Search results for "Computer Science::Information Theory"
showing 10 items of 272 documents
Sparse multipath channels: Modelling, analysis, and simulation
2013
A sparse multipath channel is characterized by a small number of randomly distributed scatterers. This study proposes a methodology for the modelling of sparse multipath channels. The new methodology is then used to develop a sparse narrowband multipath channel model by applying the sum-of-cisoids (SOC) principle. The statistical properties of the presented sparse SOC multipath channel model are studied. Analytical expressions are derived for the mean value, variance, autocorrelation function (ACF) and cross-correlation function (CCF) of the complex channel gain, as well as for the probability density function (PDF) of the envelope. Our study shows that mobile radio channels behave in spars…
A limited feedback scheme based on spatially correlated channels for coordinated multipoint systems
2012
High spectral efficiency can be achieved in the downlink of multi-antenna coordinated multi-point systems provided that the multiuser interference is appropriately managed at the transmitter side. For this sake, downlink channel information needs to be sent back by the users, thus reducing the rate available at the uplink channel. The amount and type of feedback information required has been extensively studied and many limited feedback schemes have been proposed lately. A common pattern to all of them is that achieving low rates of feedback information is possible at the cost of increasing complexity at the user side and, sometimes, assuming that some statistics of the channel are known. I…
The influence of severity of fading on the statistical properties of the capacity of Nakagami-m channels with MRC and EGC
2010
In this article, we have studied the statistical properties of the capacity of Nakagami-m channels when spatial diversity combining, such as maximal ratio combining (MRC) and equal gain combining (EGC), is employed at the receiver. The presented results provide insight into the statistical properties of the channel capacity under a wide range of fading conditions in wireless links using L-branch diversity combining techniques. We have derived closed-form analytical expressions for the probability density function (PDF), cumulative distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the channel capacity. The statistical properties of the capacity ar…
On the statistical properties of the capacity of amplify-and-forward channels under LOS conditions
2008
Amplify-and-forward channels in cooperative networks provide a promising improvement in the network coverage and system throughput. Under line-of-sight (LOS) propagation conditions in such cooperative networks, the overall fading channel can be modeled by a double Rice process. In this article, we have studied the statistical properties of the capacity of double Rice fading channels. We have derived the analytical expressions for the probability density function (PDF), cumulative distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the channel capacity. The obtained results are studied for different values of the amplitudes of the LOS components in …
Analog Multiple Description Joint Source-Channel Coding Based on Lattice Scaling
2015
Joint source-channel coding schemes based on analog mappings for point-to-point channels have recently gained attention for their simplicity and low delay. In this paper, these schemes are extended either to scenarios with or without side information at the decoders to transmit multiple descriptions of a Gaussian source over independent parallel channels. They are based on a lattice scaling approach together with bandwidth reduction analog mappings adapted for this multiple description scenario. The rationale behind lattice scaling is to improve performance through bandwidth expansion. Another important contribution of this paper is the proof of the separation theorem for the communication …
An Improved Receiver Architecture for Cyclic-Prefixed OFDM
2009
A novel Orthogonal Frequency Division Multiplexing receiver architecture to be employed with standard (e.g. Wireless LAN) transmitters is proposed. It features enhanced error-rate performance with flexible computational complexity and robustness to imperfect channel estimation. It is based on exploitation of the redundancy available in the cyclic prefix after cancellation of interference from the previous block. In order to show the effectiveness of our proposal, a number of comparisons to the standard per-subcarrier receiver and a previously existing method are reported.
Performance analysis of amplify-and-forward cooperative communication systems with channel estimation errors
2008
Cooperative diversity is a transmission technique that achieves a diversity gain by using a combination of the relayed signal and the direct signal. In this paper, we study the symbol-error-rate (SER) performance of a cooperative communication system operating in an amplify-and-forward (AF) mode, where the channel state information (CSI) available at the receiver is an estimate of the channel gains with estimation errors. We derive both the probability density function and the moment generating function of the instantaneous signal-to-noise ratio (SNR) at the destination terminal. These statistical quantities are then applied to study the performance of an AF cooperative communication system…
Efficient Design of Waveguide Manifold Multiplexers Based on Low-Order EM Distributed Models
2015
In this paper, a new systematic technique to design manifold-coupled multiplexers in waveguide technology is proposed. The new technique uses generalized low-order electromagnetic (EM) distributed models, which constitute a half-way point between the fast, but imprecise, analytical models, and the more accurate, but costly, full-wave EM models. The method can be applied to contiguous and noncontiguous channel multiplexers, in both E-plane or H-plane configurations. This paper covers the complete design procedure for manifold multiplexers, starting from the required specifications and finishing with the physical dimensions. After explaining the general design technique for multiplexers with …
On the Statistical Properties of Equal Gain Combining over Mobile-to-Mobile Fading Channels in Cooperative Networks
2010
Paper presented at the 2010 IEEE International Conference on Communications (ICC), Cape Town. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works. Paper also available from the publisher: http://dx.doi.org/10.1109/ICC.2010.5501898 This article deals with the statistical analysis of equal gain combining (EGC) over mobile-to-mobile (M2M) fading channels in a dual-hop amplify-and-forward relay network. Here, we…
Mobile-to-mobile fading channels in amplify-and-forward relay systems under line-of-sight conditions: statistical modeling and analysis
2010
Published version of an article from the journal:Annales des Telecommunications/Annals of Telecommunications. The original publication is available at Springerlink. http://dx.doi.org/10.1007/s12243-010-0169-z This paper deals with the modeling and analysis of narrowband mobile-to-mobile (M2M) fading channels for amplify-and-forward relay links under line-of-sight (LOS) conditions. It is assumed that a LOS component exists in the direct link between the source mobile station (SMS) and the destination mobile station (DMS), as well as in the links via the mobile relay (MR). The proposed channel model is referred to as the multiple-LOS second-order scattering (MLSS) channel model. The MLSS chan…