3,101 results
Search Results
2. Achievable fixed rate capacity in emerging wireless systems (invited paper)
- Author
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Juan M. Romero-Jerez, F. Javier Lopez-Martinez, Sami Muhaidat, Kahtan Mezher, George K. Karagiannidis, Simon L. Cotton, Paschalis C. Sofotasios, Seong Ki Yoo, El Bouanani, Faissal, Sofotasios, Paschalis C., da Costa, Daniel Benevides, Ayoub, Fouad, Tampere University, Research group: Wireless Communications and Positioning, and Electrical Engineering
- Subjects
Mathematical optimization ,Computer science ,business.industry ,Quality of service ,213 Electronic, automation and communications engineering, electronics ,Statistical model ,Context (language use) ,Channel capacity ,Computer Science::Networking and Internet Architecture ,Wireless ,Fading ,Fixed interest rate loan ,business ,Multipath propagation ,Computer Science::Information Theory - Abstract
The F composite fading model was recently proposed as an accurate and tractable statistical model for the characterization of the simultaneous occurrence of multipath fading and shadowing conditions encountered in realistic wireless communication scenarios. In the present contribution we capitalize on the distinct properties of this composite model to derive the achievable capacity over F composite fading channels assuming fixed rate quality of service requirements. To this end, novel exact and tractable analytic expressions are derived for both the exact and the truncated channel inversion strategies. This also enables the derivation of additional simplified approximate and asymptotic expressions for these cases, which provide meaningful insights on the effect of fading conditions on the overall system performance. This is particularly useful in the context of numerous emerging wireless applications of interest that exhibit stringent fixed rate requirements such as vehicular communications, body area networks and telemedicine, among others. acceptedVersion
- Published
- 2019
3. An information-theoretic analysis of dirty paper coding for informed audio watermarking
- Author
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Andrea Abrardo, Gianluigi Ferrari, Andrea Gorrieri, and Mauro Barni
- Subjects
Rocks ,Audio signal ,Signal to noise ratio ,Speech recognition ,Speech coding ,Watermark ,Acoustic distortion ,Data_CODINGANDINFORMATIONTHEORY ,Acoustics ,Watermarking ,Channel capacity ,Computer Science::Sound ,Distortion ,Computer Science::Multimedia ,Watermarking, Signal to noise ratio, Random variables, Acoustic distortion, Interference, Rocks, Acoustics ,Dirty paper coding ,Random variables ,Interference ,Algorithm ,Digital watermarking ,Computer Science::Information Theory ,Communication channel ,Mathematics - Abstract
Upon the introduction a simplified distortion model for a Gaussian audio watermaking scenario, we derive a lower bound for the Gelfand-Pinsker capacity of the watermark channel. Then, we use the capacity bound for designing an efficient practical watermarking scheme based on dirty trellis codes. The proposed information-theoretic framework is then validated, through the use of experimentally acquired audio signals, with the use of a recently proposed frequency-domain audio watermarking. Both an “ideal” (reflection-free) Gaussian acoustic channel and a realistic multipath acoustic channel are considered.
- Published
- 2014
4. Secret Writing on Dirty Paper: A Deterministic View.
- Author
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El-Halabi, Mustafa, Liu, Tie, Georghiades, Costas N., and Shamai, Shlomo
- Subjects
- *
CRYPTOGRAPHY , *INTERFERENCE channels (Telecommunications) , *CODING theory , *INFORMATION theory , *COMPUTER network security , *MATHEMATICAL models , *VECTOR analysis , *GAUSSIAN processes - Abstract
Recently, there has been a lot of success in using the deterministic approach to provide approximate characterization of Gaussian network capacity. In this paper, we take a deterministic view and revisit the problem of wiretap channel with side information. A precise characterization of the secrecy capacity is obtained for a linear deterministic model, which naturally suggests a coding scheme which we show to achieve the secrecy capacity of the degraded Gaussian model (dubbed as “secret writing on dirty paper”) to within half a bit. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
5. Dirty-paper Coding without Channel Information at the Transmitter and Imperfect Estimation at the Receiver
- Author
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Pablo Piantanida and Pierre Duhamel
- Subjects
FOS: Computer and information sciences ,Computer science ,Computer Science - Information Theory ,Radio receiver ,Data_CODINGANDINFORMATIONTHEORY ,Precoding ,law.invention ,Channel capacity ,law ,Electronic engineering ,Wireless ,Fading ,Rayleigh fading ,Computer Science::Information Theory ,Channel code ,business.industry ,Information Theory (cs.IT) ,Transmitter ,Binary erasure channel ,Uncorrelated ,Single antenna interference cancellation ,Channel state information ,Dirty paper coding ,business ,Communication channel ,Computer network - Abstract
In this paper, we examine the effects of imperfect channel estimation at the receiver and no channel knowledge at the transmitter on the capacity of the fading Costa's channel with channel state information non-causally known at the transmitter. We derive the optimal Dirty-paper coding (DPC) scheme and its corresponding achievable rates with the assumption of Gaussian inputs. Our results, for uncorrelated Rayleigh fading, provide intuitive insights on the impact of the channel estimate and the channel characteristics (e.g. SNR, fading process, channel training) on the achievable rates. These are useful in practical scenarios of multiuser wireless communications (e.g. Broadcast Channels) and information embedding applications (e.g. robust watermarking). We also studied optimal training design adapted to each application. We provide numerical results for a single-user fading Costa's channel with maximum-likehood (ML) channel estimation. These illustrate an interesting practical trade-off between the amount of training and its impact to the interference cancellation performance using DPC scheme.
- Published
- 2007
6. Writing on Fading Paper and Causal Transmitter CSI
- Author
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Lizhong Zheng and Shashi Borade
- Subjects
FOS: Computer and information sciences ,Channel code ,Computer science ,business.industry ,Information Theory (cs.IT) ,Computer Science - Information Theory ,Bandwidth (signal processing) ,Transmitter ,Data_CODINGANDINFORMATIONTHEORY ,Topology ,Channel capacity ,Channel state information ,Fading ,Dirty paper coding ,Wideband ,Telecommunications ,business ,Communication channel ,Rayleigh fading ,Computer Science::Information Theory - Abstract
A wideband fading channel is considered with causal channel state information (CSI) at the transmitter and no receiver CSI. A simple orthogonal code with energy detection rule at the receiver (similar to [6]) is shown to achieve the capacity of this channel in the limit of large bandwidth. This code transmits energy only when the channel gain is large enough. In this limit, this capacity without any receiver CSI is the same as the capacity with full receiver CSI--a phenomenon also true for dirty paper coding. For Rayleigh fading, this capacity (per unit time) is proportional to the logarithm of the bandwidth. Our coding scheme is motivated from the Gel'fand-Pinsker [2,3] coding and dirty paper coding [4]. Nonetheless, for our case, only causal CSI is required at the transmitter in contrast with dirty-paper coding and Gel'fand-Pinsker coding, where non-causal CSI is required. Then we consider a general discrete channel with i.i.d. states. Each input has an associated cost and a zero cost input "0" exists. The channel state is assumed be to be known at the transmitter in a causal manner. Capacity per unit cost is found for this channel and a simple orthogonal code is shown to achieve this capacity. Later, a novel orthogonal coding scheme is proposed for the case of causal transmitter CSI and a condition for equivalence of capacity per unit cost for causal and non-causal transmitter CSI is derived. Finally, some connections are made to the case of non-causal transmitter CSI in [8].
- Published
- 2005
7. Channel Capacity Analysis for Dirty Paper Coding With the Binary Codeword and Interference.
- Author
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Xu, Zhengguang and Xie, Yongbiao
- Abstract
Dirty paper coding is an interference pre-cancellation method for known interference at the transmitter and serves as a basic building block in the digital watermarking system. In this letter, we investigate the dirty paper model in the simplest digital communication system, where both the codeword and the interference are binary. For watermark embedment, we derive the relevant coding, the constant coding, and the symmetric relevant coding when the encoder focuses on the binary codeword and interference. The channel capacity is analyzed and the optimal parameter is discussed in the case. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
8. Dirty-Paper Coding Versus TDMA for MIMO Broadcast Channels.
- Author
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Jindal, Nihar and Goldsmith, Andrea
- Subjects
- *
COMPARISON (Philosophy) , *BROADCASTING industry , *NOISE , *INVESTIGATIONS , *INFORMATION theory , *DIGITAL electronics - Abstract
We compare the capacity of dirty-paper coding (DPC) to that of time-division multiple access (TDMA) for a multiple-antenna (multiple- input multiple-output (MIMO)) Gaussian broadcast channel (BC). We find that the sum-rate capacity (achievable using DPC) of the multiple-antenna BC Is at most min(M, K) times the largest single-user capacity (i.e., the TDMA sum-rate) in the system, where M is the number of transmit antennas and K is the number of receivers. This result is Independent of the number of receive antennas and the channel gain matrix, and is valid at all signal-to-noise ratios (SNRs). We investigate the tightness of this bound In a time-varying channel (assuming perfect channel knowledge at receivers and transmitters) where the channel experiences uncorrelated Rayleigh fading and In some situations we find that the dirty paper gain is upper-bounded by the ratio of transmit-to-receive antennas. We also show that min(M, K) upper-bounds the sum-rate gain of successive decoding over TDMA for the uplink channel, where M is the number of receive antennas at the base station and K is the number of transmitters. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
9. High SNR Analysis for MIMO Broadcast Channels: Dirty Paper Coding Versus Linear Precoding.
- Author
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Lee, Juyul and Jindal, Nihar
- Subjects
- *
DATA transmission systems , *DIGITAL communications , *ELECTRONIC data processing , *TELECOMMUNICATION systems , *INFORMATION theory , *WIRELESS communications , *TELECOMMUNICATION , *MULTIPLEXING , *SIGNAL-to-noise ratio - Abstract
In this correspondence, we compare the achievable throughput for the optimal strategy of dirty paper coding (DPC) to that achieved with suboptimal and lower complexity linear precoding techniques (zero-forcing and block diagonalization). Both strategies utilize all available spatial dimensions and therefore have the same multiplexing gain, but an absolute difference in terms of throughput does exist. The sum rate difference between the two strategies is analytically computed at asymptotically high SNR. Furthermore, the difference is not affected by asymmetric channel behavior when each user has a different average SNR. Weighted sum rate maximization is also considered. In the process, it is shown that allocating user powers in direct proportion to user weights asymptotically maximizes weighted sum rate. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
10. Physics-based models for communications in random complex propagation media, including keyhole effects in MIMO.
- Author
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Ishimaru, Akira
- Subjects
GREEN'S functions ,COMMUNICATION models ,ATMOSPHERIC turbulence ,OCEAN turbulence ,STATISTICAL physics ,MIMO systems ,SIGNAL-to-noise ratio - Abstract
Extensive research has been reported on MIMO systems for complex environments. It is noted that many communications studies make use of the channel matrix of transmitters and receivers, signal vectors, SNR, and eigenvalues. However, the channel matrix is often expressed in terms of channel modeling, and the detailed statistical characteristics of the channel in terms of physical characteristics of atmospheric turbulence, particulate matter, and rough surfaces and terrain are often not explicitly shown. This paper discusses the inclusion of expressions of physical characteristics of the random medium in the channel matrix. Therefore, the key point of this paper is that the channel matrix is explicitly given in terms of the actual physical parameters of the random environment using the mutual coherence function and stochastic Green's functions; we call this a 'physics-based' communications model. This paper presents a formulation of physics-based communications models in the presence of a random medium based on analytical statistical EM theory. We use the keyhole MIMO as an example to show the key points of this approach. It is hoped that this study may help extend channel modeling to include analytical statistical EM theory for atmospheric turbulence, ocean turbulence, and rough terrain. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
11. Channel capacity limit of multi-beam satellite system.
- Author
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Yang, Mingchuan, Liu, Botao, Yang, Yupu, and Xue, Guanchang
- Subjects
MEAN square algorithms ,TELECOMMUNICATION satellites ,MINI-Mental State Examination - Abstract
The requests of broadband coverage area and the expected user demand is satisfied by the satellite industry by using multiple spot beams of high throughput satellites with fixed multi-beam pattern and footprint planning. The technology core of high-throughput satellite is multi-beam technology, and the means to efficiently reuse spectrum is a full-frequency reuse scheme. In order to study the channel capacity limit of multi-beam satellite systems, the Wiener-Gaussian access model of terrestrial cellular systems is analyzed in this paper. This paper analyzes the Wiener-Gaussian access model of terrestrial cellular systems, then considers the difference between the spatial characteristics and gain characteristics of the multi-beam satellite system compared with the terrestrial cellular system, and proposes a Wiener model suitable for the multi-beam satellite communication system. On this basis, the channel capacity limit of multi-beam satellites under different fading conditions is deduced when using optimal linear precoding and minimum mean square error precoding. It provides theoretical support for the in-depth study of the channel capacity mechanism and system performance of multi-beam satellites. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
12. Performance Analysis of Multiport Antennas in Vehicle-to-Vehicle Communication Channels
- Author
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Pour Sohrab, Abed, Huang, Yingke, and Karadimas, Petros
- Published
- 2024
- Full Text
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13. Performance comparison of advanced antenna systems for wireless mesh routers in an outdoor environment
- Author
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Babich, Fulvio, Comisso, Massimiliano, and Manià, Lucio
- Published
- 2009
- Full Text
- View/download PDF
14. Variable-Length Coding With Shared Incremental Redundancy: Design Methods and Examples.
- Author
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Wang, Haobo, Ranganathan, Sudarsan V. S., and Wesel, Richard D.
- Subjects
VIDEO coding ,LOW density parity check codes ,PARALLEL processing ,REDUNDANCY in engineering - Abstract
Variable-length (VL) coding with feedback is a commonly used technique that can approach point-to-point Shannon channel capacity with a significantly shorter average codeword length than fixed-length coding without feedback. This paper uses the inter-frame coding of Zeineddine and Mansour, originally introduced to address varying channel-state conditions in broadcast wireless communication, to approach capacity on point-to-point channels using VL codes without feedback. The per-symbol complexity is comparable to decoding the VL code with feedback (plus the additional complexity of a small peeling decoder amortized over many VL codes) and presents the opportunity for encoders and decoders that utilize massive parallel processing, where each VL decoder can process simultaneously. This paper provides an analytical framework and a design process for the degree distribution of the inter-frame code that allows the feedback-free system to achieve 96% or more of the throughput of the original VL code with feedback. As examples of VL codes, we consider non-binary (NB) low-density parity-check (LDPC), binary LDPC, and convolutional VL codes. The NB-LDPC VL code with an 8-bit CRC and an average codeword length of 336 bits achieves 85% of capacity with four rounds of ACK/NACK feedback. The proposed scheme using shared incremental redundancy without feedback achieves 97% of that performance or 83% of the channel capacity. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
15. Multi-Level Dirty Paper Coding.
- Author
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Sae-Young Chung
- Abstract
We propose multi-level coding and successive decoding for dirty paper coding (DPC) in the high signal-to-noise ratio (SNR) regime. We divide the channel code into two levels, the upper code interacting with the shaping code and the lower code that does not such that it is information lossless. Our code design is more intuitive for designing DPC in the high SNR regime. The design of the lower code becomes trivial since it does not interact with the shaping code anymore. The design of the upper code is also simplified since we can now assume binary signaling for the code. We evaluate the capacity of each level and design codes to approach the estimated capacity. We demonstrate a good performance can indeed be achieved by simulations using low- density parity-check (LDPC) codes at each level. Our best code is only 0.45 dB from the no-interference Gaussian capacity at the spectral efficiency of 3 b/s/Hz. [ABSTRACT FROM PUBLISHER]
- Published
- 2008
- Full Text
- View/download PDF
16. Analysis of the Convergence Speed of the Arimoto-Blahut Algorithm by the Second-Order Recurrence Formula.
- Author
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Nakagawa, Kenji, Takei, Yoshinori, Hara, Shin-ichiro, and Watabe, Kohei
- Subjects
TAYLOR'S series ,ALGORITHMS ,SPEED ,JACOBIAN matrices ,HESSIAN matrices ,MEMORYLESS systems - Abstract
In this paper, we investigate the convergence speed of the Arimoto-Blahut algorithm. For many channel matrices, the convergence speed is exponential, but for some channel matrices it is slower than exponential. By analyzing the Taylor expansion of the defining function of the Arimoto-Blahut algorithm, we will make the conditions clear for the exponential or slower convergence. The analysis of the slow convergence in this paper is new. Based on this analysis, we will compare the convergence speeds of the Arimoto-Blahut algorithm numerically with the values obtained in our theorems for several channel matrices. The purpose of this paper is to obtain a complete understanding of the convergence speed of the Arimoto-Blahut algorithm. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
17. Impact of Action-Dependent State and Channel Feedback on Gaussian Wiretap Channels.
- Author
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Dai, Bin, Li, Chong, Liang, Yingbin, Ma, Zheng, and Shamai Shitz, Shlomo
- Subjects
GAUSSIAN channels ,SECRECY ,TRANSMITTERS (Communication) - Abstract
We investigate the state-dependent Gaussian wiretap channel with noncausal channel state information at the transmitter (GWTC-N-CSIT), and explore whether three strategies (i.e., taking action on the state, legitimate receiver’s channel output feedback, and combining the former two strategies together) help to enhance the secrecy capacity of the GWTC-N-CSIT. To be specific, we first determine the secrecy capacity of the GWTC-N-CSIT with noiseless feedback. Next, we derive lower and upper bounds on the secrecy capacity of the GWTC-N-CSIT with action-dependent state. Finally, we derive lower and upper bounds on the secrecy capacity of the GWTC-N-CSIT with both action-dependent state and noiseless feedback, and show that these bounds meet for a special case. Numerical results of this paper indicate that all three strategies enhance the secrecy capacity of the GWTC-N-CSIT. The study of this paper offers new options for enhancing the secrecy rates of the state-dependent wiretap channel models. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
18. Hybrid Precoding Algorithm for Millimeter-Wave Massive MIMO-NOMA Systems.
- Author
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Sur, Samarendra Nath, Kandar, Debdatta, Silva, Adão, Nguyen, Nhan Duc, Nandi, Sukumar, and Do, Dinh-Thuan
- Subjects
ALGORITHMS ,MATRIX inversion ,ENERGY consumption ,COMPUTATIONAL complexity ,HYBRID systems - Abstract
In this paper, the performance of the millimeter-wave (mmWave) massive multiple-input multiple-output (mMIMO) non-orthogonal multiple access (NOMA) systems is investigated under multiple user scenarios. The performance of the system has been analyzed in terms of spectral efficiency (SE), energy efficiency (EE), and computational complexity. In the case of the mMIMO system, the linear precoder with matrix inversion becomes less efficient due to its high computational complexity. Therefore, the design of a low-complex hybrid precoder (HP) is the main aim of this paper. Here, the authors have proposed a symmetric successive over-relaxation (SSOR) complex regularized zero-forcing (CRZF) linear precoder. Through simulation, this paper demonstrates that the proposed SSOR-CRZF-HP performs better than the conventional linear precoder with reduced complexity. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
19. PhantomNet: Exploring Optimal Multicellular Multiple Antenna Systems
- Author
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Jafar, Syed A., Foschini, Gerard J., and Goldsmith, Andrea J.
- Published
- 2004
- Full Text
- View/download PDF
20. Power Allocation Based on Multi-Agent Deep Deterministic Policy Gradient for Underwater Acoustic Communication Networks.
- Author
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Geng, Xuan and Hui, Xinyu
- Subjects
UNDERWATER acoustic communication ,TELECOMMUNICATION systems ,FRACTIONAL programming ,MULTIAGENT systems ,MARKOV processes ,REINFORCEMENT learning - Abstract
This paper proposes a reinforcement learning-based power allocation for underwater acoustic communication networks (UACNs). The objective function is formulated as maximizing channel capacity under constraints of maximum power and minimum channel capacity. To solve this problem, a multi-agent deep deterministic policy gradient (MADDPG) approach is introduced, where each transmitter node is considered as an agent. Given the definition of a Markov decision process (MDP) model for this problem, the agents learn to collaboratively maximize the channel capacity by deep deterministic policy gradient (DDPG) learning. Specifically, the power allocation of each agent is obtained by a centralized training and distributed execution (CTDE) method. Simulation results show the sum rate achieved by the proposed algorithm approximates that of the fractional programming (FP) algorithm and improves by at least 5% compared with the DQN (deep Q-learning network) -based power allocation algorithm. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. On information theoretical modelling of the communications between neurons and the corresponding information rate.
- Author
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Kalatiani, Sedighe and Hodtani, Ghosheh Abed
- Subjects
NEURONS ,COMMUNICATION models ,NERVOUS system ,MEMBRANE potential ,NONLINEAR estimation ,NEURAL transmission - Abstract
In a nervous system propagation of spikes among neurons can be interpreted as an information transmission process, where, a neural response carries information about the stimulus. Quantification of this information might be of theoretical and practical importance. In this paper, (i) The interaction between two neurons with an electrically coupled transport of ions is modelled mathematically, where the communication through the junction gap between very close neurons occurs with a specific time delay; (ii) then, the connection structure of neurons is proposed based on a particular Rulkov network model. The corresponding process is modelled as a non‐linear binary channel with memory; and (iii) by assuming a recurrence relation for number of available membrane potential changing due to the arrival of the spike to the axonal terminal, the mutual information between channel input and output is obtained and the input range maximizing mutual information, and hence, the information rate of channel is derived. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
22. On the Capacity of the Peak Power Constrained Vector Gaussian Channel: An Estimation Theoretic Perspective.
- Author
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Dytso, Alex, Al, Mert, Poor, H. Vincent, and Shamai Shitz, Shlomo
- Subjects
CAPACITY management (Computers) ,GAUSSIAN channels ,HARMONIC functions ,STANDARD deviations ,ESTIMATION theory - Abstract
This paper studies the capacity of an $n$ -dimensional vector Gaussian noise channel subject to the constraint that an input must lie in the ball of radius $R$ centered at the origin. It is known that in this setting, the optimizing input distribution is supported on a finite number of concentric spheres. However, the number, the positions, and the probabilities of the spheres are generally unknown. This paper characterizes necessary and sufficient conditions on the constraint $R$ , such that the input distribution supported on a single sphere is optimal. The maximum $\bar {R}_{n}$ , such that using only a single sphere is optimal, is shown to be a solution of an integral equation. Moreover, it is shown that $\bar {R}_{n}$ scales as $\sqrt {n}$ and the exact limit of $\frac {\bar {R}_{n}}{\sqrt {n}}$ is found. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
23. Capacity of a Full-Duplex Wirelessly Powered Communication System With Self-Interference and Processing Cost.
- Author
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Nikoloska, Ivana, Zlatanov, Nikola, and Hadzi-Velkov, Zoran
- Abstract
In this paper, we investigate the capacity of a point-to-point, full-duplex (FD) wirelessly powered communication system impaired by self-interference. This system is comprised of an energy transmitter (ET) and an energy harvesting user (EHU), which operates in the FD mode. The ET transmits energy toward the EHU. The EHU harvests this energy and uses it to transmit information back to the ET. As a result of the FD mode, both nodes are affected by self-interference. The self-interference has different effects at the two nodes. In particular, the self-interference impairs the decoding of the received information signal at the ET, whereas it serves as an additional source of energy at the EHU. In this paper, we derive the capacity of the adopted system model assuming a processing cost at the EHU and an additive white Gaussian noise channel with block fading. Thereby, we show that the capacity achieving scheme is relatively simple and therefore applicable to devices with limited resources. Moreover, our numerical results show significant improvements in terms of data rate when the capacity achieving strategy is employed compared to half-duplex transmission, even for very high self-interference at the ET. Moreover, we show the positive effects of the self-interference at the EHU, as well as the crippling effect of the processing cost. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
24. On Zero-Error Capacity of Binary Channels With One Memory.
- Author
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Cao, Qi, Cai, Ning, Guo, Wangmei, and Yeung, Raymond W.
- Subjects
INFORMATION theory ,ERROR correction (Information theory) ,FINITE state machines ,BINARY codes ,MATHEMATICAL bounds - Abstract
The zero-error capacity of a channel is defined as the maximum rate at which it is possible to transmit information with zero probability of error. In this paper, we settle all previously unsolved cases for the zero-error capacity of binary channels with one memory. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
25. Capacity Characterization for State-Dependent Gaussian Channel With a Helper.
- Author
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Sun, Yunhao, Duan, Ruchen, Liang, Yingbin, Khisti, Ashish, and Shamai Shitz, Shlomo
- Subjects
GAUSSIAN channels ,TRANSMITTERS (Communication) ,ARBITRARY constants ,MATHEMATICAL constants ,MATHEMATICS - Abstract
The state-dependent point-to-point Gaussian channel with a helper is first studied, in which a transmitter communicates with a receiver via a state-corrupted channel. The state is not known to the transmitter nor to the receiver, but known to a helper noncausally, which then wishes to assist the receiver to cancel the state. Differently from the previous work that characterized the capacity only in the infinite state power regime, this paper explores the general case with arbitrary state power. A lower bound on the capacity is derived based on an achievable scheme that integrates direct state subtraction and single-bin dirty paper coding. By analyzing this lower bound and further comparing it with the existing upper bounds, the capacity of the channel is characterized for a wide range of channel parameters. Such an idea of characterizing the capacity is further extended to study the two-user state-dependent multiple access channel with a helper. By comparing the derived inner and outer bounds, the channel parameters are partitioned into appropriate cases, and for each case, either segments on the capacity region boundary or the full capacity region are characterized. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
26. The Wideband Slope of Interference Channels: The Small Bandwidth Case.
- Author
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Shen, Minqi and Host-Madsen, Anders
- Subjects
BANDWIDTHS ,GAUSSIAN channels ,RANDOM noise theory ,MULTIUSER channels - Abstract
This paper studies the low-SNR regime performance of a scalar complex $K$ -user interference channel with the Gaussian noise. The finite bandwidth case is considered, where the low-SNR regime is approached by letting the input power go to zero, while the bandwidth is small and fixed. We show that for all $\delta >0$ , there exists a set of channel coefficients with non-zero measure (probability), in which the wideband slope per user satisfies $ \mathcal {S}_{0}< {\scriptstyle {}^{\scriptstyle 2}}\hspace{-0.224em}/\hspace{-0.112em}{\scriptstyle K}+\delta $. This is quite contrary to the large bandwidth case, where a slope of 1 per user is achievable with probability 1. We also develop an interference alignment scheme for the finite bandwidth case that shows some gain in wideband slope. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
27. Dual Capacity Upper Bounds for Binary-Input Single-Tap ISI Channels.
- Author
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Mohanan, Ajay and Thangaraj, Andrew
- Subjects
GAUSSIAN channels ,INTERSYMBOL interference ,MARKOV processes ,COMPUTATIONAL complexity ,NOISE measurement - Abstract
The capacity of noisy channels with memory and finite input has been difficult to characterize explicitly in many cases. In this paper, we consider single-tap binary-input Gaussian channels with inter-symbol interference (ISI). The dual capacity method is used to obtain upper bounds using Markov test distributions. The bound, expressed as a single-letter optimization problem, is solved numerically. For higher memory, the notion of cycle basis is used to provide an exponential reduction in the computational complexity of the optimization problem. Bounds were obtained for the important case of the dicode channel, and these are better than the previously known upper bounds and are close to achievable rates over a wide range of SNRs. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
28. Iterative minimization algorithm on a mixture family
- Author
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Hayashi, Masahito
- Published
- 2024
- Full Text
- View/download PDF
29. Asymptotics of Input-Constrained Erasure Channel Capacity.
- Author
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Li, Yonglong and Han, Guangyue
- Subjects
CODING theory ,ASYMPTOTIC distribution ,ASYMPTOTIC normality ,DISTRIBUTION (Probability theory) ,MARKOV processes - Abstract
In this paper, we examine an input-constrained erasure channel and we characterize the asymptotics of its capacity when the erasure rate is low. More specifically, for a general memoryless erasure channel with its input supported on an irreducible finite-type constraint, we derive partial asymptotics of its capacity, using some series expansion type formula of its mutual information rate; and for a binary erasure channel with its first-order Markovian input supported on the $(1, \infty )$ -RLL constraint based on the concavity of its mutual information rate with respect to some parameterization of the input, we numerically evaluate its first-order Markov capacity and further derive its full asymptotics. The asymptotics obtained in this paper, when compared with the recently derived feedback capacity for a binary erasure channel with the same input constraint, enable us to draw the conclusion that feedback may increase the capacity of an input-constrained channel, even if the channel is memoryless. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
- Full Text
- View/download PDF
30. Non-Binary LDPC Code Design for the Poisson PPM Channel.
- Author
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Matuz, Balazs, Paolini, Enrico, Zabini, Flavio, and Liva, Gianluigi
- Subjects
LOW density parity check codes ,CHANNEL capacity (Telecommunications) ,CHANNEL coding ,PHOTON counting ,PULSE position modulation - Abstract
This paper investigates the design of non-binary protograph low-density parity-check codes for the Poisson channel with $m$ -ary pulse position modulation. The field order over which the code is constructed is matched to the pulse position modulation order yielding a coded modulation scheme. The optimization of the low-density parity-check code structure is performed via protograph density evolution on a surrogate $m$ -ary erasure channel. The surrogate design is illustrated to be not only accurate, but also robust for a range of practical values of channel background noise and various modulation orders. As a result the proposed codes show excellent performance over the Poisson channel with pulse position modulation outperforming competing schemes. As a side-product of this paper, finite-length benchmarks on the block error probability are provided, together with a union bound to characterize the code performance in the error floor region. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
31. Asymptotically Equivalent Sequences of Matrices and Capacity of a Discrete-Time Gaussian MIMO Channel With Memory.
- Author
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Gutierrez-Gutierrez, Jesus, Crespo, Pedro M., Zarraga-Rodriguez, Marta, and Hogstad, Bjorn Olav
- Subjects
MIMO systems ,EMAIL systems ,GAUSSIAN channels ,NOISE measurement ,INFINITE impulse response filters - Abstract
Using some recent results on asymptotically equivalent sequences of matrices, we present in this paper, a new derivation of the capacity formula given by Brandenburg and Wyner for a discrete-time Gaussian multiple-input-multiple-output channel with memory. In this paper, we tackle not only the case considered by them, where the number of channel inputs and the number of channel outputs are the same, but also when both numbers are different. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
32. Space-Time Block Diagonalization for Frequency-Selective MIMO Broadcast Channels
- Author
-
Carlos A. Viteri-Mera and Fernando L. Teixeira
- Subjects
FOS: Computer and information sciences ,Beamforming ,time-reversal beamforming ,General Computer Science ,Computer science ,Computer Science - Information Theory ,MIMO ,0211 other engineering and technologies ,Data_CODINGANDINFORMATIONTHEORY ,02 engineering and technology ,Space-division multiple access ,space division multiple access (SDMA) ,Topology ,Multiplexing ,Precoding ,Delay spread ,Channel capacity ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,frequency-selective channels ,Multiuser MIMO systems ,021101 geological & geomatics engineering ,Computer Science::Information Theory ,Information Theory (cs.IT) ,Transmitter ,General Engineering ,020206 networking & telecommunications ,Dirty paper coding ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,lcsh:TK1-9971 ,Communication channel - Abstract
The most important linear precoding method for frequency-flat MIMO broadcast channels is block diagonalization (BD) which, under certain conditions, attains the same nonlinear dirty paper coding channel capacity. However, BD is not easily translated to frequency-selective channels, since space-time information must be included in the transceiver design. In this paper, we demonstrate that BD is possible in frequency-selective MIMO broadcast channels to eliminate inter-user interference and derive the conditions on the number of transmit antennas and the transmission block length (as functions of the number of users and channel delay spread) for the existence of BD precoders. We also propose three different approaches to mitigate/eliminate inter-symbol interference in block transmissions: time-reversal-based BD (TRBD), equalized BD (EBD), and joint processing BD (JPBD). We show that any transmit-processing-only method (including TRBD and EBD) yields zero diversity and multiplexing gains (high SNR regime). We also demonstrate that JPBD, which uses linear processing at the transmitter and the receiver, approximates full multiplexing gain for a sufficiently large transmit block length, and show its diversity-multiplexing tradeoff. Extensive numerical simulations show that the achievable rate and probability of error performance of all the proposed techniques remarkably improve that of conventional time-reversal beamforming. Moreover, JPBD provides the highest achievable rate region for frequency-selective MIMO broadcast channels.
- Published
- 2016
33. Cooperative Multiple-Access Channels With Distributed State Information.
- Author
-
Miretti, Lorenzo, Kobayashi, Mari, Gesbert, David, and de Kerret, Paul
- Subjects
TRANSMITTERS (Communication) ,GAUSSIAN channels ,TRANSMITTING antennas ,COOPERATIVE societies ,CHANNEL coding ,WIRELESS communications - Abstract
This paper studies a memoryless state-dependent multiple access channel (MAC) where two transmitters wish to convey a message to a receiver under the assumption of causal and imperfect channel state information at transmitters (CSIT) and imperfect channel state information at receiver (CSIR). In order to emphasize the limitation of transmitter cooperation between physically distributed nodes, we focus on the so-called distributed CSIT assumption, i.e., where each transmitter has its individual channel knowledge, while the message can be assumed to be partially or entirely shared a priori between transmitters by exploiting some on-board memory. Under this setup, the first part of the paper characterizes the common message capacity of the channel at hand for arbitrary CSIT and CSIR structure. The optimal scheme builds on Shannon strategies, i.e., optimal codes are constructed by letting the channel inputs be a function of current CSIT only. For a special case when CSIT is a deterministic function of CSIR, the considered scheme also achieves the capacity region of a common message and two private messages. The second part addresses an important instance of the previous general result in a context of a cooperative multi-antenna Gaussian channel under i.i.d. fading operating in frequency-division duplex mode, such that CSIT is acquired via an explicit feedback of perfect CSIR. The capacity of the channel at hand is achieved by distributed linear precoding applied to Gaussian codes. Surprisingly, we demonstrate that it is suboptimal to send a number of data streams bounded by the number of transmit antennas as typically considered in a centralized CSIT setup. Finally, numerical examples are provided to evaluate the sum capacity of the binary MAC with binary states as well as the Gaussian MAC with i.i.d. fading. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
34. Channel Capacity and Polarization Diversity Study for Novel Compact UWB MIMO Antennas.
- Author
-
Ahmed, M. I., Ahmed, M. F., and Seleem, H.
- Subjects
CHANNEL capacity (Telecommunications) ,ULTRA-wideband antennas ,MIMO systems ,TELECOMMUNICATION systems ,ANTENNAS (Electronics) - Abstract
This paper compares two dualpolarization (DP) MIMO systems with compact size, full isolation, and channel capacity for modern applications. Demonstrates two different designs of compact ultra-wideband (UWB) antennas. It presents two different designs of compact ultra-wide-band (UWB) antenna. These antennas are manufactured and designed to fit and compare to a four-element MIMO system. The first design is a compact UWB cup-antenna with a notch in the partial ground plane. The second design is a coplanar waveguide (CPW) UWB antenna. In this paper, the isolated coefficient for two dual-polarization (DP) and the channel capacity of the MIMO system is calculated to achieve the optimum antenna system for modern communications that are very low, approximately - 20 dB. Further, the BW and channel capacity of these designs are better than the other previous works. The simulation results are taken using CST STUDIO SUITETM 2018. Furthermore, there is a great agreement between simulations and fabricated results. [ABSTRACT FROM AUTHOR]
- Published
- 2021
35. On the Concatenated Code Constructions for Slotted Multiuser Communication Channel.
- Author
-
Ivanov, F. I. and Kruglik, S. A.
- Subjects
MULTIUSER channels ,GAUSSIAN channels ,DISTRIBUTION (Probability theory) ,RANDOM variables - Abstract
In this paper we investigate a multiuser vector-disjunctive channel where users transmit binary vectors of length . Previously the capacity of this channel was estimated and it was shown that there are some cases when it achieves on non-uniform input distributions. This fact motivates us to investigate concatenated code constructions that allow us to reach target input distribution and detect or correct some error patterns appearing due to user interference or channel noise. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
36. PhantomNet: Exploring Optimal Multicellular Multiple Antenna Systems
- Author
-
Foschini Gerard J, Goldsmith Andrea J, and Jafar Syed A
- Subjects
channel capacity ,dirty paper coding ,duality ,broadcast channel ,successive decoding ,multiple-input multiple-output systems ,Telecommunication ,TK5101-6720 ,Electronics ,TK7800-8360 - Abstract
We present a network framework for evaluating the theoretical performance limits of wireless data communication. We address the problem of providing the best possible service to new users joining the system without affecting existing users. Since, interference-wise, new users are required to be invisible to existing users, the network is dubbed PhantomNet. The novelty is the generality obtained in this context. Namely, we can deal with multiple users, multiple antennas, and multiple cells on both the uplink and the downlink. The solution for the uplink is effectively the same as for a single cell system since all the base stations (BSs) simply amount to one composite BS with centralized processing. The optimum strategy, following directly from known results, is successive decoding (SD), where the new user is decoded before the existing users so that the new users' signal can be subtracted out to meet its invisibility requirement. Only the BS needs to modify its decoding scheme in the handling of new users, since existing users continue to transmit their data exactly as they did before the new arrivals. The downlink, even with the BSs operating as one composite BS, is more problematic. With multiple antennas at each BS site, the optimal coding scheme and the capacity region for this channel are unsolved problems. SD and dirty paper (DP) are two schemes previously reported to achieve capacity in special cases. For PhantomNet, we show that DP coding at the BS is equal to or better than SD. The new user is encoded before the existing users so that the interference caused by his signal to existing users is known to the transmitter. Thus the BS modifies its encoding scheme to accommodate new users so that existing users continue to operate as before: they achieve the same rates as before and they decode their signal in precisely the same way as before. The solutions for the uplink and the downlink are particularly interesting in the way they exhibit a remarkable simplicity and an unmistakable, near-perfect, up-down symmetry.
- Published
- 2004
- Full Text
- View/download PDF
37. A slotted frustum-shaped 4 × 4 MIMO dielectric resonator antenna with enhanced isolation for 5G Wi-Fi applications.
- Author
-
Chandra, Ravi and Upadhyay, Dileep Kumar
- Subjects
- *
DIELECTRIC resonator antennas , *CHANNEL capacity (Telecommunications) , *WIRELESS Internet , *DIELECTRIC resonators , *REFLECTANCE , *5G networks - Abstract
In this paper, a slotted frustum-shaped $ 4\times 4 $ 4 × 4 multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) is designed and developed for portable 5G Wi-Fi ( $ 5.15{-}5.85\, {\rm GHz} $ 5.15 − 5.85 GHz ) applications. The DRA is excited by $ HEM_{11\delta } $ HE M 11 δ and $ HEM_{21\delta } $ HE M 21 δ modes. A slotted right-angle frustum-shaped (SRFS) structure of alumina material as a dielectric resonator (DR) is positioned on the ground plane of the FR4 substrate to design a DRA. Based on the designed DRA, a compact ( $ 2.57\, \lambda _g\times 2.57 \,\lambda _g $ 2.57 λ g × 2.57 λ g , where $ \lambda _g $ λ g is guided wavelength and calculated at a lower cut-off frequency, $ 5.0\, {\rm GHz} $ 5.0 GHz , for $ \epsilon _f $ ϵ f of $ 4.4 $ 4.4) $ 4\times 4 $ 4 × 4 MIMO antenna with high isolation of greater than $ 27.13\, {\rm dB} $ 27.13 dB (from $ 5.0 $ 5.0 to $ 6.1\, {\rm GHz} $ 6.1 GHz ) and $ 24.3\, {\rm dB} $ 24.3 dB (from $ 6.1 $ 6.1 to $ 6.25\, {\rm GHz} $ 6.25 GHz ) is proposed. The developed MIMO antenna's measured working frequency ranges from $ 5.0 $ 5.0 to $ 6.25\, {\rm GHz} $ 6.25 GHz , with an impedance bandwidth, $ BW_i $ B W i of $ 22.22\% $ 22.22 % , peak gain, $ G_P $ G P of $ 5.85\, {\rm dBi} $ 5.85 dBi and an average peak gain, $ G_{av} $ G av of $ 5.25\, {\rm dBi} $ 5.25 dBi . The calculated MIMO antenna's diversity performance parameters, channel capacity loss $ (C_{CL}^{ij}) $ (C CL ij) , diversity gain $ (D_G^{ij}) $ (D G ij) , envelop correlation coefficient $ (E_{CC}^{ij}) $ (E CC ij) , mean effective gain $ (M_{EG}^i) $ (M EG i) , total active reflection coefficient $ (T_{ARC}) $ (T ARC) , and channel capacity $ (C_C) $ (C C) are obtained as $ { \lt }0.17\, {\rm bits}/{\rm sec}/{\rm Hz} $ < 0.17 bits / sec / Hz , $ { \gt }9.99 \, {\rm dB} $ > 9.99 dB , $ { \lt }0.0301 $ < 0.0301 , $ { \lt }-6.06\, {\rm dB} $ < − 6.06 dB , $ { \lt }-12.5\, {\rm dB} $ < − 12.5 dB , and $ { \lt }21.6\, {\rm bits}/{\rm sec}/{\rm Hz} $ < 21.6 bits / sec / Hz , respectively. The agreement between the simulation and measurement results is found to be remarkably consistent. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. A 3D Wideband Channel Model for RIS-Assisted MIMO Communications.
- Author
-
Sun, Guiqi, He, Ruisi, Ai, Bo, Ma, Zhangfeng, Li, Panpan, Niu, Yong, Ding, Jianwen, Fei, Dan, and Zhong, Zhangdui
- Subjects
TELECOMMUNICATION systems ,RADIO waves ,TELECOMMUNICATION ,STATISTICAL correlation ,THREE-dimensional modeling ,NEAR field communication ,MIMO radar - Abstract
Recently, reconfigurable intelligent surface (RIS) has drawn much attention due to its capability of improving coverage and communication performance. The development of RIS-assisted communication technology relies on deep understanding of RIS channel characteristics. However, most of the existing investigations focus on the impact of RIS, ignoring the existence of local scatterers in the real propagation environment. The ideal propagation condition limits the accuracy and application of the developed channel model. In this paper, we aim to analyze the channel characteristics of RIS-assisted near-filed communication by considering different conditions of local scatterers. Specifically, we propose a three-dimensional (3D) RIS-assisted multiple-input multiple-output (MIMO) channel model based on a three-dimensional cylinder model, which considers line-of-sight, single-bounced at RIS (SBR) and double-bounced (DB) modes where radio waves reflect from RIS and scatterers near receiver. Based on the proposed channel model, we investigate some key statistical properties for SBR and DB propagation, including the time-frequency-space correlation function and Doppler power spectrum. From the simulation results, it is found that RIS element number, RIS horizontal and vertical locations, distribution of surrounding scatterers, and movement of Rx have significant impacts on channel characteristics. Finally, channel capacities of SBR and DB modes are calculated, where the large size and appropriate locations of RIS significantly improve the channel capacity of RIS-assisted communication. These numerical results and observations can be used for design of RIS-assisted near-field communication systems. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
39. Gaussian Mixture Noise Channels With Minimum and Peak Amplitude Constraints.
- Author
-
Ni, Zhengwei and Motani, Mehul
- Subjects
RANDOM noise theory ,ADDITIVE white Gaussian noise channels ,PROBABILITY density function ,GAUSSIAN channels - Abstract
Motivated by the idea of “transmitting energy and information simultaneously,” we investigate, in this paper, the impact of constraints on the amount of energy that individual symbols carry, i.e., minimum amplitude constraints. We consider a Gaussian mixture noise channel with both minimum and peak amplitude constraints. First, we prove that the capacity-achieving input has a discrete distribution with a finite number of probability mass points. Then, we further investigate the number and positions of the probability mass points for the capacity-achieving input. Specifically, when the interference is constant and known at both the transmitter and the receiver, it can be totally eliminated so that the channel operates like an AWGN channel. In this case, we give a theorem to determine whether the optimal input is binary. For more general cases, such as non-binary inputs and non-constant interference, we investigate optimal inputs and capacities via numerical computations. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
40. The Capacity of Online (Causal) $q$ -Ary Error-Erasure Channels.
- Author
-
Chen, Zitan, Jaggi, Sidharth, and Langberg, Michael
- Subjects
CHANNEL capacity (Telecommunications) ,CODING theory ,ERROR correction (Information theory) ,MATHEMATICAL bounds ,ENCODING - Abstract
In the $q$ -ary online (or “causal”) channel coding model, a sender wishes to communicate a message to a receiver by transmitting a codeword $\mathbf {x} =(x_{1},\ldots,x_{n}) \in \{0,1,\ldots,q-1\}^{n}$ symbol-by-symbol via a channel limited to at most $pn$ errors and $p^{*} n$ erasures. The channel is “online” in the sense that at the $i$ th step of communication the channel decides whether to corrupt the $i$ th symbol or not based on its view so far, i.e., its decision depends only on the transmitted symbols $(x_{1},\ldots,x_{i})$. This is in contrast to the classical adversarial channel in which the corruption is chosen by a channel that has full knowledge of the sent codeword $\mathbf {x}$. In this paper, we study the capacity of $q$ -ary online channels for a combined corruption model, in which the channel may impose at most $pn$ errors and at most $p^{*} n$ erasures on the transmitted codeword. The online channel (in both the error and erasure case) has seen a number of recent studies, which present both upper and lower bounds on its capacity. In this paper, we give a full characterization of the capacity as a function of $q,p$ , and $p^{*}$. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
41. The Error Probability of Sparse Superposition Codes With Approximate Message Passing Decoding.
- Author
-
Rush, Cynthia and Venkataramanan, Ramji
- Subjects
ITERATIVE decoding ,MESSAGE passing (Computer science) ,MAXIMUM likelihood decoding ,ERROR probability ,ADDITIVE white Gaussian noise channels - Abstract
Sparse superposition codes, or sparse regression codes, are a recent class of codes for reliable communication over the AWGN channel at rates approaching the channel capacity. Approximate message passing (AMP) decoding, a computationally efficient technique for decoding SPARCs, has been proven to be asymptotically capacity-achieving for the AWGN channel. In this paper, we refine the asymptotic result by deriving a large deviation bound on the probability of an AMP decoding error. This bound gives insight into the error performance of the AMP decoder for large but finite problem sizes, giving an error exponent as well as guidance on how the code parameters should be chosen at finite block lengths. For an appropriate choice of code parameters, we show that for any fixed rate less than the channel capacity, the decoding error probability decays exponentially in $n/(\log n)^{2T}$ , where $T$ , the number of AMP iterations required for successful decoding, is bounded in terms of the gap from capacity. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
42. Horse (Electromagnetics) is More Important Than Horseman (Information) for Wireless Transmission.
- Author
-
Migliore, Marco Donald
- Subjects
ELECTROMAGNETISM ,WIRELESS channels ,ELECTROMAGNETIC fields ,WIRELESS communications ,ENGINEERING reliability theory - Abstract
This paper addresses the question of how much information can be transmitted reliably over a wireless channel. It is shown that the limit of this mode of transmission is dictated by the amount of information that an electromagnetic field is capable of carrying. The methodology for the analysis of this problem is along the theory developed by Kolmogorov. This allows one to quantify the amount of information that can be transmitted by a wireless communication system taking into account the physical limitations governed by the laws of electromagnetism. Starting from the results related to the amount of information carried by an electromagnetic field, a novel antenna synthesis technique that simultaneously takes into account the requirements of information and antenna theory is introduced and applied to the synthesis of multiantenna systems. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
43. Resource Allocation for LDPC-Coded OFDM Downlink Channels.
- Author
-
Bluvshtein, Max and Amrani, Ofer
- Subjects
RESOURCE allocation ,LOW density parity check codes ,ORTHOGONAL frequency division multiplexing ,DECODERS (Electronics) ,GAUSSIAN channels - Abstract
Various techniques have been proposed to address the problem of resource allocation in multi-carrier communications. These techniques, for the most part, arise from information-theoretic measures or otherwise associated with the channel behavior, which does not necessarily model the coding being employed. In this paper, an optimization technique is tailored for low density parity-check (LDPC) coded orthogonal frequency-division multiplexing (OFDM) systems, by employing the so-called general stability condition introduced by Richardson et al. The latter formulates a necessary condition for the belief-propagation decoder to perfectly decode a received vector with no errors. The general condition is re-formulated so as to model practical multi-carrier systems, such as OFDM. Consequently, a general resource-allocation framework is laid down for optimizing the transmitted power based on the characteristics of the LDPC code in use. The proposed optimization technique is utilized for power allocation in orthogonal frequency-division multiple access systems; and the transmitted power is minimized while guaranteeing reliable decoding. To validate the proposed approach, it is compared to information-theoretic-based methods that aim at optimizing the mutual information between the transmitter and the receiver. Both approaches are shown to provide almost identical performance for the scenarios addressed in this paper. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
44. Capacity of Cellular Wireless Networks.
- Author
-
Vaze, Rahul and Iyer, Srikanth
- Abstract
In this paper, a tractable model of cellular wireless networks is considered, where both the basestation (BS) and mobile user (MU) locations are distributed as independent Poisson point processes, and each MU connects to its nearest BS. Each packet from the BS is transmitted using an automatic-repeat-request strategy until the signal-to-interference-plus-noise ratio (SINR) is larger than a threshold, and the packet delay is equal to the expected number of retransmissions required for successful reception. We define the network capacity as the product of the BS density and the reciprocal of the packet delay, maximized over all BS strategies. This definition of capacity, while being natural, is non-trivial to analyses because of the temporal correlations of SINRs and arbitrary BS strategies. An exact characterization (non-asymptotic) of this natural capacity metric is derived, which shows that the capacity increases polynomially with the BS density in the low BS density regime and then scales inverse exponentially with the increasing BS density. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
45. Finite-Field Matrix Channels for Network Coding.
- Author
-
Blackburn, Simon R. and Claridge, Jessica
- Subjects
MATRICES (Mathematics) ,LINEAR network coding ,FINITE element method ,NUMERICAL analysis ,SUBSPACES (Mathematics) - Abstract
In 2010, Silva et al. studied certain classes of finite-field matrix channels in order to model random linear network coding where exactly $t$ random errors are introduced. In this paper, we consider a generalization of these matrix channels where the number of errors is not required to be constant, indeed the number of errors may follow any distribution. We show that a capacity-achieving input distribution can always be taken to have a very restricted form (the distribution should be uniform given the rank of the input matrix). This result complements, and is inspired by a paper of Nobrega et al., which establishes a similar result for a class of matrix channels that model network coding with link erasures. Our result shows that the capacity of our channels can be expressed as maximization over probability distributions on the set of possible ranks of input matrices: a set of linear rather than exponential size. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
46. Mitigating LED Nonlinearity to Enhance Visible Light Communications.
- Author
-
Deng, Xiong, Mardanikorani, Shokoufeh, Wu, Yan, Arulandu, Kumar, Chen, Bin, Khalid, Amir M., and Linnartz, Jean-Paul M. G.
- Subjects
VISIBLE spectra ,OPTICAL communications ,LED lighting ,QUANTUM wells ,DIFFERENTIAL equations - Abstract
This paper addresses the nonlinear memory effects in the response of typical illumination light emitting diodes (LEDs), in order to enhance the performance of visible light communication (VLC) systems. These LEDs have a limited bandwidth of only several MHz. To reflect the physical mechanisms in the quantum well, we describe the LED transient response by a nonlinear dynamic differential equation. Three different mechanisms of the nonlinearity are relevant in the double hetero-structure LEDs, which result in dynamic nonlinearities, that is, a mixture of nonlinearities and memory effects. Hitherto, generic pre-distorter and non-linear equalizers have been studied for the LEDs. Yet this paper shows that recombination rates of photon generation can be translated into an equivalent discrete-time circuit that can be inverted. This allows us to develop a new pre-distorter with a simpler and more efficient structure than previously studied and overly generic approaches. The novel pre-distorter along with a parameter estimation can effectively overcome LED nonlinearity for high-speed VLC with amplitude-based single carrier modulations, including ON–OFF keying and pulse amplitude modulation-4 systems, and with the multi-carrier orthogonal frequency-division multiplexing. We report experimentally obtained eye-diagrams, first to justify our choice for the LED model on which our nonlinear pre-distorter have been based, and second to verify the effectiveness in enhancing the VLC link performance to the extent predicted by our model. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
47. The Two-User Causal Cognitive Interference Channel: Novel Outer Bounds and Constant Gap Result for the Symmetric Gaussian Noise Channel in Weak Interference.
- Author
-
Cardone, Martina, Tuninetti, Daniela, and Knopp, Raymond
- Subjects
INTERFERENCE channels (Telecommunications) ,TRANSMITTERS (Communication) ,CAUSAL models ,COGNITIVE radio ,INTERFERENCE (Telecommunication) - Abstract
This paper studies the two-user causal cognitive interference channel (CCIC), where two transmitters aim to communicate independent messages to two different receivers via a common channel. One source, referred to as the cognitive, is capable of overhearing the other source, referred to as the primary, through a noisy in-band link and thus can assist in sending the primary’s data. The authors of this paper recently characterized to within a constant gap the capacity of the symmetric Gaussian CCIC in: 1) the strong interference regime and 2) for a subset of the weak interference regime when the cooperation link is larger than a given threshold. This paper characterizes to within a constant gap the capacity for the symmetric Gaussian CCIC in the regime that was still open. To this end, two novel outer bounds of the types 2 R\mathsf {p}+ R\mathsf {c} and R\mathsf {p}+2 R\mathsf {c} are derived for the class of injective semideterministic CCICs, where the noises at the different source-destination pairs are independent. These outer bounds, as well as an achievable rate region based on Gelfand-Pinsker binning, superposition coding, and simultaneous decoding at the receivers, are then specialized to the Gaussian noise case. It is shown that the novel outer bounds are necessary to characterize the capacity within a constant gap when the cooperation link is weaker than the direct links, that is, in this regime unilateral cooperation leaves some system resources underutilized. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
48. Efficient Six-Port MIMO Antenna System for 5G Mobile Handsets.
- Author
-
Rajesh Kumar, D. and Venkat Babu, G.
- Subjects
MIMO systems ,HARBORS ,CHANNEL capacity (Telecommunications) ,SIGNAL-to-noise ratio ,ANTENNA arrays ,ANTENNAS (Electronics) ,MOBILE antennas ,5G networks - Abstract
A six-port MIMO antenna system for forthcoming mobile applications (Sub 6 GHz) is presented in this paper. Four F-shaped antenna elements are placed at four extreme corners and two at the middle side edges of 0.8 mm thick FR4 substrate. An open-ended slot is carved into the ground plane to improve the impedance matching. The proposed antenna operates in the frequency range of 3.4–3.6 GHz (LTE Band 42), with a-10 dB (2:1 voltage standing wave ratio) impedance bandwidth of 200 MHz. The proposed antenna operates in the frequency range of 3.4–3.6 GHz (LTE Band 42), with a-10 dB (2:1 voltage standing wave ratio) impedance bandwidth of 200–MHz. The fabricated MIMO antenna is practically measured and compared with simulated results. The obtained isolation is lower than 20 dB without employing isolation enhancing procedures, making the antenna highly appropriate for 5G smartphone applications. High isolation results in lower values of Envelope Correlation Coefficient (ECC) below 0.01. The antenna's diversity performance is validated by calculating Total Active Reflection Co-efficient (TARC) which is better than 40 dB. The calculated channel capacity of the six-port antenna array is 32.5 bps/Hz at 20 dB Signal to Noise Ratio (SNR). The six-antenna array's reliability is evaluated by examining the influence of hand effects and Specific Absorption Rate (SAR). The measured results are consistent with simulated results which exhibit the antenna presented in this article is highly capable of mobile phone applications for future cellular communication. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
49. Design and Analysis of High-Capacity MIMO System in Line-of-Sight Communication.
- Author
-
Jiang, Kuangming, Wang, Xiaoyong, Jin, Yanliang, Saleem, Asad, and Zheng, Guoxin
- Subjects
MIMO systems ,MOBILE communication systems ,ANTENNA arrays ,TELECOMMUNICATION systems - Abstract
The phase of the channel matrix elements has a significant impact on channel capacity in a mobile multiple-input multiple-output (MIMO) communication system, notably in line-of-sight (LoS) communication. In this paper, the general expression for the phase of the channel matrix at maximum channel capacity is determined. Moreover, the optimal antenna configuration of the 2 × 2 and 3 × 3 transceiver antenna array is realized for LoS communication, providing methods for n × n optimal antenna placement, which can be used in short-range LoS communication and non-scattering environment communication, such as coupling train communication and inter-satellite communication. Simulation results show that the 2 × 2 rectangular antenna array is more suitable for the communication of coupling trains, while the 3 × 3 circular arc antenna array is more suitable for virtual coupling trains according to antenna configurations. Moreover, the 2 × 2 antenna rectangular configuration proposed in this paper has reached the optimal channel in inter-satellite communication, which lays a foundation for the deployment of communication systems. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
50. Maximum Shannon Information Delivered in a Lecture.
- Author
-
Alksne, L. and Ozols, A.
- Subjects
LECTURES & lecturing ,ABSOLUTE value ,EAR - Abstract
The aim of our paper is to evaluate the maximum Shannon (syntactic) information carried through a video lecture. To achieve the aim, we have considered a natural lecture delivered by a lecturer as a signal transmitted over the physical communication channel consisting of a sound sub-channel and light sub-channel. Receivers are eyes and ears of listeners whose physical characteristics are taken into account. The physiological, neurological and cognitive aspects of the problem are neglected in calculations. The method has been developed to calculate the absolute maximum values of Shannon information characteristics of a natural lecture basing on the capacity formula of continuous communication channel and physical considerations taken into account for the first time, to our knowledge. Maximum Shannon information characteristics (entropies of sound and light frames, amounts of total acoustical and optical information, capacities of sound and light sub-channels, total amount of information and total capacity) of a natural lecture perceived by the audience have been calculated. These values are the upper bounds of a video lecture. The obtained results are discussed in the paper. After some modification, the proposed method can be practically applied for the optimization of both natural and video lectures because there is some correlation between syntactic and semantic information characteristics. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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