Pub Date : 2007-12-04DOI: 10.1109/ISCIT.2007.4392213
W.V. Siricharoen
The Internet is already the primary source of tourist destination information for travelers. Digital business is changed from the recommended usual business using the Internet and e-commerce. E-tourism Software adapted from original e-commerce, ready for creating online reservation/booking. It is the total solution of instant e-commerce for travel 24 hour. E-tourism is a perfect candidate for Semantic Web because it is information-based and depends on the World Wide Web, both as a means of marketing and transaction channel. Ontologies can assist organization, browsing, parametric search, and in general, more intelligent access to online information and services. Ontology-based information retrieval makes it possible to handle the known challenges in connection with Web-based information systems in a more efficient way. This paper discusses some ontological trends that support the growing domain of online tourism. The first part introduces the e-tourism implementation and using ontologies in e-tourism. The second part describes fundamental background of ontologies; definition, modeling, language and etc. The third part discusses the example concepts of existing e-tourism using ontologies and it is a briefly summary on the important e-tourism ontologies. Finally, the last part is the conclusion.
{"title":"E-commerce adaptation using ontologies for e-tourism","authors":"W.V. Siricharoen","doi":"10.1109/ISCIT.2007.4392213","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392213","url":null,"abstract":"The Internet is already the primary source of tourist destination information for travelers. Digital business is changed from the recommended usual business using the Internet and e-commerce. E-tourism Software adapted from original e-commerce, ready for creating online reservation/booking. It is the total solution of instant e-commerce for travel 24 hour. E-tourism is a perfect candidate for Semantic Web because it is information-based and depends on the World Wide Web, both as a means of marketing and transaction channel. Ontologies can assist organization, browsing, parametric search, and in general, more intelligent access to online information and services. Ontology-based information retrieval makes it possible to handle the known challenges in connection with Web-based information systems in a more efficient way. This paper discusses some ontological trends that support the growing domain of online tourism. The first part introduces the e-tourism implementation and using ontologies in e-tourism. The second part describes fundamental background of ontologies; definition, modeling, language and etc. The third part discusses the example concepts of existing e-tourism using ontologies and it is a briefly summary on the important e-tourism ontologies. Finally, the last part is the conclusion.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127298359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-04DOI: 10.1109/ISCIT.2007.4392022
H. H. Kha, H. Tuan, T.Q. Nguyen
This paper proposes a computationally efficient method for designing a class of triplet halfband filter banks. We show that the design of perfect reconstruction two-channel Alter banks with arbitrary regularity order can be precisely formulated as a semi-definite programming problem. We also show that the dual problem has a significant smaller number of variables and, hence, can be solved efficiently. The effectiveness of the proposed method is demonstrated by the design examples of filter banks with high filter order and arbitrary regularity order.
{"title":"Optimal design of triplet halfband filter banks via Semidefinite Programming","authors":"H. H. Kha, H. Tuan, T.Q. Nguyen","doi":"10.1109/ISCIT.2007.4392022","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392022","url":null,"abstract":"This paper proposes a computationally efficient method for designing a class of triplet halfband filter banks. We show that the design of perfect reconstruction two-channel Alter banks with arbitrary regularity order can be precisely formulated as a semi-definite programming problem. We also show that the dual problem has a significant smaller number of variables and, hence, can be solved efficiently. The effectiveness of the proposed method is demonstrated by the design examples of filter banks with high filter order and arbitrary regularity order.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114268499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-04DOI: 10.1109/ISCIT.2007.4392263
D. Farrokhi, R. Togneri, A. Zaknich
A pre and post processing technique is proposed to enhance the speech signal of highly non-stationary noisy speech. The purpose of this research has been to build on current speech enhancement algorithms to produce an improved algorithm for enhancement of speech contaminated with non-stationary babble type noise. The pre processing involves two stages. In stage one, the variance of the noisy speech spectrum is reduced by utilizing the Discrete or Prolate Spheroidal Sequence (DPSS) multi-taper algorithm plus a Controlled Forward Moving Average (CFMA) technique. We introduced the CFMA algorithm to smooth and reduce variance of the estimated non-stationary noise spectrum. In the second stage the noisy speech power spectrum is de-noised by applying Stein's Unbiased Risk Estimator (SURE) wavelet thresholding technique. In the third layer, use is made of a noise estimation algorithm with rapid adaptation for a highly non-stationary noise environment. The noise estimate is updated in three frequency sub-bands, by averaging the noisy speech power spectrum using a frequency dependent smoothing factor, which is adjusted, based on a signal presence probability factor. In the fourth layer a spectral subtraction algorithm is used to enhance the speech signal, by subtracting each estimated noise from the original noisy speech. The new proposed post processing is then applied to the complete signal when the speech enhancement is processed using segmental speech enhancement. The enhanced signal is further improved by applying a soft wavelet thresholding technique to the un-segmented enhanced speech at the final processing stage. The results show improvements both quantitatively and qualitatively compared to the speech enhancement that does not apply the CFMA algorithm.
{"title":"Speech enhancement of non-stationary noise based on controlled forward moving average","authors":"D. Farrokhi, R. Togneri, A. Zaknich","doi":"10.1109/ISCIT.2007.4392263","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392263","url":null,"abstract":"A pre and post processing technique is proposed to enhance the speech signal of highly non-stationary noisy speech. The purpose of this research has been to build on current speech enhancement algorithms to produce an improved algorithm for enhancement of speech contaminated with non-stationary babble type noise. The pre processing involves two stages. In stage one, the variance of the noisy speech spectrum is reduced by utilizing the Discrete or Prolate Spheroidal Sequence (DPSS) multi-taper algorithm plus a Controlled Forward Moving Average (CFMA) technique. We introduced the CFMA algorithm to smooth and reduce variance of the estimated non-stationary noise spectrum. In the second stage the noisy speech power spectrum is de-noised by applying Stein's Unbiased Risk Estimator (SURE) wavelet thresholding technique. In the third layer, use is made of a noise estimation algorithm with rapid adaptation for a highly non-stationary noise environment. The noise estimate is updated in three frequency sub-bands, by averaging the noisy speech power spectrum using a frequency dependent smoothing factor, which is adjusted, based on a signal presence probability factor. In the fourth layer a spectral subtraction algorithm is used to enhance the speech signal, by subtracting each estimated noise from the original noisy speech. The new proposed post processing is then applied to the complete signal when the speech enhancement is processed using segmental speech enhancement. The enhanced signal is further improved by applying a soft wavelet thresholding technique to the un-segmented enhanced speech at the final processing stage. The results show improvements both quantitatively and qualitatively compared to the speech enhancement that does not apply the CFMA algorithm.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126016598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-04DOI: 10.1109/ISCIT.2007.4392029
J. DasGupta, K. Ziri-Castro, H. Suzuki
This paper presents the results of dynamic channel capacity measurements for a multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) system in two populated indoor environments with and without line-of-sight (LoS). The experiment used 4 sending and 4 receiving antennas and 114 sub-carriers at 5 GHz as per draft IEEE 802.11n. MIMO-OFDM channel capacity is analysed both with fixed receiver signal-to-noise ratio (SNR) and fixed transmitter (Tx) power criteria. It is found that fixed SNR capacity increased while fixed Tx power capacity decreased in both environments by the presence of pedestrian. It is also revealed that the spread of the capacity cumulative distribution function (CDF) increased due to the pedestrians in both environments with both criteria.
{"title":"Capacity analysis of MIMO-OFDM broadband channels in populated indoor environments","authors":"J. DasGupta, K. Ziri-Castro, H. Suzuki","doi":"10.1109/ISCIT.2007.4392029","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392029","url":null,"abstract":"This paper presents the results of dynamic channel capacity measurements for a multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) system in two populated indoor environments with and without line-of-sight (LoS). The experiment used 4 sending and 4 receiving antennas and 114 sub-carriers at 5 GHz as per draft IEEE 802.11n. MIMO-OFDM channel capacity is analysed both with fixed receiver signal-to-noise ratio (SNR) and fixed transmitter (Tx) power criteria. It is found that fixed SNR capacity increased while fixed Tx power capacity decreased in both environments by the presence of pedestrian. It is also revealed that the spread of the capacity cumulative distribution function (CDF) increased due to the pedestrians in both environments with both criteria.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123117063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-04DOI: 10.1109/ISCIT.2007.4392053
Wei Peng, Shaodan Ma, T. Ng, Jiang Wang
The QR decomposition based M algorithm (QRD-M) is a sub-optimal detection algorithm which can achieve a tradeoff between bit error rate (BER) performance and computational complexity for multiple input multiple output (MIMO) systems. In this paper, an adaptive QRD-M algorithm with variable number of surviving paths is proposed for MIMO systems. The number of surviving paths at each detection stage is adaptively determined according to the instantaneous value and the statistics of channel conditions. The required statistics of the channel conditions is directly derived and given in closed form without a large number of training observations. The proposed algorithm is simple to implement and it is verified by computer simulations that the proposed algorithm has lower computational complexity than the fixed QRD-M algorithms thus can offer a better tradeoff between BER performance and computational complexity.
{"title":"Adaptive QRD-M detection with variable number of surviving paths for MIMO systems","authors":"Wei Peng, Shaodan Ma, T. Ng, Jiang Wang","doi":"10.1109/ISCIT.2007.4392053","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392053","url":null,"abstract":"The QR decomposition based M algorithm (QRD-M) is a sub-optimal detection algorithm which can achieve a tradeoff between bit error rate (BER) performance and computational complexity for multiple input multiple output (MIMO) systems. In this paper, an adaptive QRD-M algorithm with variable number of surviving paths is proposed for MIMO systems. The number of surviving paths at each detection stage is adaptively determined according to the instantaneous value and the statistics of channel conditions. The required statistics of the channel conditions is directly derived and given in closed form without a large number of training observations. The proposed algorithm is simple to implement and it is verified by computer simulations that the proposed algorithm has lower computational complexity than the fixed QRD-M algorithms thus can offer a better tradeoff between BER performance and computational complexity.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127539246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-04DOI: 10.1109/ISCIT.2007.4392153
Chiu-Kuo Liang, Yu-Jie Huang, J. Lin
In wireless sensor networks, it is an important task to periodically collect data from an area of interest for time-sensitive applications. The sensed data must be gathered and transmitted to a base station for further processing to meet the end-user queries. Since the network consists of low-cost nodes with limited battery power, it is a challenging task to design an efficient routing scheme that can minimize delay and offer good performance in energy efficiency, and long network lifetimes. In this paper, we propose a new routing protocol, called Degree-Constrained Minimal Spanning Tree (DCMST), to collect information efficiently. DCMST is efficient in the ways that it ensures maximal utilization of network energy, it makes the lifetime of the network longer, as well as it takes much lower time to complete a round. Simulation results show that DCMST achieves around 20% better performance than that of COSEN in respect of delay time. It also shows that DCMST can perform better than COSEN in total transmission distance, which implies the less total energy consumption. Therefore, our DCMST scheme gives a good compromise between energy efficiency and latency.
{"title":"Energy efficient routing for achieving shorter latency in sensor networks","authors":"Chiu-Kuo Liang, Yu-Jie Huang, J. Lin","doi":"10.1109/ISCIT.2007.4392153","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392153","url":null,"abstract":"In wireless sensor networks, it is an important task to periodically collect data from an area of interest for time-sensitive applications. The sensed data must be gathered and transmitted to a base station for further processing to meet the end-user queries. Since the network consists of low-cost nodes with limited battery power, it is a challenging task to design an efficient routing scheme that can minimize delay and offer good performance in energy efficiency, and long network lifetimes. In this paper, we propose a new routing protocol, called Degree-Constrained Minimal Spanning Tree (DCMST), to collect information efficiently. DCMST is efficient in the ways that it ensures maximal utilization of network energy, it makes the lifetime of the network longer, as well as it takes much lower time to complete a round. Simulation results show that DCMST achieves around 20% better performance than that of COSEN in respect of delay time. It also shows that DCMST can perform better than COSEN in total transmission distance, which implies the less total energy consumption. Therefore, our DCMST scheme gives a good compromise between energy efficiency and latency.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123021111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-04DOI: 10.1109/ISCIT.2007.4392182
T.T. Nguyen, H. Tuan, T.Q. Nguyen
This paper presents a robust approach for spread spectrum (SS) based watermarking process. Unlike the traditional SS or other improvements, this method can work properly in case of absence of watermark and achieve good performance. If the channel has no noise, the error probability of the new design is zero, which is not existed in almost SS-based watermarking systems. Based on analysis by theory, the optimal threshold is calculated. Moreover, the simulations are implemented to verify to the theory.
{"title":"Robust watermarking with improved modified spread spectrum","authors":"T.T. Nguyen, H. Tuan, T.Q. Nguyen","doi":"10.1109/ISCIT.2007.4392182","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392182","url":null,"abstract":"This paper presents a robust approach for spread spectrum (SS) based watermarking process. Unlike the traditional SS or other improvements, this method can work properly in case of absence of watermark and achieve good performance. If the channel has no noise, the error probability of the new design is zero, which is not existed in almost SS-based watermarking systems. Based on analysis by theory, the optimal threshold is calculated. Moreover, the simulations are implemented to verify to the theory.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129086713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-04DOI: 10.1109/ISCIT.2007.4392114
K. Gopalan
A method of implementing image steganography in a color image for applications such as covert communication via the Internet and authentication of an employee carrying a picture identification card is described. By converting the color image to a one-dimensional signal in red, green, or blue, audibly masked frequencies in the 1-D signal are determined for each segment or block. Embedding of secure or confidential data is carried out by modifying the spectral power at a pair of commonly occurring masked frequencies. Compressing the data-embedded image to standard JPEG coding enables its transmission via the Internet. Experimental results show that the technique is simple to implement and causes barely noticeable distortion in the stego image. Using an oblivious technique and a key consisting of the frequencies where the spectrum is modified, successful data retrieval even at low level noise levels and at low-loss compression has been achieved. Higher payload of hidden data can be obtained at a cost of perceptibility of embedding. Lossy JPEG compression, however, leads to low payloads.
{"title":"An image steganography implementation for JPEG-compressed images","authors":"K. Gopalan","doi":"10.1109/ISCIT.2007.4392114","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392114","url":null,"abstract":"A method of implementing image steganography in a color image for applications such as covert communication via the Internet and authentication of an employee carrying a picture identification card is described. By converting the color image to a one-dimensional signal in red, green, or blue, audibly masked frequencies in the 1-D signal are determined for each segment or block. Embedding of secure or confidential data is carried out by modifying the spectral power at a pair of commonly occurring masked frequencies. Compressing the data-embedded image to standard JPEG coding enables its transmission via the Internet. Experimental results show that the technique is simple to implement and causes barely noticeable distortion in the stego image. Using an oblivious technique and a key consisting of the frequencies where the spectrum is modified, successful data retrieval even at low level noise levels and at low-loss compression has been achieved. Higher payload of hidden data can be obtained at a cost of perceptibility of embedding. Lossy JPEG compression, however, leads to low payloads.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129348222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-04DOI: 10.1109/ISCIT.2007.4392108
Jinsheng Sun, M. Zukerman, M. Palaniswami
Active queue management (AQM) mechanisms have been proposed to support end-to-end congestion control mechanisms of transmission control protocol (TCP) in TCP/IP networks. This paper introduces a new AQM based on a stable adaptive proportional-integral (SAPI) controller. SAPI adaptively adjusts the PI controller parameters based on estimated network parameters to improve the transient performance of a fixed-gain PI controller. We present the SAPI scheme in detail, and provide guidelines for the selection of its parameters. Through extensive simulations, we demonstrate that SAPI maintains satisfactory transient and steady-state performance independent of traffic loads, round trip propagation delay, and bottleneck capacity. The simulation results also demonstrate that SAPI is robust to non-responsive UDP traffic and HTTP traffic, and it is effective for networks with multiple bottlenecks. Comparison with other well-known AQM algorithms like PI, REM and Q-SAPI shows that SAPI achieves faster convergence to queue length target and smaller queue length jitter.
{"title":"A stable adaptive PI controller for AQM","authors":"Jinsheng Sun, M. Zukerman, M. Palaniswami","doi":"10.1109/ISCIT.2007.4392108","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392108","url":null,"abstract":"Active queue management (AQM) mechanisms have been proposed to support end-to-end congestion control mechanisms of transmission control protocol (TCP) in TCP/IP networks. This paper introduces a new AQM based on a stable adaptive proportional-integral (SAPI) controller. SAPI adaptively adjusts the PI controller parameters based on estimated network parameters to improve the transient performance of a fixed-gain PI controller. We present the SAPI scheme in detail, and provide guidelines for the selection of its parameters. Through extensive simulations, we demonstrate that SAPI maintains satisfactory transient and steady-state performance independent of traffic loads, round trip propagation delay, and bottleneck capacity. The simulation results also demonstrate that SAPI is robust to non-responsive UDP traffic and HTTP traffic, and it is effective for networks with multiple bottlenecks. Comparison with other well-known AQM algorithms like PI, REM and Q-SAPI shows that SAPI achieves faster convergence to queue length target and smaller queue length jitter.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116942190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-04DOI: 10.1109/ISCIT.2007.4391986
H. Ryu, Chengxiang Wang, Sang-Burm Ryu
Orthogonal frequency division multiplexing (OFDM) has been used widely in many communication systems. However, the major drawback of OFDM is the high peak-to-average-power ratio (PAPR) which results in the bit error rate (BER) performance degradation in nonlinear environments. In this paper, we introduce a new phase weighting method to reduce the nonlinear distortion of OFDM signals in the nonlinear high power amplifier, which is different from the well-known PAPR reduction method. Especially, the proposed method is based on the nonlinear distortion reduction criterion rather than the conventional PAPR reduction criterion so that we can improve the BER performance more effectively. The simulation results show that the BER performance of the OFDM system using the proposed method is better than that of the ordinary OFDM and other OFDM systems using the PAPR reduction criterion.
{"title":"Nonlinear distortion reduction for the improvement of the BER performance in OFDM communication systems","authors":"H. Ryu, Chengxiang Wang, Sang-Burm Ryu","doi":"10.1109/ISCIT.2007.4391986","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4391986","url":null,"abstract":"Orthogonal frequency division multiplexing (OFDM) has been used widely in many communication systems. However, the major drawback of OFDM is the high peak-to-average-power ratio (PAPR) which results in the bit error rate (BER) performance degradation in nonlinear environments. In this paper, we introduce a new phase weighting method to reduce the nonlinear distortion of OFDM signals in the nonlinear high power amplifier, which is different from the well-known PAPR reduction method. Especially, the proposed method is based on the nonlinear distortion reduction criterion rather than the conventional PAPR reduction criterion so that we can improve the BER performance more effectively. The simulation results show that the BER performance of the OFDM system using the proposed method is better than that of the ordinary OFDM and other OFDM systems using the PAPR reduction criterion.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117070263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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