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Kong, Bo, Wei Heng Dai, Xiao Jie, and Fei Hong Dong. "Research on Coded Cooperative Strategy in Satellite Communications." Applied Mechanics and Materials 198-199 (September 2012): 1684–89. http://dx.doi.org/10.4028/www.scientific.net/amm.198-199.1684.
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Aiming at the satellite mobile communication, the cooperative communication technology is applied to the forward downlink in this paper, and one scheme with two satellites based on the coded cooperative which used the Alamouti space time block code is presented. Simulation results show the coded cooperative strategy can obtain better performance than the traditional uncoded systems, which is lower than the MIMO system with two transmit antennas and one receive antenna based on the Alamouti code, but the power of the terminal was decreased. It has the advantage in communication range and low complex mobile terminal, which has a certain application prospects in satellite mobile communications in the future.
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Sterian, Corneliu Eugen D., Yuanyuan Ma, Matthias Pätzold, Ion Bǎnicǎ, and Huaqiang He. "New super-orthogonal space-time trellis codes using differential M-PSK for noncoherent mobile communication systems with two transmit antennas." annals of telecommunications - annales des télécommunications 66, no. 3-4 (July 22, 2010): 257–73. http://dx.doi.org/10.1007/s12243-010-0191-1.
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Sah, Dhaneshwar. "Iterative Decoding of Turbo Codes." Journal of Advanced College of Engineering and Management 3 (January 10, 2018): 15. http://dx.doi.org/10.3126/jacem.v3i0.18810.
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<p><strong> </strong>This paper presents a Thesis which consists of a study of turbo codes as an error-control Code and the software implementation of two different decoders, namely the Maximum a Posteriori (MAP), and soft- Output Viterbi Algorithm (SOVA) decoders. Turbo codes were introduced in 1993 by berrouet at [2] and are perhaps the most exciting and potentially important development in coding theory in recent years. They achieve near- Shannon-Limit error correction performance with relatively simple component codes and large interleavers. They can be constructed by concatenating at least two component codes in a parallel fashion, separated by an interleaver. The convolutional codes can achieve very good results. In order of a concatenated scheme such as a turbo codes to work properly, the decoding algorithm must affect an exchange of soft information between component decoders. The concept behind turbo decoding is to pass soft information from the output of one decoder to the input of the succeeding one, and to iterate this process several times to produce better decisions. Turbo codes are still in the process of standardization but future applications will include mobile communication systems, deep space communications, telemetry and multimedia. Finally, we will compare these two algorithms which have less complexity and which can produce better performance.</p><p><strong>Journal of Advanced College of Engineering and Management</strong>, Vol.3, 2017, Page: 15-30</p>
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Abu, Mohd Azlan, Harlisya Harun, Mohammad Yazdi Harmin, and Noor Izzri Abdul Wahab. "Power Consumption Optimization Technique in ACS for Space Time Trellis Code Viterbi Decoder." Applied Mechanics and Materials 785 (August 2015): 734–38. http://dx.doi.org/10.4028/www.scientific.net/amm.785.734.
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To provide fast digital communications systems, energy efficient, high-performance, low power is critical for decoding mobile receiver device. This paper proposes a low power optimization techniques in the Add Compare Select (ACS) unit for Space Time trellis codes (STTC) Viterbi decoder. STTC Viterbi decoder is used as a reference case. This paper discusses about how to lower the power in the ACS architecture, to optimize the Viterbi decoder STTC in reducing the total power consumption. Based on the results of design and analysis, power consumption Viterbi decoder modeling, low power system for STTC Viterbi decoder is proposed. Design and optimization of ACS unit in STTC Viterbi decoding is done using Verilog HDL language. Power analysis tools in the software Altera Quartus 2 is used for the synthesis of total system power consumption. Optimization strategy showed an increase of 83% power reduction compared to previous studies.
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Solodovnyk, V. I., and M. I. Naumenko. "SYNTHESIS OF SPECTRALLY AND ENERGY-EFFICIENT SIGNAL-CODE CONSTRUCTIONS FOR MIMO SYSTEMS WITH SIGNALS SPATIAL CODING." Proceedings of the O.S. Popov ОNAT 1, no. 1 (August 27, 2020): 68–81. http://dx.doi.org/10.33243/2518-7139-2020-1-1-68-81.
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Wireless communication systems are considered, the main task of which is to increase their spectral (SE) and energy efficiency (EE) in conditions of limited frequency and energy resources. Additional use of the spatial resource based on flexible and universal methods of signals Space-Time Coding (STC) in MIMO-systems (Multiple Input - Multiple Output) can significantly increase the SE and EE values, as well as significantly improve the capabilities and conditions for EE exchange on SE. The advantages and disadvantages of Orthogonal Space-Time Block Coding (OSTBC) and Non-Orthogonal STBC (NOSTBC) are shown. Two main methods of synthesis of spectrally and energy-efficient information transmission methods are demonstrated. The first method is implemented by creating Perfect-codes that simultaneously achieve maximum diversity and multiplexing gains. The exponential computational decoding complexity of such codes makes it impossible for their practical implementation in mobile terminals at the present stage of development of circuitry. The second method of synthesis is based on improving the simple basic STC methods in terms of increasing the SE and EE by creating Signal-Code Constructions (SCC), which have the advantages of the basic STC methods and are devoid of the disadvantages inherent in Perfect-codes. A technique for the synthesis of SCC is proposed, the essence of which is to determine the priority areas (by the value of the Signal-to-Noise Ratio (SNR)) of using the STC and corresponding signal constellations, which provide the maximum SE for a guaranteed Bit Error Rate (BER). It was found that MIMO 2x2 with Alamouti OSTBC has an advantage in terms of EE over NOSTBC type VBLAST for SE not more than 8 b/s/Hz and SNR under 35 dB, BER not exceeding 10-5. In MIMO 4x4, OSTBC codes are inferior to NOSTBC in terms of EE. VBLAST code allows to provide SE 4 - 8 b/s/Hz at SNR 10 - 20 dB, BER not exceeding 10-5. Based on the results obtained, propositions for further improvement of OSTBC and NOSTBC are formulated.
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Timofeev, A. L., and A. Kh Sultanov. "Building a noise-tolerant code based on a holographic representation of arbi-trary digital information." Computer Optics 44, no. 6 (December 2020): 978–84. http://dx.doi.org/10.18287/2412-6179-co-739.
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The article considers a method of error-correcting coding based on the holographic representation of a digital signal. The message encoding process is a mathematical simulation of a hologram created in virtual space by a wave from an input signal source. The code word is a hologram of a point, it is also a one-dimensional zone ruler that carries information about the input data block in the form of an n-bit code of the coordinate of the center of the Fresnel zones. It is shown that the holographic representation of the signal has significantly greater noise immunity and allows you to restore the original digital combination when most of the code message is lost and when the encoded signal is distorted by noise several times higher than the signal level. To assess the noise immunity, the reliability of information transmission over the channel with additive white Gaussian noise is compared using the Reed-Solomon code, the Reed-Muller code, the majority code, and the holographic code. The comparative efficiency of codes in the presence of packet errors caused by the effect of fading due to multipath propagation in radio channels is considered. It is shown that holographic coding provides the correction of packet errors regardless of the length of the packet and its location in the codeword. The holographic code is of interest for transmitting information over channels with a low signal-to-noise ratio (space communications and optical communication systems using free space as a transmission channel, terrestrial, including mobile radio communications), as well as for storing information in systems exposed to ionizing radiation.
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Adeagbo, Oluwafemi, Carina Herbst, Ann Blandford, Rachel McKendry, Claudia Estcourt, Janet Seeley, and Maryam Shahmanesh. "Exploring People’s Candidacy for Mobile Health–Supported HIV Testing and Care Services in Rural KwaZulu-Natal, South Africa: Qualitative Study." Journal of Medical Internet Research 21, no. 11 (November 18, 2019): e15681. http://dx.doi.org/10.2196/15681.
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Background The use of mobile communication technologies (mHealth: mobile health) in chronic disease management has grown significantly over the years. mHealth interventions have the potential to decentralize access to health care and make it convenient, particularly in resource-constrained settings. It is against this backdrop that we aimed to codevelop (with potential users) a new generation of mobile phone–connected HIV diagnostic tests and Web-based clinical care pathways needed for optimal delivery of decentralized HIV testing, prevention, and care in low- and middle-income countries. Objective The aim of this study was to understand ways in which an mHealth intervention could be developed to overcome barriers to existing HIV testing and care services and promote HIV self-testing and linkage to prevention and care in a poor, HIV hyperendemic community in rural KwaZulu-Natal, South Africa. Methods A total of 54 in-depth interviews and 9 focus group discussions were conducted with potential users (including health care providers) in 2 different communities. Theoretically informed by the candidacy framework, themes were identified from the interview transcripts, manually coded, and thematically analyzed. Results Participants reported barriers, such as fear of HIV identity, stigma, long waiting hours, clinic space, and health care workers’ attitudes, as major impediments to effective uptake of HIV testing and care services. People continued to reassess their candidacy for HIV testing and care services on the basis of their experiences and how they or others were treated within the health systems. Despite the few concerns raised about new technology, mobile phone–linked HIV testing was broadly acceptable to potential users (particularly men and young people) and providers because of its privacy (individual control of HIV testing over health provider–initiated testing), convenience (individual time and place of choice for HIV testing versus clinic-based testing), and time saving. Conclusions Mobile phone–connected HIV testing and Web-based clinical care and prevention pathways have the potential to support access to HIV prevention and care, particularly for young people and men. Although mHealth provides a way for individuals to test their candidacy for HIV services, the barriers that can make the service unattractive at the clinic level will also need to be addressed if potential demand is to turn into actual demand.
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Lema, Gebrehiwet Gebrekrstos, Teklehaymanot Baweke Reda, Dawit Hailu, and Tole Sutikno. "Performance evaluation of space time trellis coded MIMO for mobile communications." Indonesian Journal of Electrical Engineering and Computer Science 15, no. 3 (September 1, 2019): 1501. http://dx.doi.org/10.11591/ijeecs.v15.i3.pp1501-1508.
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<p>The major enemy of wireless communication is multipath fading that highly degrades the received signal. Spatial diversity highly reduces deep fades of the wireless communication. Higher signal to noise ratio (SNR) requirement can be reduced by using space time coding. In this paper, the error performance of un-coded MIMO, different diversity combing methods, space time block codes and space time trellis codes are analyzed using different parameters including number of antennas, M-array modulations, trace criteria, rank and determinant. The simulation results have shown that the Bit Error Rate (BER) significantly reduces with increasing number of receiver antennas. However, the number of antennas that a mobile device can have is limited by its size and this is inconvenient for mobile communication. Hence, this paper suggests space time codes to mitigate multipath problems in mobile communication. So, BER performance of space time block codes scheme was evaluated by varying the number of transmitter and receiver antennas along with varying M-array PSK modulation orders. The results have shown that better BER is possible by integrating space time codes with spatial diversity. Finally, the error performance of space time trellis codes was evaluated by using trace, rank and determinant, and the simulation results depicted that better error performance is achieved using the proposed multipath reduction method.</p>
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de Abreu, G. T. F., H. Ochiai, and R. Kohno. "Linear maximum likelihood decoding of space – time block coded OFDM systems for mobile communications." IEE Proceedings - Communications 151, no. 5 (2004): 447. http://dx.doi.org/10.1049/ip-com:20040663.
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Wu, Gang, Ming Chen, Haifeng Wang, and Shixin Cheng. "Low rate space-time trellis codes in power limited wireless communication systems." Journal of Electronics (China) 19, no. 3 (July 2002): 241–47. http://dx.doi.org/10.1007/s11767-002-0044-9.
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Sadoudi, Said, Ibrahim Fennouh, and Camel Tanougast. "Hyperchaos-Based Spreading Codes Generator for DS-CDMA Communication Systems." Journal of Circuits, Systems and Computers 27, no. 13 (August 3, 2018): 1850207. http://dx.doi.org/10.1142/s0218126618502079.
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In this paper, we propose a new hyperchaos-based spreading codes generator (HSCG) for multi-users direct sequence spread spectrum (DSSS) communication systems. For experimental validation, we implement the proposed generator in Xilinx FPGA Virtex-5 technology. Contrary to the traditional spreading codes, the proposed HSCG offers interesting statistical properties such as good autocorrelation, very small cross-correlation, no repetition of the generated spreading codes and high degree of security. In addition, the developed hardware architecture used for implementing the HSCG permits to generate simultaneously an infinite number of multi-length spreading codes with high hardware performances in terms of logic area consumption, throughput and latency. Real-time results are given for 32-, 64- and 128-bit chaotic spreading codes. All of these properties are validated and compared with that of classical codes (Gold sequences, Walsh–Hadamard) through bit error rate (BER) performance evaluation in a DS-CDMA system in AWGN and time-invariant multipath channels. With its interesting performances, the proposed HSCG is very useful for the next generations of mobile communication systems.
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Dayal, P., M. Brehler, and M. K. Varanasi. "Leveraging Coherent Space–Time Codes for Noncoherent Communication Via Training." IEEE Transactions on Information Theory 50, no. 9 (September 2004): 2058–80. http://dx.doi.org/10.1109/tit.2004.833341.
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Marinkovic, S., B. Vucetic, and A. Ushirokawa. "Space-time iterative and multistage receiver structures for CDMA mobile communication systems." IEEE Journal on Selected Areas in Communications 19, no. 8 (2001): 1594–604. http://dx.doi.org/10.1109/49.942520.
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Fischer, G., F. Pivit, and W. Wiebeck. "Link budget comparison of different mobile communication systems based on EIRP and EISL." Advances in Radio Science 2 (May 27, 2005): 127–33. http://dx.doi.org/10.5194/ars-2-127-2004.
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Abstract. The metric EISL (Equivalent Isotropic Sensitivity Level) describing the effective sensitivity level usable at the air interface of a mobile or a basestation is used to compare mobile communication systems either based on time division or code division multiple access in terms of coverage and emission characteristics. It turns out that systems that organize the multiple access by different codes rather than different timeslots run at less emission and offer greater coverage.
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Moskalets, Nickolai Vadіmovіch, and Konstantіn Alexandrovich Selіvanov. "Analysis of efficiency of space-time signal processing methods in mobile communication systems." Problemi telekomunìkacìj, no. 2(23) (December 27, 2018): 3–21. http://dx.doi.org/10.30837/pt.2018.2.01.
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Kaur, Satwinder, Lavish Kansal, Gurjot Singh Gaba, and Mohannad A. M. Al-Ja'afari. "BER Assessment of FBMC Systems Augmented with Different Space-Time Coding Schemes Over Diverse Channels." International Journal of Engineering & Technology 7, no. 3.8 (July 7, 2018): 111. http://dx.doi.org/10.14419/ijet.v7i3.8.16844.
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Diverse methodologies of encoding schemes like space-time block codes (STBC), orthogonal space-time block codes (OSTBC) &quasi-orthogonal space-time block codes (QOSTBC) are being proposed as alternatives of basic Alamouti space-time encoding scheme for multiple input multiple output (MIMO) scheme for existing wireless communication systems. Since filter bank multi-carrier (FBMC) scheme is an integral part of the 5th generation (5G) cellular systems, the performance of these schemes needs to be investigated for FBMC methodology also. Alamouti and Space-time block codes are widely used in MIMO system because of their ability to achieve full diversity and the different channels are used at the receiver. In this work, we proposed different approaches for the bit error rate (BER) of Alamouti, STBC3, and STBC4 in FBMC. These approaches are based on the type of space-time encoding and number of receiving antennas being used for each space time encoding scheme for analyzing the MIMO-FBMC. Moreover, we also investigation the performance of these proposed MIMO schemes over Rayleigh and additive white Gaussian noise (AWGN) channel and compared it with the performance of BER or signal to noise ratio (SNR) of different channels.
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Chan, Shirley, Douglas Vogel, and Louis C. K. Ma. "Mobile Phone Communication Innovation in Multiple Time and Space Zones." Journal of Global Information Management 15, no. 4 (October 2007): 79–85. http://dx.doi.org/10.4018/jgim.2007100105.
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Chu, Yan, Chun Hua Deng, Yan Shao, and Hai Guang Wang. "Space-Time Coding Technique Based on Four-Antenna Transceiver System." Applied Mechanics and Materials 135-136 (October 2011): 913–17. http://dx.doi.org/10.4028/www.scientific.net/amm.135-136.913.
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Space-time block code, as one of the space-time codes, greatly improves the performance in the cooperative wireless communication systems by the use of space and time diversity. However, traditional STBC can’t enhance the overall transmission rate and there is no form of complex codes with the rate of 1 when the number of antenna is more than 2. In order to design codes with full-rate, we refer to quasi-orthogonal STBC whose generator matrix is orthogonal between its subspaces. In this paper, based on the combination of QO-STBC and Self-adaptation technology, we propose a new plan of space-time coding which dismisses the interference among symbols when decoding and advances the coding capabilities in the context of full-rate transmission, finally we justify the new plan through lots of computational simulations.
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Dayal, Pranav, and Mahesh K. Varanasi. "Distributed QAM-Based Space-Time Block Codes for Efficient Cooperative Multiple-Access Communication." IEEE Transactions on Information Theory 54, no. 9 (September 2008): 4342–54. http://dx.doi.org/10.1109/tit.2008.928252.
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Mietzner, J., and P. A. Hoeher. "Improving the performance of mobile broadcasting systems using multiple base stations and distributed space–time codes." IET Communications 1, no. 3 (2007): 348. http://dx.doi.org/10.1049/iet-com:20050185.
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Almeida, A. L. F., F. R. P. Cavalcanti, J. C. M. Mota, and C. E. R. Fernandes. "Decoupled Space-Time Processing for Eqialization and Co-Channel Interference Cancellation in Mobile Communication Systems." Journal of Communication and Information Systems 18, no. 1 (April 30, 2003): 106–17. http://dx.doi.org/10.14209/jcis.2003.12.
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Bakhshi, Gholamreza, Reza Saadat, and Kamal Shahtalebi. "Modeling and Simulation of MIMO Mobile-to-Mobile Wireless Fading Channels." International Journal of Antennas and Propagation 2012 (2012): 1–13. http://dx.doi.org/10.1155/2012/846153.
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Analysis and design of multielement antenna systems in mobile fading channels require a model for the space-time cross-correlation among the links of the underlying multipleinput multiple-output (MIMO) Mobile-to-Mobile (M-to-M) communication channels. In this paper, we propose the modified geometrical two-ring model, a MIMO channel reference model for M-to-M communication systems. This model is based on the extension of single-bounce two-ring scattering model for flat fading channel under the assumption that the transmitter and the receiver are moving. Assuming single-bounce scattering model in both isotropic and nonisotropic environment, a closed-form expression for the space-time cross-correlation function (CCF) between any two subchannels is derived. The proposed model provides an important framework in M-to-M system design, where includes many existing correlation models as special cases. Also, two realizable statistical simulation models are proposed for simulating both isotropic and nonisotropic reference model. The realizable simulation models are based onSum-of-Sinusoids (SoS)simulation model. Finally, the correctness of the proposed simulation models is shown via different simulation scenarios.
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Hu, Feng, Li Biao Jin, and Jian Zeng Li. "A Parallel Space-Time Block Code Based Transmission Scheme." Advanced Materials Research 605-607 (December 2012): 1959–64. http://dx.doi.org/10.4028/www.scientific.net/amr.605-607.1959.
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We present a new transmit strategy based on modified Alamouti codes for the simple two branch transmit diversity scheme. The OFDM payload cells from the output of the frequency interleaver is done on one transmit antenna, and the encoding is proceeded on another branch. The proposed encoding scheme can significantly simplify the processes of transforming SISO into MIMO in wireless communication systems. The scheme may easily be generalized to two transmit antennas and M receive antennas to provide a diversity order of 2M, its coding gain is similar to Alamouti code. Computer simulations are performed to investigate the performance of the proposed parallel STBC scheme in a multi-input (MI) system.
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CYCON, H. L., M. PALKOW, T. C. SCHMIDT, M. WÄHLISCH, and D. MARPE. "A FAST WAVELET-BASED VIDEO CODEC AND ITS APPLICATION IN AN IP VERSION 6-READY SERVERLESS VIDEOCONFERENCING SYSTEM." International Journal of Wavelets, Multiresolution and Information Processing 02, no. 02 (June 2004): 165–71. http://dx.doi.org/10.1142/s0219691304000445.
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The purpose of this paper is twofold: On the one hand, we propose a fast wavelet-based video codec which is implemented into a real-time video conferencing tool. The proposed codec uses temporal frame difference coding, a computationally low-complex 5/3 tap wavelet transform, and a fast entropy coding scheme based on Golomb–Rice codes. On the other hand, we present an application of the video conferencing tool in a serverless peer-to-peer IP-based communication framework. For mobile communication we propose a simple, ready-to-use location scheme for video conference users in a global network.
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van der Hofstad, Remco, and Marten J. Klok. "Improving the performance of third-generation wireless communication systems." Advances in Applied Probability 36, no. 04 (December 2004): 1046–84. http://dx.doi.org/10.1017/s0001867800013318.
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The third-generation (3G) mobile communication system uses a technique called code division multiple access (CDMA), in which multiple users use the same frequency and time domain. The data signals of the users are distinguished using codes. When there are many users, interference deteriorates the quality of the system. For more efficient use of resources, we wish to allow more users to transmit simultaneously, by using algorithms that utilize the structure of the CDMA system more effectively than the simple matched filter (MF) system used in the proposed 3G systems. In this paper, we investigate an advanced algorithm called hard-decision parallel interference cancellation (HD-PIC), in which estimates of the interfering signals are used to improve the quality of the signal of the desired user. We compare HD-PIC with MF in a simple case, where the only two parameters are the number of users and the length of the coding sequences. We focus on the exponential rate for the probability of a bit-error, explain the relevance of this parameter, and investigate how it scales when the number of users grows large. We also review extensions of our results, proved elsewhere, showing that in HD-PIC, more users can transmit without errors than in the MF system.
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van der Hofstad, Remco, and Marten J. Klok. "Improving the performance of third-generation wireless communication systems." Advances in Applied Probability 36, no. 4 (December 2004): 1046–84. http://dx.doi.org/10.1239/aap/1103662958.
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The third-generation (3G) mobile communication system uses a technique called code division multiple access (CDMA), in which multiple users use the same frequency and time domain. The data signals of the users are distinguished using codes. When there are many users, interference deteriorates the quality of the system. For more efficient use of resources, we wish to allow more users to transmit simultaneously, by using algorithms that utilize the structure of the CDMA system more effectively than the simple matched filter (MF) system used in the proposed 3G systems. In this paper, we investigate an advanced algorithm called hard-decision parallel interference cancellation (HD-PIC), in which estimates of the interfering signals are used to improve the quality of the signal of the desired user. We compare HD-PIC with MF in a simple case, where the only two parameters are the number of users and the length of the coding sequences. We focus on the exponential rate for the probability of a bit-error, explain the relevance of this parameter, and investigate how it scales when the number of users grows large. We also review extensions of our results, proved elsewhere, showing that in HD-PIC, more users can transmit without errors than in the MF system.
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Brožová, Helena, and Miroslav Růžička. "THE PREDICTION OF PARKING SPACE AVAILABILITY." Transport 35, no. 5 (December 21, 2020): 462–73. http://dx.doi.org/10.3846/transport.2020.14016.
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Intelligent Parking Systems (IPS) allow customers to select a car park according to their preferences, rapidly park their vehicle without searching for the available parking space (place) or even book their place in advance avoiding queues. IPS provides the possibility to reduce the wastage of fuel (energy) while finding a parking place and consequently reduce harmful emissions. Some systems interact with in-vehicle navigation systems and provide users with information in real-time such as free places available at a given parking lot (car park), the location and parking fees. Few of these systems, however, provide information on the forecasted utilisation at specific time. This paper describes results of a traffic survey carried out at the parking lot of supermarket and the proposal of the model predicting real-time parking space availability based on these surveyed data. The proposed model is formulated as the non-homogenous Markov chains that are used as a tool for the forecasting of parking space availability. The transition matrices are calculated for different time periods, which allow for and include different drivers’ behaviour and expectations. The proposed forecasting model is adequate for potential use by IPS with the support of different communication means such as the internet, navigation systems (GPS, Galileo etc.) and personal communication services (mobile-phones).
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Babich, Fulvio, Guido Montorsi, and Francesca Vatta. "Turbo Codes Performance Optimization over Block Fading Channels." Journal of Communications Software and Systems 2, no. 3 (April 5, 2017): 228. http://dx.doi.org/10.24138/jcomss.v2i3.285.
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In this paper, the best achievable performance of a turbo coded system on a block fading channel is obtained, assuming binary antipodal modulation. A rate 1/3 turbo code is considered, obtained by concatenating, through a random interleaver, an 8-states rate 1/2 and a rate 1 convolutional codes (CC). The block fading channel model is motivated by the fact that in many wireless systems the coherence time of the channel is much longer than one symbol interval, resulting in adjacent symbols being affected by the same fading value. The fading blocks will experience independent fades, assuming a sufficient separation in time, in frequency, or both in time and in frequency. This channel model is suitable for analyzing, forinstance, wireless communication systems employing techniques such as slow frequency-hopping, as is done in the Global System for Mobile communications (GSM).In such systems, coded information is transmitted over a small number of fading channels in order to achieve diversity. The best coded information allocations over a certain number of fading channels are evaluated, using the Eades-McKay algorithm to generate distinct permutations of a multiset. Bounds on the achievable performance due to coding are derived using information-theoretic techniques. In particular, in the paper an analytical method is proposed, based on the sphere-packing bounding technique, to assess the achievable performance. Moreover, simulation results are obtained and compared with the theoretical ones.
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Fey, Anne, Remco van der Hofstad, and Marten J. Klok. "Large deviations for eigenvalues of sample covariance matrices, with applications to mobile communication systems." Advances in Applied Probability 40, no. 04 (December 2008): 1048–71. http://dx.doi.org/10.1017/s0001867800002962.
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We study sample covariance matrices of the form W = (1 / n) C C T, where C is a k x n matrix with independent and identically distributed (i.i.d.) mean 0 entries. This is a generalization of the so-called Wishart matrices, where the entries of C are i.i.d. standard normal random variables. Such matrices arise in statistics as sample covariance matrices, and the high-dimensional case, when k is large, arises in the analysis of DNA experiments. We investigate the large deviation properties of the largest and smallest eigenvalues of W when either k is fixed and n → ∞ or k n → ∞ with k n = o(n / log log n), in the case where the squares of the i.i.d. entries have finite exponential moments. Previous results, proving almost sure limits of the eigenvalues, require only finite fourth moments. Our most explicit results for large k are for the case where the entries of C are ∓ 1 with equal probability. We relate the large deviation rate functions of the smallest and largest eigenvalues to the rate functions for i.i.d. standard normal entries of C . This case is of particular interest since it is related to the problem of decoding of a signal in a code-division multiple-access (CDMA) system arising in mobile communication systems. In this example, k is the number of users in the system and n is the length of the coding sequence of each of the users. Each user transmits at the same time and uses the same frequency; the codes are used to distinguish the signals of the separate users. The results imply large deviation bounds for the probability of a bit error due to the interference of the various users.
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Fey, Anne, Remco van der Hofstad, and Marten J. Klok. "Large deviations for eigenvalues of sample covariance matrices, with applications to mobile communication systems." Advances in Applied Probability 40, no. 4 (December 2008): 1048–71. http://dx.doi.org/10.1239/aap/1231340164.
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We study sample covariance matrices of the form W = (1 / n)CCT, where C is a k x n matrix with independent and identically distributed (i.i.d.) mean 0 entries. This is a generalization of the so-called Wishart matrices, where the entries of C are i.i.d. standard normal random variables. Such matrices arise in statistics as sample covariance matrices, and the high-dimensional case, when k is large, arises in the analysis of DNA experiments. We investigate the large deviation properties of the largest and smallest eigenvalues of W when either k is fixed and n → ∞ or kn → ∞ with kn = o(n / log log n), in the case where the squares of the i.i.d. entries have finite exponential moments. Previous results, proving almost sure limits of the eigenvalues, require only finite fourth moments. Our most explicit results for large k are for the case where the entries of C are ∓ 1 with equal probability. We relate the large deviation rate functions of the smallest and largest eigenvalues to the rate functions for i.i.d. standard normal entries of C. This case is of particular interest since it is related to the problem of decoding of a signal in a code-division multiple-access (CDMA) system arising in mobile communication systems. In this example, k is the number of users in the system and n is the length of the coding sequence of each of the users. Each user transmits at the same time and uses the same frequency; the codes are used to distinguish the signals of the separate users. The results imply large deviation bounds for the probability of a bit error due to the interference of the various users.
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Shah, Hardip K., Tejal N. Parmar, Nikhil Kothari, and K. S. Dasgupt. "Performance Evaluation of Full Diversity QOSTBC MIMO Systems with Multiple Receive Antenna." International Journal of Grid and High Performance Computing 3, no. 4 (October 2011): 29–38. http://dx.doi.org/10.4018/ijghpc.2011100103.
Full textAbstract:
Multipath fading is inherent in wireless communication systems. Diversity is the technique which takes advantage of multipath to mitigate the effect of fading and increase signal strength. Space Time Block codes (STBC) are used in MIMO systems to improve the performance by maximizing transmit and/or receive diversity. Among different schemes based on STBC, Quasi Orthogonal Space Time Block Code (QOSTBC) is able to achieve full rate transmission for more than two transmit antennas. Constellation Rotation QOSTBC (CR-QOSTBC) achieves full diversity and improves performance further along with full rate, to overcome the limitation of QOSTBC, which is unable to maintain orthogonality amongst the codes transmitted by different antennas. Higher diversity can be achieved by increasing uncorrelated paths between transmitter and receivers using higher number of receive antennas. This paper examines improvement in BER with reference to a number of receive antennas. Simulations were carried out under ideal as well as realistic environments, using least square technique with four antennas at transmitter side and variable receive antennas. Results of simulations presented in this paper indicate performance improvement of CR-QOSTBC over QOSTBC in flat fading channel environment. Simulation results also show performance degradation in BER when channel is estimated at the receiver.
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Lian, Jie, Mohammad Noshad, and Maïté Brandt-Pearce. "Indoor multiuser visible light communication systems using Hadamard-coded modulation." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2169 (March 2, 2020): 20190183. http://dx.doi.org/10.1098/rsta.2019.0183.
Full textAbstract:
Visible light communications (VLC) is a short-range optical wireless communication technology that uses light-emitting diodes (LEDs) as lighting devices and data transmitters. This paper describes a multiuser VLC system using Hadamard-coded modulation (HCM) for indoor data transmission. Considering the peak transmitted power limit of the LEDs, a DC-reduced HCM (DCR-HCM) is used to reduce the nonlinear clipping distortion. Since the Hadamard codewords have different bandwidth requirements for a given symbol rate, they can be assigned to users with varying hardware capabilities. Optimally assigning codewords to users is found to significantly improve the average throughput, up to twice higher than a random assignment for a typical scenario. When the number of active users is less than the size of the Hadamard matrix used, more than one codeword can be assigned per user, which further improves the throughput. This paper also examines a scenario where multiple lamps in an indoor space transmit the same data. Since the time of arrival for the received signals emitted from different lamps is different, the Hadamard codes received are no longer orthogonal, resulting in multiple access interference and inter-chip interference. The number of acceptable codewords is computed based on the specific interference experienced in different parts of the indoor space. The spatial distribution of the maximum throughput is also simulated, showing that the ratio of the maximum to the minimum data rate can be as high as 10 when considering the entire area of a typical indoor room. This article is part of the theme issue ‘Optical wireless communication’.
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Nasser, Y., J. F. Hélard, and M. Crussière. "System Level Evaluation of Innovative Coded MIMO-OFDM Systems for Broadcasting Digital TV." International Journal of Digital Multimedia Broadcasting 2008 (2008): 1–12. http://dx.doi.org/10.1155/2008/359206.
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Single-frequency networks (SFNs) for broadcasting digital TV is a topic of theoretical and practical interest for future broadcasting systems. Although progress has been made in the characterization of its description, there are still considerable gaps in its deployment with MIMO technique. The contribution of this paper is multifold. First, we investigate the possibility of applying a space-time (ST) encoder between the antennas of two sites in SFN. Then, we introduce a 3D space-time-space block code for future terrestrial digital TV in SFN architecture. The proposed 3D code is based on a double-layer structure designed for intercell and intracell space time-coded transmissions. Eventually, we propose to adapt a technique called effective exponential signal-to-noise ratio (SNR) mapping (EESM) to predict the bit error rate (BER) at the output of the channel decoder in the MIMO systems. The EESM technique as well as the simulations results will be used to doubly check the efficiency of our 3D code. This efficiency is obtained for equal and unequal received powers whatever is the location of the receiver by adequately combining ST codes. The 3D code is then a very promising candidate for SFN architecture with MIMO transmission.
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Bendelhoum, Mohammed Sofiane, Mohamed Rida Lahcene, Fayssal Menezla, and Abderraouf Elarbi. "Studying and Modeling the Performance of the TCM-STBC Systems in the Rayleigh Channel." Journal of Telecommunications and Information Technology 1 (March 30, 2021): 1–7. http://dx.doi.org/10.26636/jtit.2021.147020.
Full textAbstract:
Multiple-input multiple-output (MIMO) systems will play an important role in future generations of wireless networks. Space-time block code (STBC) and space-time trellis code (STTC) are two techniques that may be used in multi-antenna radio systems. This paper aims, most importantly, to study the performance of STBC systems at different vallues of such parameters as spectral efficiency, matrix codes and constellations. A performance comparison between STBC and STTC schemes is performed. In order to show the efficiency of the system’s ability to communicate with uncoded and coded transmission structures over AWGN and Rayleigh channels, the trellis-coded modulation (TCM) is introduced. The results obtained show that the proposed TCM-STBC system model, using one and two receiving antennas, improves the performance of Rayleigh channel communication systems at 9.5 dB and 11.5 dB for a BER of 10−5
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Granados, Omar, and Jean Andrian. "Quasi-Orthogonal Space-Time Block Coding Using Polynomial Phase Modulation." ISRN Communications and Networking 2011 (June 20, 2011): 1–6. http://dx.doi.org/10.5402/2011/157927.
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Recently, polynomial phase modulation (PPM) was shown to be a power- and bandwidth-efficient modulation format. These two characteristics are in high demand nowadays specially in mobile applications, where devices with size, weight, and power (SWaP) constraints are common. In this paper, we propose implementing a full-diversity quasiorthogonal space-time block code (QOSTBC) using polynomial phase signals as modulation format. QOSTBCs along with PPM are used in order to improve the power efficiency of communication systems with four transmit antennas. We obtain the optimal PPM constellations that ensure full diversity and maximize the QOSTBC's minimum coding gain distance. Simulation results show that by using QOSTBCs along with a properly selected PPM constellation, full diversity in flat fading channels and thus low BER at high signal-to-noise ratios (SNR) can be ensured. More importantly, it is also shown that QOSTBCs using PPM achieve a better error performance than those using conventional modulation formats.
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Art., G. Yasser. "Mobile Phone: Sejarah, Tuntutan Kebutuhan Komunikasi, Hingga Prestise." ALHADHARAH 15, no. 30 (April 20, 2017): 1. http://dx.doi.org/10.18592/alhadharah.v15i30.1222.
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Human desire to keep on communicating bulldoze constraints of time and space in turn trigger an attempt to create a tool to bridge the limitations of earlier. The codes are transmitted in the conventional form of simple visual and sound that still leaves human dissatisfaction remote communication (tele-communication), effectiveness and efficiency of the smoke, sound, sign of morse, certainly not yet enough. Jump skip the age, and found the telegraph to the appearance of the phone (cable) ago cordless phone which then called the cell phone (mobile phone) is then transformed into revolution. These evolution then became revolution of functions and capabilities that are owned by the cell phone. The sophisticated of mobile phone technology finaly push it not just as a phone but far beyond that, also its additional functions. Which should be recognized and taken into account is the impact of which was carrying was also becoming more sophisticated.Hasrat manusia untuk tetap dapat berkomunikasi melibas kendala batasan ruang dan waktu pada akhirnya memicu usaha untuk menciptakan alat untuk menjembatani keterbatasan tadi. Kode-kode yang dikirimkan secara konvensional berupa visual dan suara yg sederhana masih menyisakan ketidakpuasan komunikasi jarak jauh manusia, efektifitas dan efisiensi pada asap, bunyi, tanda morse, tentu belumlah cukup. Sedikit melompati masa, lalu ditemukan telegraf hingga kemunculan telepon (kabel) kemudian telepon tanpa kabel yang kemudian disebut ponsel (telepon selular). Evolusi ini kemudian berubah revolusi fungsi dan kemampuan yang dimiliki oleh ponsel. Kecanggihan teknologi mendorongnya menjadi selain fungsi bukan hanya sekadar telepon tapi juga fungsi tambahannya. Kesadaran dan yang perlu dipertimbangkan adalah dampak yang dibawanya pun juga semakin canggih.
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Wang, Liangliang, Xiang Chen, and Hongzhou Tan. "Research and Implementation of Rateless Spinal Codes Based Massive MIMO System." Wireless Communications and Mobile Computing 2018 (2018): 1–9. http://dx.doi.org/10.1155/2018/6101853.
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The potential performance gains promised by massive multi-input and multioutput (MIMO) rely heavily on the access to accurate channel state information (CSI), which is difficult to obtain in practice when channel coherence time is short and the number of mobile users is huge. To make the system with imperfect CSI perform well, we propose a rateless codes-aided massive MIMO scheme, with the aim of approaching the maximum achievable rate (MAR) as well as improving the achieved rate over that based on the fixed-rate codes. More explicitly, a recently proposed family of rateless codes, called spinal codes, are applied to massive MIMO systems, where the spinal codes bring the benefit of approximately achieving the MAR with sufficiently large encoding block size. In addition, the multilevel puncturing and dynamic block-size allocation (MPDBA) scheme is proposed, where the block sizes are determined by user MAR to curb the average retransmission delay for successfully decoding the messages, which further enhances the system retransmission efficiency. Multilevel puncturing, which is MAR dependent, narrows the gap between the system MAR and the related achieved rate. Theoretical analysis is provided to demonstrate that spinal codes with the MPDBA can guarantee the system retransmission efficiency as well as achieved rate, which are also verified by numerical simulations. Finally, a simplified but comparable MIMO testbed with 2 transmit antennas and 2 single-antenna users, based on NI Universal Software Radio Peripheral (USRP) and LabVIEW communication toolkits, is built up to demonstrate the effectiveness of our proposal in realistic wireless channels, which is easy to be extended to massive MIMO scenarios in future.
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Xu, Zhiyan, Min Luo, Neeraj Kumar, Pandi Vijayakumar, and Li Li. "Privacy-Protection Scheme Based on Sanitizable Signature for Smart Mobile Medical Scenarios." Wireless Communications and Mobile Computing 2020 (November 22, 2020): 1–10. http://dx.doi.org/10.1155/2020/8877405.
Full textAbstract:
With the popularization of wireless communication and smart devices in the medical field, mobile medicine has attracted more and more attention because it can break through the limitations of time, space, and objects and provide more efficient and quality medical services. However, the characteristics of a mobile smart medical network make it more susceptible to security threats such as data integrity damage and privacy leakage than those of traditional wired networks. In recent years, many digital signature schemes have been proposed to alleviate some of these challenges. Unfortunately, traditional digital signatures cannot meet the diversity and privacy requirements of medical data applications. In response to this problem, this paper uses the unique security attributes of sanitizable signatures to carry out research on the security and privacy protection of medical data and proposes a data security and privacy protection scheme suitable for smart mobile medical scenarios. Security analysis and performance evaluation show that our new scheme effectively guarantees data security and user privacy while greatly reducing computation and communication costs, making it especially suitable for mobile smart medical application scenarios.
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Potapychev, S., V. Malyj, and Y. Ivakin. "SUPPORT FOR DECISION-MAKING ON THE RATIONAL PLACEMENT OF ANTENNAS OF UNDERWATER COMMUNICATION SYSTEMS IN THE INTERESTS OF DISPATCHING OF GEO-SPACE PROCESSES." Telecom IT 8, no. 1 (April 2020): 90–100. http://dx.doi.org/10.31854/2307-1303-2020-8-1-90-100.
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The paper considers the main features of evaluating the efficiency of positional and mobile underwater communication systems with immersed correspondent objects at the stage of their design and deciding on the coordinates of the installation site of the transmitter-receiver antennas based on modeling and visualization of the expected underwater communication zones using intelligent geographic information systems. The influence of the quality of information support of geographic information systems on the accuracy of the calculation results of the expected zones of underwater communication in various hydrological and acoustic conditions is assessed. Research subject. The article is devoted to the issues of evaluating the efficiency of underwater communication and intellectual decision-making support for rational spatial distribution of receiving and transmitting antennas of underwater communication systems with immersed correspondent objects. Method. A method for optimizing (choosing a rational option) the spatial distribution of receiving and transmitting antennas of positional underwater communications or the depth of setting of lowered and towed antennas of marine underwater communications using specialized software and information tools and geographic information systems is considered. Core results. A new performance indicator is proposed in the form of the spatial volume of the underwater communication zone and a method has been developed to optimize the spatial distribution of the receiving and transmitting antennas according to the criterion of the maximum volume of the expected underwater communication zone for given hydrological and acoustic conditions in the area. Practical relevance. The introduction of the developed method into the systems of sonar calculations and automated decision support for advanced underwater communication systems will significantly reduce the decision-making time for the placement of antennas (when designing or planning applications) and increase the efficiency (stability and range) of underwater communication means with immersed objects - correspondents.
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Minallah, Nasru, Ishtiaque Ahmed, Muhammad Ijaz, Atif Sardar Khan, Laiq Hasan, and Atiqur Rehman. "On the Performance of Self-Concatenated Coding for Wireless Mobile Video Transmission Using DSTS-SP-Assisted Smart Antenna System." Wireless Communications and Mobile Computing 2021 (January 13, 2021): 1–10. http://dx.doi.org/10.1155/2021/8836808.
Full textAbstract:
In the current age of advanced technologies, there is an escalating demand for reliable wireless systems, catering to the high data rates of mobile multimedia applications. This article presents a novel approach to the concept of Self-Concatenated Convolutional Coding (SECCC) with Sphere Packing (SP) modulation via Differential Space-Time Spreading- (DSTS-) based smart antennas. The two transmitters provide transmit diversity which is capable of recuperating the signal from the effects of fading, even with a single receiving antenna. The proposed DSTS-SP SECCC scheme is probed for the Rayleigh fading channel. The SECCC structure is developed using the Recursive Systematic Convolutional (RSC) code with the aid of an interleaver. Interleaving generates randomness in exchange for extrinsic information between the constituent decoders. Iterative decoding is invoked at the receiving side to enhance the output performance by attaining fruitful convergence. The convergence behaviour of the proposed system is investigated using EXtrinsic Information Transfer (EXIT) curves. The performance of the proposed system is ascertained with the H.264 standard video codec. The perceived video quality of DSTS-SP SECCC is found to be significantly better than that of the DSTS-SP RSC. To be more precise, the proposed DSTS-SP SECCC system exhibits an E b / N 0 gain of 8 dB at the PSNR degradation point of 1 dB, relative to the equivalent rate DSTS-SP RSC. Similarly, an E b / N 0 gain of 10 dB exists for the DSTS-SP SECCC system at 1 dB degradation point when compared with the SECCC scheme dispensing with the DSTS-SP approach.
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Dang, Jian, Jiajun Gao, Zaichen Zhang, Liang Wu, Bingcheng Zhu, Chunguo Li, and Jiangzhou Wang. "Performance of Optical Mobile Communications with User Mobility and Multiple Light Sources." Wireless Communications and Mobile Computing 2021 (September 13, 2021): 1–14. http://dx.doi.org/10.1155/2021/5573946.
Full textAbstract:
Optical mobile communication (OMC) is a recently proposed optical wireless communication concept aiming to provide very high-speed data rate optical wireless links for multiple and, in general, distributed mobile users. Previous work analyzed the rate performance of a two-user OMC system without user mobility. This paper extends the rate analysis to multiple users with mobility. The scenario of employing multiple light sources with possible user grouping is also considered. User mobility and multiple light sources lead to new challenges on the system design which are addressed for broadcast downlink communication in this work. Simulations show that user mobility decreases the rate, and the way of how to utilize multiple light sources has great impact on the performance. In particular, simultaneous power division usage of multiple light sources through user grouping and power allocation brings almost no gain as compared with the case of single light source. On the other hand, time division usage of multiple light sources is capable of compensating for the hardware deficiency and thus increasing the rate greatly. It is found that OMC is not only superior to the conventional scheme with nonadjustable channel gains but also outperforms free space optical scheme at high signal-to-noise ratio region.
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Kumar, A. Narendra. "Low Error Rate Data Transmission in Cognitive Radio Networks." JOURNAL OF ADVANCES IN CHEMISTRY 13, no. 10 (March 4, 2017): 5899–904. http://dx.doi.org/10.24297/jac.v13i10.5832.
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Cognitive Radio (CR) has become a hopeful technology to enhance the spectrum utilization through spectrum sharing between licensed user (primary user) and unlicensed user (secondary user). An vital rule mandated for the development of such frameworks are to develop solutions that don’t require any changes to the existing primary user (PU) infrastructure. An Orthogonal Frequency Division Multiplexing (OFDM) is typically worn advancements in present wireless communication systems which has the possibility of fulfilling the demand for cognitive radios intrinsically or with slight changes. In this paper, Space time block codes is used. The various antennas used on both ends for trustworthy data broadcast and interference nulling schemes. These codes can accomplish full broadcast diversification determined via the number of broadcast antennas. The MIMO is worn for enhancing the power of a wireless link, to determine the issue for lower BER and achieve a superior performance.
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Fedosov, Valentin, Andrey Legin, and Anna Lomakina. "Adaptive algorithm based on antenna arrays for radio communication systems." Serbian Journal of Electrical Engineering 14, no. 3 (2017): 301–12. http://dx.doi.org/10.2298/sjee1703301f.
Full textAbstract:
Trends in the modern world increasingly lead to the growing popularity of wireless technologies. This is possible due to the rapid development of mobile communications, the Internet gaining high popularity, using wireless networks at enterprises, offices, buildings, etc. It requires advanced network technologies with high throughput capacity to meet the needs of users. To date, a popular destination is the development of spatial signal processing techniques allowing to increase spatial bandwidth of communication channels. The most popular method is spatial coding MIMO to increase data transmission speed which is carried out due to several spatial streams emitted by several antennas. Another advantage of this technology is the bandwidth increase to be achieved without expanding the specified frequency range. Spatial coding methods are even more attractive due to a limited frequency resource. Currently, there is an increasing use of wireless communications (for example, WiFi and WiMAX) in information transmission networks. One of the main problems of evolving wireless systems is the need to increase bandwidth and improve the quality of service (reducing the error probability). Bandwidth can be increased by expanding the bandwidth or increasing the radiated power. Nevertheless, the application of these methods has some drawbacks, due to the requirements of biological protection and electromagnetic compatibility, the increase of power and the expansion of the frequency band is limited. This problem is especially relevant in mobile (cellular) communication systems and wireless networks operating in difficult signal propagation conditions. One of the most effective ways to solve this problem is to use adaptive antenna arrays with weakly correlated antenna elements. Communication systems using such antennas are called MIMO systems (Multiple Input Multiple Output multiple input - multiple outputs). At the moment, existing MIMO-idea implementations do not always noticeably accelerate traffic at short distances from the access point, but, they are very effective at long distances. The MIMO principle allows reducing the number of errors in radio data interchange (BER) without reducing the transmission rate under conditions of multiple signal re-reflections. The work aims at developing an adaptive space-time signal algorithm for a wireless data transmission system designed to improve the efficiency of this system, as well as to study the efficiency of the algorithm to minimizing the error bit probability and maximizing the channel capacity.
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Naqvi, Aqeel, and Sungjoon Lim. "Review of Recent Phased Arrays for Millimeter-Wave Wireless Communication." Sensors 18, no. 10 (September 21, 2018): 3194. http://dx.doi.org/10.3390/s18103194.
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Owing to the rapid growth in wireless data traffic, millimeter-wave (mm-wave) communications have shown tremendous promise and are considered an attractive technique in fifth-generation (5G) wireless communication systems. However, to design robust communication systems, it is important to understand the channel dynamics with respect to space and time at these frequencies. Millimeter-wave signals are highly susceptible to blocking, and they have communication limitations owing to their poor signal attenuation compared with microwave signals. Therefore, by employing highly directional antennas, co-channel interference to or from other systems can be alleviated using line-of-sight (LOS) propagation. Because of the ability to shape, switch, or scan the propagating beam, phased arrays play an important role in advanced wireless communication systems. Beam-switching, beam-scanning, and multibeam arrays can be realized at mm-wave frequencies using analog or digital system architectures. This review article presents state-of-the-art phased arrays for mm-wave mobile terminals (MSs) and base stations (BSs), with an emphasis on beamforming arrays. We also discuss challenges and strategies used to address unfavorable path loss and blockage issues related to mm-wave applications, which sets future directions.
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Andersen, John A., Stephen D. Fulton, and John H. Andersen. "Tighter Air Control." Mechanical Engineering 124, no. 07 (July 1, 2002): 38–41. http://dx.doi.org/10.1115/1.2002-jul-2.
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This article focuses on an engineered system that uses the advantages of available modern technology, including Global Positioning System satellites, inertial reference systems, flight management systems (specialized computers), and autopilots. More than a decade ago, 85 member states of the International Civil Aviation Organization endorsed a global Communications, Navigation, Surveillance, and Automated Traffic Management concept. This concept, called Future Air Navigation System II, advocates a change from terrestrial-based technology to space-based technology and digital communication. Extensive use is made of satellites for both navigation and communication. In 1995, the first-generation system was placed in use over the Pacific, where aircraft were out of range of the older radio control systems for lengthy time periods. Perhaps the evolution in aviation technology has parallels in the past, when ASME codes for safe boilers and pressure vessels, as well as elevators and escalators were voluntarily adopted and, eventually, legislated into practice. Aviation is a vital national and international service. Problems of safety and efficient use of assets require solution.
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Ashrafinia, Saeed, Muhammad Naeem, and Daniel Lee. "Discrete Artificial Bee Colony for Computationally Efficient Symbol Detection in Multidevice STBC MIMO Systems." Advances in Artificial Intelligence 2013 (February 24, 2013): 1–14. http://dx.doi.org/10.1155/2013/578710.
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A Discrete Artificial Bee Colony (DABC) is presented for joint symbol detection at the receiver in a multidevice Space-Time Block Code (STBC) Mutli-Input Multi-Output (MIMO) communication system. Exhaustive search (maximum likelihood detection) for finding an optimal detection has a computational complexity that increases exponentially with the number of mobile devices, transmit antennas per mobile device, and the number of bits per symbol. ABC is a new population-based, swarm-based Evolutionary Algorithms (EA) presented for multivariable numerical functions and has shown good performance compared to other mainstream EAs for problems in continuous domain. This algorithm simulates the intelligent foraging behavior of honeybee swarms. An enhanced discrete version of the ABC algorithm is presented and applied to the joint symbol detection problem to find a nearly optimal solution in real time. The results of multiple independent simulation runs indicate the effectiveness of DABC with other well-known algorithms previously proposed for joint symbol detection such as the near-optimal sphere decoding, minimum mean square error, zero forcing, and semidefinite relaxation, along with other EAs such as genetic algorithm, estimation of distributions algorithm, and the more novel biogeography-based optimization algorithm.
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Feldkaemper, H. T., H. Blume, and T. G. Noll. "Study of heterogeneous and reconfigurable architectures in the communication domain." Advances in Radio Science 1 (May 5, 2003): 165–69. http://dx.doi.org/10.5194/ars-1-165-2003.
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Abstract. One of the most challenging design issues for next generations of (mobile) communication systems is fulfilling the computational demands while finding an appropriate trade-off between flexibility and implementation aspects, especially power consumption. Flexibility of modern architectures is desirable, e.g. concerning adaptation to new standards and reduction of time-to-market of a new product. Typical target architectures for future communication systems include embedded FPGAs, dedicated macros as well as programmable digital signal and control oriented processor cores as each of these has its specific advantages. These will be integrated as a System-on-Chip (SoC). For such a heterogeneous architecture a design space exploration and an appropriate partitioning plays a crucial role. On the exemplary vehicle of a Viterbi decoder as frequently used in communication systems we show which costs in terms of ATE complexity arise implementing typical components on different types of architecture blocks. A factor of about seven orders of magnitude spans between a physically optimised implementation and an implementation on a programmable DSP kernel. An implementation on an embedded FPGA kernel is in between these two representing an attractive compromise with high flexibility and low power consumption. Extending this comparison to further components, it is shown quantitatively that the cost ratio between different implementation alternatives is closely related to the operation to be performed. This information is essential for the appropriate partitioning of heterogeneous systems.
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Ogunrinola, Olawale Oluwasegun, Isaiah Opeyemi Olaniyi, Segun A. Afolabi, Gbemiga Abraham Olaniyi, and Olushola Emmanuel Ajeigbe. "Modelling and Development of a Radio Resource Control and Scheduling Algorithm for Long-Term Evolution (LTE) Uplink." Review of Computer Engineering Studies 8, no. 2 (June 30, 2021): 23–34. http://dx.doi.org/10.18280/rces.080201.
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Modern radio communication services transmit signals from an earth station to a high-altitude station, space station or a space radio system via a feeder link while in Global Systems for Mobile Communication (GSM) and computer networks, the radio uplink transmit from cell phones to base station linking the network core to the communication interphase via an upstream facility. Hitherto, the Single-Carrier Frequency Division Multiple Access (SC-FDMA) has been adopted for uplink access in the Long-Term Evolution (LTE) scheme by the 3GPP. In this journal, the LTE uplink radio resource allocation is addressed as an optimization problem, where the desired solution is the mapping of the schedulable UE to schedulable Resource Blocks (RBs) that maximizes the proportional fairness metric. The particle swarm optimization (PSO) has been employed for this research. PSO is an algorithm that is very easy to implement to solve real time optimization problems and has fewer parameters to adjust when compared to other evolutionary algorithms. The proposed scheme was found to outperform the First Maximum Expansion (FME) and Recursive Maximum Expansion (RME) in terms of simulation time and fairness while maintaining the throughput.
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He, YuanZhi, YiZhen Jia, and XuDong Zhong. "A traffic-awareness dynamic resource allocation scheme based on multi-objective optimization in multi-beam mobile satellite communication systems." International Journal of Distributed Sensor Networks 13, no. 8 (August 2017): 155014771772355. http://dx.doi.org/10.1177/1550147717723554.
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Mobile satellite communication systems play an important role in space information networks. They mostly operate at the L or S band and have multiple beams efficiently reusing the limited spectrum. Advanced technologies, such as beamforming, are used to generate numerous beams through multiple feeders, and each beam’s power allocation is correlated and constrained. Frequency reuse among multiple beams results in co-channel interference issue, which makes bandwidth allocation among multiple beams coupled. It is a challenging topic to optimize the resource allocation in the real-time service traffic. In this article, a new multi-objective programming scheme is used to solve the dynamic resource allocation problem, guaranteeing high quality-of-service for multiple services of different priorities. Since the dynamic resource allocation problem is formulated as NP-hard, a new traffic-aware dynamic resource allocation (TADRA) algorithm is proposed. This algorithm is proved to be optimal in terms of the Pareto-front under constraints of co-channel interference and onboard transmit power. Simulation results show that the trade-off is well balanced between the call completion ratio in high priority and the throughput for video and data services in medium and low priorities. Additionally, it is shown that the new multi-objective programming scheme, based on the traffic-awareness dynamic resource allocation algorithm, can rapidly achieve the Pareto-front solutions and reduce the computing complexity to a large extent.
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Berceanu, Madalina-Georgiana, Carmen Florea, and Simona Halunga. "Performance Comparison of Massive MIMO System with Orthogonal and Nonorthogonal Multiple Access for Uplink in 5G Systems." Applied Sciences 10, no. 20 (October 14, 2020): 7139. http://dx.doi.org/10.3390/app10207139.
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In the attempt to respond to market demands, new techniques for wireless communication systems have been proposed to ensure, to all active users that are sharing the same network cell, an increased quality of service, regardless of any environmental factors, such as their position within the cell, time, space, climate, and noise. One example is the nonorthogonal multiple access (NOMA) technique, proposed within the 5G standard, known for supporting a massive connectivity and a more efficient use of radio resources. This paper presents two new sets of complex codes— multiple-user shared-access (MUSA) and extended MUSA (EMUSA), and an algorithm of allocation such that the intercorrelation should be as reduced as possible that can be used in MUSA for 5G NOMA-based technique scheme. Also, it analyzes the possibility of creating complex codes starting from PN (cPN), which is a novel idea proposed in this paper, whose results are promising with respect to the overall system performances. First, a description of the basic principles of MUSA are presented; next, the description of the proposed system will be provided, whose performance will be tested using Monte Carlo MATLAB simulations based on bit error rate (BER) versus signal-to-noise ratio (SNR). The system performances are evaluated in different scenarios and compared with classical code division multiple access (CDMA) having the following system parameters in sight: the number of antennas at the receiver side and the number of active users.