In the analysis of large random wireless ad hoc networks, the underlying node distribution is almost ubiquitously assumed to be the homogeneous Poisson point process. Despite the nice analytical properties of such model, the spatial randomness has been, however, mainly exploited for connectivity and interference analysis, but has not yet been taken into account explicitly in the scaling laws evaluation. We move here a first step toward the evaluation of an upper bound on the aggregate throughput when the additional randomness due to the spatial node distribution is taken into account, together with the presence of power attenuation and random phase changes. This could be seen as a first attempt to connect some overoptimistic results based on stochastic channel model to more realistic analysis, relying on electromagnetic propagation arguments.
{"title":"Scaling Laws for Large Ad-Hoc Wireless Networks with Wishart-Poisson Fading","authors":"G. Alfano, M. Guillaud, A. Tulino","doi":"10.1109/ISSSTA.2008.51","DOIUrl":"https://doi.org/10.1109/ISSSTA.2008.51","url":null,"abstract":"In the analysis of large random wireless ad hoc networks, the underlying node distribution is almost ubiquitously assumed to be the homogeneous Poisson point process. Despite the nice analytical properties of such model, the spatial randomness has been, however, mainly exploited for connectivity and interference analysis, but has not yet been taken into account explicitly in the scaling laws evaluation. We move here a first step toward the evaluation of an upper bound on the aggregate throughput when the additional randomness due to the spatial node distribution is taken into account, together with the presence of power attenuation and random phase changes. This could be seen as a first attempt to connect some overoptimistic results based on stochastic channel model to more realistic analysis, relying on electromagnetic propagation arguments.","PeriodicalId":334589,"journal":{"name":"2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122046889","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}
A. Molino, G. Girau, M. Nicola, M. Fantino, M. Pini
The first step of the digital processing within a Global Navigation Satellite System (GNSS) receiver is the signal acquisition. The receiver has to detect the satellites in view, and for each of them, has to estimate the Doppler shift and the code phase of the received signal. In order to speed up the acquisition process, modern receivers use fast acquisition technique based on the fast Fourier transform (FFT). This paper presents the complexity evaluation of a FFT-based acquisition technique, suitable for new GNSS signals and for both software and hardware implementations. After the description of the algorithm, the focus will be on the comparison of the results obtained with a Xilinx FPGA board and a software receiver implemented on a general-purpose processor.
{"title":"Evaluation of a FFT-Based Acquisition in Real Time Hardware and Software GNSS Receivers","authors":"A. Molino, G. Girau, M. Nicola, M. Fantino, M. Pini","doi":"10.1109/ISSSTA.2008.13","DOIUrl":"https://doi.org/10.1109/ISSSTA.2008.13","url":null,"abstract":"The first step of the digital processing within a Global Navigation Satellite System (GNSS) receiver is the signal acquisition. The receiver has to detect the satellites in view, and for each of them, has to estimate the Doppler shift and the code phase of the received signal. In order to speed up the acquisition process, modern receivers use fast acquisition technique based on the fast Fourier transform (FFT). This paper presents the complexity evaluation of a FFT-based acquisition technique, suitable for new GNSS signals and for both software and hardware implementations. After the description of the algorithm, the focus will be on the comparison of the results obtained with a Xilinx FPGA board and a software receiver implemented on a general-purpose processor.","PeriodicalId":334589,"journal":{"name":"2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130262619","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}
We consider minimum mean squared error (MSE) channel estimators operating on the basis of time-frequency signal observations comprising mixtures of known pilot and unknown data signals. These estimators are useful for a general class of receivers resorting to a time-frequency signal representation of the received signal - obtained by, e.g., a filter bank - which have recently been considered in the context of reconfigurable radio. Taking advantage of the Kronecker product properties we derive two-dimensional filter formulations for doubly-dispersive channel estimation, which afford implementations with moderate complexities. Rank reduction and the use of fast Fourier transform methods are shown to offer further complexity reductions. The different estimator variants are compared in terms of MSE performance and complexity.
{"title":"Efficient Two-Dimensional Filters for Doubly-Dispersive Channel Estimation in Time-Frequency Signal Processing","authors":"T. Hunziker, S. Stefanatos","doi":"10.1109/ISSSTA.2008.76","DOIUrl":"https://doi.org/10.1109/ISSSTA.2008.76","url":null,"abstract":"We consider minimum mean squared error (MSE) channel estimators operating on the basis of time-frequency signal observations comprising mixtures of known pilot and unknown data signals. These estimators are useful for a general class of receivers resorting to a time-frequency signal representation of the received signal - obtained by, e.g., a filter bank - which have recently been considered in the context of reconfigurable radio. Taking advantage of the Kronecker product properties we derive two-dimensional filter formulations for doubly-dispersive channel estimation, which afford implementations with moderate complexities. Rank reduction and the use of fast Fourier transform methods are shown to offer further complexity reductions. The different estimator variants are compared in terms of MSE performance and complexity.","PeriodicalId":334589,"journal":{"name":"2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121575172","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, flexible operation of an OFDM transceiver in a wireless environment is considered in the framework of the game theory. The intelligent control unit of the transceiver, playing the bit-and-power loading game against the radio channel is assumed to have limited, erroneous or obsolete channel state information. The strategies, utilities and payoffs of the game are defined. Simulation experiments show that the well-suited choice of the utility function, reflecting user's preferences for throughput maximization and the power economy has a near-optimum effect on bit rate and power consumption under the assumed bit-error probability and mean power constraints.
{"title":"Bit and Power Loading Game of the Flexible OFDM Transceiver in a Wireless Environment","authors":"H. Bogucka","doi":"10.1109/ISSSTA.2008.133","DOIUrl":"https://doi.org/10.1109/ISSSTA.2008.133","url":null,"abstract":"In this paper, flexible operation of an OFDM transceiver in a wireless environment is considered in the framework of the game theory. The intelligent control unit of the transceiver, playing the bit-and-power loading game against the radio channel is assumed to have limited, erroneous or obsolete channel state information. The strategies, utilities and payoffs of the game are defined. Simulation experiments show that the well-suited choice of the utility function, reflecting user's preferences for throughput maximization and the power economy has a near-optimum effect on bit rate and power consumption under the assumed bit-error probability and mean power constraints.","PeriodicalId":334589,"journal":{"name":"2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications","volume":"154 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127606377","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}
Code selection plays a prominent role in the performance of CDMA based communication systems. Codes are designed to have desirable autocorrelation and crosscorrelation properties. In this work, a new expression for autocorrelation is presented for delays within a chip period. Based on this expression, a new criterion is proposed for Code selection in quasi-synchronous CDMA communication. This criterion may be used to select a finite number of codes from a given codeset in quasi-synchronous environment. It is found that with the proposed criterion there is about 0.9 dB and 2 dB improvement in BER performance at synchronization errors of 0.1 Tc and 0.2 Tc respectively for WH codes of length 64, compared to random selection of codes. The analysis is limited to codes employing rectangular pulse shape.
{"title":"A Code Selection Criterion Based on Autocorrelation Properties for Quasi-Synchronous CDMA Communication System","authors":"S. Jos, P. Kumar, S. Chakrabarti","doi":"10.1109/ISSSTA.2008.35","DOIUrl":"https://doi.org/10.1109/ISSSTA.2008.35","url":null,"abstract":"Code selection plays a prominent role in the performance of CDMA based communication systems. Codes are designed to have desirable autocorrelation and crosscorrelation properties. In this work, a new expression for autocorrelation is presented for delays within a chip period. Based on this expression, a new criterion is proposed for Code selection in quasi-synchronous CDMA communication. This criterion may be used to select a finite number of codes from a given codeset in quasi-synchronous environment. It is found that with the proposed criterion there is about 0.9 dB and 2 dB improvement in BER performance at synchronization errors of 0.1 Tc and 0.2 Tc respectively for WH codes of length 64, compared to random selection of codes. The analysis is limited to codes employing rectangular pulse shape.","PeriodicalId":334589,"journal":{"name":"2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128087099","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 describes a full synchronization method for OFDM/OQAM and OFDM/QAM modulations utilizing frequency domain scattered pilots in the time domain. Most of the OFDM based standards provide this kind of known pilots mainly for channel estimation purposes. The time domain complex correlation results between the modulated received signal and the time representation of the scattered pilots sequence are successively exploited to perform first clock sampling and symbol synchronization, then frequency synchronization and finally frame synchronization (if specific attention is paid to scattered pilots definition). Correlation operation is optimized in complexity and is fragmented for a better robustness to frequency offsets. This full synchronization method brings really satisfactory performance and has already found an early application in the new DVB-T2 standard, for conventional OFDM modulation.
{"title":"Full Synchronization Method for OFDM/OQAM and OFDM/QAM Modulations","authors":"B. Jahan, M. Lanoiselée, G. Degoulet, R. Rabineau","doi":"10.1109/ISSSTA.2008.69","DOIUrl":"https://doi.org/10.1109/ISSSTA.2008.69","url":null,"abstract":"This paper describes a full synchronization method for OFDM/OQAM and OFDM/QAM modulations utilizing frequency domain scattered pilots in the time domain. Most of the OFDM based standards provide this kind of known pilots mainly for channel estimation purposes. The time domain complex correlation results between the modulated received signal and the time representation of the scattered pilots sequence are successively exploited to perform first clock sampling and symbol synchronization, then frequency synchronization and finally frame synchronization (if specific attention is paid to scattered pilots definition). Correlation operation is optimized in complexity and is fragmented for a better robustness to frequency offsets. This full synchronization method brings really satisfactory performance and has already found an early application in the new DVB-T2 standard, for conventional OFDM modulation.","PeriodicalId":334589,"journal":{"name":"2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications","volume":"162 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132781321","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 novel system which provides 3-axis orientation and 3D location estimation for a Mobile Device based on Time of Flight (ToF) and Angle of Arrival (AoA) measurements using ultrasonic signals. Robustness is provided to the system by means of a Slow Frequency-Hop Spread Spectrum modulation and a robust 2D AoA estimation method with a Uniform Circular Array (UCA). In simulation, the system shows an accuracy of 1.7 degrees in the orientation estimates and location estimates under 1 cm in 95% of cases under conditions of noise and reverberation.
{"title":"Ultrasonic Orientation-Location Algorithm Based on ToA and AoA Measurements","authors":"J. R. Gonzalez, C. Bleakley","doi":"10.1109/ISSSTA.2008.156","DOIUrl":"https://doi.org/10.1109/ISSSTA.2008.156","url":null,"abstract":"This paper proposes a novel system which provides 3-axis orientation and 3D location estimation for a Mobile Device based on Time of Flight (ToF) and Angle of Arrival (AoA) measurements using ultrasonic signals. Robustness is provided to the system by means of a Slow Frequency-Hop Spread Spectrum modulation and a robust 2D AoA estimation method with a Uniform Circular Array (UCA). In simulation, the system shows an accuracy of 1.7 degrees in the orientation estimates and location estimates under 1 cm in 95% of cases under conditions of noise and reverberation.","PeriodicalId":334589,"journal":{"name":"2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132907053","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}
Many systems exist (TOA, AOA, RSSI) that can be used with diverse technologies (ultrasounds, infrared, Bluetooth, 802,11...) for the indoor location. In this article we chose to apply TOA on a network ZigBee, to be able to add a useful functionality for other applications in an existing network and, in addition, presents characteristics of minimum consumption and low cost. The results that we obtain are promising, because we obtain a precision near the meter in 90% of the cases.
{"title":"Distance Estimation System Based on ZigBee","authors":"P. Corral, V. Almenar, A. de C. Lima","doi":"10.1109/ISSSTA.2008.159","DOIUrl":"https://doi.org/10.1109/ISSSTA.2008.159","url":null,"abstract":"Many systems exist (TOA, AOA, RSSI) that can be used with diverse technologies (ultrasounds, infrared, Bluetooth, 802,11...) for the indoor location. In this article we chose to apply TOA on a network ZigBee, to be able to add a useful functionality for other applications in an existing network and, in addition, presents characteristics of minimum consumption and low cost. The results that we obtain are promising, because we obtain a precision near the meter in 90% of the cases.","PeriodicalId":334589,"journal":{"name":"2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115355439","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}
We recall the principles of cyclic delay diversity (CDD) and discuss the properties and impact of this transmit antenna diversity technology. Different applications motivate variations of the CDD principle. This variants are briefly introduced and discussed. We show the application to several types of wireless systems, in particular terrestrial digital video broadcasting, cellular mobile radio communications systems and a wireless communications system using adaptive bit loading. Simulation results show the benefits of CDD for these kind of systems.
{"title":"Cyclic Delay Diversity - A Simple, Flexible and Effective Multi-Antenna Technology for OFDM","authors":"A. Dammann, S. Plass, S. Sand","doi":"10.1109/ISSSTA.2008.108","DOIUrl":"https://doi.org/10.1109/ISSSTA.2008.108","url":null,"abstract":"We recall the principles of cyclic delay diversity (CDD) and discuss the properties and impact of this transmit antenna diversity technology. Different applications motivate variations of the CDD principle. This variants are briefly introduced and discussed. We show the application to several types of wireless systems, in particular terrestrial digital video broadcasting, cellular mobile radio communications systems and a wireless communications system using adaptive bit loading. Simulation results show the benefits of CDD for these kind of systems.","PeriodicalId":334589,"journal":{"name":"2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115717227","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}
Gaussian distributed random signals are analyzed for encoding and spreading users' message sequences in code division multiple access systems (CDMA). Using theoretical analysis and practical implementation in DSP technology it has been shown that the random sequences generated from the Gaussian distribution can be efficiently used in this CDMA system. In this way the security of the message transmission is enhanced due to the random nature of all signals generated and used for users' message signal spreading and coding in this communication system. The signal processing blocks of the system, including the transmitter, receiver and the channel, are theoretically described. The expressions for the probability of error are derived for the case when the additive white Gaussian noise and fading are present in the channel. The system, including the transceiver and the channel, is implemented in DSP technology and the theoretical results are confirmed by measurements on the designed system. Moreover the acquisition phase of a synchronization block using Gaussian distributed random signals is also theoretically analyzed and implemented in DSP technology.
{"title":"Secure Communication in Asynchronous Noise Phase Shift Keying CDMA Systems","authors":"R. Vali, S. Berber","doi":"10.1109/ISSSTA.2008.104","DOIUrl":"https://doi.org/10.1109/ISSSTA.2008.104","url":null,"abstract":"Gaussian distributed random signals are analyzed for encoding and spreading users' message sequences in code division multiple access systems (CDMA). Using theoretical analysis and practical implementation in DSP technology it has been shown that the random sequences generated from the Gaussian distribution can be efficiently used in this CDMA system. In this way the security of the message transmission is enhanced due to the random nature of all signals generated and used for users' message signal spreading and coding in this communication system. The signal processing blocks of the system, including the transmitter, receiver and the channel, are theoretically described. The expressions for the probability of error are derived for the case when the additive white Gaussian noise and fading are present in the channel. The system, including the transceiver and the channel, is implemented in DSP technology and the theoretical results are confirmed by measurements on the designed system. Moreover the acquisition phase of a synchronization block using Gaussian distributed random signals is also theoretically analyzed and implemented in DSP technology.","PeriodicalId":334589,"journal":{"name":"2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115803430","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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