Topic
Communication channel
About: Communication channel is a research topic. Over the lifetime, 137411 publications have been published within this topic receiving 1715077 citations. The topic is also known as: communication channel & communications channel.
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TL;DR: This letter proposes a solid analytical formulation and analyzes the signal metrics (attenuation and propagation delay) for molecular communication via diffusion channel with an absorbing receiver in a 3-D environment and proposes a model and the formulation that match well with the simulations without any normalization.
Abstract: Within the domain of molecular communications, researchers mimic the techniques in nature to come up with alternative communication methods for collaborating nanomachines. This letter investigates the channel transfer function for molecular communications via diffusion. In nature, information-carrying molecules are generally absorbed by the target node via receptors. Using the concentration function, without considering the absorption process, as the channel transfer function implicitly assumes that the receiver node does not affect the system. In this letter, we propose a solid analytical formulation and analyze the signal metrics (attenuation and propagation delay) for molecular communication via diffusion channel with an absorbing receiver in a 3-D environment. The proposed model and the formulation match well with the simulations without any normalization.
354 citations
24 Jun 2007
TL;DR: It is shown that, the optimal communication strategy in all cases, is beamforming.
Abstract: A Gaussian MISO (multiple input single output) channel is considered where a transmitter is communicating to a receiver in the presence of an eavesdropper. The transmitter is equipped with multiple antennas, while the receiver and the eavesdropper each have a single antenna. The transmitter maximizes the communication rate, while concealing the message from the eavesdropper. The channel input is restricted to Gaussian signalling, with no preprocessing of information. For these channel inputs, and under different channel fading assumptions, optimal transmission strategies are found, in terms of the input covariance matrices. It is shown that, the optimal communication strategy in all cases, is beamforming.
352 citations
06 Jun 2013
TL;DR: An iterative hybrid beamforming algorithm for the single user mmWave channel is developed and results show that the proposed algorithm can approach the rates achieved by unconstrained digital beamforming solutions.
Abstract: Next-generation cellular standards may leverage the large bandwidth available at millimeter wave (mmWave) frequencies to provide gigabit-per-second data rates in outdoor wireless systems. A main challenge in realizing mmWave cellular is achieving sufficient operating link margin, which is enabled via directional beamforming with large antenna arrays. Due to the high cost and power consumption of high-bandwidth mixed-signal devices, mmWave beamforming will likely include a combination of analog and digital processing. In this paper, we develop an iterative hybrid beamforming algorithm for the single user mmWave channel. The proposed algorithm accounts for the limitations of analog beamforming circuitry and assumes only partial channel knowledge at both the base and mobile stations. The precoding strategy exploits the sparse nature of the mmWave channel and uses a variant of matching pursuit to provide simple solutions to the hybrid beamforming problem. Simulation results show that the proposed algorithm can approach the rates achieved by unconstrained digital beamforming solutions.
352 citations
TL;DR: A statistical channel model which is a combination of Rice and lognormal statistics, and is suitable in principle to all types of environment (rural, suburban, urban) simply by tuning the model parameters, is introduced.
Abstract: The paper introduces a statistical channel model which is a combination of Rice and lognormal statistics, and is suitable in principle to all types of environment (rural, suburban, urban) simply by tuning the model parameters. The model validity is confirmed by comparisons with measurement data collected in the literature. Empirical formulas are derived for the model parameters to fit measured data over a wide range of elevation angles. In particular, the model is applied to nongeostationary satellite channels, such as low-Earth orbit and medium-Earth orbit channels, in which for a given user located in a generic site the elevation angle changes continuously. Finally, examples of average bit error probability evaluations in the channel are provided. >
352 citations
Patent•
09 Apr 2004TL;DR: In this paper, the scale factor between the first and second sets of channel estimates from a least squares error criterion is used to determine the first transmission channel as a channel estimate of the second transmission channel scaled by the determined scale factor.
Abstract: A method of determining a channel estimate of a first transmission channel in a communications system. The method comprises deriving a first set of channel estimates from symbols received through said first transmission channel; deriving a second set of channel estimates from symbols received through a second transmission channel in the communications system; determining a scale factor between the first and second sets of channel estimates from a least squares error criterion; and determining the channel estimate of the first transmission channel as a channel estimate of the second transmission channel scaled by the determined scale factor.
350 citations