenario.
In this paper, we consider different performance comparison of the OMA and formance parameters, such as achievable for 6G urban, suburban and rural deplo NOMA scheme as superior to the OMA sc including average energy efficiency, fairn This paper is organized as follows: In is described. Section 3 presents the rate, considered system. The concluded results Section 4 demonstrates the results of ble 2 presents the numerous notations use

Contributions
Conforming to the survey of the literature, the per thoroughly evaluated in different multi-user 6G wireles narios. Therefore, we have analyzed the performance of channel in 6G urban, suburban and rural deployment scenario are densely populated in a small space. The u distributed in a comparatively larger area. The users ar nario in a comparatively moderate area.
Further, the performance characterization of OMA powers of user devices, in a 6G system using the THz cha In previous works [26] we have proposed an adapt different power levels of relay equipment employing the scenario.
In this paper, we consider different power levels performance comparison of the OMA and NOMA syst formance parameters, such as achievable rates, energy for 6G urban, suburban and rural deployment scena NOMA scheme as superior to the OMA scheme in term including average energy efficiency, fairness factor, and This paper is organized as follows: In Section 2, th is described. Section 3 presents the rate, fairness, and considered system. The concluded results are finally sh Section 4 demonstrates the results of simulations. ble 2 presents the numerous notations used in the pape

Contributions
Conforming to the survey of the literature thoroughly evaluated in different multi-user 6G narios. Therefore, we have analyzed the perform channel in 6G urban, suburban and rural depl scenario are densely populated in a small spac distributed in a comparatively larger area. The nario in a comparatively moderate area.
Further, the performance characterization o powers of user devices, in a 6G system using the T In previous works [26] we have proposed a different power levels of relay equipment employ scenario.
In this paper, we consider different powe performance comparison of the OMA and NOM formance parameters, such as achievable rates, for 6G urban, suburban and rural deployme NOMA scheme as superior to the OMA scheme including average energy efficiency, fairness fa This paper is organized as follows: In Secti is described. Section 3 presents the rate, fairne considered system. The concluded results are fi Section 4 demonstrates the results of simu ble 2 presents the numerous notations used in t

Contributions
Conforming to the survey of the lite thoroughly evaluated in different multi-u narios. Therefore, we have analyzed the p channel in 6G urban, suburban and rura scenario are densely populated in a sma distributed in a comparatively larger are nario in a comparatively moderate area.
Further, the performance characteriz powers of user devices, in a 6G system usi In previous works [26] we have prop different power levels of relay equipment scenario.
In this paper, we consider different performance comparison of the OMA an formance parameters, such as achievable for 6G urban, suburban and rural dep NOMA scheme as superior to the OMA including average energy efficiency, fairn This paper is organized as follows: is described. Section 3 presents the rate considered system. The concluded result Section 4 demonstrates the results o ble 2 presents the numerous notations us

Contributions
Conforming to the su thoroughly evaluated in di narios. Therefore, we have channel in 6G urban, subu scenario are densely popu distributed in a comparati nario in a comparatively m Further, the performa powers of user devices, in a In previous works [26 different power levels of re scenario.
In this paper, we con performance comparison o formance parameters, such for 6G urban, suburban NOMA scheme as superio including average energy This paper is organiz is described. Section 3 pr considered system. The co Section 4 demonstrate ble 2 presents the numerou In a practical scenario of non-uniform relay ba powers, a comparative evaluation of OMA and NOMA systems in three different deployment scenarios

Contributions
Conforming to thoroughly evaluate narios. Therefore, w channel in 6G urba scenario are densely distributed in a com nario in a comparat Further, the pe powers of user devic In previous wo different power leve scenario.
In this paper, w performance compa formance paramete for 6G urban, subu NOMA scheme as s including average e This paper is o is described. Sectio considered system. Section 4 demo ble 2 presents the nu Signal-to-b is the transmitted BS power for g m . The OMA achieves more interference than NOMA; hence, the achievable capacity in the case of OMA is less than NOMA. With a varying total number of users in the cell, Figure 2 presents an average sum rate analysis of cell-edge users in different deployment scenarios.  In contrast to OMA, NOMA can simultaneously transmit the signal to multiple users; therefore, the achievable average sum rate of NOMA is better than OMA. As the number of users increases, the average sum-rate upsurges. As the distance between the source and destination increases, the channel gain becomes poorer. In suburban and rural scenarios, the interference decreases but the channel gain becomes poorer as compared to the urban scenario. Therefore, the performance of each scheme is better in urban and sub-urban scenarios than in rural scenarios.
The fairness factor for N number of users lies between 1 N to 1, where 1 denotes the maximum fairness. The fairness of the system reduces with the rise in the number of users. The fairness factor defines resource allocation fairness, which describes the quality of the signal available to the users with poor channel qualities. The fairness factor is given in (12). Figure 3 evaluates the performance of the two schemes in the different deployment scenarios for a case of Z = 300. The figure shows that the fairness factor of the NOMA scheme is better than the OMA scheme. As the channel gain is poorest in the case of OMA in the rural scenarios, its fairness factor is the poorest, as observed from the figure.
For 5G, power-saving and energy optimization in the communication system are crucial. The energy efficiency of the link between the BS and cell-edge user in a coordinated relay OMA and NOMA system is shown in Figure 4. It is found that the average energy efficiency takes an upswing with the rise in the cell users. Energy efficiency is a function of achieved data rate and equipment power consumption. It is observed from Figure 2 that the rate in the rural scenario is the poorest; therefore, its energy efficiency is also the least, as seen in Figure 4. The NOMA scheme serves multiple users simultaneously, whereas OMA can use servers one user at a time. Therefore, the NOMA scheme outstrips the OMA scheme in terms of average energy efficiency. signal available to the users with poor channel qualities. The fairness factor is g (12). Figure 3 evaluates the performance of the two schemes in the different deplo scenarios for a case of = 300. The figure shows that the fairness factor of the N scheme is better than the OMA scheme. As the channel gain is poorest in the case o in the rural scenarios, its fairness factor is the poorest, as observed from the figure For 5G, power-saving and energy optimization in the communication system a cial. The energy efficiency of the link between the BS and cell-edge user in a coord relay OMA and NOMA system is shown in Figure 4. It is found that the average efficiency takes an upswing with the rise in the cell users. Energy efficiency is a fu of achieved data rate and equipment power consumption. It is observed from F that the rate in the rural scenario is the poorest; therefore, its energy efficiency is a least, as seen in Figure 4. The NOMA scheme serves multiple users simultan whereas OMA can use servers one user at a time. Therefore, the NOMA scheme ou the OMA scheme in terms of average energy efficiency.

Conclusions
This paper analyzes cooperative relaying in both OMA and NOMA technique

Conclusions
This paper analyzes cooperative relaying in both OMA and NOMA techniques in a system where the relay nodes aid the communications between the BS and the cell-edge users. A practical scenario of non-uniform relay battery power levels is considered. The performance of the two schemes is compared in a multi-user system in three different deployment scenarios. It is proved that the NOMA scheme outstrips the OMA scheme in terms of average sum rate and average energy efficiency. Furthermore, it is shown that the NOMA scheme provides better average fairness to the system. Performance analyses of OMA and NOMA systems in a heterogeneous network can be a promising future research direction in 5G. Further, with the introduction of the Internet of Things (IoT) and Device-to-Device (D2D) communications, security is a big issue in the 5G communication system. Implementation of cooperative-NOMA with physical layer security is another 5G future research direction.