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1

Performance Enhancement of Cooperative MIMO-NOMA Systems Over Sub-6 GHz and mmWave Bands

Saleh Ahmed A., Ahmed Mohamad A.

Journal of Telecommunications and Information Technology

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2023

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nr 2

70--77

EN

In this paper, two radio links with diﬀerent frequency bands are considered for base stations (BS) serving users via decode-and-forward (DF) cooperative relays. Backhaul and access links are proposed with sub-6 GHz and millimeter wave (mmWave) bands, respectively. Non-orthogonal multiple access (NOMA) is employed in the backhaul link to simultaneously transmit a superposed signal in the power domain, using the same band. The superposed signals, containing two signals that diﬀer in terms of power allocation factors (PAFs), are designed for two selected DF relays in the BS. The two relays are chosen from several relays to be serviced by the BS based on a pairing algorithm that depends on diﬀerent users’ circumstances. The furthest DF relay detects the incoming NOMA signal directly, while the nearest one applies successive interference cancellation (SIC) before extracting its signal. Each DF relay forwards the detected signals toward their intended users over mmWave channels. Three performance metrics are utilized to evaluate the system’s performance: outage probability, achievable throughput, and bit error rate. Comparisons between two mmWave bands in the access link (28 and 73 GHz) are made to demonstrate the superiority of the 28 GHz band in terms of the three performance-related metrics.

2

Przepustowość systemów radiowych z blokiem RF pracującym w temperaturach kriogenicznych

Markiewicz T. G., Wesołowski K.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2018

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nr 6

377--382, CD

PL

W pracy zaproponowano i przeanalizowano wpływ chłodzenia kriogenicznego części RF (ang. Radio Frequency) węzłów sieci bezprzewodowej na pojemność kanału oraz prawdopodobieństwo błędu symbolowego i bitowego. Analiza została przeprowadzona w kanale AWGN (ang. Additive White Gaussian Noise) oraz rayleighowskim. Zyski względem systemu bez chłodzenia wynoszą ok. 10dB-12dB. Dyskusji poddano również możliwe ograniczenia takiego systemu oraz potencjalne możliwości zastosowania.

EN

This paper proposes and analyses the impact of the cryogenic cooling of the RF front-end of wireless network entities on the channel capacity and bit and symbol error probabilities. The performed analysis was conducted assuming AWGN and Rayleigh channel models. Gains compared to the system without such a cooling are approx. 10dB-12dB. We also discuss possible limitations and deployments of such systems.

3

Calculation of Signalling RTP Packet Error Probability in Internet

Lebl A., Mitic D., Markov Z.

Przegląd Elektrotechniczny

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2011

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R. 87, nr 10

364-368

EN

We analyze the errors in the Internet packets carrying telephony signalling information. Error probability, obtained by using redundant packet sending, is also calculated. It is proved that fatal error probability, when signalling packets are sent according to standardized RTP packets, is better than it is allowed in international recommendation for analog signalling systems, but worse than it is allowed for No7 signalling systems. The improvement is achieved by using redundant packet sending, when the error probability drops below the value intended for No7 signalling.

PL

Przeanalizowano błędy w pakiecie internetowym przenoszącym informację telefoniczną. Stwierdzono, że prawdopodobieństwo błędu w pakiecie zgodnym ze standardem RTP jest mniejsze w układach analogowych ale większe w systemie CCS No 7. Pomocne w tym przypadku może być przesłanie pakietu rezerwowego.

4

Multiple hypotheses optimal testing for Markov chains and identification subject to the reliability criterion

Navaei L.

Journal of Mathematics and Applications

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2010

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Vol. 33

79-90

EN

The problem of many (L > 2)hypotheses testing on distributions of a finite state Markov chain is studied. We apply large deviation techniques (LDT). It is demonstrated that this method of investigation in solving the problem of logarithmically asymptotically optimal (LAO) hypotheses testing is easier, compared with the procedure introduced by Haroutunian. The matrix of exponents [formula/wzór], of error probabilities of the LAO test [formula/wzór] is the probability to accept the hypothesis l, when the hypothesis m is true, is determined. Moreover, the identification of distributions for one object and two independent objects via simple homogeneous stationary Markov chains with finite number of states is discussed in the present paper.