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1
Content available Modified PSO Based Channel Allocation Scheme for Interference Management in 5G Wireless Mesh Networks
Benni Nirmalkumar S., Manvi Sunilkumar S.
Journal of Telecommunications and Information Technology
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2022
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nr 2
1--13
EN
Efficient channel management is a challenge that next-generation wireless networks need to meet in order to satisfy increasing bandwidth demand and transmission rate requirements. Non-orthogonal multiple access (NOMA) is one of such efficient channel allocation methods used in 5G backhaul wireless mesh networks. In this paper, we propose a power demand-based channel allocation method for 5G backhaul wireless mesh networks by employing NOMA and considering traffic demands in small cells, thereby improving channel utility. In this scheme, we work with physical layer transmission. The foremost aim is to mutually optimize the uplink/downlink NOMA channel assignment in order to increase user fairness. The approach concerned may be divided into two steps. First, initial channel allocation is performed by employing the traveling salesman problem (TSP), due to its similarity to many-to-many double-side user-channel allocation. Second, the modified particle swarm optimization (PSO) method is applied for allocation updates, by introducing a decreasing coefficient which may have the form of a standard stochastic estimate algorithm. To enhance exploration capacity of modified the PSO, a random velocity is included to optimize the convergence rate and exploration behavior. The performance of the designed scheme is estimated through simulation, taking into account such parameters as through put, spectral efficiency, sum-rate, outage probability, signal to-interference plus noise ratio (SINR), and fairness. The proposed scheme maximizes network capacity and improves fairness between the individual stations. Experimental results show that the proposed technique performs better than existing solutions.
2
Content available First and Second Order Characteristics of a Wireless Three-hop Relay Channel with the Presence of Rayleigh Fading
Krstic Dragana, Nikolic Petar, Popovic Zoran, Stefanovic Mihajlo
Journal of Telecommunications and Information Technology
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2020
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nr 2
36--44
EN
In this paper, a wireless three-hop relay communication system operating in a Rayleigh multipath fading environment is analyzed. The output signal from such a system is a product of signal envelopes from all sections, meaning that it is actually a product of three random variables (RVs) with Rayleigh distribution. We considered here the first-order characteristics: probability density function (PDF), cumulative distribution function and outage probability (OP). Then, the moments and amount of fading (AoF) were derived in the closed forms. The second order characteristics we present include the following: level crossing rate (LCR) and average fade duration (AFD). A few graphs are given to show the impact of the specific parameters of the wireless three-hop relay system.
3
Content available Product of Three Random Variables and its Application in Relay Telecommunication Systems in the Presence of Multipath Fading
Krstic Dragana, Nikolic Petar, Aleksic Danijela, Minic Sinisa, Vuckovic Dragan, Stefanovic Mihajlo
Journal of Telecommunications and Information Technology
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2019
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nr 1
83--92
EN
In this paper, the product of three random variables (RVs) will be considered. Distribution of the product of independent random variables is very important in many applied problems, including wireless relay telecommunication systems. A few of such products of three random variables are observed in this work: the level crossing rate (LCR) of the product of a Nakagami-m random variable, a Rician random variable and a Rayleigh random variable, and of the products of two Rician RVs and one Nakagami-m RV is calculated in closed forms and presented graphically. The LCR formula may be later used for derivation of average fade duration (AFD) of a wireless relay communication radio system with three sections, working in the multipath fading channel. The impact of fading parameters and multipath fading power on the LCR is analyzed based on the graphs presented.
4
Content available Performance Analysis of SPSK with Dual Polarized Transmit Antennas over Rayleigh Fading Channel
Subramani M., Neduncheran A. V., Ponnusamy V.
Journal of Telecommunications and Information Technology
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2018
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nr 1
58--61
EN
In this paper, the Space Polarization Shift Keying (SPSK) system, which is an extended version of Space Shift Keying (SSK) and includes both space and polarization dimensions with dual polarized antennas, is studied. The capacity and error probability analysis of SPSK for different polarization configurations are dealt with over the Rayleigh fading channel with a rich scattering environment. The analysis conducted shows that the SPSK with a dual polarized antenna (DP) offers better results than SPSK with a single orthogonal polarized antenna SPSK(SP), under non-LOS conditions. SPSK(DP) outperforms SSK by 4.2 dB over the correlated Rayleigh fading channel at 3 bits/s/Hz.
5
Content available remote Multiple co-channel interferers influence on the selection diversity system over Rayleigh fading channels
Stefanović H., Petrović I., Stefanović M., Panić S., Spalević P.
Przegląd Elektrotechniczny
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2012
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R. 88, nr 1a
222-224
EN
Selection combining (SC) diversity receiver experiencing an arbitrary number of multiple, independent, equal power co-channel interferers, in the presence of Rayleigh fading channels was analyzed. Closed form expressions are obtained for the output SIR’s probability density function (PDF) and cumulative distribution function (CDF). In order to show the effects of the number of multiple interferers, diversity order and input SIR unbalance to the system performances, an outage probability (OP) analysis is derived. Another important measure of the system’s performances, an average bit error probability (ABER) is efficiently evaluated for non-coherent modulation schemes such as binary frequency-shift keying (BFSK) and binary differentially phase-shift keying (BDPSK).
PL
Przeanalizowano wpływ interferencji między wieloma niezależnymi kanałami (w obecności kanału Rayleigha z zanikami) na wybór najlepszego sygnału. Przedstawiono wyrażenie na prawdopodobieństwo parametru SIR (signal to interference ratio) oraz średnie prawdopodobieństwo bitu błędu (ABER).
6
Content available Overview of Fading Channel Modeling
Noga K. M., Pałczyńska B.
International Journal of Electronics and Telecommunications
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2010
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Vol. 56, No. 4
339-344
EN
VisSim and LabVIEW based approaches are proposed and implemented to demonstrate fading in the communication systems. The introduction to fading, models for flat fading like Rayleigh, Weibull, Nakagami-m and the results of simulations are presented.
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