• Title, Summary, Keyword: Superposition coding

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On Power of Correlated Superposition Coding in NOMA

  • Chung, Kyuhyuk
    • Journal of IKEEE
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    • v.24 no.1
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    • pp.360-363
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    • 2020
  • We present the power of the correlated superposition coding (SC) in non-orthogonal multiple access (NOMA). This paper derives closed-form expressions for the total allocated power with the constant total transmitted power. It is shown that the total allocated power is the function of a correlation coefficient. In result, the correlated SC NOMA should be designed with consideration of the correlation coefficient.

Performance Analysis of NOMA with Symmetric Superposition Coding

  • Chung, Kyuhyuk
    • Journal of IKEEE
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    • v.23 no.1
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    • pp.314-317
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    • 2019
  • Recently, the symmetric superposition coding (SSC) [3] is proposed for a solution for the error propagation (EP) due to the non-perfect successive interference cancelation (SIC) in non-orthogonal multiple access (NOMA). We analyze the performance of NOMA with the SSC. It is shown that the performance of the SSC NOMA is the same as that of NOMA with the normal superposition coding (NSC) for the power allocation factor less than 20%, the SSC NOMA performance is better than the NSC NOMA performance up to the power allocation factor 80%, and the SSC NOMA performs worse than the NSC NOMA for the power allocation factor greater than 80%. As a result, the SSC should be used with consideration of the power allocation.

Impact of Correlation on Superposition Coding in NOMA for Interactive Mobile Users in 5G System: Achievable Sum Rate Perspective

  • Chung, Kyuhyuk
    • International Journal of Internet, Broadcasting and Communication
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    • v.12 no.3
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    • pp.39-45
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    • 2020
  • The fifth generation (5G) mobile communication has been more commercialized worldwide. One of the promising 5G technologies is non-orthogonal multiple access (NOMA). We present the achievable sum rate of non-orthogonal multiple access (NOMA) with correlated superposition coding (SC). Then this paper investigates the impacts of correlation on the achievable sum rate of correlated SC NOMA. It is shown that the achievable sum rate of correlated SC NOMA is greater than that of standard independent SC NOMA, for the most of the values of the power allocation factor over the meaningful range of the user fairness. In result, correlated SC could be a promising scheme for NOMA.

Modified Clipping for Iterative Decoding of Superposition Coding (중첩 부호의 반복 복호를 위한 개선된 클리핑 기법)

  • Yan, Yi-Er;Kim, Jeong-Ki;Chen, Zhu;Lee, Moon-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.2
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    • pp.44-51
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    • 2008
  • In this paper, we propose a modified clipping scheme for iterative decoding of superposition coding system by losing less power than clipping scheme. Our proposed scheme in superposition coding system shows good performance in peak-to-average power ratio(PAPR) and system performance with the same Clipping Ratio especially in low Clipping Ratio case. Finally in order to alleviate the performance degradation due to clipping noises, we combine a soft compensation algorithm that is combined with soft-input-soft-output(SISO) decoding algorithms in an iterative manner proposed by [1][2]. Simulation results show that with the proposed scheme, most performance loss can be recovered.

Spike Response Model and Coding of Neurons (뉴런의 스파이크 응답 모델과 코딩)

  • Lee, Ho-Suk
    • Proceedings of the Korean Information Science Society Conference
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    • pp.5-8
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    • 2007
  • This paper discusses the spike response model of neurons. First, this paper discusses the coding of spikes, the function of spikes, and the construction of the spikes of neurons by the superposition of simple kernel functions. This paper discusses the method of kernel superposition is general than the response of the IF (Integrate-and-Fire) neuron model, too. Next, this paper discusses the coincidence detection and the input weight computation of spiking neurons and the activity of neuron populations in some detail.

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Performance Evaluation of Overlaid Single Frequency Broadcast and Cellular network using Superposition Coding (중첩부호를 이용한 단일주파수 방송 서비스 및 데이터 서비스 오버레이 시스템의 성능 평가)

  • Yoon, Seok-Hyun;Kim, Dong-Hee
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.7
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    • pp.32-38
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    • 2009
  • In this paper, we consider the overlaid system of single frequency network broadcast service and cellular-based unicast data service. In general, broadcast service and unicast data service were considered as a separate services so that different frequency resources have been allocated for each. As the frequency resource get more expensive, however, there were some efforts to provide both the broadcast and unicast service over the same frequency resource by employing the so-called superposition coding. In fact, such an service overlay system has already been accepted as a standards in 3GPP long-term evolution (LTE). In this paper, we specifically investigate such overlay system within 3GPP framework and evaluate their performance in terms of BC coverage and UC data throughput.

On Power Splitting under User-Fairness for Correlated Superposition Coding NOMA in 5G System

  • Chung, Kyuhyuk
    • International journal of advanced smart convergence
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    • v.9 no.2
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    • pp.68-75
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    • 2020
  • Non-orthogonal multiple access (NOMA) has gained the significant attention in the fifth generation (5G) mobile communication, which enables the advanced smart convergence of the artificial intelligence (AI), the internet of things (IoT), and many of the state-of-the-art technologies. Recently, correlated superposition coding (SC) has been proposed in NOMA, to achieve the near-perfect successive interference cancellation (SIC) bit-error rate (BER) performance for the stronger channel users, and to mitigate the severe BER performance degradation for the weaker channel users. In the correlated SC NOMA scheme, the stronger channel user BER performance is even better than the perfect SIC BER performance, for some range of the power allocation factor. However, such excessively good BER performance is not good for the user-fairness, i.e., the more power to the weaker channel user and the less power to the stronger channel user, because the excessively good BER performance of the stronger channel user results in the worse BER performance of the weaker channel user. Therefore, in this paper, we propose the power splitting to establish the user-fairness between both users. First, we derive a closed-form expression for the power splitting factor. Then it is shown that in terms of BER performance, the user-fairness is established between the two users. In result, the power splitting scheme could be considered in correlated SC NOMA for the user-fairness.

On Non-Orthogonal Multiple Access (NOMA) in 5G Systems (5G 시스템에서의 비-직교 다중 액세스(NOMA))

  • Islam, SM Riazul;Kim, Jae Moung;Kwak, Kyung Sup
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.12
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    • pp.2549-2558
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    • 2015
  • The non-orthogonal multiple access (NOMA) is one of the fledging paradigms which next generation radio access technologies are sprouting toward. The NOMA with superposition coding (SC) in the transmitter and successive interference cancellation (SIC) at the receiver comes with many desirable features and benefits over orthogonal multiple access (OMA) such as orthogonal frequency division multiple access (OFDMA) adopted by Long-Term Evolution (LTE). In this paper, we study the recent research trends on NOMA in 5G systems. We discuss the basic concept of NOMA and explain its aspects of importance for future radio access. Then, we provide a survey of the state of the art in NOMA for 5G systems in a categorized manner. Further, we analyze the NOMA performances with numerical examples; and provide some avenues for future research on NOMA on a set of open issues and challenges.

Superposition Coding Multiplexing for Fading Broadcast Channels with Rate Constraints (전송률 제한을 둔 페이딩 방송채널을 위한 중첩코딩 다중화)

  • Lee, Min;Oh, Seong-Keun;Jeong, Byung-Jang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.11A
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    • pp.1072-1078
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    • 2008
  • In this paper, we propose an efficient superposition coding multiplexing(SCM) method based on power allocation in descending order for fading broadcast channels in which per-user minimum and maximum rate constraints are considered in order to maximize the transmission effectiveness. It consists of three steps as follows. In the first step, a user group is selected to maximize the number of users with whom a transmitter can communicate instantaneously. In the second step, per-user power allocation for each user is done in descending order of transmit power by determining a maximum allowable interference power from all subsequent interfering users in order to guarantee its corresponding minimum rate, and then a residual power is calculated. The final step is performed if some power remains even after the second step. In this step, additional power allocation is performed up to the maximum transmit power to provide the maximum rate to the corresponding user, again in ascending order, starting from the last user in descending order. But, this method does not require power reallocation to subsequent users because tentative power allocation in the second step has been performed in descending order to guarantee the minimum rate for each user, taking into account the maximum allowable interference power from all the subsequent users. Therefore, the proposed method gets more efficient in term of computational complexity when per-user minimum as well as maximum rate constraints exist, especially as the number of users increases.

Performance Analysis of a Full-Duplex Two-Way Relay Network over Rayleigh Fading Channels (레일레이 페이딩 채널에서 전이중 양방향 중계 네트워크의 성능 분석)

  • Choi, Dongwook;Lee, Jae Hong
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.3
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    • pp.3-9
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    • 2014
  • Two-way full-duplex relay network provides improved spectral efficiency by using either superposition coding or physical layer network coding at relays compared to conventional two-way half-duplex relay network. In this paper, we investigate the impact of residual loop interference on the performance of the two-way full-duplex relay network. Users and relays in the two-way full-duplex relay network estimate the residual loop interference in order to cancel it. However, it is difficult to perfectly cancel the residual loop interference from the received signal due to the estimation error. Numerical results show the impact of the estimation error on the outage probability of the two-way full-duplex relay network.