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Achieved data rate (BER < 1 0 - 5 ) compared to both the constrained and unconstrained capacity of orthogonal signaling as well as the ultimate capacity of RRC with β = 0.3 .
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A structure of faster-than-Nyquist (FTN) signaling combined with superposition coded modulation (SCM) is considered. The so-called FTN-SCM structure is able to achieve the constrained capacity of FTN signaling and only requires a low detection complexity. By deriving a new observation model suitable for FTN-SCM, we offer the power allocation based...
Citations
... Moreover, NOMA transmission based on faster-than-Nyquist (FTN) signaling was also considered in the literature [12]. Indeed, FTN signaling is a classic nonorthogonal signaling scheme exhibiting an enhanced spectral efficiency [13]- [16], where data is transmitted at a symbol rate higher than the Nyquist intersymbol interference (ISI)-free rate 1 [19]. Although FTN-based NOMA (FTN-NOMA) transmission is expected to have an increased achievable rate, its theoretical rate analysis has not been disseminated in the open literature. ...
Faster-than-Nyquist (FTN) signaling aided non-orthogonal multiple access (NOMA) is conceived and its achievable rate is quantified in the presence of random link delays of the different users. We reveal that exploiting the link delays may potentially lead to a signal-to-interference-plus-noise ratio (SINR) gain, while transmitting the data symbols at FTN rates has the potential of increasing the degree-of-freedom (DoF). We then unveil the fundamental trade-off between the SINR and DoF. In particular, at a sufficiently high symbol rate, the SINR gain vanishes while the DoF gain achieves its maximum, where the achievable rate is almost (1 + β) times higher than that of the conventional synchronous NOMA transmission in the high signal-to-noise ratio (SNR) regime, with β being the roll-off factor of the signaling pulse. Our simulation results verify our analysis and demonstrate considerable rate improvements over the conventional power-domain NOMA scheme.
... Moreover, NOMA transmission based on faster-than-Nyquist (FTN) signaling was also considered in the literature [12]. Indeed, FTN signaling is a classic non-orthogonal signaling scheme exhibiting an enhanced spectral efficiency [13]- [16], where data is transmitted at a symbol rate higher than the Nyquist intersymbol interference (ISI)-free rate 1 [19]. Although FTN-based NOMA (FTN-NOMA) transmission is expected to have an increased achievable rate, its theoretical rate analysis has not been disseminated in the open literature. ...
Faster-than-Nyquist (FTN) signaling aided non-orthogonal multiple access (NOMA) is conceived and its achievable rate is quantified in the presence of \emph{random} link delays of the different users. We reveal that exploiting the link delays may potentially lead to a signal-to-interference-plus-noise ratio (SINR) gain, while transmitting the data symbols at FTN rates has the potential of increasing the degree-of-freedom (DoF). We then unveil the fundamental trade-off between the SINR and DoF. In particular, at a sufficiently high symbol rate, the SINR gain vanishes while the DoF gain achieves its maximum, where the achievable rate is almost $(1+\beta)$ times higher than that of the conventional synchronous NOMA transmission in the high signal-to-noise ratio (SNR) regime, with $\beta$ being the roll-off factor of the signaling pulse. Our simulation results verify our analysis and demonstrate considerable rate improvements over the conventional power-domain NOMA scheme.
... Faster-than-Nyquist (FTN) signaling [2]- [4] has long been one of the promising communication paradigms for future high data rate wireless networks. Different from the conventional methods of enhancing the data rate, which normally requires more time/bandwidth/spatial resources, FTN signaling enhances the spectral efficiency by intentionally transmitting the symbols faster than the Nyquist rate. ...
A deep learning assisted sum-product detection algorithm (DL-SPDA) for faster-than-Nyquist (FTN) signaling is proposed in this paper. The proposed detection algorithm works on a modified factor graph which concatenates a neural network function node to the variable nodes of the conventional FTN factor graph to approach the maximum a posterior probabilities (MAP) error performance. In specific, the neural network performs as a function node in the modified factor graph to deal with the residual intersymbol interference (ISI) that is not considered by the conventional detector with a limited complexity. We modify the updating rule in the conventional sum-product algorithm so that the neural network assisted detector can be complemented to a Turbo equalization receiver. Furthermore, we propose a compatible training technique to improve the detection performance of the proposed DL-SPDA with Turbo equalization. In particular, the neural network is optimized in terms of the mutual information between the transmitted sequence and the extrinsic information. We also investigate the maximum-likelihood bit error rate (BER) performance of a finite length coded FTN system. Simulation results show that the error performance of the proposed algorithm approaches the MAP performance, which is consistent with the analytical BER.
... In his pioneering paper [1], Mazo showed that when signaling transmits 25% faster than Nyquist rate, the minimum Euclidean distance between binary phase shift keying (BPSK) modulated sinc pulses remains the same, which indicates that FTN signaling can boost the data rate by 25% without performance degradation or bandwidth expansion. More importantly, it has been proved that FTN signaling can achieve a higher Shannon capacity than classic Nyquist signaling with a non-sinc signaling pulse [2], [3]. Therefore FTN signaling has been recognized as bandwidth-efficient signaling scheme, which has a great potential for supporting high speed data transmissions in next generation wireless communication systems [4], [5]. ...
Faster-than-Nyquist (FTN) signaling has been recognized as a promising technique for next-generation high data rate communications. By intentionally packing the symbol interval, FTN signaling is capable of transmitting more symbols than classic Nyquist signaling within the same time period and bandwidth. However, the intentional non-orthogonality of the bandlimited signaling pulses imposes severe inter-symbol interference (ISI), which requires powerful equalization at the receiver. Hence, we embark on the comparison of time- and frequency-domain equalization for FTN signaling both by theoretical analysis and numerical simulations. It is shown that frequency-domain equalization fails to reliably detect the FTN signal with a low FTN packing factor, while the time-domain equalization still performs well.
... It has been proved in [33] that such a signaling method can enjoy a higher channel capacity than that of conventional Nyquist signaling over the additive white Gaussian noise (AWGN) channels. To combat the severe ISI induced by the FTN signaling, various approaches with a reduced-complexity [34], [35] have been proposed in the literature. In [34], two reduced-search algorithms based on the Ungerboeck Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm [36] were proposed. ...
Intelligent vehicular networks (IVNs) have drawn substantial interests in recent years due to its great potential for beyond 5G (B5G) communications. In IVNs, vehicles are equipped with multi-functional advanced wireless sensors which are capable to collect real-time and practical environmental information. In this paper, we first provide an overview of the existing researches on IVNs for B5G communications, while emphasizing the requirements and technical approaches. We then introduce a generalized framework which formulates the acquisition of desired variables as a joint estimation and detection problem. We further propose a distributed estimation framework to improve the scalability and robustness, in which vehicles can communicate wirelessly with other vehicles within the communication range. In particular, we introduce different consensus operations as a realization of this proposed framework and briefly compare them in terms of implementation feasibility and convergence behavior. Three approximation schemes are further considered for reducing the required communication signaling overhead. To shed light on the proposed distributed estimation framework, we focus on two cases, i.e., target tracking and network decoding in IVNs. Through simulations, we show that the distributed algorithms can efficiently track the target and decode the broadcasted messages, while achieving the same performance of the centralized schemes.
... e simulation results of Anderson et al. [10] reveal that when the transmitted pulse has excessive bandwidth, FTN transmission can achieve higher capacity than transmission under Nyquist rate. In other works, the research of FTN has been extended on multicarrier systems [11,12] and low-complexity demodulation [13]. ...
The rapid booming of future smart city applications and Internet of things (IoT) has raised higher demands on the next-generation radio access technologies with respect to connection density, spectral efficiency (SE), transmission accuracy, and detection latency. Recently, faster-than-Nyquist (FTN) and nonorthogonal multiple access (NOMA) have been regarded as promising technologies to achieve higher SE and massive connections, respectively. In this paper, we aim to exploit the joint benefits of FTN and NOMA by superimposing multiple FTN-based transmission signals on the same physical recourses. Considering the complicated intra- and interuser interferences introduced by the proposed transmission scheme, the conventional detection methods suffer from high computational complexity. To this end, we develop a novel sliding-window detection method by incorporating the state-of-the-art deep learning (DL) technology. The data-driven offline training is first applied to derive a near-optimal receiver for FTN-based NOMA, which is deployed online to achieve high detection accuracy as well as low latency. Monte Carlo simulation results validate that the proposed detector achieves higher detection accuracy than minimum mean squared error-frequency domain equalization (MMSE-FDE) and can even approach the performance of the maximum likelihood-based receiver with greatly reduced computational complexity, which is suitable for IoT applications in smart city with low latency and high reliability requirements.
... In 1997, Daunt et al. designed a multilevel coded modulation scheme in [2][3] and pointed out that huge signal constellation and active signal shaping are indeed not mandatory to approach the channel capacity. Li Ping followed this work and did extensive analysis in [4]. Superposition coded modulation with one layer can achieve similar performance as presented by the authors of [4]. ...
... Li Ping followed this work and did extensive analysis in [4]. Superposition coded modulation with one layer can achieve similar performance as presented by the authors of [4]. But the results are limited to 2 bps per signal dimension. ...
... In 1997, Daunt et al. designed a multilevel coded modulation scheme in [2][3] and pointed out that huge signal constellation and active signal shaping are indeed not mandatory to approach the channel capacity. Li Ping followed this work and did extensive analysis in [4]. Superposition coded modulation with one layer can achieve similar performance as presented by the authors of [4]. ...
... Li Ping followed this work and did extensive analysis in [4]. Superposition coded modulation with one layer can achieve similar performance as presented by the authors of [4]. But the results are limited to 2 bps per signal dimension. ...
OFDM system loses the orthogonality between subcarriers due to carrier frequency offset resulting in inter-carrier interference (ICI) in the OFDM system. CFO impedes the performance of the demodulation process in baseband receiver increasing BER in the OFDM system. In the proposed scheme, the estimation of CFO is performed using the Extended Kalman filter (EKF) and sigma pointed Kalman filter (SPKF) on the SCM-OFDM system. The simulation results show that the estimation using SPKF can achieve better results than other variants of the Kalman filter. The proposed system improves the BER performance of the OFDM system. Further, it is shown that SPKF outperforms than of EKF.
