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Yongjun Kwak - One of the best experts on this subject based on the ideXlab platform.

  • VTC-Fall - Non-Orthogonal Multiple Access with Low Code Rate Spreading and Short Sequence Based Spreading
    2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017
    Co-Authors: Sergey D Sosnin, Debdeep Chatterjee, Gang Xiong, Yongjun Kwak
    Abstract:

    In the 5th generation of mobile cellular systems, Non-Orthogonal Multiple Access (NOMA) is being considered as a potential candidate for uplink (UL) Multiple Access (MA) in addition to the basic orthogonal Multiple Access scheme in order to support various usage scenarios including small packet transmissions, support of a massive number of users , and low latency and high reliability services. In this paper, two simple Multiple Access schemes, low code rate spreading (LCRS) and short-sequence-based spreading Multiple Access (SSMA), with corresponding use of advanced receivers, are analyzed, demonstrating system capacity improvements compared to orthogonal Multiple Access (OMA) scheme. The robustness and gain of Non-Orthogonal Multiple Access scheme over orthogonal approaches are maximized when the packet size is small and suitable code rate is guaranteed.

  • Non-Orthogonal Multiple Access with Low Code Rate Spreading and Short Sequence Based Spreading
    2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017
    Co-Authors: Sergey D Sosnin, Debdeep Chatterjee, Gang Xiong, Yongjun Kwak
    Abstract:

    In the 5th generation of mobile cellular systems, Non-Orthogonal Multiple Access (NOMA) is being considered as a potential candidate for uplink (UL) Multiple Access (MA) in addition to the basic orthogonal Multiple Access scheme in order to support various usage scenarios including small packet transmissions, support of a massive number of users , and low latency and high reliability services. In this paper, two simple Multiple Access schemes, low code rate spreading (LCRS) and short-sequence-based spreading Multiple Access (SSMA), with corresponding use of advanced receivers, are analyzed, demonstrating system capacity improvements compared to orthogonal Multiple Access (OMA) scheme. The robustness and gain of Non-Orthogonal Multiple Access scheme over orthogonal approaches are maximized when the packet size is small and suitable code rate is guaranteed.

Zhiguo Ding - One of the best experts on this subject based on the ideXlab platform.

  • Two-way relay assisted Non-Orthogonal Multiple Access
    Computer Communications, 2019
    Co-Authors: Chun Yeen Ho, Chee Yen Leow, Zhiguo Ding
    Abstract:

    Abstract The use of two-way relaying in infrastructure network to support both downlink and uplink has not been considered in existing literature on cooperative Non-Orthogonal Multiple Access (NOMA). This paper proposes a novel cooperative NOMA that uses two-way relaying with analog network coding to improve the data rates of the users and the base station in an infrastructure based information exchange scenario, without utilizing additional channel resource. Analytical results on uplink and downlink ergodic rates are derived. In order to guarantee the rate of the proposed scheme always surpasses the orthogonal Multiple Access (OMA) scheme, a power allocation region is derived. Simulation and analytical results show that the proposed scheme achieves better sum rates when compared to the OMA scheme and existing cooperative NOMA scheme.

  • ICASSP - Unsupervised User Clustering in Non-Orthogonal Multiple Access
    ICASSP 2019 - 2019 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2019
    Co-Authors: Zulin Wang, Mai Xu, Fang Fang, Zhiguo Ding
    Abstract:

    Non-Orthogonal Multiple Access (NOMA) is one of the most promising technologies in fifth-generation mobile communication system for its advantages in serving multiuser simultaneously and enhancing spectrum efficiency. In this paper, we investigate the optimization problem of sum-rate maximization for NOMA-based system, and mainly focus on user clustering. Inspired by the correlation features of users, we introduce machine learning in user clustering. We first develop an expectation maximization (EM) based algorithm for fixed user scenario. Then, the dynamic user scenario is considered and an online EM (OLEM) based clustering algorithm is proposed. Simulation results show that the proposed EM-based and OLEM-based algorithms outperform the state-of-the-art algorithms in fixed and dynamic user scenario, respectively.

  • ICC - Cache-Aided Non-Orthogonal Multiple Access
    2018 IEEE International Conference on Communications (ICC), 2018
    Co-Authors: Lin Xiang, Xi Aohu Ge, Derrick Wing Kwan Ng, Vincent W.s. Wong, Zhiguo Ding, Robert Schober
    Abstract:

    In this paper, we propose a novel joint caching and Non-Orthogonal Multiple Access (NOMA) scheme to facilitate advanced downlink transmission for next generation cellular networks. In addition to reaping the conventional advantages of caching and NOMA transmission, the proposed cache-aided NOMA scheme also exploits cached data for interference cancellation which is not possible with separate caching and NOMA transmission designs. Furthermore, as caching can help to reduce the residual interference power, several decoding orders are feasible at the receivers, and these decoding orders can be flexibly selected for performance optimization. We characterize the achievable rate region of cache-aided NOMA and investigate its benefits for minimizing the time required to complete video file delivery. Our simulation results reveal that, compared to several baseline schemes, the proposed cache-aided NOMA scheme significantly expands the achievable rate region for downlink transmission, which translates into substantially reduced file delivery times.

  • Cache-aided Non-Orthogonal Multiple Access
    IEEE International Conference on Communications, 2018
    Co-Authors: Lin Xiang, Xi Aohu Ge, Derrick Wing Kwan Ng, Vincent W.s. Wong, Zhiguo Ding, Robert Schober
    Abstract:

    In this paper, we propose a cache-aided Non-Orthogonal Multiple Access (NOMA) scheme for spectrally efficient downlink transmission in the fifth-generation (5G) cellular networks. The proposed scheme not only reaps the benefits associated with caching and NOMA, but also exploits the data cached at the users for interference cancellation. As a consequence, caching can help to reduce the residual interference power, making Multiple decoding orders at the users feasible. The resulting flexibility in decoding can be exploited for realizing additional performance gains. We characterize the achievable rate region of cache-aided NOMA and derive the Pareto optimal rate tuples forming the boundary of the rate region. Moreover, we optimize cache-aided NOMA for minimization of the time required for video file delivery. The optimal decoding order and the optimal transmit power and rate allocation are derived as functions of the cache status, the file sizes, and the channel conditions. Our simulation results confirm that compared to several baseline schemes, the proposed cache-aided NOMA scheme significantly expands the achievable rate region and increases the sum rate for downlink transmission, which translates into substantially reduced file delivery times.

  • Secrecy Sum Rate Maximization in Non-Orthogonal Multiple Access
    IEEE Communications Letters, 2016
    Co-Authors: Yizhen Zhang, Hui-ming Wang, Huahui Wang, Qian Yang, Yi Zhang, Zhiguo Ding
    Abstract:

    Non-Orthogonal Multiple Access (NOMA) has been recognized as a promising technique for providing high data rates in 5G systems. This letter is to study physical layer security in a single-input single-output (SISO) NOMA system consisting of a transmitter, Multiple legitimate users and an eavesdropper. The aim of this letter is to maximize the secrecy sum rate (SSR) of the NOMA system subject to the users' quality of service (QoS) requirements. We firstly identify the feasible region of the transmit power for satisfying all users' QoS requirements. Then we derive the closed-form expression of an optimal power allocation policy that maximizes the SSR. Numerical results are provided to show a significant SSR improvement by NOMA compared with conventional orthogonal Multiple Access (OMA).

Sergey D Sosnin - One of the best experts on this subject based on the ideXlab platform.

  • VTC-Fall - Non-Orthogonal Multiple Access with Low Code Rate Spreading and Short Sequence Based Spreading
    2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017
    Co-Authors: Sergey D Sosnin, Debdeep Chatterjee, Gang Xiong, Yongjun Kwak
    Abstract:

    In the 5th generation of mobile cellular systems, Non-Orthogonal Multiple Access (NOMA) is being considered as a potential candidate for uplink (UL) Multiple Access (MA) in addition to the basic orthogonal Multiple Access scheme in order to support various usage scenarios including small packet transmissions, support of a massive number of users , and low latency and high reliability services. In this paper, two simple Multiple Access schemes, low code rate spreading (LCRS) and short-sequence-based spreading Multiple Access (SSMA), with corresponding use of advanced receivers, are analyzed, demonstrating system capacity improvements compared to orthogonal Multiple Access (OMA) scheme. The robustness and gain of Non-Orthogonal Multiple Access scheme over orthogonal approaches are maximized when the packet size is small and suitable code rate is guaranteed.

  • Non-Orthogonal Multiple Access with Low Code Rate Spreading and Short Sequence Based Spreading
    2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017
    Co-Authors: Sergey D Sosnin, Debdeep Chatterjee, Gang Xiong, Yongjun Kwak
    Abstract:

    In the 5th generation of mobile cellular systems, Non-Orthogonal Multiple Access (NOMA) is being considered as a potential candidate for uplink (UL) Multiple Access (MA) in addition to the basic orthogonal Multiple Access scheme in order to support various usage scenarios including small packet transmissions, support of a massive number of users , and low latency and high reliability services. In this paper, two simple Multiple Access schemes, low code rate spreading (LCRS) and short-sequence-based spreading Multiple Access (SSMA), with corresponding use of advanced receivers, are analyzed, demonstrating system capacity improvements compared to orthogonal Multiple Access (OMA) scheme. The robustness and gain of Non-Orthogonal Multiple Access scheme over orthogonal approaches are maximized when the packet size is small and suitable code rate is guaranteed.

Hamid Jafarkhani - One of the best experts on this subject based on the ideXlab platform.

  • Trellis-Coded Non-Orthogonal Multiple Access
    IEEE Wireless Communications Letters, 2020
    Co-Authors: Mehdi Ganji, Hamid Jafarkhani
    Abstract:

    In this letter, we propose a trellis-coded Non-Orthogonal Multiple Access (NOMA) scheme. The signals for different users are produced by trellis coded modulation (TCM) and then superimposed on different power levels. By interpreting the encoding process via the tensor product of trellises, we introduce a joint detection method based on the Viterbi algorithm. Then, we determine the optimal power allocation between the two users by maximizing the free distance of the tensor product trellis. Finally, we manifest that the trellis-coded NOMA outperforms the uncoded NOMA at high signal-to-noise ratio (SNR).

  • An Analysis of Two-User Uplink Asynchronous Non-Orthogonal Multiple Access Systems
    IEEE Transactions on Wireless Communications, 2019
    Co-Authors: Biao He, Hamid Jafarkhani
    Abstract:

    Recent studies have numerically demonstrated the possible advantages of the asynchronous Non-Orthogonal Multiple Access (ANOMA) over the conventional synchronous Non-Orthogonal Multiple Access (NOMA). The ANOMA makes use of the oversampling technique by intentionally introducing a timing mismatch between symbols of different users. Focusing on a two-user uplink system, for the first time, we analytically prove that the ANOMA with a sufficiently large frame length can always outperform the NOMA in terms of the sum throughput. To this end, we derive the expression for the sum throughput of the ANOMA as a function of signal-to-noise ratio, frame length, and normalized timing mismatch. Based on the derived expression, we find that users should transmit at full powers to maximize the sum throughput. In addition, we obtain the optimal timing mismatch as the frame length goes to infinity. Moreover, we comprehensively study the impact of timing error on the ANOMA throughput performance. Two types of timing error, i.e., the synchronization timing error and the coordination timing error, are considered. We derive the throughput loss incurred by both types of timing error and find that the synchronization timing error has a greater impact on the throughput performance compared with the coordination timing error.

  • An Analysis of Uplink Asynchronous Non-Orthogonal Multiple Access Systems.
    arXiv: Information Theory, 2018
    Co-Authors: Biao He, Hamid Jafarkhani
    Abstract:

    Recent studies have numerically demonstrated the possible advantages of the asynchronous Non-Orthogonal Multiple Access (ANOMA) over the conventional synchronous Non-Orthogonal Multiple Access (NOMA). The ANOMA makes use of the oversampling technique by intentionally introducing a timing mismatch between symbols of different users. Focusing on a two-user uplink system, for the first time, we analytically prove that the ANOMA with a sufficiently large frame length can always outperform the NOMA in terms of the sum throughput. To this end, we derive the expression for the sum throughput of the ANOMA as a function of signal-to-noise ratio (SNR), frame length, and normalized timing mismatch. Based on the derived expression, we find that users should transmit at full powers to maximize the sum throughput. In addition, we obtain the optimal timing mismatch as the frame length goes to infinity. Moreover, we comprehensively study the impact of timing error on the ANOMA throughput performance. Two types of timing error, i.e., the synchronization timing error and the coordination timing error, are considered. We derive the throughput loss incurred by both types of timing error and find that the synchronization timing error has a greater impact on the throughput performance compared to the coordination timing error.

  • ICC - On Uplink Asynchronous Non-Orthogonal Multiple Access Systems with Timing Error
    2018 IEEE International Conference on Communications (ICC), 2018
    Co-Authors: Biao He, Hamid Jafarkhani
    Abstract:

    Recent studies have shown that asynchronous non- orthogonal Multiple Access (ANOMA) outperforms conventional synchronous Non-Orthogonal Multiple Access (NOMA) by taking advantage of artificial timing mismatch with oversampling. For the first time, we comprehensively study the impact of timing errors on the performance of uplink ANOMA systems in this paper. We consider two types of timing errors, which are the synchronization timing error and the coordination timing error. We analyze how the timing errors affect ANOMA systems, and derive the throughput loss of ANOMA systems incurred by both the synchronization timing error and the coordination timing error. An interesting finding is that the synchronization timing error has a larger impact on the throughput performance of ANOMA systems compared with the coordination timing error.

  • Downlink Asynchronous Non-Orthogonal Multiple Access with Quantizer Optimization
    IEEE Wireless Communications Letters, 1
    Co-Authors: Mehdi Ganji, Hamid Jafarkhani
    Abstract:

    In this letter, we study a two-user downlink asynchronous Non-Orthogonal Multiple Access (ANOMA) with limited feedback. We employ the max-min criterion for the power allocation and derive the closed-form expressions for the upper and lower bounds of the max-min rate. It is demonstrated that ANOMA can achieve the same or even higher average max-min rate with a lower feedback rate compared with NOMA. Moreover, we propose a quantizer optimization algorithm which applies to both NOMA and ANOMA. Simulation results show that the optimized quantizer significantly improves the average max-min rate compared with the conventional uniform quantizer, especially in the scenario with a low feedback rate.

Soo Young Shin - One of the best experts on this subject based on the ideXlab platform.

  • Non-Orthogonal Multiple Access in downlink coordinated multipoint transmissions
    Physical Communication, 2020
    Co-Authors: Denny Kusuma Hendraningrat, Bhaskara Narottama, Soo Young Shin
    Abstract:

    Abstract In this paper, a joint transmission coordinated multi-point based Non-Orthogonal Multiple Access (JT-CoMP NOMA) combined with spatial modulation (SM), termed as JT-CoMP NOMA-SM, is proposed to enhance capacity. User capacity and ergodic sum capacity (ESC) of K coordinated multi-point base stations (CoMP BSs) within N number of cells are analyzed by considering imperfect successive interference cancellation (SIC) and imperfect channel state information (CSI). The performances of the proposed system are compared with orthogonal Multiple Access (OMA), Non-Orthogonal Multiple Access (NOMA), and joint transmission coordinated multi-point combined with virtual user pairing based Non-Orthogonal Multiple Access (JT-CoMP VP-NOMA) through both simulation and analysis. The results show that the proposed system has the same cell center user (CCU) capacity compared to JT-CoMP VP-NOMA and a higher cell edge user (CEU) capacity than the other schemes. ESC of the proposed system outperforms the other schemes due to enhancing CEU capacity. Imperfect SIC and imperfect CSI may degrade capacity. To achieve an optimal capacity, the power allocated for CCU should be increased if the transmit signal-to-noise ratio (SNR) is reduced. The proposed system can maintain CEU capacity better than the other schemes if the number of cells is increased. It happens because SM works beyond Shannon upper bounds, which can mitigate inter-cell interference (ICI).

  • Non-Orthogonal Multiple Access with Spatial Modulation in Downlink Coordinated Multipoint Transmission.
    arXiv: Information Theory, 2019
    Co-Authors: Denny Kusuma Hendraningrat, Bhaskara Narottama, Soo Young Shin
    Abstract:

    In this paper, a joint transmission coordinated multi-point based Non-Orthogonal Multiple Access (JT-COMP NOMA) combined with spatial modulation (SM), termed as JT-COMP NOMA-SM, is proposed to enhance capacity. User capacity and ergodic sum capacity (ESC) of M number coordinated multi-point base stations (COMP BSs) within N number of cells are analyzed by considering imperfect successive interference cancellation (SIC) and imperfect channel state information (CSI). The performances of the proposed syatem are compared with Non-Orthogonal Multiple Access (NOMA), and joint transmission coordinated multi-point combined with virtual user pairing based Non-Orthogonal Multiple Access (JT-COMP VP-NOMA) by both simulation and analysis. The results show that the proposed system has the same cell center user (CCU) capacity compared to JT-COMP VP-NOMA and a higher cell edge user (CEU) capacity than the other schemes. ESC of the proposed system outperforms the other schemes due to enhancing CEU capacity. Imperfect SIC and imperfect CSI may degrade capacity. The proposed system can maintain CEU capacity better than the other schemes if the number of cells is increased. It happens because SM works beyond Shannon upper bounds which can mitigate inter-cell interference (ICI).

  • Bidirectional relaying using Non-Orthogonal Multiple Access
    Physical Communication, 2019
    Co-Authors: Fazlul Kader, Mohammed Belal Uddin, Abdul Latif Sarker, Soo Young Shin
    Abstract:

    Abstract A half-duplex bidirectional relaying (BR) technique using Non-Orthogonal Multiple Access (NOMA) (termed as BR-NOMA) is proposed and investigated in this paper. In BR-NOMA, Multiple users in one NOMA group can exchange information simultaneously with Multiple users in another NOMA group through a common relay. The optimal information exchanging user set that maximizes the ergodic sum capacity (ESC) of BR-NOMA is investigated. The performance of BR-NOMA is examined in terms of ESC, outage probability (OP), and outage sum capacity (OSC). The analytical expressions of ESC, OP, and OSC are also provided considering the optimal information exchanging user set under both perfect and imperfect successive interference cancellation. Based on the simulation and analytical results, it is demonstrated that BR-NOMA can attain significant capacity gains as compared to half-duplex BR using conventional Multiple Access.

  • Virtual User Pairing Non-Orthogonal Multiple Access in Downlink Coordinated Multipoint Transmission
    arXiv: Networking and Internet Architecture, 2019
    Co-Authors: Denny Kusuma Hendraningrat, Muhammad Basit Shahab, Soo Young Shin
    Abstract:

    In this paper, joint transmission coordinated multipoint (JT-CoMP) is exploited by using virtual user pairing Non-Orthogonal Multiple Access (VP-NOMA), termed as JT-CoMP VP-NOMA. The technique combines both VP-NOMA for enhancing ergodic sum capacity (ESC) and JT-CoMP for inter-cell interference mitigation. To show the performance gains, ESC of a three-cell scenario is analyzed as a key performance metric. The analytical and simulation results of JT-CoMP VP-NOMA are compared with orthogonal Multiple Access (OMA), Non-Orthogonal Multiple Access (NOMA), and VP-NOMA. It is shown that the proposed JT-CoMP VP-NOMA outperforms the other schemes in the viewpoint of ESC.

  • Cooperative Relaying Using Space-Time Block Coded Non-Orthogonal Multiple Access
    IEEE Transactions on Vehicular Technology, 2017
    Co-Authors: Fazlul Kader, Soo Young Shin
    Abstract:

    Non-Orthogonal Multiple Access (NOMA) has attracted significant attention in the research community as a potential radio Access technology for future wireless networks. In this work, we propose a two-phase cooperative decode-and-forward (DF) relaying scheme based on Alamouti (2  $\times$  1 Multiple-input single-output mode) space-time block-coded Non-Orthogonal Multiple Access (STBC-NOMA). Closed-form solutions for ergodic sum capacity and outage probability of the proposed scheme are analyzed over independent Rayleigh fading channels. Asymptotic approximations for ergodic sum capacity, outage probability, and outage sum capacity at the high signal-to-noise ratio regime are also provided. It has been pointed out that the proposed cooperative relaying system (CRS) using STBC-NOMA can attain significant performance gains compared to the conventional CRS using NOMA and the traditional DF relaying schemes. It is also demonstrated that the relay position between the transmitter and the receiver has a significant impact on the performance of the proposed protocol. In addition, the proximity between analytical and simulation results confirms the efficiency of the proposed protocol.