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Dissertations / Theses on the topic 'Rician fading'
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1
Haiou, Zheng, and Zhang Naitong. "ANALYSIS OF HYBRID FDMA/CDMA SYSTEMS IN RICIAN FADING." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/606808.
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International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, NevadaIn this paper, a hybrid frequency division multiple access/code division multiple access (FDMA/CDMA) system in a Rician fading channel is described and analysis. The performance of the hybrid system is compared with a wideband CDMA system, which occupies the same total bandwidth. The results show that for DPSK modulation with a RIKE receiver, a hybrid system can have a greater capacity with a strong direct path component or a high signal to noise ratio (SNR). Otherwise, a wideband system remains optimal.
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Schlenker, Joshua. "Improving and bounding asymptotic approximations for diversity combiners in correlated generalized rician fading." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/43932.
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Although relatively simple exact error rate expression are available for selection combining (SC) and equal gain combining (EGC) with independent fading channels, results for correlated channels are highly complex, requiring multiple levels of integration when more than two branches are involved. Not only does the complexity make numeric computation resource intensive, it obscures how channel statistics and correlation affect system performance. Asymptotic analysis has been used to derive simple error expressions valid in high signal-to-noise ratio (SNR) regimes. However, it is not clear at what SNR value the asymptotic results are an accurate approximation of the exact solution. In this thesis, we derive asymptotic results for SC, EGC, and maximal ratio combining (MRC) in correlated generalized Rician fading channels. By assuming generalized Rician fading, our results incorporate Rician, Rayleigh, and Nakagami-m fading scenarios as special cases. Furthermore, the asymptotic results for SC are expanded into an exact infinite series. Although this series grows quickly in complexity as more terms are included, truncation to even two or three terms has much greater accuracy than the first (asymptotic) term alone. Finally, we derive asymptotically tight lower and upper bounds on the error rate for EGC. Using these bounds, we are able to show at what SNR values the asymptotic results are valid.
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Wijeratne, Dissanayakage Geethika Sonali. "Fundamental Limits of Non-Coherent Rician Fading Channels with 1-Bit Output Quantization." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1499864736575987.
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Rasmussen, Lars Kildehoj. "Trellis coded, adaptive rate hybrid-ARQ protocols over AWGN channels and slowly fading rician channels." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/13434.
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Sendogan, Maruf. "Performance analysis of noncoherent DPSK with various diversity combining techniques over a Rician fading channel." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA344647.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, June 1998.Thesis advisor(s): Tri T. Ha, Ralph D. Hippenstiel. "June 1998." Includes bibliographical references (p. 65-66). Also available online.
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Kragh, Melody. "The effect of Rician fading and partial-band interference on noise-normalized fast frequency-hopped MFSK receivers." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/28142.
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The performance of an M-ary orthogonal frequency-shift keying (MFSK) communication system employing fast frequency-hopped spread spectrum waveforms transmitted over a frequency-nonselective, slowly fading channel with partial- band interference is analyzed. A procedure referred to as noise-normalization combining is employed by the system receiver to minimize partial-band interference effects. Each hop is assumed to fade independently. The partial- band interference is modeled as a Gaussian process. Both the signal and the partial-band interference are assumed to be affected by the fading channel which is modeled as Rician. The effect of fading of the partial-band interference on worst-case receiver performance is relatively minor. When there is no signal fading or when the signal fading is Rician, then the counter-intuitive result of poorer receiver performance when the partial-band interference experiences fading is obtained. This effect is most pronounced when the signal does not fade and the partial-band interference experiences Rayleigh fading
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Kmiecik, Chris G. "Effects of non-uniform windowing in a Rician-fading channel and simulation of adaptive automatic repeat request protocols." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA236940.
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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, June 1990.Thesis Advisor(s): Ha, Tri T. Second Reader: Myers, Glen A. "June 1990." Description based on signature page. DTIC Identifier(s): Digital communications, frequent shift keyers, program listings, protocols. Author(s) subject terms: FFT windowwing, ARQ, fading, frequency shifts. Includes bibliographical references (p. 58). Also available online.
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Peng, Ziqi. "Performance and Complexity Comparison of Doppler Spread Estimation for WCDMA Systems." Thesis, KTH, Kommunikationsteori, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-152225.
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In cellular communication systems, the estimation of Doppler spread has a wide range of applications such as handoff, channel assignment scheme, adaptivetransmission, power control, etc. A great quantity of Doppler spread estimation algorithms have been proposed in the literature. But there has been few investigations which gives a comprehensive comparison of these algorithms. Therefore, it is of great signicance to compare and evaluate the performance of the existing algorithms in the same simulation framework. In this report, the uplink of WCDMA is considered. Four different types of Doppler spread estimation algorithms are evaluated and compared in a link level baseband simulator. The performance and the ability to implement are considered as the metrics for evaluation. Both Rayleigh and Rician fading channel model are applied, and the effect of speed, signal to noise ratio, Rician factor and the angle of arrived line of sight component are also tested. Moreover, the computational complexity is analysed to evaluate the practical value for implementation.Estimatering av en mobils hastighet i form av Dopplerspridning har ett brett spektrum av tillmpningar i cellulra kommunikationssystem ssom fr yttningen avmobiler mellan celler, kanaltilldelningsschema, adaptiv sndning, eektstyrning,etc. En stor mngd algoritmer fr estimering av Dopplerspriding har frslagitsi litteraturen, men det r ovanligt med heltckande jmfrelser mellan med dessaalgoritmer. Drfr r det av stor betydelse att jmfra och utvrdera resultaten avbentliga algoritmer inom ramen fr samma simuleringsvertyg.I denna rapport anvnds upplnken fr WCDMA fr utvrdering av fyra olikatyper av algoritmer fr estimering av Dopplerspridning. Metriker fr utvrderingenr prestanda och implementeringsvnlighet. Bde Rayleigh och Rician fdningskanalmodeller har utvrderas, samt eekten av mobilens hastighet, signaltill brus frhllande, Rician faktor och infallsvinkel i ppet flt scenario. Dessutomhar den berkningsmssiga komplexiteten analyseras fr att utvrdera den praktiskaanvndbarheten i riktiga system.
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Moon, Todd K., and Chet Lo. "Bandwidth Efficient Signaling Using Multiscale Wavelet Functions and its Performance in a Rician Fast Fading Channel Employing Differential Detection." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/608755.
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International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, NevadaIn this paper, orthogonal wavelets are employed to produce multiscale signaling. It is shown that signaling using these functions is bandwidth efficient compared other signaling schemes, including SFSK and GMSK. For signaling in Rician fast fading channel, it is also shown that scaling functions is superior in term of achieving low level of probability of error. Even for multiscale signaling, the level probability of error achieved by using wavelet is lower than conventional flat-top signaling. The benefits are largest for channels with small B(D)T , in which the degradation due to fading is most severe.
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Karaagac, Ahmet Cem. "Noncoherent detection of BFSK signals with linear and nonlinear diversity combing over Rician fading channels with partial-band interference." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/26650.
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Hanafi, Effariza binti. "Quickest spectrum sensing with multiple antennas: performance analysis in various fading channels." Thesis, University of Canterbury. Electrical and Computer Engineering, 2014. http://hdl.handle.net/10092/9642.
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Traditional wireless networks are regulated by a fixed spectrum assignment policy. This results in situations where most of the allocated radio spectrum is not utilized. In order to address this spectrum underutilization, cognitive radio (CR) has emerged as a promising solution. Spectrum sensing is an essential component in CR networks to discover spectrum opportunities. The most common spectrum sensing techniques are energy detection, matched filtering or cyclostationary feature detection, which aim to maximize the probability of detection subject to a certain false alarm rate. Besides probability of detection, detection delay is also a crucial criterion in spectrum sensing. In an interweave CR network, quick detection of the absence of primary user (PU), which is the owner of the licensed spectrum, allows good utilization of unused spectrum, while quick detection of PU transmission is important to avoid any harmful interference.
This thesis consider quickest spectrum sensing, where the aim is to detect the PU with minimal detection delay subject to a certain false alarm rate. In the earlier chapters of this thesis, a single antenna cognitive user (CU) is considered and we study quickest spectrum sensing performance in Gaussian channel and classical fading channel models, including Rayleigh, Rician, Nakagami-m and a long-tailed channel. We prove that the power of the complex received signal is a sufficient statistic and derive the probability density function (pdf) of the received signal amplitude for all of the fading cases. The novel derivation of the pdfs of the amplitude of the received signal for the Rayleigh, Rician and Nakagami-m channels uses an approach which avoids numerical integration. We also consider the event of a mis-matched channel, where the cumulative sum (CUSUM) detector is designed for a specific channel, but a different channel is experienced. This scenario could occur in CR network as the channel may not be known and hence the CUSUM detector may be experiencing a different channel. Simulations results illustrate that the average detection delay depends greatly on the channel but very little on the nature of the detector. Hence, the simplest time-invariant detector can be employed with minimal performance loss.
Theoretical expressions for the distribution of detection delay for the time-invariant CUSUM detector, with single antenna CU are developed. These are useful for a more detailed analysis of the quickest spectrum sensing performance. We present several techniques to approximate the distribution of detection delay, including deriving a novel closed-form expression for the detection delay distribution when the received signal experiences a Gaussian channel. We also derive novel approximations for the distribution of detection delay for the general case due to the absence of a general framework. Most of the techniques are general and can be applied to any independent and identically distributed (i.i.d) channel. Results show that different signal-to-noise ratio (SNR) and detection delay conditions require different methods in order to achieve good approximations of the detection delay distributions. The remarkably simple Brownian motion approach gives the best approximation for longer detection delays. In addition, results show that the type of fading channel has very little impact on long detection delays.
In later chapters of this thesis, we employ multiple receive antennas at the CU. In particular, we study the performance of multi-antenna quickest spectrum sensing when the received signal experiences Gaussian, independent and correlated Rayleigh and Rician channels. The pdfs of the received signals required to form the CUSUM detector are derived for each of the scenarios. The extension into multiple antennas allows us to gain some insight into the reduction in detection delay that multiple antennas can provide. Results show that the sensing performance increases with an increasing Rician K-factor. In addition, channel correlation has little impact on the sensing performance at high SNR, whereas at low SNR, increasing correlation between channels improves the quickest spectrum sensing performance. We also consider mis-matched channel conditions and show that the quickest spectrum sensing performance at a particular correlation coefficient or Rician K-factor depends heavily on the true channel irrespective of the number of antennas at the CU and is relatively insensitive to the channel used to design the CUSUM detector. Hence, a simple multi-antenna time-invariant detector can be employed. Based on the results obtained in the earlier chapters, we derive theoretical expressions for the detection delay distribution when multiple receive antennas are employed at the CU. In particular, the approximation of the detection delay distribution is based on the Brownian motion approach.
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Betancourt, R. Miguel A. "Coded performance of a fast frequency-hopped noncoherent BFSK ratio statistic receiver over a Rician fading channel with partial-band interference." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23568.
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Approved for public release; distribution is unlimitedA frequency-hopping binary frequency shift keying (BSFK) ratio-statistic receiver with multihops per data bit is an effective electronic counter-countermeasures (ECCM) system against partial-band jamming interference. Interference is modeled as Gaussian noise. Orthogonal binary signaling and independent fading diversity is considered over frequency-nonselective, slow fading Rayleigh, Rician, and Gaussian channels. A forward error correcting coding scheme is implemented for a 1/2 rate convolutional code algorithm. The probability of bit error is examined for different levels of diversity, thermal noise, severity of fading, fraction of bandwidth jammed, and jamming power. Uncoded and coded system comparisons are done to determine worst case performance.
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Riley, John F. "Performance of a fast frequency-hopped noncoherent MFSK receiver with ratio-statistic combining over Rician fading channels with partial-band interference." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/30966.
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Approved for public release; distribution is unlimitedAn error probability analysis is performed for a fast frequency- hopped, frequency-shift keyed noncoherent receiver with ratio-statistic combining for a Rician channel with partial-band interference. Results are obtained for binary and M-ary FSK receivers where M is 4, 8, or 16. Both envelope and square-law detectors were analyzed. The probability of bit error is examined for different levels of diversity, thermal noise, severity of fading, fractions of bandwidth jammed, and varying jamming power. Comparisons for the different parameters are done to determine when diversity should be used. For the special case when there is no diversity, an analytic expression for receiver performance is obtained, and the performance of a receiver using envelope detection is found to be identical to that of a receiver using square-law detection for this special case. The results show that, for diversities of three and four, the envelope detector performs better than the square-law detector. It is shown that, for low signal-to-jammer ratios, diversity is generally a disadvantage, and for high signal-to-jammer ratios, diversity is generally an advantage. The transition is dependent on thermal noise and the value of M. Ratio-Statistic Combining, Fast Frequency-Hopping, Rician Fading, FSK modulation, Partial-Band Interference.
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Sheltry, Joseph Francis. "Performance of a fast frequency-hopped noncoherent MFSK receiver over Rician fading channels with either partial-band interference or multi-tone interference." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA286168.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, September 1994.Thesis advisor(s): R. Clark Robertson. "September 1994." Includes bibliographical references. Also available online.
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Theodoss, Michael D. "Performance of FFH/BFSK systems with convolutional coding and soft decision Viterbi decoding over Rician fading channels with partial-band noise interference." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA305964.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, December 1995."December 1995." Thesis advisor(s): R. Clark Robertson. Includes bibliographical references. Also available online.
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Vece, Thomas W. "Effects of non-uniform windowing on the performance of a fast frequency-hopped noncoherent MFSK receiver over Rician fading channels with partial-band interference and Doppler shift." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28147.
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Approved for public release; distribution is unlimitedAn error probability analysis is done for a DFT based, M-ary frequency-shift keying (MFSK) communications system employing fast frequency-hopped spread spectrum signals. A linear combination procedure referred to as noise-normalization is employed at the receiver to minimize the effects of partial-band interference, which is modeled as additive Gaussian noise. The performance of the receiver is studied as a function of signal Doppler shift and type of windowing used in the DFT. The use of fast frequency-hopped spread spectrum is found to improve the performance of the DFT based receiver in all but the most severe cases of Doppler shift. The use of a non-uniform window (i. e., a Hamming window) to improve receiver performance is effective only in the presence of large Doppler shifts. The amount of Doppler shift necessary to warrant the use of a non-uniform window depends on the amount of jamming noise power at the receiver, but is relatively insensitive to the frequency hop rate used
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Jurák, Petr. "Model fyzické vrstvy komunikačního systému IEEE 802.11ah." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-376918.
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This diploma thesis deals with the analysis of the IEEE 802.11ah wireless communication system. For such a purpose, an appropriate simulation model in program environment MATLAB is created. The first part of thesis focuses on the IEEE 802.11 standard. Basic blocks of the transmitter and receiver are described. Attention is also devoted on the brief description of considered transmission channels. The second part contains the description of the proposed and realized simulation model in MATLAB. Individual blocks of the simulation model are described in details. Finally, the obtained simulation results are evaluated and discussed.
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Ganji, Saichand. "Space-Time Block Coding to Achieve Spatial Diversity in a Multiple Input Multiple Output System." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1534432423784957.
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Badawy, Ahmed Mohamed H. "A hardware based Ricean fading radio channel simulator." Thesis, Montana State University, 2010. http://etd.lib.montana.edu/etd/2010/badawy/BadawyA0510.pdf.
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As the signal propagates from the transmitter to the receiver, it is subjected to fading. One of the fading distributions is Ricean distribution that assumes a line of sight signal and an infinite number of multipath signals between the transmitter and the receiver. The key parameter in the Ricean distribution is the K factor which is a measure of the severity of fading; the lower the K value, the more severe the fading. The problem was to develop a hardware based fading simulator that is based on the Ricean distribution. The key component of the hardware is an eight channel beamformer board; each channel has a 6-bit attenuator and a 6-bit phase shifter controlled by a on board FPGA for beamforming purpose. To approximate the Ricean fading, one of the eight channels was designated the line of sight signal, and the seven other channels were used to emulate the multipath signals. Cables with different lengths were used as delay lines to emulate the actual delays that occur to the multipath signals. The signals were then normalized to account for the cable losses. The fade simulator was controlled using a MATLAB program that sent a serial bit stream to the attenuators and phase shifters on the beamformer board. The MATLAB program generated random attenuations and phase shifts according to the Ricean distribution for the inputted K value. For a constant amplitude input RF signal, as K was increased, the fluctuation in the signal at the output of the fade simulator decreased. The estimated K values from the collected data were close to the inputted K values. The probability density functions (PDFs), the cumulative density functions (CDFs) and the level crossing rates (LCRs) of the collected data compared closely to the theoretical Ricean fading distribution PDFs, CDFs and LCRs, which showed that the fade simulator provides an accurate simulation of Ricean fading. The fade simulator was used to evaluate the performance of Airspan and Harris radios. The throughput of the radios was tested under different K values and for different SNR. As K increased, the fluctuation in the signal decreased which led to higher throughput.
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Kao, Chi-Han. "Performance of IEEE 802.11a wireless LAN standard over frequency-selective, slow, ricean fading channels." Thesis, Monterey California. Naval Postgraduate School, 2002. http://hdl.handle.net/10945/5020.
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Approved for public release, distribution is unlimitedWith the rapidly growing demand for more reliable and higher data rate wireless communications, the Institute of the Electrical and Electronics Engineers (IEEE) 802.11 working group approved a standard for 5 GHz band, wireless local area networks (WLAN) in 1999. This standard, IEEE 802.11a, supports data rates from 6 up to 54 Mbps, and uses orthogonal frequency division multiplexing (OFDM) for transmission in indoor wireless environments. This thesis examines the performance of the IEEE 802.11a standard for different combinations of sub-carrier modulation type and code rate and determines the signal-to-noise ratio required to obtain a probability of bit error b P of 10-5. The channel is modeled as a frequency-selective, slow, Ricean fading channel with additive white Gaussian noise (AWGN). Contrary to expectations, for the combinations of sub-carrier modulation type and code rate utilized by the IEEE 802.11a standard, some of the higher data rate combinations outperform some of the lower data rate combinations. On the other hand, the results also show significant coding gain when applying convolutional coding with Viterbi decoding, and hence highlight the importance of forward error correction (FEC) coding to the performance of wireless communications systems.
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Kao, Chi-han. "Performance of IEEE 802.11a wireless LAN standard over frequency-selective, slow, ricean fading channels /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02sep%5FKao.pdf.
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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, September 2002.Thesis advisor(s): R. Clark Robertson, Roberto Cristi. Includes bibliographical references (p. 93-94). Also available online.
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Sng, Sin Hie. "Radio channel modeling for mobile ad hoc wireless networks." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FSng.pdf.
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Thesis (M.S. in Engineering Science (Electrical Engineering))--Naval Postgraduate School, June 2004.Thesis advisor(s): Murali Tummala, Roberto Cristi. Includes bibliographical references (p. 71). Also available online.
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Green, Mary Ellen. "Performance of fast frequency-hopped self-normalized BFSK receivers over Ricean fading channels with multitone interference." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA303228.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, June 1995.Thesis advisor(s): R. Clark Robertson, Ralph Hippenstiel. "June 1995." Includes bibliographical references. Also available online.
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Kowalske, Kyle. "Performance of coherent and noncoherent RAKE receivers with convolutional coding ricean fading and pulse-noise interference /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FKowalske.pdf.
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Thesis (Doctor of Philosophy in Electrical Engineering)--Naval Postgraduate School, June 2004.Thesis advisor(s): Clark Robertson. Includes bibliographical references (p. 85-87). Also available online.
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Kowalske, Kyle E. "Performance of coherent and noncoherent RAKE receivers with convolutional coding ricean fading and pulse-noise interference." Thesis, Monterey, California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1557.
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Approved for public release, distribution is unlimitedThe performance of coherent and noncoherent RAKE receivers over a fading channel in the presence of pulse-noise interference and additive white Gaussian noise is analyzed. Coherent RAKE receivers require a pilot tone for coherent demodulation. Using a first order phase-lock-loop to recover a pilot tone with additive white Gaussian noise causes phase distortions at the phase-lock-loop output, which produce an irreducible phase noise error floor for soft decision Viterbi decoding. Both coherent and noncoherent RAKE receivers optimized for additive white Gaussian noise perform poorly when pulse-noise interference is present. When soft decision convolutional coding is considered, the performance degrades as the duty cycle of the pulse-noise interference signal decreases. The reverse is true for hard decision Viterbi decoding, since fewer bits experience interference and bit errors with high noise variance cannot dominate the decision statistics. Soft decision RAKE receiver optimized for pulse-noise interference and additive white Gaussian noise performed the best for both the coherent and noncoherent RAKE receivers. This receiver scales the received signal by the inverse of the variance on a bit-by-bit basis to minimize the effect of pulse-noise interference. The efficacy is demonstrated by analytical results, which reveal that this receiver reduces the probability of bit error down to the irreducible phase noise error floor when pulse-noise interference is present. This demonstrates how important it is to design the receiver for the intended operational environment.
Civilian, Department of Defense
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Spyrou, Evangelos. "Performance analysis of wireless LAN signals transmitted over a ricean fading channel in a pulsed-noise preference environment." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FSpyrou.pdf.
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Thesis (M.S. in Electrical Engineering and M.S. in Systems Engineering)--Naval Postgraduate School, Sept. 2004.Thesis Advisor(s): R. Clark Robertson. Includes bibliographical references (p. 67-68). Also available online.
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Iwasaki, Hidetoshi. "Performance of a fast frequency-hopped noncoherent MFSK receiver with non-ideal noise normalization combining over Ricean fading channels with partial-band interference." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA284989.
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Thesis (M.S. in Electrical Engineering and M.S. in Systems Engineering) Naval Postgraduate School, September 1994.Thesis advisor(s): R. Clark Robertson. "September 1994." Includes bibliographical references. Also available online.
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He, Xiaohui. "Bit-interleaved coded modulation for hybrid rf/fso systems." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2868.
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In this thesis, we propose a novel architecture for hybrid radio frequency
(RF)/free–space optics (FSO) wireless systems. Hybrid RF/FSO systems
are attractive since the RF and FSO sub–systems are affected differently by
weather and fading phenomena. We give a thorough introduction to the RF
and FSO technology, respectively. The state of the art of hybrid RF/FSO systems
is reviewed. We show that a hybrid system robust to different weather
conditions is obtained by joint bit–interleaved coded modulation (BICM) of the
bit streams transmitted over the RF and FSO sub–channels. An asymptotic
performance analysis reveals that a properly designed convolutional code can
exploit the diversity offered by the independent sub–channels. Furthermore,
we develop code design and power assignment criteria and provide an efficient
code search procedure. The cut–off rate of the proposed hybrid system is also
derived and compared to that of hybrid systems with perfect channel state
information at the transmitter. Simulation results show that hybrid RF/FSO
systems with BICM outperform previously proposed hybrid systems employing
a simple repetition code and selection diversity.
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Mendes, Jose Ricardo. "Coeficientes de correlação e parametros de coerencia de canais com desvanecimento." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259674.
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Orientador: Michel Daoud YacoubDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-07T11:29:09Z (GMT). No. of bitstreams: 1 Mendes_JoseRicardo_M.pdf: 915286 bytes, checksum: e4cfda5648e3725df9db2ff028e5c811 (MD5) Previous issue date: 2006
Resumo: Esta dissertação deduz e analisa coeficientes de correlação de sinais em diversos canais com desvanecimento, bem como especifica os respectivos parâmetros de coerência - distância de coerência, tempo de coerência e largura de banda de coerência. Tais parâmetros são extraídos do coeficiente de correlação da envoltória, estatística fornecida aqui apenas para canais com desvanecimento Rice, devido à complexidade de seu cálculo. Para modelos mais abrangentes de canais com desvanecimento, provê-se o coeficiente de correlação da potência, aproximação simples e geralmente acurada daquele coeficiente. Por fim, através de resultados numéricos, discriminam-se fatores que atuam sobre os parâmetros de coerência: ondas dominantes influem fundamentalmente na distância de coerência e no tempo de coerência; desequilíbrios de potência média dos componentes aleatórios em quadratura, primordialmente na largura de banda de coerência; anisotropia do espalhamento das ondas difusas e diretividade das antenas receptoras, somente na distância de coerência e no tempo de coerência; e a não-estacionariedade do ambiente, em todos os parâmetros de coerência
Abstract: This dissertation derives and examines correlation coefficients of signals in many fading channels, as well as specifies the respective coherence parameters - coherence distance, coherence time, and coherence bandwidth. Such parameters are extracted from the envelope correlation coefficient, statistic calculated here only for Ricean fading channels, owing to the complexity of its deduction. For more comprehensive models of fading channels, it is provided the power correlation coefficient, simple and usually accurate approximation of that coefficient. Finally, by means of numerical results, factors that affect the coherence parameters are enumerated: dominant waves influence fundamentally on the coherence distance and on the coherence time; mean power inequalities between the quadrature random components, mainly on the coherence bandwidth; anisotropy of the diffuse waves spreading, only on the coherence distance and on the coherence time; and nonstationarity of the environment, on all coherence parameters
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
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Tedesso, Thomas W. "Performance analysis of a SFH/NCBFSK communication system with rate 1/2 convolutional coding and soft decision Viterbi detection over a Ricean fading channel with partial-band noise jamming." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA345047.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, March 1998.Thesis advisor(s): R. Clark Robertson. "March 1998." Includes bibliographical references (p. 67-68). Also available online.
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Rosário, Maria do Socorro Soares. "Um modelo de desagregação de encargos de produção variáveis da Base RICA por actividade." Master's thesis, Universidade de Évora, 2011. http://hdl.handle.net/10174/15123.
Full textAbstract:
A informação desagregada relativamente a factores de produção é um problema generalizado das ciências agrárias. Recorre-se à utilização de inquéritos directos e pessoais junto do agricultor, com recurso a amostras pequenas, que são dispendiosos e demorados. O uso de técnicas e métodos alternativos pode ser uma experiência válida para estimar os custos variáveis de produção com um menor encargo. A base de dados da Rede de Informação de Contabilidades Agrícolas (RICA) é uma fonte de informação útil para estudar aspectos da política agrícola, respeita o total dos custos por tipo de factor não sendo desagregada por actividade. A obtenção dos custos variáveis por actividade é extremamente importante para a gestão da exploração e para a análise da política agrícola.
Esta dissertação tem como principal objectivo estimar os coeficientes de afectação dos custos às actividades agrícolas, a partir da RICA: é desenvolvido um modelo de desagregação dos custos de factores de produção variáveis por actividade com base na teoria da máxima entropia, aplicado na região do Alentejo e usando os dados da base RICA de 2008.
Os resultados mostram que a utilização da teoria da entropia é uma opção adequada para a estimação de coeficientes de afectação dos custos dos factores de produção às actividades num contexto de informação incompleta. Os estimadores de entropia apresentam de um modo geral bons resultados do ponto de vista estatístico e econométrico, mas os modelos de Mínima Entropia Cruzada permitem obter resultados mais aderentes à realidade do que os modelos de Máxima Entropia Generalizada; ABSTRACT:The lack of disaggregated data on factors of production is a widespread problem in the agricultural sciences. Usually, to obtain such information we do direct and personal surveys, using small samples. As these surveys are expensive and time consuming, the use of alternative techniques and methods to estimate the variable costs of production, with significantly lower costs, may be a worthwhile experience. The Farm Accounting Data Network (FADN) is a very useful source of data for studying agricultural policy. However FADN data concerns total costs by type of cost, being not broken down by activity. The attainment of variable unit costs of production by activity is extremely important, not only from the standpoint of business management, but also in the context of agricultural policy analysis.
To mitigate the lack of information on input costs in agriculture, the main goal of this paper is to estimate good coefficients for allocating those costs to farming activities, from the FADN database. We develop a model based on the theory of maximum entropy to breakdown the input variable costs by activity. This model is applied in the context of the Alentejo agricultural region, using FADN 2008 data.
The results show that the use of theory of entropy is an appropriate method for the estimating of coefficients for allocation costs of factors of production activities in a context of incomplete information. The entropy estimators have generally good results in terms of statistical and models but the Minimum Cross Entropy model results allow more adherent to reality than the Generalized Maximum Entropy models.
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Kirsch, Alessandra. "Politique agricole commune, aides directes de l'agriculture et environnement : analyse en France, en Allemagne et au Royaume-Uni." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCG001/document.
Full textAbstract:
La distribution des aides directes de la PAC bénéficie-t-elle aux exploitations agricoles les plus favorables à l’environnement ? Suite à un état de l’art sur les méthodes d’évaluation environnementales existantes, le développement d’une méthode originale a permis de classer des exploitations agricoles du RICA en fonction de leurs effets sur l'environnement à partir d’une série d’indicateurs agro-environnementaux. Ces classes ont ensuite été mises en relation avec les montants d'aides perçus à l’hectare. Les résultats sont traités pour 3 OTEX (céréales et oléo-protéagineux, bovins lait, bovins viande). Associée à un examen approfondi des réformes de la PAC depuis 1992, cette étude empirique permet de prendre du recul sur les conséquences des décisions politiques. Il apparait que si les aides du 2nd pilier sont orientées en faveur des exploitations les plus favorables à l’environnement, leur poids reste trop faible par rapport aux aides du 1er pilier, dont les paiements par hectare sont plus élevés dans les exploitations moins vertueuses. Ceci est lié en grande partie au poids des DPU dans les paiements directs, et au choix français de baser leur calcul par rapport à l’historique de l’exploitation. C’est pourquoi les simulations de la redistribution des aides du 1er pilier à horizon 2019 montrent que le rééquilibrage de ces aides entre les exploitations par une harmonisation nationale contribuera à niveler les écarts de paiements directs du 1er pilier par hectare entre les exploitations. La comparaison avec le Royaume-Uni et l’Allemagne montre les effets de la subsidiarité, notamment lors du découplage : l’harmonisation des paiements découplés en permet aux exploitations les plus favorables à l’environnement de toucher des paiements directs par hectare plus élevésDoes the CAP direct payment distribution benefit to the most environmentally friendly farms? Following an environmental assessment state of the art, a set of environmental indicators has been created to rank farms on their potential environmental impacts using FADN datas. Then, these classes have been connected with the amounts of direct payments received. Results are processed on three types of farm (specialized in cereals and oilseeds, meat cows and milk cows). Associated with a comprehensive study of the reforms of the CAP since 1992, this empirical study allows to stand back on the consequences of the political decisions. It seems that if the 2nd pillar direct payments are directed in favour of the more environmental friendly farms, their weight remains too low compared with the aids of the 1st pillar, which are higher in the less virtuous farms. This is largely connected to the weight of the DPU in the direct payments, and to the French choice to base their calculation with regard to the history of the farm. That is why the simulations of the redistribution of the subsidies of the 1st pillar on horizon 2019 show that the rebalancing of these payments between the farms by a national harmonization will contribute to level the gap of 1st pillar direct payments by hectare between french farms. The comparison with the United Kingdom and Germany shows the effects of the subsidiarity, in particular during the decoupling: the harmonization of the decoupled payments allows the most environmental friendly farms to get higher direct payments per hectare
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Chou, Yu-Hsing, and 周育興. "The Fading Number of Multiple-Access Rician Fading Channel with Memory." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/27142956587737472672.
Full textAbstract:
碩士國立交通大學
電信工程研究所
101
In this thesis we analyze the sum-rate capacity of the Rician fading multiple-access channel (MAC) with memory. The fading process of the channel is Gaussian in addition to a line-of-sight component. Moreover, there are more than one user sending data at the same time. To simplify our analysis, we consider the single-input single-output (SISO) case, i.e., all the transmitters and the receiver use one antenna. In the analysis of the fading channel capacity, the exact expression of the capacity is not yet known. A way called asymptotic analysis is used to derive the channel capacity in the limit when the available power tends to infinity. It is shown that at high signal-to-noise ratio (SNR), the sum-rate capacity grows to infinity doublelogarithmically. The second term in the high-SNR expansion is a constant called fading number. In our work, we derive an upper bound on the fading number of the general m-user SISO Rician fading MAC with memory. Combining the natural lower bound on the fading number of the single-user SISO channel, we then obtain the exact fading number of the general m-user SISO Rician fading MAC with memory. To achieve the fading number, we have to switch off the worse users and allow the best users communicate by time-sharing.
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Lin, Gu-Rong, and 林谷嶸. "Capacity Analysis of Multiple-Access Rician Fading Channel." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/95493875007894211721.
Full textAbstract:
碩士國立交通大學
電信工程系所
97
In this thesis the channel capacity of the noncoherent multiple-access Rician fading channel is investigated. In this channel, the transmitted signal is subject to additive Gaussian noise and Rician fading, i.e., the fading process is Gaussian in addition to a line-of-sight component. On the transmitter side the cooperation between users is not allowed, i.e., the users are assumed to be statistically independent. Based on the known result of the asymptotic capacity of a single-user fading channel, our work is to generalize it to the multiple-user sum-rate capacity. We study the single-antenna case only: all transmitters and the receiver use one antenna. We get a natural upper bound on the capacity if the constraint of independence between the users is relaxed, in which case the channel becomes a multiple-input single-output (MISO) channel. Also, a lower bound can be obtained if all users apart from one are switched off, which corresponds to a single-input single-output (SISO) channel. We improve these bounds and get an exact formula of the asymptotic capacity. The main concept we use in this thesis is escaping to infinity of input distributions, which means that when the available power tends to infinity, the input must use symbols that also tend to infinity. We propose that in the multiple-access fading channel, at least one user's distribution must escape to infinity. Based on this we obtain the result that the asymptotic sum-rate capacity is identical to the previously mentioned lower bound: the single-user SISO capacity. We conclude that in order to achieve the best sum-rate capacity in the multiple-access system, we have to switch off the users with bad channels and only allow those with the best channel to transmit.
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Dinesh, Vaibhav. "Matched filter bounds for fast fading Rician channels." Thesis, 2002. http://hdl.handle.net/2429/12061.
Full textAbstract:
A new matched filter bound (MFB) for a dispersive Rician fading channel with
unrestricted normalized Doppler rate is presented. Analytical expressions are derived for BPSK
modulation.
The channel model is based on the standard linear time varying filter. The BER performance,
in general, is found to improve with an increase in the fading rate due to the inherent
diversity present within a single pulse. The shape of the transmitted pulse is shown to affect the
BER in fast fading conditions. It has been found that the specular component improves the BER at
lower fading rates; for very high fading rates, the implicit diversity effect becomes dominant in
diminishing the effect of fading.
Discrete (two and three beam) models are assumed for the dispersive channel. The error
bounds for the three-beam model are derived as a function of the inter-beam delay and correlation
parameters. In general, the delay spread was found to result in lowering the BER for both the slow
and fast fading cases when the fading in the beams is uncorrelated. In the two-beam frequency
selective case, the BER is very sensitive to the degree of beam overlap.
Finally, assuming errors in estimating the channel fading waveform, the BER for a non-ideal
receive filter is obtained. It was observed that, for the specified model, the system degradation
is higher for phase mismatches than for amplitude mismatches for a given error variance.
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Huang, M. H., and 黃銘宏. "Performance Analysis of 8-PSK Modulation over Rician Fading Channnel." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/60683373444050112926.
Full textAbstract:
碩士國立海洋大學
航運技術研究所
89
The GSM evolution towards higher bit rate has been developed by the enhanced data rates for global evolution (EDGE). It offers data rate upto 2Mbps for in-door or static condition in wireless communications, where the system is used as third generation (3G) upgrade solution for currently operational 2/2.5G TDMA systems (GSM/GPRS). Since EDGE reuses the GSM carrier bandwidth and multi-timeslot structure, it facilitates co-existing concepts with GSM system over the air. EDGE introduces higher level modulation and new coding schemes for packet-switched and circuit-switched data services. Hence eight-symbol phase shift key(8-PSK) modulation is employed to fulfill 270.833K symbols per second, as GMSK symbol rates. In practice, the multipath fading channel causes the down grade in the system performance, especially time dispersion over partial symbol duration that severely results in the inter-symbol-interference. However, robust coding and GMSK modulation schemes are selected to combat the poor radio propagations, whereas in good conditions, less robust coding and 8-PSk modulation are employed. For EDGE system, higher data rate, approximately 384kbps, is therefore used in most indoor environment, where spectular component exists over multipath fading environment. The performance of 8-PSK modulation has been evaluated, in terms of symbol error rate, though Rician fading channel and with various roll-off factor of Raised-cosine filter. The conventional phase decision method are employed in the receiver , The carrier phase recovery is assumed to be performed with coherent detection at receiver side. The performance equal gain combining (EGC) diversity were also investigated and presented in the paper. Critical issue of the Rician factor, in terms of error performance, is also investigated and presented in the paper.
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Lin, Chung-So, and 林仲鑠. "Investigation on the Rician Factor of Indoor Flat Fast Fading Radio Channels." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/53704735184541023302.
Full textAbstract:
碩士國立交通大學
電信研究所
85
A newly developed hybrid model,composed of a two- dimensional(2-D)site-specific model and a randomly scattered model,is employed toinvestigation the Rician Factor of indoor flat fast fading channels.In our model,the averaged scattered( diffused)envelop,which has a significanteffect on the Rician Distribution and is usually neglected,can be effectivelyquantified by a ratio factor r. With a proper chosen value of r,our model yields a reasonable prediction accuracy of the Rician factor. It is foundthat a larger value of r represents a stronger scattered field and yields a small value of K,which is usually happened at the sites with heavy surroundingclutters or in NLOS(non Line-Of-Sign)propagation situations.
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Huang, Chun-I., and 黃俊溢. "Doppler Spread and Line-of-sight Component Estimation in Rician Fading Channels." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/31795079026047502923.
Full text
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"Cutoff rate performance of memoryless modulation schemes operating on slow-fading Rician channels." Massachusetts Institute of Technology, Laboratory for Information and Decision Systems], 1996. http://hdl.handle.net/1721.1/3435.
Full textAbstract:
Kyuhyoun Park and James W. Modestino.Caption title. "October 10, 1995."
Includes bibliographical references (p. 35-36).
Supported by ARPA. F30602-92-C-0030 Supported in part by the Laboratory for Information and Decision Systems, Massachusetts Institute of Technology. DAAH04-95-1-0103
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CHEN, YU-LONG, and 陳玉龍. "Performance analysis and evaluation of convolutional codes with MPSK on Rician fading channels." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/03062694828071512561.
Full text
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Zhang, Yi Mo, and 張義謨. "Using spread-spectrum technigues in packet radio over rician and nakagami fading channels with capture." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/82096363131323973388.
Full text
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Lyu, Wei-Jhe, and 呂維哲. "Fast Ricean Fading Signal Analysis in Ken-Ting Spring Scream Festival Hot Zone." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/99700890897211367453.
Full textAbstract:
碩士亞東技術學院
資訊與通訊工程研究所
102
In this study, the speed test software Nemo Handy installed on an engineering-mode mobile phone was used to measure the key performance indicators (KPI) of circuit-switched (CS) and packet-switched (PS) signal parameters generated from Node B located around the venue of the Spring Scream festival held in Kenting, Taiwan between April 3, 2013 and April 7, 2013. The measured signal parameters were then processed using the postprocessing software of Nemo Outdoor and Nemo Analyze to examine the quality of the communication signals. The items of the KPI parameters that were analyzed included slope, standard deviation (SD), drop call, UL throughput, DL throughput, and web open time (web time). The resulting data were then compared with the internal data generated at the system end of the switching device to understand the behavior of mobile phone users in various environments. Based on the varying behavioral models, the parameters of the node B were adjusted to optimize the performance of the node B. The mobility test yielded a slope value and SD of 0.1055 and 4.07, respectively; the stationary test produced a slope value and SD of 0.0571 and 4.87, respectively. These results showed that the signal quality of the mobility test was superior to that of the stationary test, as indicated by the slope. In addition, the representativeness of the mobility test result was greater than that of the stationary test, as indicated by the SD. Subsequent analysis revealed that the steady values of small-scale fading in the mobility test were all approximately 0.28, implying that the signals of the mobility tests exhibited Ricean fading. During the mobility test, 1 drop call occurred out of the 55 call attempts, yielding a DCR of 1.818%. According to the Splunk software at the system end, the DCRs during circuit switching and packet switching remained below 2%. The connection success rate of the radio resource control (RRC) and radio access bearer (RAB) was maintained above 98% and 97%, respectively. This high success rate was sustained despite using the mobile phone during peak hours, indicating that the resources available at the system end are sufficient.
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Μαλακάτας, Κωνσταντίνος-Επαμεινώνδας. "Μελέτη και προσδιορισμός του συντελεστή Κ της κατανομής Rice για ασύρματα κανάλια σε εσωτερικούς και εξωτερικούς χώρους." Thesis, 2014. http://hdl.handle.net/10889/8044.
Full textAbstract:
Σκοπός της παρούσας διπλωματικής εργασίας είναι η μελέτη και ο προσδιορισμός, θεωρητικός και πειραματικός, του συντελεστή Κ της Rician κατανομής σε ένα κανάλι στα 2.4 GHz. Η κατανομή Rice χρησιμοποιείται για την περιγραφή του πλάτους του λαμβανόμενου σήματος σε ένα κανάλι μετάδοσης με ισχυρή επίδραση οπτικής επαφής (Line-of-Sight) μεταξύ κεραίας πομπού και δέκτη. Ο συντελεστής Κ Rice εκφράζει τον λόγο της συνεισφοράς της ισχύος της απευθείας συνιστώσας του σήματος ως προς την συνολική λαμβανόμενη ισχύ λόγω φαινομένων διάχυσης. Χρησιμοποιείται για τον χαρακτηρισμό του καναλιού καθώς και τον υπολογισμό του BER (bit-error-ratio) και της πλέον σημαντικής παραμέτρου των τηλεπικοινωνιών SNR (Signal-to-Noise-Ratio), δηλαδή του λόγου σήματος προς θόρυβο.
Στο 1ο κεφάλαιο αναλύονται και περιγράφονται μερικές από τις σημαντικότερες τεχνολογίες ασυρμάτων δικτύων, από την πρώτη στιγμή της εμφάνισής τους (δίκτυα 1ης και 2ης γενιάς) έως τα πιο σύγχρονα δίκτυα 3ης και 4ης γενιάς, και παρουσιάζονται οι ζώνες συχνοτήτων που καταλαμβάνουν αυτές οι τεχνολογίες στο διαθέσιμο ηλεκτρομαγνητικό φάσμα.
Στο 2ο κεφάλαιο μελετώνται οι 3 βασικότεροι μηχανισμοί διάδοσης του ηλεκτρομαγνητικού κύματος μέσα σε ένα ασύρματο κανάλι (ανάκλαση, περίθλαση, σκέδαση), περιγράφονται οι τύποι των απωλειών που υφίσταται ένα σήμα κατά την μετάδοση του και τα φαινόμενα των διαλείψεων, που παρατηρούνται πολύ έντονα σε ένα κινητό και μεταβαλλόμενο περιβάλλον διάδοσης.
Στο 3ο κεφάλαιο γίνεται περιγραφή του μοντέλου ηλεκτρομαγνητικής μετάδοσης κατά Rice, δηλαδή όταν η απευθείας συνιστώσα του σήματος είναι η ισχυρότερη διαδρομή που ακολουθεί το εκπεμπόμενο σήμα κατά την πορεία του μέχρι τον δέκτη (LoS). Αναλύεται η σημαντικότερη παράμετρος αυτού του τύπου μετάδοσης, δηλαδή ο συντελεστής Κ, και παρουσιάζονται διάφορες μέθοδοι προσδιορισμού του τόσο θεωρητικά όσο και πειραματικά.
Στο 4ο κεφάλαιο παρουσιάζονται τα αποτελέσματα των πειραματικών μας μετρήσεων σε διάφορες τοπολογίες μετάδοσης με LoS για ένα δίκτυο Wi-Fi, δηλαδή για συχνότητα λειτουργίας στα 2.4 GHz. Για κάθε τοπολογία, περιγράφεται πλήρως το περιβάλλον μετάδοσης καθώς και ολόκληρη η διαδικασία εκπόνησης των μετρήσεων (μετρητικά όργανα, απαραίτητο λογισμικό, τυχόν προσεγγίσεις κτλ.).
Τέλος, στο 5ο και τελευταίο κεφάλαιο, παρουσιάζεται μια μέθοδος υπολογισμού του συντελεστή Κ μέσω των μετρήσεων και με τη βοήθεια του μοντέλου ελευθέρου χώρου, που χρησιμοποιείται για τον υπολογισμό των συνολικών απωλειών διαδρομής του σήματος. Τα αποτελέσματα των υπολογισμών χρησιμοποιήθηκαν, με την βοήθεια του Matlab, για την κατασκευή της CDF των τιμών του Κ αλλά και της γραφικής παράστασης της μεταβολής του Κ συναρτήσει της απόστασης. Οι εμπειρικές CDF συγκριθήκαν και προσεγγιστήκαν με γνωστές θεωρητικές CDF, και η συνάρτηση της μεταβολής του Κ με την απόσταση προσεγγίστηκε με όρους Goodness of Fit με την βοήθεια της γενικής μορφής γνωστών συναρτήσεων. Κλείνοντας, στην τελευταία παράγραφο της εργασίας αφήνεται περιθώριο και δίνεται τροφή για μελλοντική εργασία πάνω στην μελέτη και τον προσδιορισμό του συντελεστή Κ της Rice τόσο για εσωτερικούς όσο και για εξωτερικούς χώρους.The main purpose of this thesis, is the analysis and estimation , theoretical and empirical, of the Rician K factor for a wireless channel at 2.4 GHz. The Rician power density function is used to describe the amplitude of the received signal when there is a strong LOS component. The Rician K factor expresses the ratio of the power component due to LOS signal propagation and the received signal power due to diffuse components (reflection, scattering, diffraction etc.). It is commonly used for the channel's characterization and the estimation of BER (bit error rate) and SNR (signal to noise ratio), a very important parameter for telecommunications. In the 1st chapter, some of the most important wireless systems are described, since their very first appearance (1G & 2G networks) until the latest 3rd and 4rth generation systems. We also present the current frequency bands and how they are spread at the given electromagnetic spectrum. In the 2nd chapter, the 3 basic propagation mechanisms (reflection, scattering, diffraction) are studied. In addition, we describe all types of signal attenuation within a wireless channel and the fading phenomena that are so commonly seen in mobile and continuously changing propagation environments. In the 3rd chapter, the Rician model of electromagnetic propagation, where LOS is the strongest path of signal components, is analyzed. The most important parameter of this propagation type, the Rician K factor, is also studied. Therefore, various methods of theoretical and empirical estimation of the K factor are presented. In the 4rth chapter, we include the results of our measurements in various LOS propagation topologies for a Wi-Fi system at 2.4 GHz. For each measurement topology, the propagation environment as well as the entire measurement procedure, are thoroughly described. Lastly, in the 5th and final chapter, a K factor estimation method based on the empirical set of data and the Free Space Model, used for the average path loss calculation, is presented. The results of our measurements via the help of the Matlab software were used in order to plot the CDF of K values as well as the K values versus d (distance) curve. Using curve fitting methods, the empirical CDFs and plots were compared to theoretical ones in terms of Goodness of Fit. In the closing section, possible future research in the aforementioned fields is proposed.