Pub Date : 2018-06-01DOI: 10.1109/SPAWC.2018.8445935
G. Vougioukas, Panos N. Alevizos, A. Bletsas
This work studies ambient backscatter, where the tag utilizes a frequency-shifted form of on-off keying (OOK), which may be coined as pseudo-frequency shift keying (pseudo-FSK). Such scheme, offers the possibility of simple, frequency-domain multiple access (due to FSK), by appropriate selection of the switching frequencies among (possibly receiverless) tags, while reserving bandwidth (due to OOK). A constant envelope-modulated ambient signal is assumed to illuminate the tag, resembling signals from (analog) FM radio, (digital) minimum-shift keying (MSK), or phase-shift keying (PSK) broadcasting stations. Fully coherent, maximum likelihood (ML) detection is derived for tag information, without estimating or detecting the ambient signal; instead, the law of large numbers is exploited, in conjunction with channel estimation techniques, even though the ambient unknown signal changes between successive tag bits. Closed-form expression for the probability of error is also given and simulations verify theoretical results. Ambient is a special case of bistatic backscatter; thus, useful design principles for ambient systems can stem from the bistatic backscatter literature.
{"title":"Coherent Detector for Pseudo-FSK Backscatter Under Ambient Constant Envelope Illumination","authors":"G. Vougioukas, Panos N. Alevizos, A. Bletsas","doi":"10.1109/SPAWC.2018.8445935","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445935","url":null,"abstract":"This work studies ambient backscatter, where the tag utilizes a frequency-shifted form of on-off keying (OOK), which may be coined as pseudo-frequency shift keying (pseudo-FSK). Such scheme, offers the possibility of simple, frequency-domain multiple access (due to FSK), by appropriate selection of the switching frequencies among (possibly receiverless) tags, while reserving bandwidth (due to OOK). A constant envelope-modulated ambient signal is assumed to illuminate the tag, resembling signals from (analog) FM radio, (digital) minimum-shift keying (MSK), or phase-shift keying (PSK) broadcasting stations. Fully coherent, maximum likelihood (ML) detection is derived for tag information, without estimating or detecting the ambient signal; instead, the law of large numbers is exploited, in conjunction with channel estimation techniques, even though the ambient unknown signal changes between successive tag bits. Closed-form expression for the probability of error is also given and simulations verify theoretical results. Ambient is a special case of bistatic backscatter; thus, useful design principles for ambient systems can stem from the bistatic backscatter literature.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123935094","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 : 2018-06-01DOI: 10.1109/SPAWC.2018.8445905
Martin Schlüter, Meik Dörpinghaus, G. Fettweis
In the design of energy-efficient communication systems with very high bandwidths, the analog-to-digital converter (ADC) plays a crucial role, since its energy consumption grows exponentially with the number of quantization bits. However, high resolution in time domain is less difficult to achieve than high resolution in amplitude domain. This motivates for the design of receivers with L-bit quantization and oversampling w.r.t. Nyquist rate. On the downside, standard receiver synchronization algorithms cannot be applied, since L-bit quantization is a highly non-linear function. To understand the channel parameter estimation performance of such a receiver, the Fisher information (FI) is a helpful measure. Since the closed form evaluation of the FI is not possible for correlated Gaussian noise, we give a lower bound that is an extension of a lower bound by Stein et al. to complex valued channel outputs. If the noise is white, the lower bound is tight. Furthermore, we apply the lower bound for the evaluation of the performance of carrier phase estimation of a QPSK based communication system. We show that for any SNR level oversampling reduces the performance loss due to 1-bit quantization. In the mid and low SNR regime, oversampling reduces the performance loss beyond the loss of 2π encountered in case of 1-bit quantization at Nyquist sampling in the low SNR regime.
{"title":"Bounds on Channel Parameter Estimation with 1-Bit Quantization and Oversampling","authors":"Martin Schlüter, Meik Dörpinghaus, G. Fettweis","doi":"10.1109/SPAWC.2018.8445905","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445905","url":null,"abstract":"In the design of energy-efficient communication systems with very high bandwidths, the analog-to-digital converter (ADC) plays a crucial role, since its energy consumption grows exponentially with the number of quantization bits. However, high resolution in time domain is less difficult to achieve than high resolution in amplitude domain. This motivates for the design of receivers with L-bit quantization and oversampling w.r.t. Nyquist rate. On the downside, standard receiver synchronization algorithms cannot be applied, since L-bit quantization is a highly non-linear function. To understand the channel parameter estimation performance of such a receiver, the Fisher information (FI) is a helpful measure. Since the closed form evaluation of the FI is not possible for correlated Gaussian noise, we give a lower bound that is an extension of a lower bound by Stein et al. to complex valued channel outputs. If the noise is white, the lower bound is tight. Furthermore, we apply the lower bound for the evaluation of the performance of carrier phase estimation of a QPSK based communication system. We show that for any SNR level oversampling reduces the performance loss due to 1-bit quantization. In the mid and low SNR regime, oversampling reduces the performance loss beyond the loss of 2π encountered in case of 1-bit quantization at Nyquist sampling in the low SNR regime.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128568217","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 : 2018-06-01DOI: 10.1109/SPAWC.2018.8446017
Ayswarya Padmanabhan, Antti Tölli
We consider a single cell downlink (DL) massive multiple-input multiple-output (MIMO) set-up with user clustering based on statistical information. The problem is to design a fully digital two-stage beamforming aiming to reduce the complexity involved in the conventional MIMO processing. The fully digital two-stage beamforming consists of a slow varying channel statistics based outer beamformer (OBF) and an inner beamformer (IBF) accounting for fast channel variations. Two different methods are presented to design the OBF matrix, so as to reduce the size of effective channel used for IBF design. A group specific two-stage optimization problem with weighted sum rate maximization (WSRM) objective is formulated to find the IBF for fixed OBF. We begin by proposing centralized IBF design were the optimization is carried out for all sub group jointly with user specific inter-group interference constraints. In order to further reduce the complexity, we also propose a group specific IBF design by fixing the inter group interference to a constant or by ignoring them from the problem altogether. In spite of incurring a small loss in performance, the computational complexity can be saved to a large extent with the group specific processing. Numerical experiments are used to demonstrate the performance of various proposed schemes by comparing the total sum rate of all users and the design complexity.
{"title":"Interference Management via User Clustering in Two-Stage Precoder Design","authors":"Ayswarya Padmanabhan, Antti Tölli","doi":"10.1109/SPAWC.2018.8446017","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8446017","url":null,"abstract":"We consider a single cell downlink (DL) massive multiple-input multiple-output (MIMO) set-up with user clustering based on statistical information. The problem is to design a fully digital two-stage beamforming aiming to reduce the complexity involved in the conventional MIMO processing. The fully digital two-stage beamforming consists of a slow varying channel statistics based outer beamformer (OBF) and an inner beamformer (IBF) accounting for fast channel variations. Two different methods are presented to design the OBF matrix, so as to reduce the size of effective channel used for IBF design. A group specific two-stage optimization problem with weighted sum rate maximization (WSRM) objective is formulated to find the IBF for fixed OBF. We begin by proposing centralized IBF design were the optimization is carried out for all sub group jointly with user specific inter-group interference constraints. In order to further reduce the complexity, we also propose a group specific IBF design by fixing the inter group interference to a constant or by ignoring them from the problem altogether. In spite of incurring a small loss in performance, the computational complexity can be saved to a large extent with the group specific processing. Numerical experiments are used to demonstrate the performance of various proposed schemes by comparing the total sum rate of all users and the design complexity.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130890237","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 : 2018-06-01DOI: 10.1109/SPAWC.2018.8446010
C. Thomas, D. Slock
This work deals with hybrid beamforming (HBF) for the MIMO Interfering Broadcast Channel (IBC), i.e. the Multi-Input Multi-Output (MIMO) Multi-User (MU) Multi-Cell downlink channel. HBF is a low complexity alternative to fully digital precoding in Massive MIMO systems. Hybrid architectures involve a combination of digital and analog processing that enables both beamforming and multiplexing gains. We consider BF design by maximizing the Weighted Sum Rate (WSR) for the case of Perfect Channel State Information at the Transmitter (CSIT). We optimize the WSR using minorization and alternating optimization, the result of which is observed to converge fast. We furthermore propose a deterministic annealing based approach to avoid issues of local optima that plague phase shifter constrained analog beamformers. Simulation results indicate that the proposed deterministic annealing based approach performs significantly better than state of the art Weighted Sum Mean Squared Error (WSMSE) or WSR based solutions. We also propose a closed form solution for the analog BF in case the number of RF chains equals or exceeds the total number of multipath components and the antenna array responses are phasors.
{"title":"Deterministic Annealing for Hybrid Beamforming Design in Multi-Cell MU-MIMO Systems","authors":"C. Thomas, D. Slock","doi":"10.1109/SPAWC.2018.8446010","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8446010","url":null,"abstract":"This work deals with hybrid beamforming (HBF) for the MIMO Interfering Broadcast Channel (IBC), i.e. the Multi-Input Multi-Output (MIMO) Multi-User (MU) Multi-Cell downlink channel. HBF is a low complexity alternative to fully digital precoding in Massive MIMO systems. Hybrid architectures involve a combination of digital and analog processing that enables both beamforming and multiplexing gains. We consider BF design by maximizing the Weighted Sum Rate (WSR) for the case of Perfect Channel State Information at the Transmitter (CSIT). We optimize the WSR using minorization and alternating optimization, the result of which is observed to converge fast. We furthermore propose a deterministic annealing based approach to avoid issues of local optima that plague phase shifter constrained analog beamformers. Simulation results indicate that the proposed deterministic annealing based approach performs significantly better than state of the art Weighted Sum Mean Squared Error (WSMSE) or WSR based solutions. We also propose a closed form solution for the analog BF in case the number of RF chains equals or exceeds the total number of multipath components and the antenna array responses are phasors.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130331216","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 : 2018-06-01DOI: 10.1109/SPAWC.2018.8445897
P. Ciblat, I. Stupia, L. Vandendorpe
We address the problem of allocating different powers amongst parallel channels when effective capacity is the performance metric and sum-power is constrained. We assume that Chase-Combining-HARQ mechanism is applied. Closed-form expressions for the powers are exhibited. Numerical comparisons with other power allocations obtained through either ergodic capacity or throughput optimizations are done.
{"title":"Effective Capacity Based Resource Allocation for Rayleigh-Fading Parallel Channels","authors":"P. Ciblat, I. Stupia, L. Vandendorpe","doi":"10.1109/SPAWC.2018.8445897","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445897","url":null,"abstract":"We address the problem of allocating different powers amongst parallel channels when effective capacity is the performance metric and sum-power is constrained. We assume that Chase-Combining-HARQ mechanism is applied. Closed-form expressions for the powers are exhibited. Numerical comparisons with other power allocations obtained through either ergodic capacity or throughput optimizations are done.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128483570","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 : 2018-06-01DOI: 10.1109/SPAWC.2018.8445856
Michele Polese, M. Zorzi
Communication at mmWave frequencies is one of the major innovations of the fifth generation of cellular networks, because of the potential multi-gigabit data rate given by the large amounts of available bandwidth. The mmWave channel, however, makes reliable communications particularly challenging, given the harsh propagation environment and the sensitivity to blockage. Therefore, proper modeling of the mmWave channel is fundamental for accurate results in system simulations of mmWave cellular networks. Nonetheless, complex models, such as the 3GPP channel model for frequencies above 6 GHz, may introduce a significant overhead in terms of computational complexity. In this paper we investigate the trade offs related to the accuracy and the simplicity of the channel model in end-to-end network simulations, and the impact on the performance evaluation of transport protocols.
{"title":"Impact of Channel Models on the End-to-End Performance of Mmwave Cellular Networks","authors":"Michele Polese, M. Zorzi","doi":"10.1109/SPAWC.2018.8445856","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445856","url":null,"abstract":"Communication at mmWave frequencies is one of the major innovations of the fifth generation of cellular networks, because of the potential multi-gigabit data rate given by the large amounts of available bandwidth. The mmWave channel, however, makes reliable communications particularly challenging, given the harsh propagation environment and the sensitivity to blockage. Therefore, proper modeling of the mmWave channel is fundamental for accurate results in system simulations of mmWave cellular networks. Nonetheless, complex models, such as the 3GPP channel model for frequencies above 6 GHz, may introduce a significant overhead in terms of computational complexity. In this paper we investigate the trade offs related to the accuracy and the simplicity of the channel model in end-to-end network simulations, and the impact on the performance evaluation of transport protocols.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122973027","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 : 2018-06-01DOI: 10.1109/SPAWC.2018.8445982
C. Charalambous, C. Kourtellaris, Themistoklis Charalambous
In this paper, we transform the n-finite transmission feedback information (FTFI) capacity of unstable Gaussian decision models with memory on past outputs, subject to an average cost constraint of quadratic form derived in [1], into controllers-encoders-decoders that control the output process, encode a Gaussian process, reconstruct the Gaussian process via a mean-square error (MSE) decoder, and achieve the n-FTFI capacity. For a Gaussian RV message X N(0,σ2X) it is shown that the MSE decays according to E X-X'n n2= -2C0, n(k)σX2, Kɞ(kmin,∞), where C0, n(k) is the n-FTFI capacity, and kmin is the threshold on the power to ensure convergence.
本文将不稳定高斯决策模型的n-有限传输反馈信息(FTFI)容量转化为控制器-编码器-解码器，控制输出过程，编码高斯过程，通过均方误差(MSE)解码器重构高斯过程，从而实现n-FTFI容量。对于高斯RV消息X N(0，σ2X)， MSE的衰减符合E X-X'n N = -2C0, N(k)σX2, k (kmin，∞)，其中，C0, N(k)为N - ftfi容量，kmin为保证收敛的功率阈值。
{"title":"A General Coding Scheme for Signaling Gaussian Processes Over Gaussian Decision Models","authors":"C. Charalambous, C. Kourtellaris, Themistoklis Charalambous","doi":"10.1109/SPAWC.2018.8445982","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445982","url":null,"abstract":"In this paper, we transform the n-finite transmission feedback information (FTFI) capacity of unstable Gaussian decision models with memory on past outputs, subject to an average cost constraint of quadratic form derived in [1], into controllers-encoders-decoders that control the output process, encode a Gaussian process, reconstruct the Gaussian process via a mean-square error (MSE) decoder, and achieve the n-FTFI capacity. For a Gaussian RV message X N(0,σ<sup>2</sup>X) it is shown that the MSE decays according to E X-X'<inf>n</inf> n<sup>2</sup>= -2C<inf>0, n</inf>(k)σ<inf>X</inf><sup>2</sup>, Kɞ(k<inf>min</inf>,∞), where C<inf>0, n</inf>(k) is the n-FTFI capacity, and k<inf>min</inf> is the threshold on the power to ensure convergence.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126833729","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 : 2018-06-01DOI: 10.1109/SPAWC.2018.8445963
Ammar Ahmed, Yujie Gu, D. Silage, Yimin D. Zhang
Dual-function radar-communications (DFRC) systems have emerged as a promising solution for spectrum sharing problem in recent years. In this paper, we propose a novel DFRC strategy by exploiting directional power control and waveform diversity. The proposed technique ensures the highest possible magnitude of the radar main beam resulting in an improved signal-to-noise ratio for the radar operation. This maximization objective is achieved while considering the pre-allocated or adjustable transmit energy requirement for radar and communication operations. The secondary communication objective enabling multi-user access is realized by transmitting distinct amplitude levels and phases towards different communication receivers located in the sidelobe region of radar. As an example, power allocation for different orthogonal frequency-division multiplexing (OFDM) subcarriers projected towards the radar main beam and the communication receivers is discussed by considering the frequency response of target returns. Simulation results illustrate the performance of the proposed technique.
{"title":"Power-Efficient Multi-User Dual-Function Radar-Communications","authors":"Ammar Ahmed, Yujie Gu, D. Silage, Yimin D. Zhang","doi":"10.1109/SPAWC.2018.8445963","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445963","url":null,"abstract":"Dual-function radar-communications (DFRC) systems have emerged as a promising solution for spectrum sharing problem in recent years. In this paper, we propose a novel DFRC strategy by exploiting directional power control and waveform diversity. The proposed technique ensures the highest possible magnitude of the radar main beam resulting in an improved signal-to-noise ratio for the radar operation. This maximization objective is achieved while considering the pre-allocated or adjustable transmit energy requirement for radar and communication operations. The secondary communication objective enabling multi-user access is realized by transmitting distinct amplitude levels and phases towards different communication receivers located in the sidelobe region of radar. As an example, power allocation for different orthogonal frequency-division multiplexing (OFDM) subcarriers projected towards the radar main beam and the communication receivers is discussed by considering the frequency response of target returns. Simulation results illustrate the performance of the proposed technique.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127050165","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 : 2018-06-01DOI: 10.1109/SPAWC.2018.8445953
N. Saeed, Abdulkadir Celik, T. Al-Naffouri, Mohamed-Slim Alouini
Location is one of the basic information required for underwater optical wireless sensor networks (UOWSNs) for three main purposes: 1) Relating the sensing measurements with precise sensor positions, 2) Enabling efficient routing techniques by exploiting the sensor locations, and 3) Sustaining link connectivity and performance via pointing and alignment mechanisms between the nodes. Even though various two-dimensional UOWSNs localization methods have been proposed in the past, the directivity of optical wireless communications and three dimensional (3D) deployment of sensors require to develop 3D underwater localization methods. Therefore, we propose a robust 3D localization method for partially connected UOWSNs with a limited number of anchors. The proposed method achieves an accurate 3D localization of all the nodes in the network by using a novel low-rank matrix approximation and outliers removal method. The performance of the proposed method is compared with the well known iterative majorization approach. The numerical results indicate that the proposed method outperforms the iterative majorization method substantially.
{"title":"Robust 3D Localization of Underwater Optical Wireless Sensor Networks via Low Rank Matrix Completion","authors":"N. Saeed, Abdulkadir Celik, T. Al-Naffouri, Mohamed-Slim Alouini","doi":"10.1109/SPAWC.2018.8445953","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445953","url":null,"abstract":"Location is one of the basic information required for underwater optical wireless sensor networks (UOWSNs) for three main purposes: 1) Relating the sensing measurements with precise sensor positions, 2) Enabling efficient routing techniques by exploiting the sensor locations, and 3) Sustaining link connectivity and performance via pointing and alignment mechanisms between the nodes. Even though various two-dimensional UOWSNs localization methods have been proposed in the past, the directivity of optical wireless communications and three dimensional (3D) deployment of sensors require to develop 3D underwater localization methods. Therefore, we propose a robust 3D localization method for partially connected UOWSNs with a limited number of anchors. The proposed method achieves an accurate 3D localization of all the nodes in the network by using a novel low-rank matrix approximation and outliers removal method. The performance of the proposed method is compared with the well known iterative majorization approach. The numerical results indicate that the proposed method outperforms the iterative majorization method substantially.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127148876","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 : 2018-06-01DOI: 10.1109/SPAWC.2018.8446036
F. Bellili, Foad Sohrabi, Wei Yu
This paper tackles the problem of channel estimation in mmWave large-scale communication systems. To leverage the sparsity of mmWave MIMO channels in the beam domain, we use discrete Fourier transform (DFT) precoding and combining and recast the channel estimation problem as a compressed sensing (CS) problem. The generalized approximate message passing (GAMP) algorithm is then used to find the minimum mean square estimate (MMSE) of each entry of the unknown mmWave MIMO channel matrix. Unlike the existing works, this paper models the angular-domain channel coefficients by a Laplacian prior and accordingly establishes the closed-form expressions for all the statistical quantities that need to be updated iteratively by GAMP. Further, to render the proposed algorithm fully automated, we develop an expectation-maximization (EM)-based procedure which can be readily embedded within GAMP's iteration loop in order to learn the unknown scale parameter of the underlying Laplacian prior along with the noise variance. Numerical results indicate that the proposed EM-GAMP algorithm under a Laplacian prior yields substantial improvements both in terms of channel estimation accuracy and computational complexity as compared to the existing methods that advocate a Gaussian mixture (GM) prior.
{"title":"Massive MIMO mmWave Channel Estimation Using Approximate Message Passing and Laplacian Prior","authors":"F. Bellili, Foad Sohrabi, Wei Yu","doi":"10.1109/SPAWC.2018.8446036","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8446036","url":null,"abstract":"This paper tackles the problem of channel estimation in mmWave large-scale communication systems. To leverage the sparsity of mmWave MIMO channels in the beam domain, we use discrete Fourier transform (DFT) precoding and combining and recast the channel estimation problem as a compressed sensing (CS) problem. The generalized approximate message passing (GAMP) algorithm is then used to find the minimum mean square estimate (MMSE) of each entry of the unknown mmWave MIMO channel matrix. Unlike the existing works, this paper models the angular-domain channel coefficients by a Laplacian prior and accordingly establishes the closed-form expressions for all the statistical quantities that need to be updated iteratively by GAMP. Further, to render the proposed algorithm fully automated, we develop an expectation-maximization (EM)-based procedure which can be readily embedded within GAMP's iteration loop in order to learn the unknown scale parameter of the underlying Laplacian prior along with the noise variance. Numerical results indicate that the proposed EM-GAMP algorithm under a Laplacian prior yields substantial improvements both in terms of channel estimation accuracy and computational complexity as compared to the existing methods that advocate a Gaussian mixture (GM) prior.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"0 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121875435","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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