Mobile communications offer wireless connectivity that enables mobility and computing in many different communication environments. The huge demands from social markets are driving the growing development of mobile communications more rapidly than ever before. Consequently, a large set of new advanced techniques have emerged brought up by a larger bandwidth, more powerful processing capability, and advances in computing technology. Many new services are provided, or will be provided to potential users, and delivered with high level quality by usage of GSM, 3G networks and wireless mesh networks in public, home, and corporate scenarios. The exceptional growth in mobile and wireless communications gives rise to serious problems of security at the level of the subscriber, network operator, and service provider. The causes of such rise, typically due to the fragility of the wireless link nature, the mobility features, and the variety of the provided services, can be classified into the following six categories: a) the physical weaknesses and limitations of mobile and communications; b) the architecture limitations; c) the complexity of services; d) the user requirements; e) the contents of provided services; and f) the evolution of hacking techniques. Many studies have addressed carefully the mobile subscriber authentication, radio-path encryption, and secure mobility, but the so-called "security of mobile communications" does no involve only these relative independent domains. It indeed needs a more systematic approach to build up a framework layout capable of allowing: 1) the risk analysis of threats and vulnerabilities of a mobile communication system; 2) the assessment of a mobile communication system in terms of provided QoS, roaming capabilities, and security; and 3) the protection of a service provided via mobile communication systems. The major goals of this tutorial consist in five issues: 1) analyzing and discussing the security proposals made available by the mobile cellular and ad-hoc communications systems; 2) discussing the security attacks and hacking techniques; 3) discussing security policies and security practices to help better addressing the security problem; 4) discussing the role of the network operator, the service provider, and customer in securing mobile communications; and 5) analyzing the promises, requirements, and limits of service provision in terms of security needs.
{"title":"Security of Mobile Communications","authors":"N. Boudriga","doi":"10.1201/9780849379420","DOIUrl":"https://doi.org/10.1201/9780849379420","url":null,"abstract":"Mobile communications offer wireless connectivity that enables mobility and computing in many different communication environments. The huge demands from social markets are driving the growing development of mobile communications more rapidly than ever before. Consequently, a large set of new advanced techniques have emerged brought up by a larger bandwidth, more powerful processing capability, and advances in computing technology. Many new services are provided, or will be provided to potential users, and delivered with high level quality by usage of GSM, 3G networks and wireless mesh networks in public, home, and corporate scenarios. The exceptional growth in mobile and wireless communications gives rise to serious problems of security at the level of the subscriber, network operator, and service provider. The causes of such rise, typically due to the fragility of the wireless link nature, the mobility features, and the variety of the provided services, can be classified into the following six categories: a) the physical weaknesses and limitations of mobile and communications; b) the architecture limitations; c) the complexity of services; d) the user requirements; e) the contents of provided services; and f) the evolution of hacking techniques. Many studies have addressed carefully the mobile subscriber authentication, radio-path encryption, and secure mobility, but the so-called \"security of mobile communications\" does no involve only these relative independent domains. It indeed needs a more systematic approach to build up a framework layout capable of allowing: 1) the risk analysis of threats and vulnerabilities of a mobile communication system; 2) the assessment of a mobile communication system in terms of provided QoS, roaming capabilities, and security; and 3) the protection of a service provided via mobile communication systems. The major goals of this tutorial consist in five issues: 1) analyzing and discussing the security proposals made available by the mobile cellular and ad-hoc communications systems; 2) discussing the security attacks and hacking techniques; 3) discussing security policies and security practices to help better addressing the security problem; 4) discussing the role of the network operator, the service provider, and customer in securing mobile communications; and 5) analyzing the promises, requirements, and limits of service provision in terms of security needs.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134251381","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}
Orthogonal frequency division multiplexing (OFDM) is a promising technique for the broadband wireless communication system. However, the inter-sub-carrier-interference (ICI) produced by the phase noise of transceiver local oscillator is a serious problem. Bit error rate (BER) performance is degraded because the orthogonal properties between the sub-carriers are broken down. In this paper, the number of sub-carriers is chosen according to the consideration of the trade off between the amount of ICI and data rate of the system. ICI self-cancellation of Mapping Method introduced here is also studied to reduce ICI effectively. Then the system performance of the Mapping Method is compared with those of the original OFDM and the conventional data-conversion method.
{"title":"An Improved ICI Reduction Method in OFDM Communication System in Presence of Phase Noise","authors":"N. M. Moghaddam, A. Falahati","doi":"10.1109/PIMRC.2007.4394766","DOIUrl":"https://doi.org/10.1109/PIMRC.2007.4394766","url":null,"abstract":"Orthogonal frequency division multiplexing (OFDM) is a promising technique for the broadband wireless communication system. However, the inter-sub-carrier-interference (ICI) produced by the phase noise of transceiver local oscillator is a serious problem. Bit error rate (BER) performance is degraded because the orthogonal properties between the sub-carriers are broken down. In this paper, the number of sub-carriers is chosen according to the consideration of the trade off between the amount of ICI and data rate of the system. ICI self-cancellation of Mapping Method introduced here is also studied to reduce ICI effectively. Then the system performance of the Mapping Method is compared with those of the original OFDM and the conventional data-conversion method.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"3 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":"126225212","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}
Sensor nodes are deployed to sense an environment for observing the physical world. The sensing field (an area of interest) can be represented as an ellipse. This paper proposes an algorithm for covering an elliptical shaped area of interest within wireless sensor network fields by modifying the Hilbert-space filling curve. Conventionally, an area is partitioned into 2n times 2n square grid (Hilbert cells). Hilbert space-filling curve is modified to map only specific area of interest. To cover the entire area of interest, the algorithm requires a mobility pattern for a sink node in order to collect data for a specific mission. This is done by traversing the area from an entry point and finishing at an exit point from the square grids. Simulation results show that modified Hilbert space-filling curve achieves its best Hilbert-covering for an ellipse that is almost circular as opposed to a narrow ellipse.
{"title":"Modified Hilbert Space-Filling Curve for Ellipsoidal Coverage in Wireless Ad Hoc Sensor Networks","authors":"M. Kamat, A. Ismail, S. Olariu","doi":"10.1109/ICSPC.2007.4728592","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728592","url":null,"abstract":"Sensor nodes are deployed to sense an environment for observing the physical world. The sensing field (an area of interest) can be represented as an ellipse. This paper proposes an algorithm for covering an elliptical shaped area of interest within wireless sensor network fields by modifying the Hilbert-space filling curve. Conventionally, an area is partitioned into 2n times 2n square grid (Hilbert cells). Hilbert space-filling curve is modified to map only specific area of interest. To cover the entire area of interest, the algorithm requires a mobility pattern for a sink node in order to collect data for a specific mission. This is done by traversing the area from an entry point and finishing at an exit point from the square grids. Simulation results show that modified Hilbert space-filling curve achieves its best Hilbert-covering for an ellipse that is almost circular as opposed to a narrow ellipse.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129699080","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}
In this paper, the implementation of a baseline profile H.264 decoder based on a DM 642 digital signal processor is described. An initial standard compliant raw-C decoder has been optimized in speed for the target processor. The parallelism between algorithm execution and data movement has been fully exploited using DMA. Also, critical parts of the algorithm have been encoded directly in assembly code to increase the number of instructions per cycle. The decoder has been tested in simulation with actual (transcoded) DVD and digital TV streams. According to these tests, standard definition real time decoding can be obtained with a DM 642@600 MHz.
{"title":"A Real-Time H.264 BP Decoder based on a DM642 DSP","authors":"F. Pescador, M. Garrido, C. Sanz, E. J. Martínez, Manuel César Rodríguez Lacruz, D. S. Martínez","doi":"10.1109/ICECS.2007.4511223","DOIUrl":"https://doi.org/10.1109/ICECS.2007.4511223","url":null,"abstract":"In this paper, the implementation of a baseline profile H.264 decoder based on a DM 642 digital signal processor is described. An initial standard compliant raw-C decoder has been optimized in speed for the target processor. The parallelism between algorithm execution and data movement has been fully exploited using DMA. Also, critical parts of the algorithm have been encoded directly in assembly code to increase the number of instructions per cycle. The decoder has been tested in simulation with actual (transcoded) DVD and digital TV streams. According to these tests, standard definition real time decoding can be obtained with a DM 642@600 MHz.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116051700","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}
This paper proposes a method for online feedback path modeling in multichannel active noise control (ANC) systems. Previously we have proposed a method for online feedback path molding for single-channel ANC system. Here we modify and extend this method to multichannel ANC systems, in particular, we consider a 1 × 2 × 2 system comprising one reference microphone, two secondary loudspeakers and two error microphones. The computational complexity of the proposed method is lower than the existing methods. Computer simulations are used to demonstrate the effectiveness of the proposed method.
{"title":"Online Acoustic Feedback Path Modeling in Multichannel (1 × 2 × 2) Active Noise Control Systems","authors":"M. Akhtar, M. Abe, M. Kawamata, M. Tufail","doi":"10.1109/ICSPC.2007.4728397","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728397","url":null,"abstract":"This paper proposes a method for online feedback path modeling in multichannel active noise control (ANC) systems. Previously we have proposed a method for online feedback path molding for single-channel ANC system. Here we modify and extend this method to multichannel ANC systems, in particular, we consider a 1 × 2 × 2 system comprising one reference microphone, two secondary loudspeakers and two error microphones. The computational complexity of the proposed method is lower than the existing methods. Computer simulations are used to demonstrate the effectiveness of the proposed method.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134463939","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}
Given a collection of lightpath requests, we consider the problem of allocating fibers to the links of a WDM network at minimum cost, such that all lightpath requests can be simultaneously realized. It is known that, under modular fiber capacity assumptions, shortest path routing may not minimize the total fiber cost. In this paper, we extend our previous work for wavelength convertible networks, and theoretically quantify the increase in fiber cost due to shortest path routing in networks without wavelength converters. In particular, we prove that shortest path routing is asymptotically cost-optimal in heavily loaded networks, and asymptotically near-optimal in large, sparse networks that support all-to-all communication.
{"title":"Wavelength Selective WDM Network Design: How Bad is Shortest Path Routing?","authors":"M. Saad, Z. Luo","doi":"10.1109/ICSPC.2007.4728373","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728373","url":null,"abstract":"Given a collection of lightpath requests, we consider the problem of allocating fibers to the links of a WDM network at minimum cost, such that all lightpath requests can be simultaneously realized. It is known that, under modular fiber capacity assumptions, shortest path routing may not minimize the total fiber cost. In this paper, we extend our previous work for wavelength convertible networks, and theoretically quantify the increase in fiber cost due to shortest path routing in networks without wavelength converters. In particular, we prove that shortest path routing is asymptotically cost-optimal in heavily loaded networks, and asymptotically near-optimal in large, sparse networks that support all-to-all communication.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132633284","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}
New steganography methods are being proposed to embed secret information into text cover media in order to search for new possibilities employing languages other than English. This paper utilizes the advantages of diacritics in Arabic to implement text steganography. Diacritics - or Harakat - in Arabic are used to represent vowel sounds and can be found in many formal and religious documents. The proposed approach uses eight different diacritical symbols in Arabic to hide binary bits in the original cover media. The embedded data are then extracted by reading the diacritics from the document and translating them back to binary.
{"title":"Arabic Diacritics based Steganography","authors":"Mohammed A. Aabed, Sameh Awaideh, Abdul-Rahman M. Elshafei, A. Gutub","doi":"10.1109/ICSPC.2007.4728429","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728429","url":null,"abstract":"New steganography methods are being proposed to embed secret information into text cover media in order to search for new possibilities employing languages other than English. This paper utilizes the advantages of diacritics in Arabic to implement text steganography. Diacritics - or Harakat - in Arabic are used to represent vowel sounds and can be found in many formal and religious documents. The proposed approach uses eight different diacritical symbols in Arabic to hide binary bits in the original cover media. The embedded data are then extracted by reading the diacritics from the document and translating them back to binary.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122961557","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}
This paper presents a novel fast mode decision algorithm for H.264/AVC based on a Pareto-optimal macroblock classification strategy. Previously published H.264 low complexity schemes mostly concentrated on improving class decision metrics, but did not justify the choice of MD classes. Herein, we use Pareto analysis to derive the optimal set of MD classes and to define efficient class decision metrics. For each MD class only rate-distortion optimal complexity settings are used. Experimental results show that the proposed algorithm outperforms previously published algorithms, providing a 57-73% reduction in total computational complexity with some reduction in bit rate and acceptable visual quality.
{"title":"Pareto-Optimal Macroblock Classification for Fast Mode Decision in H.264","authors":"Y. Ivanov, C. Bleakley","doi":"10.1109/ICSPC.2007.4728600","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728600","url":null,"abstract":"This paper presents a novel fast mode decision algorithm for H.264/AVC based on a Pareto-optimal macroblock classification strategy. Previously published H.264 low complexity schemes mostly concentrated on improving class decision metrics, but did not justify the choice of MD classes. Herein, we use Pareto analysis to derive the optimal set of MD classes and to define efficient class decision metrics. For each MD class only rate-distortion optimal complexity settings are used. Experimental results show that the proposed algorithm outperforms previously published algorithms, providing a 57-73% reduction in total computational complexity with some reduction in bit rate and acceptable visual quality.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115723971","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}
In the Northern part of the Netherlands ASTRON is building the largest radio telescope in the world for low frequencies. The telescope is based on phased array principles and is known as the LOw Frequency ARray (LOFAR). LOFAR is optimized for detecting astronomical signals in the 30-80 MHz and 120-240 MHz frequency window. LOFAR detects the incoming radio signals by using an array of simple omni-directional antennas. The antennas are grouped in so called stations mainly to reduce the amount of data generated. More than fifty stations will be built, mainly within a circle of 150 kilometres in diameter but also internationally. The signals of all the stations are distributed to the central processor facility, where all the station signals are correlated with each other. In this paper the signal processing aspects on system level will be presented mainly for the astronomical application.
{"title":"Signal Processing Aspects of the Low Frequency Array","authors":"A. Gunst, M. Bentum","doi":"10.1109/ICSPC.2007.4728390","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728390","url":null,"abstract":"In the Northern part of the Netherlands ASTRON is building the largest radio telescope in the world for low frequencies. The telescope is based on phased array principles and is known as the LOw Frequency ARray (LOFAR). LOFAR is optimized for detecting astronomical signals in the 30-80 MHz and 120-240 MHz frequency window. LOFAR detects the incoming radio signals by using an array of simple omni-directional antennas. The antennas are grouped in so called stations mainly to reduce the amount of data generated. More than fifty stations will be built, mainly within a circle of 150 kilometres in diameter but also internationally. The signals of all the stations are distributed to the central processor facility, where all the station signals are correlated with each other. In this paper the signal processing aspects on system level will be presented mainly for the astronomical application.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132154052","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}
The present paper deals with blind identification of frequency selective communication channel. The problem of frequency selectivity is more encountered in mobile communication channel. In this manuscript, we have considered two channels as the Proakis's `B' channel and the Macchi's channel, in order to identify these channel we propose an algorithm based on Higher Order Statistics (HOS). The simulation results in noisy environment and for different data input channel, demonstrate that the proposed method could estimate the phase and magnitude of these channels blindly and without any information about the input, except that the input excitation is i.i.d (Identically and Independent Distributed) and non-Gaussian.
{"title":"Blind Identification of Frequency Selective Channel using Higher Order Statistics","authors":"S. Safi, M. Frikel, M. M'Saad, A. Zeroual","doi":"10.1109/ICSPC.2007.4728283","DOIUrl":"https://doi.org/10.1109/ICSPC.2007.4728283","url":null,"abstract":"The present paper deals with blind identification of frequency selective communication channel. The problem of frequency selectivity is more encountered in mobile communication channel. In this manuscript, we have considered two channels as the Proakis's `B' channel and the Macchi's channel, in order to identify these channel we propose an algorithm based on Higher Order Statistics (HOS). The simulation results in noisy environment and for different data input channel, demonstrate that the proposed method could estimate the phase and magnitude of these channels blindly and without any information about the input, except that the input excitation is i.i.d (Identically and Independent Distributed) and non-Gaussian.","PeriodicalId":425397,"journal":{"name":"2007 IEEE International Conference on Signal Processing and Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125474584","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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