Pub Date : 2008-07-06DOI: 10.1109/SPAWC.2008.4641670
C. Gaie, M. Assaad, M. Muck, P. Duhamel
Nowadays, the emergence of many radio technologies has increased the research interest towards Radio Resources Management (RRM) in heterogeneous systems. In this context, we seek a distributed scheme for discrete resource allocation. The algorithm proposed should reduce computation and signalling overhead, compared to centralized optimization or distributed solutions based on Game Theory. Therefore, the solution proposed here consists in splitting the resource allocation problem into two parts. First, Users and Base Stations negotiate a mean allocation using a Multisystem Minimum Mean Rate Scheduling (M3RS) algorithm presented here. Then, Base Stations allocate power independantly and instantaneously in order to cope with changing radio conditions. This problem is widely known in literature and is not developped here.
{"title":"Distributed discrete resource optimization in heterogeneous networks","authors":"C. Gaie, M. Assaad, M. Muck, P. Duhamel","doi":"10.1109/SPAWC.2008.4641670","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641670","url":null,"abstract":"Nowadays, the emergence of many radio technologies has increased the research interest towards Radio Resources Management (RRM) in heterogeneous systems. In this context, we seek a distributed scheme for discrete resource allocation. The algorithm proposed should reduce computation and signalling overhead, compared to centralized optimization or distributed solutions based on Game Theory. Therefore, the solution proposed here consists in splitting the resource allocation problem into two parts. First, Users and Base Stations negotiate a mean allocation using a Multisystem Minimum Mean Rate Scheduling (M3RS) algorithm presented here. Then, Base Stations allocate power independantly and instantaneously in order to cope with changing radio conditions. This problem is widely known in literature and is not developped here.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125948143","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641582
V.V. do Nascimento, J. Portugheis, D.C. da Cunha
This paper presents a study about q-ary product turbo codes applied to FFH-CDMA systems. A method to implement the q-ary soft decoding is proposed. First, an adaptation of Chase decoding algorithm to satisfy q-ary symbols requirements is developed. The adaptation does not significantly increase decoding complexity when compared to the binary algorithm. Second, a modification of iterative (turbo) decoding allows appropriate feedback of decoded q-ary symbols and their reliabilities in each decoder iteration. Simulation results indicate a good performance/complexity trade-off of the q-ary turbo coded system when compared to other previous proposed systems.
{"title":"Iterative decoding of q-ary product turbo codes in FFH-CDMA systems","authors":"V.V. do Nascimento, J. Portugheis, D.C. da Cunha","doi":"10.1109/SPAWC.2008.4641582","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641582","url":null,"abstract":"This paper presents a study about q-ary product turbo codes applied to FFH-CDMA systems. A method to implement the q-ary soft decoding is proposed. First, an adaptation of Chase decoding algorithm to satisfy q-ary symbols requirements is developed. The adaptation does not significantly increase decoding complexity when compared to the binary algorithm. Second, a modification of iterative (turbo) decoding allows appropriate feedback of decoded q-ary symbols and their reliabilities in each decoder iteration. Simulation results indicate a good performance/complexity trade-off of the q-ary turbo coded system when compared to other previous proposed systems.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129491657","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641585
T. Ferreira, S. L. Netto, P. Diniz
This work presents a new version, with reduced computational complexity, of the covariance-based direction-of-arrival (CB-DoA) algorithm. The new algorithm incorporates the concept of beamspace projection before performing the DoA estimation. Such modification reduces the dimensions of the matrices employed by the elements pace CB-DoA, simplifying the resulting computations while preserving the detectability of the original algorithm. The Beamspace CB-DoA algorithm is compared to the traditional algorithm Beamspace ESPRIT, as well as to element space CB-DoA.
{"title":"Beamspace covariance-based DoA estimation","authors":"T. Ferreira, S. L. Netto, P. Diniz","doi":"10.1109/SPAWC.2008.4641585","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641585","url":null,"abstract":"This work presents a new version, with reduced computational complexity, of the covariance-based direction-of-arrival (CB-DoA) algorithm. The new algorithm incorporates the concept of beamspace projection before performing the DoA estimation. Such modification reduces the dimensions of the matrices employed by the elements pace CB-DoA, simplifying the resulting computations while preserving the detectability of the original algorithm. The Beamspace CB-DoA algorithm is compared to the traditional algorithm Beamspace ESPRIT, as well as to element space CB-DoA.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129586496","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641667
N. ul Hassan, M. Assaad
This paper studies the downlink multiuser multiple input multiple output-orthogonal frequency division multiple access (MIMO-OFDMA) system for margin adaptive multiuser eigenmode transmission (MET) with perfect channel state information at the transmitter. In margin adaptive objective, base station (BS) has to satisfy individual quality of service (QoS) constraints of the users subject to transmit power minimization. The solution is hard to achieve because multiple streams from different users on the same subcarrier cause inter-stream interference which forces the use of low complexity beamforming techniques and makes it a joint beamforming and resource allocation problem. We propose a sub-optimal two step solution which decouples beamforming from subcarrier and power allocation. First a reduced number of user groups are formed and then the problem is formulated as a convex optimization problem. Finally an efficient algorithm is developed which allocates subcarriers to these user groups. Simulation results reveal comparable performance with the hugely complex optimal solution.
{"title":"Margin adaptive resource allocation in downlink multiuser MIMO-OFDMA system with Multiuser Eigenmode transmission","authors":"N. ul Hassan, M. Assaad","doi":"10.1109/SPAWC.2008.4641667","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641667","url":null,"abstract":"This paper studies the downlink multiuser multiple input multiple output-orthogonal frequency division multiple access (MIMO-OFDMA) system for margin adaptive multiuser eigenmode transmission (MET) with perfect channel state information at the transmitter. In margin adaptive objective, base station (BS) has to satisfy individual quality of service (QoS) constraints of the users subject to transmit power minimization. The solution is hard to achieve because multiple streams from different users on the same subcarrier cause inter-stream interference which forces the use of low complexity beamforming techniques and makes it a joint beamforming and resource allocation problem. We propose a sub-optimal two step solution which decouples beamforming from subcarrier and power allocation. First a reduced number of user groups are formed and then the problem is formulated as a convex optimization problem. Finally an efficient algorithm is developed which allocates subcarriers to these user groups. Simulation results reveal comparable performance with the hugely complex optimal solution.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130415314","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641656
J. A. Apolinário, M. D. De Campos
This paper introduces a constrained version of a recently proposed generalized data windowing scheme applied to the conjugate gradient algorithm. This scheme combines two types of data windowing, the finite-data sliding window and the exponentially weighted data window, in an attempt to attain the best of both methods in a linearly constrained scenario. The proposed algorithm was tested in a simple adaptive beamforming application, where the expected better performance was demonstrated.
{"title":"The constrained generalized data windowing conjugate gradient algorithm","authors":"J. A. Apolinário, M. D. De Campos","doi":"10.1109/SPAWC.2008.4641656","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641656","url":null,"abstract":"This paper introduces a constrained version of a recently proposed generalized data windowing scheme applied to the conjugate gradient algorithm. This scheme combines two types of data windowing, the finite-data sliding window and the exponentially weighted data window, in an attempt to attain the best of both methods in a linearly constrained scenario. The proposed algorithm was tested in a simple adaptive beamforming application, where the expected better performance was demonstrated.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125357991","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641570
J. M. Paredes, B. Khalaj, A. Gershman
Recently, distributed space-time coding over half duplex wireless relay networks has been proposed to achieve higher diversity at the receiver. The use of orthogonal and quasi-orthogonal designs in such relay networks has the advantage of providing maximum diversity at a low decoding complexity. However, similar to their originating space-time codes, these designs are restricted in terms of rate and number of relays. In order to alleviate such restrictions, we propose an extension of group-coherent codes (GCCs) to wireless relay networks. As will be shown, with a very limited amount of feedback from receiver to the relays, it is possible to achieve a distributed code that is applicable for any number of relays without an additional rate loss. In addition, our approach offers the advantages of linear ML decoding complexity, maximum diversity, lower delay, and increased power gain. We further show that it is possible to improve the performance at the price of a higher feedback rate. Finally, the robustness of our scheme against node failures is verified.
{"title":"Using orthogonal designswith feedback in wireless relay networks","authors":"J. M. Paredes, B. Khalaj, A. Gershman","doi":"10.1109/SPAWC.2008.4641570","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641570","url":null,"abstract":"Recently, distributed space-time coding over half duplex wireless relay networks has been proposed to achieve higher diversity at the receiver. The use of orthogonal and quasi-orthogonal designs in such relay networks has the advantage of providing maximum diversity at a low decoding complexity. However, similar to their originating space-time codes, these designs are restricted in terms of rate and number of relays. In order to alleviate such restrictions, we propose an extension of group-coherent codes (GCCs) to wireless relay networks. As will be shown, with a very limited amount of feedback from receiver to the relays, it is possible to achieve a distributed code that is applicable for any number of relays without an additional rate loss. In addition, our approach offers the advantages of linear ML decoding complexity, maximum diversity, lower delay, and increased power gain. We further show that it is possible to improve the performance at the price of a higher feedback rate. Finally, the robustness of our scheme against node failures is verified.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"55 33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116208852","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641604
D. B. Haddad, M. R. Petraglia, P. B. Batalheiro
Blind source separation methods resort to very weak hypothesis concerning the source signals, as well as the mixing matrix. This paper verifies experimentally the performance improvement in two different source separation algorithms when some statistical knowledge about the mixing matrix is used. A natural way of inserting such information in source separation methods is to put them in a Bayesian framework. This approach presents immediate applications in digital communication and speech signal processing systems, among many others.
{"title":"Performance evaluation of two semi-blind source separation methods","authors":"D. B. Haddad, M. R. Petraglia, P. B. Batalheiro","doi":"10.1109/SPAWC.2008.4641604","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641604","url":null,"abstract":"Blind source separation methods resort to very weak hypothesis concerning the source signals, as well as the mixing matrix. This paper verifies experimentally the performance improvement in two different source separation algorithms when some statistical knowledge about the mixing matrix is used. A natural way of inserting such information in source separation methods is to put them in a Bayesian framework. This approach presents immediate applications in digital communication and speech signal processing systems, among many others.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121255132","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641608
Waleed A. Saif, M. Ghogho, D. McLernon
In recent years node localization in wireless sensor networks (WSNs) has attracted much attention due to the increase of usage and applications of WSNs. Many algorithms and techniques for locating sensor nodes have been proposed in the literature. A recent algorithm, which is based on a given set of pairwise distance estimates among nodes and the target, generates a map of node locations. This algorithm, known as FastMap, uses projections onto orthogonal hyperplanes to find the coordinates successively. In this paper, we analytically study the performance of the FastMap algorithm for 2D positioning. Moreover a modified version of FastMap with better performance is proposed and analyzed. The analysis shows that the optimum anchor placement should be at the edge of the network.
{"title":"A modified fastmap algorithm for node localization in Wireless Sensor Networks","authors":"Waleed A. Saif, M. Ghogho, D. McLernon","doi":"10.1109/SPAWC.2008.4641608","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641608","url":null,"abstract":"In recent years node localization in wireless sensor networks (WSNs) has attracted much attention due to the increase of usage and applications of WSNs. Many algorithms and techniques for locating sensor nodes have been proposed in the literature. A recent algorithm, which is based on a given set of pairwise distance estimates among nodes and the target, generates a map of node locations. This algorithm, known as FastMap, uses projections onto orthogonal hyperplanes to find the coordinates successively. In this paper, we analytically study the performance of the FastMap algorithm for 2D positioning. Moreover a modified version of FastMap with better performance is proposed and analyzed. The analysis shows that the optimum anchor placement should be at the edge of the network.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122686556","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641680
C. Bordin, Marcelo G. S. Bruno
This article describes a new distributed blind equalization algorithm based on particle filters suitable for CDMA systems operating on frequency-selective channels. The proposed approach processes the signal received by multiple receivers in a non-centralized fashion, determining approximately optimal estimates (MAP) of the transmitted symbols, which minimizes the expected error rate. The described receiver structure dispenses with the need of a data fusion center, and is capable of operating either independently or in cooperation with other receivers. As we verified via numerical simulations, cooperative operation leads to a significant performance improvement, without substantially increasing the algorithmpsilas computational complexity.
{"title":"A new sequential Monte Carlo algorithm for distributed blind equalization","authors":"C. Bordin, Marcelo G. S. Bruno","doi":"10.1109/SPAWC.2008.4641680","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641680","url":null,"abstract":"This article describes a new distributed blind equalization algorithm based on particle filters suitable for CDMA systems operating on frequency-selective channels. The proposed approach processes the signal received by multiple receivers in a non-centralized fashion, determining approximately optimal estimates (MAP) of the transmitted symbols, which minimizes the expected error rate. The described receiver structure dispenses with the need of a data fusion center, and is capable of operating either independently or in cooperation with other receivers. As we verified via numerical simulations, cooperative operation leads to a significant performance improvement, without substantially increasing the algorithmpsilas computational complexity.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133210465","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 : 2008-07-06DOI: 10.1109/SPAWC.2008.4641640
A. Bouzegzi, P. Jallon, P. Ciblat
In the framework of cognitive radio, electro-magnetic environment sensing is a crucial task. In order to distinguish various systems relying on OFDM modulations from each others (such as WiMAX, WiFi, DVB-T), we need to be able to estimate precisely the inter-carrier spacing used in the transmitted signal. When the ratio between cyclic prefix and OFDM symbol duration is small or when the multipath propagation channel is almost as large as the cyclic prefix, standard approaches based on detection of cyclic prefix via an autocorrelation fall down. Therefore we propose a new algorithm to estimate the parameters of an OFDM modulated signal (especially the inter-carrier spacing) relying on the fourth order statistics of the received signal. We theoretically prove its robustness to multipath channels, time offset and frequency offset. Then its performance is analysed through numerical simulations and compared to standard approach which confirms the accuracy of the new algorithm.
{"title":"A fourth-order algorithm for blind characterization of OFDM signals","authors":"A. Bouzegzi, P. Jallon, P. Ciblat","doi":"10.1109/SPAWC.2008.4641640","DOIUrl":"https://doi.org/10.1109/SPAWC.2008.4641640","url":null,"abstract":"In the framework of cognitive radio, electro-magnetic environment sensing is a crucial task. In order to distinguish various systems relying on OFDM modulations from each others (such as WiMAX, WiFi, DVB-T), we need to be able to estimate precisely the inter-carrier spacing used in the transmitted signal. When the ratio between cyclic prefix and OFDM symbol duration is small or when the multipath propagation channel is almost as large as the cyclic prefix, standard approaches based on detection of cyclic prefix via an autocorrelation fall down. Therefore we propose a new algorithm to estimate the parameters of an OFDM modulated signal (especially the inter-carrier spacing) relying on the fourth order statistics of the received signal. We theoretically prove its robustness to multipath channels, time offset and frequency offset. Then its performance is analysed through numerical simulations and compared to standard approach which confirms the accuracy of the new algorithm.","PeriodicalId":197154,"journal":{"name":"2008 IEEE 9th Workshop on Signal Processing Advances in Wireless Communications","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134373906","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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