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.2018.8445876
G. Muzio, M. Kuscu, Ö. Akan
Molecular Communications (MC) is a bio-inspired wireless communication technique that uses molecules as a means of information transfer among bio-nano devices. In this paper, we focus on the signal detection problem of MC receivers employing receptor molecules to infer the transmitted messages encoded into the concentration of molecules, i.e., ligands. We particularly consider a very common scenario in physiological conditions, where there is non-negligible concentration of interferer molecules in the channel, which have similar binding characteristics with the ligands, and thus, can bind to the receptors, causing substantial interference with the MC signal. We investigate three different maximum likelihood (ML) detection methods based on different observable parameters of the ligand-receptor binding mechanism, which are the instantaneous number of bound receptors and the amount of time the receptors stay unbound or bound within an observation time window. We carry out a comparative analysis to numerically evaluate the performance of the detection methods under different system settings.
{"title":"Selective Signal Detection with Ligand Receptors Under Interference in Molecular Communications","authors":"G. Muzio, M. Kuscu, Ö. Akan","doi":"10.1109/SPAWC.2018.8445876","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445876","url":null,"abstract":"Molecular Communications (MC) is a bio-inspired wireless communication technique that uses molecules as a means of information transfer among bio-nano devices. In this paper, we focus on the signal detection problem of MC receivers employing receptor molecules to infer the transmitted messages encoded into the concentration of molecules, i.e., ligands. We particularly consider a very common scenario in physiological conditions, where there is non-negligible concentration of interferer molecules in the channel, which have similar binding characteristics with the ligands, and thus, can bind to the receptors, causing substantial interference with the MC signal. We investigate three different maximum likelihood (ML) detection methods based on different observable parameters of the ligand-receptor binding mechanism, which are the instantaneous number of bound receptors and the amount of time the receptors stay unbound or bound within an observation time window. We carry out a comparative analysis to numerically evaluate the performance of the detection methods under different system settings.","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":"115970071","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.2018.8445983
Fan Zhang, Qiong Wu, Hao Wang, Yuanming Shi
In this paper, we consider solving the topological interference management (TIM) problem by using a generalized low-rank matrix completion (LRMC) model, thereby maximizing the achievable degrees of freedom (DoF) only based on the network connectivity information. The LRMC problem is NP-hard due to the nonconvex rank objective function. The nuclear norm relaxation fails as it always returns a full-rank matrix in our model. Another approach named Riemannian Pursuit (RP) is often inefficient for finding highly accurate feasible solutions. We thus propose a novel Generalized Low-Rank Optimization along with the Difference of Convex Algorithm (GLRO-DCA), which aims to find a low-rank solution while always keeping the feasiblity. The GLRO-DCA increases the rank consecutively and solves the associated fixed-rank LRMC problem, where the generalized fixed-rank LRMC problem is reformulated by minimizing the difference between the nuclear norm and the Ky Fan norm and solved by the DCA. We accelerate the DCA by applying extrapolation techniques to improve the computational efficiency. Numerical results exhibit the ability of our proposed GLRO-DCA for the TIM problem to find low-rank solutions, which is superior to the existing nuclear norm relaxation approach and the RP approach.
{"title":"Topological Interference Alignment via Generalized Low-Rank Optimization with Sequential Convex Approximations","authors":"Fan Zhang, Qiong Wu, Hao Wang, Yuanming Shi","doi":"10.1109/SPAWC.2018.8445983","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445983","url":null,"abstract":"In this paper, we consider solving the topological interference management (TIM) problem by using a generalized low-rank matrix completion (LRMC) model, thereby maximizing the achievable degrees of freedom (DoF) only based on the network connectivity information. The LRMC problem is NP-hard due to the nonconvex rank objective function. The nuclear norm relaxation fails as it always returns a full-rank matrix in our model. Another approach named Riemannian Pursuit (RP) is often inefficient for finding highly accurate feasible solutions. We thus propose a novel Generalized Low-Rank Optimization along with the Difference of Convex Algorithm (GLRO-DCA), which aims to find a low-rank solution while always keeping the feasiblity. The GLRO-DCA increases the rank consecutively and solves the associated fixed-rank LRMC problem, where the generalized fixed-rank LRMC problem is reformulated by minimizing the difference between the nuclear norm and the Ky Fan norm and solved by the DCA. We accelerate the DCA by applying extrapolation techniques to improve the computational efficiency. Numerical results exhibit the ability of our proposed GLRO-DCA for the TIM problem to find low-rank solutions, which is superior to the existing nuclear norm relaxation approach and the RP approach.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"118 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":"116010316","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.2018.8445881
Michael A. Varner, G. Durgin
This paper explores the range and signalling limitations of ambient scatter wireless communications. Using previously modulated and transmitted electromagnetic waves as a means of power and as the RF carrier for their own communications, Reflection of Modulated Radio (ReMoRa) systems require little to no power to establish a communication link. However, employing a carrier the ReMoRa users have no control over poses a set of signalling problems that must be addressed to ensure a functioning communication link. This paper seeks to outline these obstacles and the unique demands they place on ambient scatter systems. A novel waveform, the perfect pulse, is further characterized to better solidify their candidacy as a powerful tool for the ambient communications problem, paying specific attention to DC-nulling behaviors and synchronization benefits. Spectral Exceedance is proposed as a means to compare the depth and width of DC-nulling waveforms. A realistic RF link budget is proposed to model expected RF returns and range limitations of ReMoRa systems.
{"title":"Reflection of Modulated Radio (ReMoRa): Link Analysis of Ambient Scatter Radio Using Perfect Pulses","authors":"Michael A. Varner, G. Durgin","doi":"10.1109/SPAWC.2018.8445881","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445881","url":null,"abstract":"This paper explores the range and signalling limitations of ambient scatter wireless communications. Using previously modulated and transmitted electromagnetic waves as a means of power and as the RF carrier for their own communications, Reflection of Modulated Radio (ReMoRa) systems require little to no power to establish a communication link. However, employing a carrier the ReMoRa users have no control over poses a set of signalling problems that must be addressed to ensure a functioning communication link. This paper seeks to outline these obstacles and the unique demands they place on ambient scatter systems. A novel waveform, the perfect pulse, is further characterized to better solidify their candidacy as a powerful tool for the ambient communications problem, paying specific attention to DC-nulling behaviors and synchronization benefits. Spectral Exceedance is proposed as a means to compare the depth and width of DC-nulling waveforms. A realistic RF link budget is proposed to model expected RF returns and range limitations of ReMoRa systems.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"280 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120976700","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.2018.8445982
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.2018.8445953
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.2018.8446010
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.2018.8445909
Hakan Sac, Baran Tan Bacinoglu, E. Uysal-Biyikoglu, G. Durisi
We consider a communication system in which a source transmits information updates to a destination node through a binary erasure channel (BEC). When a packet containing an information update, which consists of a fixed number of information bits, arrives at the transmitter, it gets queued in a buffer, to be encoded and sent over the channel. Before transmitting a packet, the transmitter selects a channel coding blocklength n and then uses an automatic repeat request (ARQ) protocol, whereby packets that are decoded incorrectly are repeated. The choice of the coding blocklength thus affects the end-to-end status age. However, this dependency is nontrivial since, on the one hand, the duration of a single transmission attempt is directly proportional to n, so the smaller n the better. On the other hand, a smaller value of the blocklength n yields a higher probability of decoding error, which increases the end-to-end status age. Employing recent finite-blocklength information-theoretic bounds and approximations on the rate achievable on a BEC for a given blocklength and a given error probability, we study the age-optimal design of this system. We find that for any nontrivial BEC, there exists an optimal blocklength that minimizes the average age and average peak age of information.
{"title":"Age-Optimal Channel Coding Blocklength for an M/G/1 Queue with HARQ","authors":"Hakan Sac, Baran Tan Bacinoglu, E. Uysal-Biyikoglu, G. Durisi","doi":"10.1109/SPAWC.2018.8445909","DOIUrl":"https://doi.org/10.1109/SPAWC.2018.8445909","url":null,"abstract":"We consider a communication system in which a source transmits information updates to a destination node through a binary erasure channel (BEC). When a packet containing an information update, which consists of a fixed number of information bits, arrives at the transmitter, it gets queued in a buffer, to be encoded and sent over the channel. Before transmitting a packet, the transmitter selects a channel coding blocklength n and then uses an automatic repeat request (ARQ) protocol, whereby packets that are decoded incorrectly are repeated. The choice of the coding blocklength thus affects the end-to-end status age. However, this dependency is nontrivial since, on the one hand, the duration of a single transmission attempt is directly proportional to n, so the smaller n the better. On the other hand, a smaller value of the blocklength n yields a higher probability of decoding error, which increases the end-to-end status age. Employing recent finite-blocklength information-theoretic bounds and approximations on the rate achievable on a BEC for a given blocklength and a given error probability, we study the age-optimal design of this system. We find that for any nontrivial BEC, there exists an optimal blocklength that minimizes the average age and average peak age of information.","PeriodicalId":240036,"journal":{"name":"2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)","volume":"17 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":"131827781","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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