114 research outputs found
Detection and mitigation of indirect conflicts between xApps in Open Radio Access Networks
In Open Radio Access Networks, the Conflict Mitigation component, which is
part of the Near-RT RIC, aims to detect and resolve any conflicts between xApp
decisions. In this paper, we propose a universal method for detecting and
resolving of indirect conflicts between xApps. Its efficiency is validated by
extensive computer simulations. Our results demonstrate that, in the considered
scenario, the mean bitrate satisfaction of users increases by 2%, while the
number of radio link failures and ping-pong handovers in the network is
significantly reduced
Dense Wireless Network Inspired by the Nervous System
This work presents concepts of the use of algorithms inspired by the functions and properties of the nervous system in dense wireless networks. In particular, selected features of the brain consisting of a large number of nerve connections were analyzed, which is why they are a good model for a dense network. In addition, the action of a selected cells from the nervous system (such as neuron, microglia or astrocyte) as well as phenomena observed in it (e.g. neuroplasticity) are presented
Waveform flexibility in database-oriented cognitive wireless systems
© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, 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 component of this work in other works.In this paper we discuss the idea of waveform flexibility in future wireless networks utilizing cognitive radio functionality. Mainly, we consider the possibility to adjust the shape of the waveform based on the information about the surrounding environment stored in a dedicated context-information database. In our approach, the cognitive terminal has an option to select one of four available waveforms to adapt itself in the best way to the constraints delivered by the database. In this paper we present the key concept of waveform flexibility, the proposed algorithm for waveform selection and the achieved simulation results.Peer ReviewedPostprint (author's final draft
Dense Wireless Network Inspired by the Nervous System
This work presents concepts of the use of algorithms inspired by the functions and properties of the nervous system in dense wireless networks. In particular, selected features of the brain consisting of a large number of nerve connections were analyzed, which is why they are a good model for a dense network. In addition, the action of a selected cells from the nervous system (such as neuron, microglia or astrocyte) as well as phenomena observed in it (e.g. neuroplasticity) are presented
DVB-T signal detection for indoor environments in low-SNR regime
The problem of coexistence between the primary
(licensed) and secondary (non-licensed) users can be solved
in various ways. One of them assumes the application of the
detailed Radio Environment Maps being a kind of database,
where some crucial information about the licensed
transmission can be stored. In this paper we propose the
new methods for signal detection in low signal-to-noise
regime and compare it through hardware experiment with
other known techniques used for spectrum sensing.Peer ReviewedPostprint (author’s final draft
MIMO-OFDM Crystallized Rate Regions
In this paper, we introduce the generalization of the con- cept of crystallized rate regions for MIMO-OFDM trans- mission. The extension from the OFDM and MIMO case to MIMO-OFDM scenario of the time-sharing convex hull of achievable rates is discussed and a new definition of the cost function for the rate region game is derived. Based on the new game definition, the simulation results for the MIMO-OFDM case are presented
Federated Learning-Based Interference Modeling for Vehicular Dynamic Spectrum Access
A platoon-based driving is a technology allowing vehicles to follow each
other at close distances to, e.g., save fuel. However, it requires reliable
wireless communications to adjust their speeds. Recent studies have shown that
the frequency band dedicated for vehicle-to-vehicle communications can be too
busy for intra-platoon communications. Thus it is reasonable to use additional
spectrum resources, of low occupancy, i.e., secondary spectrum channels. The
challenge is to model the interference in those channels to enable proper
channel selection. In this paper, we propose a two-layered Radio Environment
Map (REM) that aims at providing platoons with accurate location-dependent
interference models by using the Federated Learning approach. Each platoon is
equipped with a Local REM that is updated on the basis of raw interference
samples and previous interference model stored in the Global REM. The model in
global REM is obtained by merging models reported by platoons. The nodes
exchange only parameters of interference models, reducing the required control
channel capacity. Moreover, in the proposed architecture platoon can utilize
Local REM to predict channel occupancy, even when the connection to the Global
REM is temporarily unavailable. The proposed system is validated via computer
simulations considering non-trivial interference patterns
Crystallized Rate Regions for MIMO Transmission
International audienceWhen considering the multiuser SISO interference channel, the allowable rate region is not convex and the maximization of the aggregated rate of all the users by the means of transmission power control becomes inefficient. Hence, a concept of the crystallized rate regions has been proposed, where the time-sharing approach is considered to maximize the sumrate.In this paper, we extend the concept of crystallized rate regions from the simple SISO interference channel case to the MIMO/OFDM interference channel. As a first step, we extend the time-sharing convex hull from the SISO to the MIMO channel case. We provide a non-cooperative game-theoretical approach to study the achievable rate regions, and consider the Vickrey-Clarke-Groves (VCG) mechanism design with a novel cost function. Within this analysis, we also investigate the case of OFDM channels, which can be treated as the special case of MIMO channels when the channel transfer matrices are diagonal. In the second step, we adopt the concept of correlated equilibrium into the case of two-user MIMO/OFDM, and we introduce a regret-matching learning algorithm for the system to converge to the equilibrium state. Moreover, we formulate the linear programming problem to find the aggregated rate of all users and solve it using the Simplex method. Finally, numerical results are provided to confirm our theoretical claims and show the improvement provided by this approach
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