협력 비직교 다중 접속 네트워크에서 새로운 인센티브 기반 주파수 할당 기법

김종원 ( Kim Jong Won ),김승욱 ( Kim Sung Wook ) 한국정보처리학회 2021 정보처리학회논문지. 컴퓨터 및 통신시스템 Vol.10 No.6

비 직교 다중 접속(NOMA : Non Orthogonal Multiple Access) 기술은 5G 네트워크의 등장으로 폭발적으로 증가한 사용자의 QoS(Quality of Service)를 보장하기 위한 기술이다. 비 직교 다중 접속 기술은 기존의 직교 다중 접속(OMA : Orthogonal Multiple Access) 기술에서 주파수의 직교성을 없애고 다른 신호를 구분하기 위해 전력을 차등적으로 할당하는 기술이다. NOMA 기술 중 협력 NOMA 기술은 거리가 먼 사용자들에게 보내기 위해 많은 전력을 소모하는 것이 아닌 중계 노드에게 신호를 보내어서 중계 노드가 대신 NOMA를 수행하는 방법이다. 하지만, 협력 NOMA에서는 중계 노드가 협력 NOMA에 참여하는 동기가 반드시 필요하다. 이를 위해 기지국은 중계 노드에게 인센티브를 지급할 수 있지만 중계 노드가 기여한 만큼 공정하게 지급해야 한다. 이러한 인센티브 체계를 수립할 때 발생하는 문제점이 있는데 그것은 중계 노드가 자신의 기여를 속인다면 기지국 입장에서는 전체 시스템 성능도 하락할 뿐 아니라 높은 인센티브를 지급해야 한다는 것이다. 본 논문에서는 협력 NOMA 네트워크에 참여하는 중계 노드들이 이기적으로 행동하여 거짓된 정보를 보고하는 것을 방지하기 위해 메커니즘 디자인을 사용한 기법을 제안한다. 메커니즘 디자인 중 VCG메커니즘을 사용하여 중계 노드들의 이기적인 행동을 제어하고 전체 시스템 성능을 높일 수 있도록 하였다. 실험 결과로 중계 노드들이 이기적으로 행동했을 때의 전체 시스템 성능보다 VCG 메커니즘을 사용하여 모두가 진실하게 행동했을 때의 전체 시스템 성능이 증가함을 보였다. Non Orthogonal Multiple Access (NOMA) is a technology to guarantee the explosively increased Quality of Service(QoS) of users in 5G networks. NOMA can remove the frequent orthogonality in Orthogonal Multiple Access (OMA) while allocating the power differentially to classify user signals. NOMA can guarantee higher communication speed than OMA. However, the NOMA has one disadvantage; it consumes a more energy power when the distance increases. To solve this problem, relay nodes are employed to implement the cooperative NOMA control idea. In a cooperative NOMA network, relay node participations for cooperative communications are essential. In this paper, a new bandwidth allocation scheme is proposed for cooperative NOMA platform. By employing the idea of Vickrey-Clarke-Groves (VCG) mechanism, the proposed scheme can effectively prevent selfishly actions of relay nodes in the cooperative NOMA network. Especially, base stations can pay incentives to relay nodes as much as the contributes of relay nodes. Therefore, the proposed scheme can control the selfish behavior of relay nodes to improve the overall system performance.

Non-orthogonal multiple access for a full-duplex cooperative network with virtually paired users

Kader, Md Fazlul,Shahab, Muhammad Basit,Shin, Soo Young Elsevier 2018 Journal of Computer Communications Vol.120 No.-

<P><B>Abstract</B></P> <P>Non-orthogonal multiple access (NOMA) is recognized as a promising radio access technology for next generation wireless networks. In this paper, a novel full-duplex (FD) cooperative relaying scheme for a NOMA based system (termed FD-NOMA-VP) is proposed, where <I>K</I> similar gain near users and relay-aided <I>N</I> similar gain far users are distributed into different NOMA cluster. In each cluster, one near user is virtually paired (VP) with multiple far users over non-overlapping frequency bands. In FD-NOMA-VP, the near user directly communicates with the base station, whereas far users communicate via a dedicated FD relay, in each cluster. The performance of FD-NOMA-VP is studied comprehensively in terms of the ergodic sum capacity, outage probability, and outage sum capacity along with analytical derivations under both perfect and imperfect interference cancellation (IC) scenarios. The results demonstrate that FD-NOMA-VP shows significant performance gains compared to the conventional multiple access scheme under perfect IC, while the residual interference has a substantial impact on the performance gain under imperfect IC. In addition, a strong agreement between analytical and simulation results affirms the correctness of our analysis.</P>

Energy-efficient semi-supervised learning framework for subchannel allocation in non-orthogonal multiple access systems

S. Devipriya,J. Martin Leo Manickam,B. Victoria Jancee 한국전자통신연구원 2023 ETRI Journal Vol.45 No.6

Non-orthogonal multiple access (NOMA) is considered a key candidate technology for next-generation wireless communication systems due to its high spectral efficiency and massive connectivity. Incorporating the concepts of multiple-input-multiple-output (MIMO) into NOMA can further improve the system efficiency, but the hardware complexity increases. This study develops an energy-efficient (EE) subchannel assignment framework for MIMO-NOMA systems under the quality-of-service and interference constraints. This framework handles an energy-efficient co-training-based semi-supervised learning (EE-CSL) algorithm, which utilizes a small portion of existing labeled data generated by numerical iterative algorithms for training. To improve the learning performance of the proposed EE-CSL, initial assignment is performed by a many-to-one matching (MOM) algorithm. The MOM algorithm helps achieve a low complex solution. Simulation results illustrate that a lower computational complexity of the EE-CSL algorithm helps significantly minimize the energy consumption in a network. Furthermore, the sum rate of NOMA outperforms conventional orthogonal multiple access.

Non-Orthogonal Multiple Access (NOMA) to Enhance Capacity in 5G

임성묵,고균병 한국콘텐츠학회 2015 International Journal of Contents Vol.11 No.4

Non-orthogonal multiple access (NOMA) where all users share the entire time and frequency resource has paid attention as one of the key technologies to enhance the spectral efficiency and the total throughput. Nevertheless, as the number of users and SIC error increase, the inter-user interference and the residual interference due to the SIC error also increase, resulting in performance degradation. In order to mitigate the performance degradation, we propose grouping-based NOMA system. In the proposed scheme, all users are divided into two groups based on the distance between the BS and each user, where one utilizes the first half of the bandwidth and the other utilizes the rest in the orthogonal manner. On the other hand, users in each group share the spectrum in the non-orthogonal manner. Grouping users can reduce both the inter-user interference and residual interference due to the SIC error, so it can outperform conventional NOMA system, especially in case that the number of users and the SIC error increase. Based on that, we also present the hybrid operation of the conventional and the proposed NOMA systems. In numerical results, the total throughput of the proposed NOMA systems is compared with that of the conventional NOMA systems with regard to the number of users and SIC error. It is confirmed that the proposed NOMA system outperforms the conventional NOMA system as the number of users and the SIC error increase.

Non-Orthogonal Multiple Access (NOMA) to Enhance Capacity in 5G

Lim, Sungmook,Ko, Kyunbyoung The Korea Contents Association 2015 International Journal of Contents Vol.11 No.4

Non-orthogonal multiple access (NOMA) where all users share the entire time and frequency resource has paid attention as one of the key technologies to enhance the spectral efficiency and the total throughput. Nevertheless, as the number of users and SIC error increase, the inter-user interference and the residual interference due to the SIC error also increase, resulting in performance degradation. In order to mitigate the performance degradation, we propose grouping-based NOMA system. In the proposed scheme, all users are divided into two groups based on the distance between the BS and each user, where one utilizes the first half of the bandwidth and the other utilizes the rest in the orthogonal manner. On the other hand, users in each group share the spectrum in the non-orthogonal manner. Grouping users can reduce both the inter-user interference and residual interference due to the SIC error, so it can outperform conventional NOMA system, especially in case that the number of users and the SIC error increase. Based on that, we also present the hybrid operation of the conventional and the proposed NOMA systems. In numerical results, the total throughput of the proposed NOMA systems is compared with that of the conventional NOMA systems with regard to the number of users and SIC error. It is confirmed that the proposed NOMA system outperforms the conventional NOMA system as the number of users and the SIC error increase.

단일 클러스터 다중안테나 비직교 다중접속 전송

신창용 대한전기학회 2023 전기학회논문지 Vol.72 No.1

To improve spectral efficiency in multi-cell systems, we propose a multiple-input multiple-output (MIMO) non-orthogonal multiple access technique that simultaneously transmits multiple data streams to a cluster consisting of one cell-center user and one cell-edge user. Based on the MIMO channel state of the cell-center user, the proposed technique for single-cell systems finds the receive beamforming matrix for the user and performs power allocation to its data streams. Considering the MIMO channel state of the cell-edge user and interference from the cell-center user, the technique designs the receive beamforming matrix for the cell-edge user and allocates the power for the user to its data streams. By extending this technique to multi-cell systems, the proposed technique finds the receive beamforming matrix for the cell-center user and performs power allocation to its data streams according to its MIMO channel state and interference from neighboring cells. The receive beamforming matrix design and power allocation for the cell-edge user is performed based on its MIMO channel state, interference from the cell-center user, and interference from neighboring cells. Simulation results demonstrate that the proposed technique achieves better performance than the existing techniques in terms of data rates and outage probabilities for the users

Capacity Analysis of Non-Coaxial OAM-NOMA Under Imperfect SIC

카윰 압둘라,신수용 한국통신학회 2023 韓國通信學會論文誌 Vol.48 No.1

Orbital angular momentum is one of the best candidates for future 6G communication and in combination with NOMA, enhanced data rates can be achieved by utilizing non-orthogonal resource allocation of NOMA and orthogonal OAM modes. In this paper, at the transmitter side fixed power allocation and at the receiver side, successive interference cancelation (SIC) for the removal of multiuser interference is considered. In practical scenarios, in the SIC process, errors can occur leading to residual interference reducing the system capacity. This paper analyzes the effect of imperfection in successive interference cancellation (SIC) for non-coaxial orbital angular momentum based non-orthogonal multiple access (NOMA) communication for multiple users. The simulation results show that although the capacity of OAM-NOMA reduces with the imperfect SIC but it performs better than the conventional methods such as orthogonal multiple access (OMA-OAM) and NOMA when the error in SIC process is not too large.

On the performance of a virtual user pairing scheme to efficiently utilize the spectrum of unpaired users in NOMA

Shahab, Muhammad Basit,Shin, Soo Young Elsevier 2017 PHYSICAL COMMUNICATION Vol.25 No.2

<P><B>Abstract</B></P> <P>This paper evaluates the performance of a virtual user pairing scheme that efficiently utilizes the spectrum of unpaired users in non-orthogonal multiple access (NOMA), termed as VP-NOMA. The scheme aims at utilizing the frequency bands of those users which remain unpaired due to the non-uniform distribution of users in a cellular area. We consider a case where the cell edge users are more than the cell center users, so that complete one-to-one correspondence does not exist between all cell center and cell edge users to be accommodated/paired using conventional NOMA (C-NOMA) user pairing. Thus, some cell edge users remain unpaired, and are served using conventional multiple access (OMA) schemes. In such scenario, VP-NOMA pairs a single cell center user with two or more clustered (closely located) cell edge users over non-overlapping frequency bands, thus enabling the cell center user to efficiently use the frequency bands of these previously unpaired cell edge users. Performance of VP-NOMA in terms of ergodic sum capacity (ESC), outage probability (OP), and outage sum capacity (OSC), is analyzed through comprehensive mathematical derivations and simulations for a generalized system model. Moreover, the mathematical analysis is validated through close concordance between analytical and simulation results of ESC, OP, and OSC.</P>

Performance Evaluation for UAV-Based UL-NOMA with Channel Coding

이혜영,이만희,신수용 한국통신학회 2023 韓國通信學會論文誌 Vol.48 No.5

Non-orthogonal multiple access is a potential technique to improve the spectral efficiency of beyond-5G systems by superposing multiple signals. For a received signal to be decoded, successive interference cancellation (SIC) process is required to subtract other signals at the receiver side. The channel coding is required to reduce the error probability when mobility is considered in non-orthogonal multiple access (NOMA) and applied after the SIC process. In this paper, we evaluate the performance of the unmanned aerial vehicle-based uplink NOMA with the concatenation of Reed–Solomon and convolutional code. Simulation results show comparisons between different conditions such as perfect and imperfect SIC processes.

Non-Orthogonal Multiple Access (NOMA) to Enhance Capacity in 5G

Sungmook Lim,Kyunbyoung Ko 한국콘텐츠학회 2015 International Journal of Contents Vol.11 No.4