The Experts below are selected from a list of 4581 Experts worldwide ranked by ideXlab platform
J M Cioffi - One of the best experts on this subject based on the ideXlab platform.
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a wire waveguide channel for terabit per second links
Applied Physics Letters, 2020Co-Authors: Rabi Shrestha, J M Cioffi, Mehdi Mohseni, Kenneth Kerpez, Chan Soo Hwang, Daniel M MittlemanAbstract:The rise in consumer data usage has increased the demand for higher data rates in telecommunication in both wireless and wired systems. In order to meet the demands for increased data rates for wired services, one possibility is to switch to higher frequencies, beyond the MHz-range frequencies typically used in digital Subscriber Line (DSL) services. In this work, we investigate the channel properties of a 200 GHz signal transmitted through a waveguide structure that is designed to approximately emulate the type of paired phone cable typically used for DSL transmissions. We report the attenuation characteristics of such a channel and explore the achievable data rates of a realistic vectored scenario that exploits the modal diversity of this multi-mode channel. We find that aggregate data rates on the order of terabits per second are feasible over short distances.The rise in consumer data usage has increased the demand for higher data rates in telecommunication in both wireless and wired systems. In order to meet the demands for increased data rates for wired services, one possibility is to switch to higher frequencies, beyond the MHz-range frequencies typically used in digital Subscriber Line (DSL) services. In this work, we investigate the channel properties of a 200 GHz signal transmitted through a waveguide structure that is designed to approximately emulate the type of paired phone cable typically used for DSL transmissions. We report the attenuation characteristics of such a channel and explore the achievable data rates of a realistic vectored scenario that exploits the modal diversity of this multi-mode channel. We find that aggregate data rates on the order of terabits per second are feasible over short distances.
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gigabit dsl
IEEE Transactions on Communications, 2007Co-Authors: Bin Lee, J M Cioffi, S Jagannathan, Mehdi MohseniAbstract:This paper applies multiple-input multiple-output (MIMO) transmission methods to multiwire communication systems. Using channel matrices generated from a binder MIMO channel model, a performance assessment of digital Subscriber Line (DSL) technology based on MIMO transmission methods finds that symmetric data rates of more than 1 Gbps are achievable over four twisted pairs (category 3) for a 300 m range. Similar results are also obtained for a ldquoquadrdquo cable. To achieve this data rate, this paper proposes that the source and load be excited using common mode.
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spc09 6 band preference dynamic spectrum management in a dsl environment
Global Communications Conference, 2006Co-Authors: Wooyul Lee, Youngjae Kim, Mark H Brady, J M CioffiAbstract:This paper introduces an algorithm for spectrum management for digital Subscriber Line (DSL) systems based on band preference. The proposed method influences the usage of spectrum through band preference factors that subtly modify the loading algorithm of DSL modems. Ad-hoc algorithms for computing such band preference factors are discussed. Simulation results in a practical ADSL environment show that the performance of the proposed method is better than that of Iterative Water-filling (IWF) [1] and is close to that of Optimal Spectrum Balancing (OSB) [2], even with a small number of control parameters.
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band preference dynamic spectrum management in a dsl environment
Global Communications Conference, 2006Co-Authors: Wooyul Lee, Youngjae Kim, Mark H Brady, J M CioffiAbstract:This paper introduces an algorithm for spectrum management for digital Subscriber Line (DSL) systems based on band preference. The proposed method influences the usage of spectrum through band preference factors that subtly modify the loading algorithm of DSL modems. Ad-hoc algorithms for computing such band preference factors are discussed. Simu- lation results in a practical ADSL environment show that the performance of the proposed method is better than that of Iterative Water-filling (IWF) (1) and is close to that of Optimal Spectrum Balancing (OSB) (2), even with a small number of control parameters. I. INTRODUCTION
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multi user discrete bit loading for dmt based dsl systems
Global Communications Conference, 2002Co-Authors: Jungwon Lee, R.v. Sonalkar, J M CioffiAbstract:This paper investigates the multiuser bit and power allocation problem in discrete multi-tone digital Subscriber Line modems. A spectrum-management center with knowledge of direct and crosstalk-coupled channel gains allocates the bits and the available power to the subchannels for all users in a common binder. The center uses a multiuser discrete bit-loading algorithm that attempts to minimize the total transmit power given a target sum-rate. This algorithm extends the greedy algorithm for the single-user channel to the multi-user channel. Simulation results for the upstream transmission in very high-speed digital Subscriber Line show that the total power can be reduced using the multi-user discrete bit-loading algorithm instead of applying. the single-user greedy algorithm iteratively.
J J Werner - One of the best experts on this subject based on the ideXlab platform.
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Digital Subscriber Line (HDSL and ADSL) capacity of the outside loop plant
IEEE Journal on Selected Areas in Communications, 1995Co-Authors: Syed V. Ahamed, P. L. Gruber, J J WernerAbstract:The fundamental limits of the outside loop plant to carry high-speed digital (bi-directional HDSL and ADSL) data are reported. The paper focuses on the copper wire pairs, drop lengths, and interconnects that convey data over the “last mile” to almost all businesses and residences in the US. The two major customers, businesses and households, are classified, characterized, and categorized by the distance to the central office or the remote terminal. Their spectral capabilities are computed and their ultimate digital capabilities are reported. The crosstalk limitations inherent in the plant are also computed and verified against the loss of signal due the distance and spectral constraints. The signal to noise ratio can thus be estimated to ascertain the transmission quality through the plant. Accordingly, the paper reports on losses, bandwidths, and bit rates in the first half, and discusses the major bottlenecks in the second half
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the hdsl environment high bit rate digital Subscriber Line
IEEE Journal on Selected Areas in Communications, 1991Co-Authors: J J WernerAbstract:The author presents a tutorial on the physical environment in which high bit rate digital Subscriber Line (HDSL) transceivers will have to evolve and succeed. Special attention is given to the most damaging impairments that are encountered in Subscriber Lines, such as propagation loss, Linear distortion, crosstalk, bridged taps, and impulse noise. Somewhat less important impairments, such as change of gauge, temperature variation, and thermal noise, are also briefly described. The author concludes with a discussion of the capacity of a twisted-pair channel in a crosstalk-dominated environment. >
H V Poor - One of the best experts on this subject based on the ideXlab platform.
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noisy interference sum rate capacity of parallel gaussian interference channels
IEEE Transactions on Information Theory, 2011Co-Authors: Xiaohu Shang, Gerhard Kramer, Biao Chen, H V PoorAbstract:The sum-rate capacity of the parallel Gaussian interference channel is shown to be achieved by independent transmission across subchannels and treating interference as noise if the channel coefficients and power constraints satisfy a certain condition. The condition requires the interference to be weak, a situation commonly encountered, e.g., in digital Subscriber Line transmission. The optimal power allocation is characterized by using the concavity of the sum-rate capacity as a function of the power constraints.
George Ginis - One of the best experts on this subject based on the ideXlab platform.
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vectored transmission for digital Subscriber Line systems
IEEE Journal on Selected Areas in Communications, 2002Co-Authors: George GinisAbstract:This paper describes the "vectored" transmission technique for digital Subscriber Line (DSL) systems, which utilizes user coordination at the central office or optical network unit. This method exploits the colocation of the downstream transmitters and of the upstream receivers, in order to achieve far-end crosstalk (FEXT) cancellation and perform multiuser transmission optimization. The performance improvements are particularly pronounced in environments with strong FEXT such as in very high-speed DSL. Discrete multitone is employed for each user with additional constraints on the cyclic prefix length and with the assumption of block-synchronized transmission and reception for downstream and upstream transmission correspondingly. Within each tone, upstream crosstalk is removed by multiple-input-multiple-output decision feedback at the receiving side, while downstream crosstalk is eliminated by analogous preprocessing at the transmitting side. Additionally, the issue of transmission energy allocation in frequency and among users is addressed. Assuming frequency-division duplexing, the corresponding optimization problem is formulated and solved via convex programming both for a fixed upstream-downstream band plan and for a dynamically programmable band plan. The case of power backoff as a means to reduce the impact of crosstalk on alien systems is also treated. Interestingly, the performance of the proposed methods is shown to be very close to known information theory bounds.
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vectored dmt a fext canceling modulation scheme for coordinating users
International Conference on Communications, 2001Co-Authors: George Ginis, J M CioffiAbstract:This paper describes a modulation scheme achieving far-end crosstalk (FEXT) cancellation, assuming that joint signal processing among the users can be performed at either the receiver or at the transmitter side. The multi-user channel is modeled as a multiple-input-multiple-output (MIMO) system, and the development starts with the zero-forcing generalized decision feedback equalizer (GDFE). Structures are derived, which combine the discrete multi-tone (DMT) transmission technique with either successive cancellation at the receiver or precoding at the transmitter. A promising application of the proposed scheme is in FEXT-limited digital Subscriber Line (DSL) systems. Computer simulations demonstrate that significant performance improvements can be realized in such scenarios.
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a multi user precoding scheme achieving crosstalk cancellation with application to dsl systems
Asilomar Conference on Signals Systems and Computers, 2000Co-Authors: George Ginis, J M CioffiAbstract:This paper describes a precoding scheme capable of achieving crosstalk cancellation in scenarios involving communication from a "base station" to a number of geographically dispersed users. We illustrate that joint processing at the "base station" of the transmitted signals of all users can succeed in removing the otherwise resulting crosstalk. The method employed borrows from the concept of the Tomlinson-Harashima (1971, 1972) precoder which is often used for equalization against intersymbol interference (ISI). One possible application of the proposed technique is in digital Subscriber Line (DSL) systems, where far end crosstalk (FEXT) poses a severe transmission constraint. Simulation results show that significant improvements can be realized in such scenarios.
Xiaohu Shang - One of the best experts on this subject based on the ideXlab platform.
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noisy interference sum rate capacity of parallel gaussian interference channels
IEEE Transactions on Information Theory, 2011Co-Authors: Xiaohu Shang, Gerhard Kramer, Biao Chen, H V PoorAbstract:The sum-rate capacity of the parallel Gaussian interference channel is shown to be achieved by independent transmission across subchannels and treating interference as noise if the channel coefficients and power constraints satisfy a certain condition. The condition requires the interference to be weak, a situation commonly encountered, e.g., in digital Subscriber Line transmission. The optimal power allocation is characterized by using the concavity of the sum-rate capacity as a function of the power constraints.
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noisy interference sum rate capacity of parallel gaussian interference channels
arXiv: Information Theory, 2009Co-Authors: Xiaohu Shang, Gerhard Kramer, Biao Chen, Vincent H PoorAbstract:The sum-rate capacity of the parallel Gaussian interference channel is shown to be achieved by independent transmission across sub-channels and treating interference as noise in each sub-channel if the channel coefficients and power constraints satisfy a certain condition. The condition requires the interference to be weak, a situation commonly encountered in, e.g., digital Subscriber Line transmission. The optimal power allocation is characterized by using the concavity of sum-rate capacity as a function of the power constraints.
