Temat: MULTIPLE - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Analysis of an LSTM-based NOMA Detector Over Time Selective Nakagami-m Fading Channel Conditions
Autorzy:: Shankar, Ravi
Bangare, Jyoti L.
Kumar, Ajay
Gupta, Sandeep
Mehraj, Haider
Kulkarni, Shriram S.
Powiązania:: https://bibliotekanauki.pl/articles/2142313.pdf
Data publikacji:: 2022
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: deep learning
DL
multiple-input multiple-output
MIMO
non-orthogonal multiple access
NOMA
orthogonal multiple access
OMA
Opis:: This work examines the efficacy of deep learning (DL) based non-orthogonal multiple access (NOMA) receivers in vehicular communications (VC). Analytical formulations for the outage probability (OP), symbol error rate (SER), and ergodic sum rate for the researched vehicle networks are established Rusing i.i.d. Nakagami-m fading links. Standard receivers, such as least square (LS) and minimum mean square error (MMSE), are outperformed by the stacked long-short term memory (S-LSTM) based DL-NOMA receiver. Under real time propagation circumstances, including the cyclic prefix (CP) and clipping distortion, the simulation curves compare the performance of MMSE and LS receivers with that of the DL-NOMA receiver. According to numerical statistics, NOMA outperforms conventional orthogonal multiple access (OMA) by roughly 20% and has a high sum rate when considering i.i.d. fading links.
Źródło:: Journal of Telecommunications and Information Technology; 2022, 3; 17--24
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Transmit Diversity in the Downlink for the TETRA-TEDS System
Autorzy:: Rutkowski, D. A.
Możdżonek, S.
Powiązania:: https://bibliotekanauki.pl/articles/308120.pdf
Data publikacji:: 2014
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: multiple-input multiple-output (MIMO)
TETRA Enhanced Data System
Opis:: In the paper a proposal for the improvement of performance for the TETRA Enhanced Data System (TEDS) employing transmit diversity based on two antennas in the downlink is described. The key idea of the considerations relies on using the space-frequency coding algorithm. The proposal described required some relatively simple changes to the existing TEDS’s Single Input Single Output (SISO) interface but the original number of payload and signaling symbols in the normal downlink burst is preserved. The simulation results obtained indicate a significant improvement in performance. The Eb/No parameter could be reduced from 5 to 8 dB with respect to Frame Error Rate (FER), compared to a single antenna transmission for the same FER = 10⁻³.
Źródło:: Journal of Telecommunications and Information Technology; 2014, 1; 49-53
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Availability of WDM Multi Ring Networks
Autorzy:: Rados, I.
Rados, K.
Powiązania:: https://bibliotekanauki.pl/articles/309294.pdf
Data publikacji:: 2015
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: algebraic
availability
multiple
WDM
Opis:: This paper presents a new approach to modeling the availability of the networks composed of multiple interconnected rings in two nodes. For availability modeling method algebraic formulation is used. Using this method, through the availability of multiple ring networks consisting of two and three-rings connected to two nodes, a general expression for the availability between two terminals of multiple ring networks is derived. To perform the expression some real assumptions were taken and the analytical calculation showed that the use of these expressions under these assumptions provides real values for availability between the two terminals of multiple ring networks. Information on the availability of links and nodes is taken from previously published works.
Źródło:: Journal of Telecommunications and Information Technology; 2015, 1; 53-58
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Examples of Objectiﬁed Multiple Criteria Ranking in the Selection of Infrastructural Projects
Autorzy:: Klimasara, E.
Wierzbicki, A. P.
Powiązania:: https://bibliotekanauki.pl/articles/308171.pdf
Data publikacji:: 2018
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: multiple criteria ranking
objectiﬁed multiple criteria ranking
objectiﬁed ranking method
subjective ranking
Opis:: The paper addresses the issue of multiple criteria rankings of infrastructural projects (buildings, roads, etc.). Although the amount of literature devoted to this subject is considerable, all methods proposed produce subjective rankings, dependent on a direct or indirect deﬁnition of weighting coefficients applicable to subsequent evaluation criteria. Infrastructural projects are usually selected and approved collegially, however, by a group of decision makers with preferences that may potentially differ signiﬁcantly. Therefore, an objectiﬁed ranking, independent from subjectively deﬁned weighting coefficients, is needed for infrastructural projects. Such a ranking is proposed, analyzed and applied by the authors of this paper. This ranking depends originally only on the multiple objective evaluation data, i.e. the values of evaluation criteria related to decision scenarios or alternatives. Such an approach does not render a fully objective ranking, since one of this kind does not exist at all. Even the choice of the ranking method is a subjective decision, but it is objectiﬁed to the extent possible. The paper presents several examples of multiple criteria evaluation of infrastructural projects, derived from literature, and compares subjective rankings published in literature with objectiﬁed rankings that are independent of weighting coefficients.
Źródło:: Journal of Telecommunications and Information Technology; 2018, 4; 18-25
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: On the performance analysis of a heuristic approach dedicated to a multiobjective dynamic routing model
Autorzy:: Craveirinha, J.
Martins, L.
Climaco, J. N.
Jorge, L.
Powiązania:: https://bibliotekanauki.pl/articles/309018.pdf
Data publikacji:: 2005
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: multiple criteria analysis
routing
heuristics
telecommunications
Opis:: In previous works the features and a complete formulation for circuit-switched networks of a multiple objective dynamic routing method (MODR) of periodic state dependent routing type were presented. The aim of the model is to resolve a very complex network bi-objective dynamic routing problem, by recurring to a heuristic for synchronous path selection enabling to obtain a good compromise solution in terms of two network performance measures. In this paper we present a study on the performance of variants of the MODR heuristic of synchronous path selection by using relaxations of the values previously calculated for the two network objective functions. This study permitted the development of an improved version of the initial heuristic. Also a comparison of the analytical values of the network objective functions obtained with selected variants of the initial heuristic with the corresponding results from a known reference method, the real time network routing (RTNR) method, given by a discrete-event simulator for single-service networks, is presented.
Źródło:: Journal of Telecommunications and Information Technology; 2005, 3; 14-23
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Performance evaluation of the multiple output queueing switch with different buffer arrangements strategy
Autorzy:: Danilewicz, G.
Kabaciński, W.
Pleban, J.
Parniewicz, D.
Dąbrowski, P.
Powiązania:: https://bibliotekanauki.pl/articles/308008.pdf
Data publikacji:: 2006
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: packet switching
switch fabric
multiple output queueing
Opis:: Performance evaluation of the multiple output queueing (MOQ) switch recently proposed by us is discussed in this paper. In the MOQ switch both the switch fabric and buffers can operate at the same speed as input and output ports. This solution does not need any speedup in the switch fabric as well as any matching algorithms between inputs and outputs. In this paper new performance measures for the proposed MOQ switch are evaluated. The simulation studies have been carried out for switches with different buffer arrangements strategy and of capacity 2×2, 4×4, 8×8, 16×16 and 32×32, and under selected traffic patterns. The simulations results are also compared with OQ switches of the same sizes.
Źródło:: Journal of Telecommunications and Information Technology; 2006, 3; 43-48
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: CG-SCMA Codebook Design Based on Maximized Euclidian Distance
Autorzy:: Mohamed, Sura S.
Abdullah, Hikmat N.
Powiązania:: https://bibliotekanauki.pl/articles/2200958.pdf
Data publikacji:: 2023
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: codebook
Euclidian distance
MPA
multiple access
sparse code
Opis:: Sparse code multiple access (SCMA) is a multi-dimensional codebook based on a class of non-orthogonal multiple access (NOMA) technologies enabling the delivery of non-orthogonal resource elements to numerous users in 5G wireless communications without increasing complexity. This paper proposes a computer-generated sparse code multiple access (CG-SCMA) technique, where the minimum Euclidian distance (MED) of a star 16-point quadrature amplitude modulation is maximized by CG-SCMA, thus creating a complex SCMA codebook based on optimizing the difference between the first and other radiuses over rotated constellations. To specify the most suitable values for this constellation, it is divided into four sub-constellations using trellis coded modulation (TCM) in an effort to optimize MED. The new codebook has four sub-constellations with MED values of 3.85, 2.26, 2.26, and 3.85, respectively. Application of the message passing algorithm (MPA) ensures low complexity of the decoding process
Źródło:: Journal of Telecommunications and Information Technology; 2023, 1; 18--24
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Implementation and performance of a new multiple objective dynamic routing method for multiexchange networks
Autorzy:: Martins, L.
Craveirinha, J.
Climaco, J.N.
Gomez, T.
Powiązania:: https://bibliotekanauki.pl/articles/307696.pdf
Data publikacji:: 2003
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: dynamic routing
multiple objective routing
multiexchange telecommunication network performance
Opis:: The paper describes new developments of a multiple objective dynamic routing method (MODR) for circuit-switched networks previously presented, based on the periodic calculation of alternative paths for every node pair by a specialised bi-objective shortest path algorithm (MMRA). A model is presented that enables the numerical calculation of two global network performance parameters, when using MMRA. This model puts in evidence an instability problem in the synchronous path computation model which may lead to solutions with poor global network performance, measured in terms of network mean blocking probability and maximum node-to-node blocking probability. The essential requirements of a heuristic procedure enabling to overcome this problem and select "good" routing solutions in every path updating period, are also discussed.
Źródło:: Journal of Telecommunications and Information Technology; 2003, 3; 60-66
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: On the Effects of Code Cardinality for TH-PPM Ultra Wideband Systems
Autorzy:: Mahfuz, M. U.
Ahmed, K. M.
Rajatheva, N.
Powiązania:: https://bibliotekanauki.pl/articles/307946.pdf
Data publikacji:: 2008
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: code cardinality
multiple user interference
TH-PPM
ultra wideband
Opis:: This paper demonstrates the effects of code cardinality at transmitter section on bit error rate (BER) performance of time hopping pulse position modulation (TH-PPM) based ultra wideband (UWB) indoor radio communication. In the transmitter, different code cardinality values have been chosen and correspondingly the effects on BER of the system have been investigated. The recently accepted IEEE 802.15.3a model of the UWB channel has been used as the propaga- tion channel model in indoor environment. Results show that the system BER performance is significantly dependent on the code cardinality value of time hopping code. For such higher code cardinality values as in the range from 30 to 50, the BER performance degrades severely. Finally, code cardinality in the range from 10 to 15 has been recommended for TH-PPM system in UWB indoor communications providing better BER performance for the same system data rate requirement
Źródło:: Journal of Telecommunications and Information Technology; 2008, 4; 73-78
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Design and Development of a UDP-Based Connection-Oriented Multi-Stream One-to-Many Communication Protocol
Autorzy:: Stanciu, V.
Andreica, M. I.
Olaru, V.
Tăpuş, N.
Powiązania:: https://bibliotekanauki.pl/articles/308499.pdf
Data publikacji:: 2012
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: communication protocol
connection oriented
multiple streams
one-to-many
Opis:: A communication protocol is a set of rules defined formally that describes the format of digital messages and the rules for exchanging those messages in or between computing systems. The Internet Protocol Suite used for communications throughout the Internet uses encapsulation to provide a way of abstracting protocols and services. This abstraction is grouped into layers of general functionality. For protocols on the transmission layer, many choices exist. But while popular protocols such as TCP, UDP and SCTP do provide connection oriented communication offering reliability, ordering and data integrity, solutions that offer such connections from one point to multiple endpoints are still limited. TCP only supports point-to-point communication and SCTP offers multi-homing functionality, but the transmission is still limited to two logical endpoints. In this paper we use the simple, stateless, transmission model of UDP in order to provide TCP-like services for one-to-many communication that is not limited to just multi-homing or other particular solutions. The protocol supports reliable communication from one endpoint to multiple endpoints in different transmission modes. In order to make it easier for developers to customize the protocol to their needs and possibly extend/modify it in order to create new variants from it, the protocol is developed in user space. Because of this design restriction performance wasn't the main objective of our work, but rather the ease of customization and experimentation with new protocol variants. The protocol was implemented in the C++ programming language using classes with virtual members. New variants of components, such as packet retransmission, can easily be implemented without changing the whole code base.
Źródło:: Journal of Telecommunications and Information Technology; 2012, 1; 3-15
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Optimum receiver performance of TH-PPM ultra wideband system in multiple user interference
Autorzy:: Mahfuz, M. U.
Ahmed, K. M.
Rajatheva, N.
Powiązania:: https://bibliotekanauki.pl/articles/308545.pdf
Data publikacji:: 2007
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: optimum receiver performance
TH-PPM
ultra wideband
multiple user interference
Opis:: This paper demonstrates optimum receiver performance in terms of bit error rate (BER) for time hopping pulse position modulation (TH-PPM) ultra wideband (UWB) system in multiple user interference environment for indoor radio communication. Equal gain combining and selective gain combining have been demonstrated in terms of ideal RAKE (ARAKE), selective RAKE (SRAKE) and partial RAKE (PRAKE) receiver performances. The recently accepted IEEE 802.15.3a model of the UWB channel has been used to describe UWB propagation in indoor environment. Two channel scenarios named CM-1 and CM-3 for IEEE 802.15.3a channel model have been investigated principally. Finally, this paper concludes with an approximation of equivalence of number of fingers in SRAKE and PRAKE receivers as well as an indication of SNR gains achievable as the RAKE finger number is increased, espe- cially with multiple user interference (MUI), for a 16.6 Mbit/s UWB system.
Źródło:: Journal of Telecommunications and Information Technology; 2007, 4; 77-84
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: CDMA wireless system with blind multiuser detector
Autorzy:: Leong, W. Y.
Homer, J.
Powiązania:: https://bibliotekanauki.pl/articles/309140.pdf
Data publikacji:: 2006
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: code division multiple access
independent component analysis
blind source separation
Opis:: In this paper we present an approach capable of countering the presence of multiple access interference (MAI) in code division multiple access (CDMA) channels. We develop and implement a blind multiuser detector, based on an independent component analysis (ICA) to mitigate both MAI and noise. This algorithm has been utilized in blind source separation (BSS) of unknown sources from their linear mixtures. It can also be used for estimation of the basis vectors of BSS. The aim is to include an ICA algorithm within a wireless receiver in order to reduce the level of interference in CDMA systems. This blind multiuser detector requires less precise knowledge of the channel than does the conventional single-user receiver. The proposed blind multiuser detector is made robust with respect to imprecise knowledge of the received signature waveforms of the user of interest. Several experiments are performed in order to verify the validity of the proposed learning algorithm.
Źródło:: Journal of Telecommunications and Information Technology; 2006, 1; 69-75
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1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: Optimum double-matched detection and its application to SSMA systems
Autorzy:: Pawelec, J.J.
Powiązania:: https://bibliotekanauki.pl/articles/309576.pdf
Data publikacji:: 2001
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: optimum detection
spread spectrum multiple access systems
NB interference
adaptation
Opis:: This paper is concerned with the issue of optimum detection of known signal in nonwhite noise and/or narrow-band interferences. The detection is carried out in three steps. First, some function related to the power spectrum of interfering process I(z) is estimated via adaptation. Second, the signal + interference is withened due to I(z). Third, the replica of signal is filtered via I(z) to match it to the deformed signal in the previous step. The simulation of SS reception in presence of NB interference shows a high gain in comparison to classical single-matched detection.
Źródło:: Journal of Telecommunications and Information Technology; 2001, 3; 80-85
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: Secrecy Rate Region Enhancement in Multiple Access Wiretap Channel
Autorzy:: Shah, Shahid Mehraj
Powiązania:: https://bibliotekanauki.pl/articles/2142307.pdf
Data publikacji:: 2022
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: multiple access channels
physical layer security
strong secrecy
wiretap channel
Opis:: It is commonly known that physical layer security is achieved with a trade-off in terms of the achievable rate. Hence, security constraints generate rate losses in wiretap channels. To mitigate such rate losses in multi-user channels, we propose a coding/decoding scheme for multi-user multiple access wiretap channel (MAC-WT), where previously transmitted messages are used as a secret key to enhance the secrecy rates of the transmitting users, until the usual Shannon capacity region of a multiple access channel (MAC) is achieved without the secrecy constraint. With this coding scheme, all messages transmitted in the recent past are secure with respect to all the information of the eavesdropper till now. To achieve this goal, we introduce secret key buffers at both the users and the legitimate receiver. Finally, we consider a fading MAC-WT and show that with this coding/decoding scheme, we can achieve the capacity region of a fading MAC channel (in the ergodic sense).
Źródło:: Journal of Telecommunications and Information Technology; 2022, 2; 14--25
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:: Multiple Criteria Evaluation and Ranking of Social Penetration of Information Society Technologies
Autorzy:: Grzegorek, J.
Wierzbicki, A. P.
Powiązania:: https://bibliotekanauki.pl/articles/307608.pdf
Data publikacji:: 2012
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: dynamic ranking
ICT social penetration
multiple criteria ranking
objective ranking
Opis:: The paper presents a comparison of two ways of multiple criteria ranking of social penetration of information society technologies (ICT): the traditional one and the socalled objective ranking, illustrated on the example of Network Readiness Index. It is shown that objective ranking stresses a balanced development more than the traditional one. Another issue presented in this paper is the concept of dynamic ranking, a systematic presentation and prediction of the change of ranking in time. This is illustrated on the example of regions of three European countries: Finland, Italy and Poland.
Źródło:: Journal of Telecommunications and Information Technology; 2012, 4; 3-13
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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