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1 – 2 of 2Shravan Kumar Bandari, V.V. Mani and A. Drosopoulos
The purpose of this paper is to study the performance of generalized frequency division multiplexing (GFDM) in some frequency selective fading channels. The exact symbol error…
Abstract
Purpose
The purpose of this paper is to study the performance of generalized frequency division multiplexing (GFDM) in some frequency selective fading channels. The exact symbol error rate (SER) expressions in Hoyt (Nakagami-q) and Weibull-v fading channels are derived. A GFDM transceiver simulation test bed is provided to validate the obtained analytical expressions.
Design/methodology/approach
Modern cellular system demands higher data rates, very low-latency transmissions and sensors with ultra low-power consumption. Current cellular systems of the fourth generation (4G) are not able to meet these emerging demands of future mobile communication systems. To address this requirement, GFDM, a novel multi-carrier modulation technique is proposed to satisfy the future needs of fifth generation technology. GFDM is a block-based transmission method where pulse shaping is applied circularly to individual subcarriers. Unlike traditional orthogonal frequency division multiplexing, GFDM transmits multiple symbols per subcarrier. The authors have used the probability density function approach in solving the final analytical expressions.
Findings
Detailed analysis of GFDM performance under Hoyt-q, Weibull-v and Log-Normal Shadowing fading channels. Exact analytical formulae were derived which support the simulations carried out by authors and other authors. The exact dependence of SER on fading parameters and roll-off factor α in the raised cosine pulse shape filter was determined.
Practical implications
Development and fabrication of high-performance GFDM systems under fading channel conditions.
Originality/value
Theoretical support to simulated system performance.
Details
Keywords
Jerzy Gołębiowski and Marek Zaręba
The purpose of this paper is to present a method of solving a thermal conduction equation in three‐zone axially‐symmetrical systems.
Abstract
Purpose
The purpose of this paper is to present a method of solving a thermal conduction equation in three‐zone axially‐symmetrical systems.
Design/methodology/approach
In the method developed, the field functions are determined in the analytical way by the superposition of states and separation of variables method. The coefficients of the field functions and eigenvalues of the boundary‐initial problem are computed by the numerical method. The coefficients are the solution to the corresponding sets of equations. These sets are the result of scalar products of non‐orthogonal functions at the respective zones of the cable. The eigenvalues are determined by an algorithm, which uses the field properties and elements of the golden cut method.
Findings
The method made it possible to develop a mathematical model of the dynamics of the thermal field in a polymer DC cable. This model has good physical interpretation. The paper also presents the field distributions determined in an analytical form. Some arguments of the expressions derived are however computed numerically. The results obtained by the paper's method and by the finite elements methods were compared. The relative differences are less than 6 per cent.
Research limitations/implications
The method concerns axially‐symmetrical three‐zone systems under nominal conditions.
Practical implications
By means of the method important parameters of DC lines can be determined (e.g. spatial‐temporal heat‐up curves, admissible sustained currents, time constants).
Originality/value
An analytical‐numerical method of analysis of the thermal field in a three‐zone axially‐symmetrical system was developed. Its original element is the algorithm of determination of eigenvalues of the boundary‐initial problem and coefficients of non‐orthogonal field functions.
Details