Pub Date : 2022-10-19DOI: 10.1109/ISWCS56560.2022.9940423
Luoluo Jiang, Caihong Luo, Xiao Li, M. Matthaiou, Shi Jin
Reconfigurable intelligent surfaces (RISs) have been proposed as a promising technology for future wireless communication systems to achieve both high spectral and energy efficiency. In this paper, we investigate a RIS-assisted downlink multi-cell communication system, where the RIS is deployed at the cell edges to serve the users in blind spots, with only statistical channel state information (CSI) being available. Under these assumptions, we investigate the optimization of beamforming at the BSs and phase shift at the RIS to maximize the approximated ergodic weighted sum spectral efficiency (WSSE). The complex circle manifold based algorithm is proposed to obtain the sub-optimal phase shift matrix while the statistical maximum ratio transmission (MRT) is applied to design the sub-optimal beamforming vectors. Our simulation results show that the approximate ergodic spectral efficiency expression is very close to the exact Monte-Carlo simulation, whilst the robustness of the ergodic WSSE is verified.
{"title":"RIS-Assisted Downlink Multi-cell Communication Using Statistical CSI","authors":"Luoluo Jiang, Caihong Luo, Xiao Li, M. Matthaiou, Shi Jin","doi":"10.1109/ISWCS56560.2022.9940423","DOIUrl":"https://doi.org/10.1109/ISWCS56560.2022.9940423","url":null,"abstract":"Reconfigurable intelligent surfaces (RISs) have been proposed as a promising technology for future wireless communication systems to achieve both high spectral and energy efficiency. In this paper, we investigate a RIS-assisted downlink multi-cell communication system, where the RIS is deployed at the cell edges to serve the users in blind spots, with only statistical channel state information (CSI) being available. Under these assumptions, we investigate the optimization of beamforming at the BSs and phase shift at the RIS to maximize the approximated ergodic weighted sum spectral efficiency (WSSE). The complex circle manifold based algorithm is proposed to obtain the sub-optimal phase shift matrix while the statistical maximum ratio transmission (MRT) is applied to design the sub-optimal beamforming vectors. Our simulation results show that the approximate ergodic spectral efficiency expression is very close to the exact Monte-Carlo simulation, whilst the robustness of the ergodic WSSE is verified.","PeriodicalId":141258,"journal":{"name":"2022 International Symposium on Wireless Communication Systems (ISWCS)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125848385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.1109/ISWCS56560.2022.9940437
Xiaopeng Yuan, Weiyu Li, Yulin Hu, A. Schmeink
In this work, we have studied an intelligent reflective surface (IRS)-assisted cognitive radio system. The non-orthogonal multiple access (NOMA) has been deployed to strengthen the spectrum sharing behaviour between two secondary users. In order to improve the secondary network in a fairness manner without significantly interfering the primary network, we formulate a minimum throughput minimization problem for the secondary network via a joint design of IRS beamforming and resource allocation at the secondary transmitter. To address the complex non-convex problem, we adopt the successive convex approximation technique and propose an iterative algorithm for alternating improving the IRS beamforming scheme and the resource allocation design. The algorithm will finally converge to an efficient suboptimal solution. Through numerical results, we highlight the advantage of deploying IRS in the considered system and also the potential superiority of NOMA scheme over the space-division multiple access (SDMA) via comparisons.
{"title":"Beamforming Design and Resource Allocation for IRS-Assisted NOMA Cognitive Radio System","authors":"Xiaopeng Yuan, Weiyu Li, Yulin Hu, A. Schmeink","doi":"10.1109/ISWCS56560.2022.9940437","DOIUrl":"https://doi.org/10.1109/ISWCS56560.2022.9940437","url":null,"abstract":"In this work, we have studied an intelligent reflective surface (IRS)-assisted cognitive radio system. The non-orthogonal multiple access (NOMA) has been deployed to strengthen the spectrum sharing behaviour between two secondary users. In order to improve the secondary network in a fairness manner without significantly interfering the primary network, we formulate a minimum throughput minimization problem for the secondary network via a joint design of IRS beamforming and resource allocation at the secondary transmitter. To address the complex non-convex problem, we adopt the successive convex approximation technique and propose an iterative algorithm for alternating improving the IRS beamforming scheme and the resource allocation design. The algorithm will finally converge to an efficient suboptimal solution. Through numerical results, we highlight the advantage of deploying IRS in the considered system and also the potential superiority of NOMA scheme over the space-division multiple access (SDMA) via comparisons.","PeriodicalId":141258,"journal":{"name":"2022 International Symposium on Wireless Communication Systems (ISWCS)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129796660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.1109/ISWCS56560.2022.9940400
Haonan Wang, Ang Li, Yuanjun Shen, B. Vucetic, Yonghui Li
Pattern reconfigurable multiple-input multiple-output (PR-MIMO) can improve the communication quality compared with the traditional MIMO via modifying the wireless propagation environment actively. In this paper, we discuss the design of the constructive interference (CI)-based symbol-level precoding (CI-SLP) in the multi-user pattern-reconfigurable multiple-input single-output (MU-PR-MISO) communication systems. Firstly, the joint design problem of SLP and the radiation pattern is formulated aimed at maximizing the worst user's service quality. Based on that, the optimization problem is further decoupled and an iterative alternating optimization algorithm is proposed to obtain the desired radiation pattern and the corresponding precoding matrix. After simplifying the joint design problem in the single-pattern case where all the antenna elements adopt the same radiation pattern, the convexity of the pattern design problem can be ensured, leading to an optimal pattern design. Numerical results demonstrate that the reconfigurable radiation pattern can manipulate the wireless channel purposefully so that the performance gains by exploiting CI can be further increased.
{"title":"Multi-User Symbol-Level Precoding for Downlink Reconfigurable MIMO Communication Systems","authors":"Haonan Wang, Ang Li, Yuanjun Shen, B. Vucetic, Yonghui Li","doi":"10.1109/ISWCS56560.2022.9940400","DOIUrl":"https://doi.org/10.1109/ISWCS56560.2022.9940400","url":null,"abstract":"Pattern reconfigurable multiple-input multiple-output (PR-MIMO) can improve the communication quality compared with the traditional MIMO via modifying the wireless propagation environment actively. In this paper, we discuss the design of the constructive interference (CI)-based symbol-level precoding (CI-SLP) in the multi-user pattern-reconfigurable multiple-input single-output (MU-PR-MISO) communication systems. Firstly, the joint design problem of SLP and the radiation pattern is formulated aimed at maximizing the worst user's service quality. Based on that, the optimization problem is further decoupled and an iterative alternating optimization algorithm is proposed to obtain the desired radiation pattern and the corresponding precoding matrix. After simplifying the joint design problem in the single-pattern case where all the antenna elements adopt the same radiation pattern, the convexity of the pattern design problem can be ensured, leading to an optimal pattern design. Numerical results demonstrate that the reconfigurable radiation pattern can manipulate the wireless channel purposefully so that the performance gains by exploiting CI can be further increased.","PeriodicalId":141258,"journal":{"name":"2022 International Symposium on Wireless Communication Systems (ISWCS)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114558933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.1109/ISWCS56560.2022.9940253
Yanhua Zhao, V. Sark, Milos Krstic, E. Grass
Radio detection and ranging (RADAR) technology has attracted a lot of attention recently, especially for hand gesture recognition. Contactless hand gesture recognition can be applied in many areas, such as in-car entertainment systems and clean room operations. In this work, a computationally efficient and fast hand gesture feature extraction approach based on frequency-modulated continuous-wave (FMCW) RADAR is proposed, which is highly beneficial for real-time applications. Unlike conventional image recognition, the features of the hand gesture are extracted directly in an efficient manner. Our approach adopts 2-dimensional Fast Fourier Transform (FFT) to form a Range-Doppler matrix, and background modelling to remove clutter. Furthermore, we use best bin selection to locate the target in the Range-Doppler matrix in order to obtain both range and velocity of targets. Fourier beam steering is employed to obtain the angle of targets. Four classifiers are trained to perform hand gesture recognition. Cross-validation is used to evaluate their performance. Experimental results indicate that the features extracted by our approach can be fed directly into the classifiers for recognition which leads to an average recognition accuracy of 98.74% across all classifiers. Compared to image based recognition, the additional feature extraction process can be skipped, saving significant processing time. Our approach could be useful in many areas such as in-car entertainment systems, smart homes and others.
{"title":"Low Computational Complexity Algorithm for Hand Gesture Recognition using mmWave RADAR","authors":"Yanhua Zhao, V. Sark, Milos Krstic, E. Grass","doi":"10.1109/ISWCS56560.2022.9940253","DOIUrl":"https://doi.org/10.1109/ISWCS56560.2022.9940253","url":null,"abstract":"Radio detection and ranging (RADAR) technology has attracted a lot of attention recently, especially for hand gesture recognition. Contactless hand gesture recognition can be applied in many areas, such as in-car entertainment systems and clean room operations. In this work, a computationally efficient and fast hand gesture feature extraction approach based on frequency-modulated continuous-wave (FMCW) RADAR is proposed, which is highly beneficial for real-time applications. Unlike conventional image recognition, the features of the hand gesture are extracted directly in an efficient manner. Our approach adopts 2-dimensional Fast Fourier Transform (FFT) to form a Range-Doppler matrix, and background modelling to remove clutter. Furthermore, we use best bin selection to locate the target in the Range-Doppler matrix in order to obtain both range and velocity of targets. Fourier beam steering is employed to obtain the angle of targets. Four classifiers are trained to perform hand gesture recognition. Cross-validation is used to evaluate their performance. Experimental results indicate that the features extracted by our approach can be fed directly into the classifiers for recognition which leads to an average recognition accuracy of 98.74% across all classifiers. Compared to image based recognition, the additional feature extraction process can be skipped, saving significant processing time. Our approach could be useful in many areas such as in-car entertainment systems, smart homes and others.","PeriodicalId":141258,"journal":{"name":"2022 International Symposium on Wireless Communication Systems (ISWCS)","volume":"198 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114875617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.1109/ISWCS56560.2022.9940356
Futian Ni, M. Lei, Ming-Min Zhao, Min-Jian Zhao
Orthogonal time frequency space (OTFS) modulation is a new promising two-dimensional (2D) modulation technique for future wireless communication systems over high-mobility channels. To achieve the performance gain promised by OTFS, the unitary approximate message passing (UAMP) based detector is widely used due to its robustness, low complexity and superior performance. However, the complexity of the UAMP-based detector is high in the case of more practical waveforms, such as the rectangular waveform, which hinders its practical implementation. In this work, we propose a low complexity UAMP-based detector which inserts null symbols in the last few rows of the delay-Doppler domain according to the max delay of the time-varying channel, and exploits the circulant property of the equivalent channel matrix to simplify the calculation process of the UAMP detector. Simulation results show that the proposed detector has similar bit error rate (BER) performance as compared with the original UAMP detector, but exhibits much lower complexity.
{"title":"Low Complexity Unitary Approximate Message Passing Based Equalization for OTFS System","authors":"Futian Ni, M. Lei, Ming-Min Zhao, Min-Jian Zhao","doi":"10.1109/ISWCS56560.2022.9940356","DOIUrl":"https://doi.org/10.1109/ISWCS56560.2022.9940356","url":null,"abstract":"Orthogonal time frequency space (OTFS) modulation is a new promising two-dimensional (2D) modulation technique for future wireless communication systems over high-mobility channels. To achieve the performance gain promised by OTFS, the unitary approximate message passing (UAMP) based detector is widely used due to its robustness, low complexity and superior performance. However, the complexity of the UAMP-based detector is high in the case of more practical waveforms, such as the rectangular waveform, which hinders its practical implementation. In this work, we propose a low complexity UAMP-based detector which inserts null symbols in the last few rows of the delay-Doppler domain according to the max delay of the time-varying channel, and exploits the circulant property of the equivalent channel matrix to simplify the calculation process of the UAMP detector. Simulation results show that the proposed detector has similar bit error rate (BER) performance as compared with the original UAMP detector, but exhibits much lower complexity.","PeriodicalId":141258,"journal":{"name":"2022 International Symposium on Wireless Communication Systems (ISWCS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130025809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.1109/ISWCS56560.2022.9940435
Zeliang Ou, Hongwen Yang
This paper presents an improved orthogonal frequency-division multiple access (OFDMA) system design aiming to reduce the power consumption and the hardware complexity of low-cost user terminals. In conventional OFDMA systems, the analog-to-digital converters (ADCs) at user side contribute a considerable part to hardware complexity and energy consumption due to high sampling rate and high resolution quantization. In the proposed design, the base station uses block diagonalization precoding to cancel the interference among $K$ users; Each user adopts a low-cost ADC where the sampling rate is reduced to 1/$K$ of the Nyquist rate, and the number of quantization bits can be reduced to 2~3 bits. To address the problem of inter-symbol interference due to sub-Nyquist sampling and non-linear distortion due to quantization, the generalized approximate message passing (GAMP) algorithm is adopted at each receiver. Compared with conventional OFDMA systems, the proposed design can greatly reduce the hardware complexity and the power consumption of user receivers while keep the bit error rate performance acceptable.
{"title":"An Improved OFDMA Design for Low-Cost Receivers","authors":"Zeliang Ou, Hongwen Yang","doi":"10.1109/ISWCS56560.2022.9940435","DOIUrl":"https://doi.org/10.1109/ISWCS56560.2022.9940435","url":null,"abstract":"This paper presents an improved orthogonal frequency-division multiple access (OFDMA) system design aiming to reduce the power consumption and the hardware complexity of low-cost user terminals. In conventional OFDMA systems, the analog-to-digital converters (ADCs) at user side contribute a considerable part to hardware complexity and energy consumption due to high sampling rate and high resolution quantization. In the proposed design, the base station uses block diagonalization precoding to cancel the interference among $K$ users; Each user adopts a low-cost ADC where the sampling rate is reduced to 1/$K$ of the Nyquist rate, and the number of quantization bits can be reduced to 2~3 bits. To address the problem of inter-symbol interference due to sub-Nyquist sampling and non-linear distortion due to quantization, the generalized approximate message passing (GAMP) algorithm is adopted at each receiver. Compared with conventional OFDMA systems, the proposed design can greatly reduce the hardware complexity and the power consumption of user receivers while keep the bit error rate performance acceptable.","PeriodicalId":141258,"journal":{"name":"2022 International Symposium on Wireless Communication Systems (ISWCS)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132461174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.1109/ISWCS56560.2022.9940255
Minghui Wu, Ziwei Wan, Yang Wang, Shicong Liu, Zhen Gao
Due to the high dimensionality of the channel state information (CSI) in massive multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems, acquiring accurate CSI at the transmitter (CSIT) with limited feedback overhead is difficult, severely degrading the performance of conventional SDMA beamforming techniques. To this end, this paper proposes a deep learning (DL)-based end-to-end (E2E) rate-splitting multiple access (RSMA) beam-forming scheme for massive MIMO-OFDM systems, including an analog beamforming network (ABN) and a model-driven RSMA digital beamforming network (RDBN). We adopt an E2E training approach to jointly train the proposed ABN and MRBN to obtain better beamforming performance. Numerical results show that the proposed DL-based E2E RSMA beam-forming scheme significantly improves the system capacity and outperforms the state-of-the-art schemes.
{"title":"Deep Learning-Based Rate-Splitting Multiple Access for Massive MIMO-OFDM Systems With Imperfect CSIT","authors":"Minghui Wu, Ziwei Wan, Yang Wang, Shicong Liu, Zhen Gao","doi":"10.1109/ISWCS56560.2022.9940255","DOIUrl":"https://doi.org/10.1109/ISWCS56560.2022.9940255","url":null,"abstract":"Due to the high dimensionality of the channel state information (CSI) in massive multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems, acquiring accurate CSI at the transmitter (CSIT) with limited feedback overhead is difficult, severely degrading the performance of conventional SDMA beamforming techniques. To this end, this paper proposes a deep learning (DL)-based end-to-end (E2E) rate-splitting multiple access (RSMA) beam-forming scheme for massive MIMO-OFDM systems, including an analog beamforming network (ABN) and a model-driven RSMA digital beamforming network (RDBN). We adopt an E2E training approach to jointly train the proposed ABN and MRBN to obtain better beamforming performance. Numerical results show that the proposed DL-based E2E RSMA beam-forming scheme significantly improves the system capacity and outperforms the state-of-the-art schemes.","PeriodicalId":141258,"journal":{"name":"2022 International Symposium on Wireless Communication Systems (ISWCS)","volume":"60 1516 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122567492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.1109/ISWCS56560.2022.9940434
Abdelhamid Salem, C. Masouros
In this paper a novel constructive multiple access (CoMA) scheme is proposed. The new CoMA technique aligns the superimposed signals to the users constructively to the signal of interest. Accordingly, there is no need to remove it at the receiver using successive interference cancellation (SIC) technique. In this regard, optimal CoMA precoders are designed for user paring NOMA multiple-input-single-output (MISO) systems. The results in this paper show that CoMA is an attractive solution for NOMA systems with low number of antennas, and transmission power.
{"title":"NOMA Made Practical: Removing the SIC Through Constructive Interference","authors":"Abdelhamid Salem, C. Masouros","doi":"10.1109/ISWCS56560.2022.9940434","DOIUrl":"https://doi.org/10.1109/ISWCS56560.2022.9940434","url":null,"abstract":"In this paper a novel constructive multiple access (CoMA) scheme is proposed. The new CoMA technique aligns the superimposed signals to the users constructively to the signal of interest. Accordingly, there is no need to remove it at the receiver using successive interference cancellation (SIC) technique. In this regard, optimal CoMA precoders are designed for user paring NOMA multiple-input-single-output (MISO) systems. The results in this paper show that CoMA is an attractive solution for NOMA systems with low number of antennas, and transmission power.","PeriodicalId":141258,"journal":{"name":"2022 International Symposium on Wireless Communication Systems (ISWCS)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131803353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.1109/ISWCS56560.2022.9940412
Junfan Hu, Yi Jin, Jia Shi, Xuan Liu, Zhenfei Dai, Zan Li
To address the reliability threat of LEO satellite (LEO-Sat) to terrestrial communications, this paper proposes a novel network using mobile multi-UAV as decoded-and-forward (DF) relays under the orthogonal time frequency space (OTFS) scheme. In particular, OTFS is used to cope with the severe Doppler frequency shift of the LEO-Sat communication (LEO-Satcom) system with higher carrier frequency tendency and relatively high-speed mobility. The addition of mobile multi-UAV not only improves the coverage performance but also compensates for the severe path loss. Stochastic geometry theory is utilized to characterize the mobile model of UAVs and thus assist in the reliability performance analysis. Simulation results demonstrate that the proposed OTFS-based LEO-Satcom network has improved system reliability compared to the conventional time-frequency domain modulation scheme. The impact of UAVs' deployment properties on reliable transmission is further illustrated.
{"title":"Reliability Analysis of Stochastic Geometry-based Multi-UAV-aided LEO-Satcom under OTFS","authors":"Junfan Hu, Yi Jin, Jia Shi, Xuan Liu, Zhenfei Dai, Zan Li","doi":"10.1109/ISWCS56560.2022.9940412","DOIUrl":"https://doi.org/10.1109/ISWCS56560.2022.9940412","url":null,"abstract":"To address the reliability threat of LEO satellite (LEO-Sat) to terrestrial communications, this paper proposes a novel network using mobile multi-UAV as decoded-and-forward (DF) relays under the orthogonal time frequency space (OTFS) scheme. In particular, OTFS is used to cope with the severe Doppler frequency shift of the LEO-Sat communication (LEO-Satcom) system with higher carrier frequency tendency and relatively high-speed mobility. The addition of mobile multi-UAV not only improves the coverage performance but also compensates for the severe path loss. Stochastic geometry theory is utilized to characterize the mobile model of UAVs and thus assist in the reliability performance analysis. Simulation results demonstrate that the proposed OTFS-based LEO-Satcom network has improved system reliability compared to the conventional time-frequency domain modulation scheme. The impact of UAVs' deployment properties on reliable transmission is further illustrated.","PeriodicalId":141258,"journal":{"name":"2022 International Symposium on Wireless Communication Systems (ISWCS)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134224636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.1109/ISWCS56560.2022.9940422
Hao Xu, Yao Zhu, Kai Xiang, Yulin Hu, A. Schmeink
In this paper, we investigate a non-orthogonal multiple access (NOMA)-assisted mobile edge computing (MEC) network supporting a time-sensitive computing task with data inputs being generated at and offloaded from multiple users. To minimize the energy consumption of both users and server, a joint power and computational resource allocation problem is formulated, which is unfortunately non-convex. To address the problem and obtain the global optimal solution, we first carefully characterize optimality conditions of the problem, and then provide an efficient approach to transform the problem to an equivalent convex one. Via numerical simulation, our analytical results are validated and the impacts of channel quality, task deadline and computation workload on the system performance are investigated and evaluated.
{"title":"Energy Consumption Minimization for NOMA-Assisted Mobile Edge Computing","authors":"Hao Xu, Yao Zhu, Kai Xiang, Yulin Hu, A. Schmeink","doi":"10.1109/ISWCS56560.2022.9940422","DOIUrl":"https://doi.org/10.1109/ISWCS56560.2022.9940422","url":null,"abstract":"In this paper, we investigate a non-orthogonal multiple access (NOMA)-assisted mobile edge computing (MEC) network supporting a time-sensitive computing task with data inputs being generated at and offloaded from multiple users. To minimize the energy consumption of both users and server, a joint power and computational resource allocation problem is formulated, which is unfortunately non-convex. To address the problem and obtain the global optimal solution, we first carefully characterize optimality conditions of the problem, and then provide an efficient approach to transform the problem to an equivalent convex one. Via numerical simulation, our analytical results are validated and the impacts of channel quality, task deadline and computation workload on the system performance are investigated and evaluated.","PeriodicalId":141258,"journal":{"name":"2022 International Symposium on Wireless Communication Systems (ISWCS)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114202917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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