Pub Date : 2014-12-05DOI: 10.1109/GlobalSIP.2014.7032091
J. Gómez-Vilardebó
This paper considers the design of online power allocation strategies for slotted energy harvesting point-to-point communications systems. The objective is to minimize the competitive rate gap that is defined as the maximum gap between the optimal rates that can be achieved by the offline and online policies over all possible energy arrival profiles. A lower-bound on the competitive rate gap is derived and a new online policy is presented. The new online policy is shown to perform very close to the competitive rate gap lower-bound for any number of slots and to outperform previously proposed online policies, such us the myopic policy.
{"title":"Competitive design of power allocation strategies for energy harvesting wireless communication systems","authors":"J. Gómez-Vilardebó","doi":"10.1109/GlobalSIP.2014.7032091","DOIUrl":"https://doi.org/10.1109/GlobalSIP.2014.7032091","url":null,"abstract":"This paper considers the design of online power allocation strategies for slotted energy harvesting point-to-point communications systems. The objective is to minimize the competitive rate gap that is defined as the maximum gap between the optimal rates that can be achieved by the offline and online policies over all possible energy arrival profiles. A lower-bound on the competitive rate gap is derived and a new online policy is presented. The new online policy is shown to perform very close to the competitive rate gap lower-bound for any number of slots and to outperform previously proposed online policies, such us the myopic policy.","PeriodicalId":362306,"journal":{"name":"2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114473190","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 : 2014-12-03DOI: 10.1109/GlobalSIP.2014.7032317
G. Peters, T. A. Myrvoll, Tomoko Matsui, Ido Nevat, F. Septier
Copula models have started to be explored in wireless communications, however to date the properties they offer have not been proven or verified on real data experiments. In this paper we provide the first real evidence that the features they offer will provide beneficial modeling capabilities in wireless channel models, which are not just theoretically justified but practically observed. We demonstrate how to utilize the concept of copula modeling in wireless communications. In particular we show for the first time the existence of non-standard dependence features between multiple frequency bands in wireless fading channels using real observations. Classical approaches based on second order statistics are not able to detect such tail dependence features. To model this important feature we fit a mixture copula model based on members of the Archimedean family of copulas to real channel measurements. The channel measurements used in this work have been performed at the Barajas airport in Spain, in conjunction with the development of the AeroMACS system for airport surface communications. We give a physical interpretation on this phenomenon and discuss its impact on the design of wireless communication systems with regard to resource allocations.
{"title":"Communications meets copula modeling: Non-standard dependence features in wireless fading channels","authors":"G. Peters, T. A. Myrvoll, Tomoko Matsui, Ido Nevat, F. Septier","doi":"10.1109/GlobalSIP.2014.7032317","DOIUrl":"https://doi.org/10.1109/GlobalSIP.2014.7032317","url":null,"abstract":"Copula models have started to be explored in wireless communications, however to date the properties they offer have not been proven or verified on real data experiments. In this paper we provide the first real evidence that the features they offer will provide beneficial modeling capabilities in wireless channel models, which are not just theoretically justified but practically observed. We demonstrate how to utilize the concept of copula modeling in wireless communications. In particular we show for the first time the existence of non-standard dependence features between multiple frequency bands in wireless fading channels using real observations. Classical approaches based on second order statistics are not able to detect such tail dependence features. To model this important feature we fit a mixture copula model based on members of the Archimedean family of copulas to real channel measurements. The channel measurements used in this work have been performed at the Barajas airport in Spain, in conjunction with the development of the AeroMACS system for airport surface communications. We give a physical interpretation on this phenomenon and discuss its impact on the design of wireless communication systems with regard to resource allocations.","PeriodicalId":362306,"journal":{"name":"2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP)","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123174415","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 : 2014-12-03DOI: 10.1109/GlobalSIP.2014.7032116
M. J. Chaudhry, S. Narayanan, M. Renzo, F. Graziosi, Azhar Ul-Haq
Network coding designs over GF(q) spans an extensive range of research directions covering a wide range of applications. Galois field used for network coding should be a function of the total number of nodes in the networks. Thus, the larger the number of sources and relays the larger the Galois field, while keeping the same diversity order in relay-aided transmission. Furthermore, the modulation order and the Galois field are the same and this solution introduces a constraint on achievable rate and decoding complexity as network code and modulation cannot be chosen independently. In order to overcome this important limitation, in this paper we propose a splitting based approach where network coding and modulation are not necessarily the same. Our results show that if the modulation order is smaller than the Galois field; we are still able to achieve the same diversity order with lower decoding complexity.
{"title":"Energy efficient and low complex wireless communication","authors":"M. J. Chaudhry, S. Narayanan, M. Renzo, F. Graziosi, Azhar Ul-Haq","doi":"10.1109/GlobalSIP.2014.7032116","DOIUrl":"https://doi.org/10.1109/GlobalSIP.2014.7032116","url":null,"abstract":"Network coding designs over GF(q) spans an extensive range of research directions covering a wide range of applications. Galois field used for network coding should be a function of the total number of nodes in the networks. Thus, the larger the number of sources and relays the larger the Galois field, while keeping the same diversity order in relay-aided transmission. Furthermore, the modulation order and the Galois field are the same and this solution introduces a constraint on achievable rate and decoding complexity as network code and modulation cannot be chosen independently. In order to overcome this important limitation, in this paper we propose a splitting based approach where network coding and modulation are not necessarily the same. Our results show that if the modulation order is smaller than the Galois field; we are still able to achieve the same diversity order with lower decoding complexity.","PeriodicalId":362306,"journal":{"name":"2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123291225","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 : 2014-12-03DOI: 10.1109/GlobalSIP.2014.7032310
A. Kalantari, S. Maleki, G. Zheng, S. Chatzinotas, B. Ottersten
Interference usually is an adverse phenomenon in wireless networks. However, the interference can potentially be used to boost the secrecy rate in wireless interference channels. This work studies the secrecy rate in a two-user interference network where unintended user may overhear one of the users, namely user 1. User 1 tunes its transmission power in order to maximize its secrecy rate as well as to maintain the quality of service at the other user's destination, user 2, while both user's power limits are considered. It is demonstrated that achieving a positive secrecy rate for user 1 only depends on the channel conditions and user 2's transmission power. Consequently, depending on the channel conditions, the exact threshold for user 2's transmission power which leads to a positive secrecy rate for user 1 is derived.
{"title":"Feasibility of positive secrecy rate in wiretap interference channels","authors":"A. Kalantari, S. Maleki, G. Zheng, S. Chatzinotas, B. Ottersten","doi":"10.1109/GlobalSIP.2014.7032310","DOIUrl":"https://doi.org/10.1109/GlobalSIP.2014.7032310","url":null,"abstract":"Interference usually is an adverse phenomenon in wireless networks. However, the interference can potentially be used to boost the secrecy rate in wireless interference channels. This work studies the secrecy rate in a two-user interference network where unintended user may overhear one of the users, namely user 1. User 1 tunes its transmission power in order to maximize its secrecy rate as well as to maintain the quality of service at the other user's destination, user 2, while both user's power limits are considered. It is demonstrated that achieving a positive secrecy rate for user 1 only depends on the channel conditions and user 2's transmission power. Consequently, depending on the channel conditions, the exact threshold for user 2's transmission power which leads to a positive secrecy rate for user 1 is derived.","PeriodicalId":362306,"journal":{"name":"2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124426688","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 : 2014-12-03DOI: 10.1109/GlobalSIP.2014.7032287
M. Abebe, T. Pouli, J. Kervec, M. Larabi
We present a new method for correcting over-exposed areas in images. The method takes advantage of the strong correlation between the RGB color channels and relies on the observation that in images the RGB components are often not over-exposed at the same position. Our solution operates on line profiles, making it ideally suited for hardware implementations. In addition to its low computational complexity, our method can accurately recover information in areas where one or two channels are over-exposed, while it reconstructs information in areas that are fully clipped. We show that our method outperforms previous algorithms through quantitative analysis and we demonstrate an important application of this type of solution in the context of high dynamic range image reconstruction.
{"title":"Correction of over-exposure using color channel correlations","authors":"M. Abebe, T. Pouli, J. Kervec, M. Larabi","doi":"10.1109/GlobalSIP.2014.7032287","DOIUrl":"https://doi.org/10.1109/GlobalSIP.2014.7032287","url":null,"abstract":"We present a new method for correcting over-exposed areas in images. The method takes advantage of the strong correlation between the RGB color channels and relies on the observation that in images the RGB components are often not over-exposed at the same position. Our solution operates on line profiles, making it ideally suited for hardware implementations. In addition to its low computational complexity, our method can accurately recover information in areas where one or two channels are over-exposed, while it reconstructs information in areas that are fully clipped. We show that our method outperforms previous algorithms through quantitative analysis and we demonstrate an important application of this type of solution in the context of high dynamic range image reconstruction.","PeriodicalId":362306,"journal":{"name":"2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122614062","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 : 2014-12-03DOI: 10.1109/GlobalSIP.2014.7032275
T. T. Dang, Azeddine Beghdadi, M. Larabi
The increasingly use of digital images in our daily life and the availability of powerful software for processing and editing images, open new challenges regarding illegal or unauthorized image manipulation. Thus, it becomes essential to authenticate digital copies, validate their content, and detect possible forgeries. In this paper, we focus on detection of a specific type of digital forgery, inpainting, where an object is removed using pixels coming from the same image. The problem of inpainting detection is investigated and an efficient and reliable detection method is proposed. The performance of the proposed method is demonstrated on several inpainted images using different inpainting techniques.
{"title":"Blind inpainting forgery detection","authors":"T. T. Dang, Azeddine Beghdadi, M. Larabi","doi":"10.1109/GlobalSIP.2014.7032275","DOIUrl":"https://doi.org/10.1109/GlobalSIP.2014.7032275","url":null,"abstract":"The increasingly use of digital images in our daily life and the availability of powerful software for processing and editing images, open new challenges regarding illegal or unauthorized image manipulation. Thus, it becomes essential to authenticate digital copies, validate their content, and detect possible forgeries. In this paper, we focus on detection of a specific type of digital forgery, inpainting, where an object is removed using pixels coming from the same image. The problem of inpainting detection is investigated and an efficient and reliable detection method is proposed. The performance of the proposed method is demonstrated on several inpainted images using different inpainting techniques.","PeriodicalId":362306,"journal":{"name":"2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126863674","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 : 2014-12-02DOI: 10.1109/GlobalSIP.2014.7032294
A. Gharanjik, K. Liolis, B. Shankar, B. Ottersten
Optical feeder links are an attractive alternative to the RF feeder links in satellite communications (SatCom). In this paper, we present initial results from an optical feeder link study. We discuss the architecture of a geostationary earth orbit (GEO) satellite system based on optical feeder links. To mitigate the effects of cloud coverage, which is the main availability-limiting factor, Optical Ground Station (OGS) diversity is employed. Moreover, a spatial multiplexing scheme is considered. Assuming an ON-OFF channel model, the number of required OGSs to ensure availability and throughput requirements is analyzed.
{"title":"Spatial multiplexing in optical feeder links for high throughput satellites","authors":"A. Gharanjik, K. Liolis, B. Shankar, B. Ottersten","doi":"10.1109/GlobalSIP.2014.7032294","DOIUrl":"https://doi.org/10.1109/GlobalSIP.2014.7032294","url":null,"abstract":"Optical feeder links are an attractive alternative to the RF feeder links in satellite communications (SatCom). In this paper, we present initial results from an optical feeder link study. We discuss the architecture of a geostationary earth orbit (GEO) satellite system based on optical feeder links. To mitigate the effects of cloud coverage, which is the main availability-limiting factor, Optical Ground Station (OGS) diversity is employed. Moreover, a spatial multiplexing scheme is considered. Assuming an ON-OFF channel model, the number of required OGSs to ensure availability and throughput requirements is analyzed.","PeriodicalId":362306,"journal":{"name":"2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP)","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123479770","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 : 2014-12-01DOI: 10.1109/GlobalSIP.2014.7032123
H. Al-Tous, I. Barhumi
An auction-based algorithm is proposed for subcarrier assignment for multiple users amplify and forward (AT) orthogonal frequency division multiple access (OFDMA) system aiming to maximize the fairness index. The proposed algorithm is based on one-shot auction, where each user submits bids for all subcarriers at once based on the Shapley value, a well-known cooperative-game theoretic concept. The user evaluates each subcarrier based on an estimate of the Shapley value using optimal power profiles at the source and relay nodes. The subcarriers are then allocated to the users based on the submitted bids using an iterative algorithm that aims to maximize the fairness index. The system throughput and fairness indices are used to evaluate the performance of the proposed algorithm. Numerical results are used to show the merits of the proposed algorithm.
{"title":"One-shot auction for resource allocation in AF-OFDMA systems","authors":"H. Al-Tous, I. Barhumi","doi":"10.1109/GlobalSIP.2014.7032123","DOIUrl":"https://doi.org/10.1109/GlobalSIP.2014.7032123","url":null,"abstract":"An auction-based algorithm is proposed for subcarrier assignment for multiple users amplify and forward (AT) orthogonal frequency division multiple access (OFDMA) system aiming to maximize the fairness index. The proposed algorithm is based on one-shot auction, where each user submits bids for all subcarriers at once based on the Shapley value, a well-known cooperative-game theoretic concept. The user evaluates each subcarrier based on an estimate of the Shapley value using optimal power profiles at the source and relay nodes. The subcarriers are then allocated to the users based on the submitted bids using an iterative algorithm that aims to maximize the fairness index. The system throughput and fairness indices are used to evaluate the performance of the proposed algorithm. Numerical results are used to show the merits of the proposed algorithm.","PeriodicalId":362306,"journal":{"name":"2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121049870","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 : 2014-12-01DOI: 10.1109/GlobalSIP.2014.7032201
Yi Han, Yan Chen, K. Liu
The success of time-reversal (TR) technique relies on the design of TR signature from the multi-path profile. In practice, the signature is of limited precision instead of being infinite due to the finite resolution in hardware. Such limited signature precision will degrade the TR focusing effect and thus the system performance. Although several works have been proposed to study the performance of TR system with one-bit signature, a general relation between the resolution of signature and the system performance has not been established to answer the question: how many bits are needed for TR systems to achieve desirable system performance? In the paper, we address the question by studying the TR system with limited signature precision. We derive theoretically the relationship between the received signal-to-interference-plus-noise ratio (SINR) and the quantization step. Through simulations, we find that for a typical TR system, 4-bit resolution for the signature is good enough to achieve good system performance.
{"title":"Time-reversal with limited signature precision: Tradeoff between complexity and performance","authors":"Yi Han, Yan Chen, K. Liu","doi":"10.1109/GlobalSIP.2014.7032201","DOIUrl":"https://doi.org/10.1109/GlobalSIP.2014.7032201","url":null,"abstract":"The success of time-reversal (TR) technique relies on the design of TR signature from the multi-path profile. In practice, the signature is of limited precision instead of being infinite due to the finite resolution in hardware. Such limited signature precision will degrade the TR focusing effect and thus the system performance. Although several works have been proposed to study the performance of TR system with one-bit signature, a general relation between the resolution of signature and the system performance has not been established to answer the question: how many bits are needed for TR systems to achieve desirable system performance? In the paper, we address the question by studying the TR system with limited signature precision. We derive theoretically the relationship between the received signal-to-interference-plus-noise ratio (SINR) and the quantization step. Through simulations, we find that for a typical TR system, 4-bit resolution for the signature is good enough to achieve good system performance.","PeriodicalId":362306,"journal":{"name":"2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127285488","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 : 2014-12-01DOI: 10.1109/GlobalSIP.2014.7032309
O. Awe, S. M. Naqvi, S. Lambotharan
The successful implementation of dynamic spectrum access in cognitive radio networks requires that the secondary user has an autonomous knowledge of the true status of the licensed user activities. This paper investigates and proposes a robust blind spectrum sensing technique that is based on the variational Bayesian learning for Gaussian mixture model framework for use in multi-antenna cognitive radio networks. The results obtained from the proposed scheme, averaged over 1000 Monte-Carlo simulations show that a probability of detection greater than 90% is achievable at the signal - to - noise ratio (SJVR) of -18 dB when the false alarm probability is kept at less than 10%. An interesting feature of the proposed scheme is its ability to determine the number of active licensed users.
{"title":"Variational Bayesian learning technique for spectrum sensing in cognitive radio networks","authors":"O. Awe, S. M. Naqvi, S. Lambotharan","doi":"10.1109/GlobalSIP.2014.7032309","DOIUrl":"https://doi.org/10.1109/GlobalSIP.2014.7032309","url":null,"abstract":"The successful implementation of dynamic spectrum access in cognitive radio networks requires that the secondary user has an autonomous knowledge of the true status of the licensed user activities. This paper investigates and proposes a robust blind spectrum sensing technique that is based on the variational Bayesian learning for Gaussian mixture model framework for use in multi-antenna cognitive radio networks. The results obtained from the proposed scheme, averaged over 1000 Monte-Carlo simulations show that a probability of detection greater than 90% is achievable at the signal - to - noise ratio (SJVR) of -18 dB when the false alarm probability is kept at less than 10%. An interesting feature of the proposed scheme is its ability to determine the number of active licensed users.","PeriodicalId":362306,"journal":{"name":"2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP)","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127492427","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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