Pub Date : 2008-12-30DOI: 10.1109/ISWCS.2008.4726130
J. Rodas, C. Escudero, D. Iglesia
Positioning systems are one of the multiple applications of the wireless sensor networks. These networks are very adequate in environments where other positioning technologies, as satellite systems, do not work. Bluetooth is a promising technology, since it is present in any kind of portable devices. By using the received signal strength indicator (RSSI) it is possible to make an estimation of the distance between a transmitter and a receiver. By using this information, it is possible to develop an algorithm that estimates positions, even with the bluetooth constraints when the RSSI is obtained. Our experimental results show that our algorithm, based on a particle filter, can achieve a good performance.
{"title":"Bayesian filtering for a bluetooth positioning system","authors":"J. Rodas, C. Escudero, D. Iglesia","doi":"10.1109/ISWCS.2008.4726130","DOIUrl":"https://doi.org/10.1109/ISWCS.2008.4726130","url":null,"abstract":"Positioning systems are one of the multiple applications of the wireless sensor networks. These networks are very adequate in environments where other positioning technologies, as satellite systems, do not work. Bluetooth is a promising technology, since it is present in any kind of portable devices. By using the received signal strength indicator (RSSI) it is possible to make an estimation of the distance between a transmitter and a receiver. By using this information, it is possible to develop an algorithm that estimates positions, even with the bluetooth constraints when the RSSI is obtained. Our experimental results show that our algorithm, based on a particle filter, can achieve a good performance.","PeriodicalId":158650,"journal":{"name":"2008 IEEE International Symposium on Wireless Communication Systems","volume":"264 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133850485","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 : 2008-12-30DOI: 10.1109/ISWCS.2008.4726151
M. I. Majid, M. Imran, R. Hoshyar
Spectrum allocation within the fixed unlicensed band affects performance of wireless networks. Fundamental limitations of spectral efficiency on capacity of wireless local area networks (WLANs) hence needs to be studied. Recently, it was shown that the performance can be increased when both non-overlapping and partially overlapping channels are used. Unlike previous studies, this is the first known attempt on analysis of information theoretic capacity for partially-overlapping channels, as characterized by IEEE 802.11b-type systems using a hyper-receiver. Using Marenko-Pastur law distribution, capacity is approximated for such systems. We implement this by proposing a novel channel model for our analysis. The results conform to Monte Carlo simulations, with an approximate mean error of less than 5%. Fundamental tradeoffs of channel interference and power gain are discussed. We further explore the effect of access point density and find that systems based on partially overlapping channels perform well in high density deployments. We also compute capacity for a range of channel overlaps and conclude that rates close to capacity are achievable for a channel overlap of 90% and above.
{"title":"Analyzing uplink capacity of partially overlapping channel based WLANs using a hyper-receiver","authors":"M. I. Majid, M. Imran, R. Hoshyar","doi":"10.1109/ISWCS.2008.4726151","DOIUrl":"https://doi.org/10.1109/ISWCS.2008.4726151","url":null,"abstract":"Spectrum allocation within the fixed unlicensed band affects performance of wireless networks. Fundamental limitations of spectral efficiency on capacity of wireless local area networks (WLANs) hence needs to be studied. Recently, it was shown that the performance can be increased when both non-overlapping and partially overlapping channels are used. Unlike previous studies, this is the first known attempt on analysis of information theoretic capacity for partially-overlapping channels, as characterized by IEEE 802.11b-type systems using a hyper-receiver. Using Marenko-Pastur law distribution, capacity is approximated for such systems. We implement this by proposing a novel channel model for our analysis. The results conform to Monte Carlo simulations, with an approximate mean error of less than 5%. Fundamental tradeoffs of channel interference and power gain are discussed. We further explore the effect of access point density and find that systems based on partially overlapping channels perform well in high density deployments. We also compute capacity for a range of channel overlaps and conclude that rates close to capacity are achievable for a channel overlap of 90% and above.","PeriodicalId":158650,"journal":{"name":"2008 IEEE International Symposium on Wireless Communication Systems","volume":"253 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134500252","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 : 2008-12-30DOI: 10.1109/ISWCS.2008.4726129
Zhe Yang, A. Mohammed
In this paper, we investigate the performance of using high altitude platforms (HAPs) for low power wireless sensor network (WSN) applications. In our study, HAPs are employed to replace the sink usually deployed on the ground and collect data from sensor nodes. Two scenarios of employing the HAP as the sink in the WSN are established. Multiple sensor nodes are organized in an ad-hoc manner or in a cluster fashion. Due to the advantages of HAP systems, integrating HAPs into WSN can efficiently extend the deployment coverage area of WSN and reduce complexity of the WSN structure. Simulation results show that HAPs can be effectively employed to provide communications for WSNs.
{"title":"High Altitude Platforms for Wireless Sensor Network applications","authors":"Zhe Yang, A. Mohammed","doi":"10.1109/ISWCS.2008.4726129","DOIUrl":"https://doi.org/10.1109/ISWCS.2008.4726129","url":null,"abstract":"In this paper, we investigate the performance of using high altitude platforms (HAPs) for low power wireless sensor network (WSN) applications. In our study, HAPs are employed to replace the sink usually deployed on the ground and collect data from sensor nodes. Two scenarios of employing the HAP as the sink in the WSN are established. Multiple sensor nodes are organized in an ad-hoc manner or in a cluster fashion. Due to the advantages of HAP systems, integrating HAPs into WSN can efficiently extend the deployment coverage area of WSN and reduce complexity of the WSN structure. Simulation results show that HAPs can be effectively employed to provide communications for WSNs.","PeriodicalId":158650,"journal":{"name":"2008 IEEE International Symposium on Wireless Communication Systems","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134329694","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 : 2008-12-30DOI: 10.1109/ISWCS.2008.4726099
Matthias Hesse, J. Lebrun, L. Deneire
In this paper, we introduce further our recently designed family of L2 orthogonal space-time codes for CPM. With their advantage of maintaining both the constant envelope properties of CPM, the diversity of Space-Time codes and moreover orthogonality, and thus reduced decoding complexity, these codes are also full rate, even for more than two transmitting antennas. The issue of power efficiency for these codes is first dealt with by proving that the inherent increase in bandwidth in these systems is quite moderate. It is then detailed how the initial state of the code influences the coding gain and has to be optimized. For the two and three antennas case, we determine the optimal values by computer simulations and show how the coding gain and therewith the bit error performance are significantly improved by this optimization.
{"title":"Optimized L2-orthogonal STC CPM for 3 antennas","authors":"Matthias Hesse, J. Lebrun, L. Deneire","doi":"10.1109/ISWCS.2008.4726099","DOIUrl":"https://doi.org/10.1109/ISWCS.2008.4726099","url":null,"abstract":"In this paper, we introduce further our recently designed family of L2 orthogonal space-time codes for CPM. With their advantage of maintaining both the constant envelope properties of CPM, the diversity of Space-Time codes and moreover orthogonality, and thus reduced decoding complexity, these codes are also full rate, even for more than two transmitting antennas. The issue of power efficiency for these codes is first dealt with by proving that the inherent increase in bandwidth in these systems is quite moderate. It is then detailed how the initial state of the code influences the coding gain and has to be optimized. For the two and three antennas case, we determine the optimal values by computer simulations and show how the coding gain and therewith the bit error performance are significantly improved by this optimization.","PeriodicalId":158650,"journal":{"name":"2008 IEEE International Symposium on Wireless Communication Systems","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114464854","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 : 2008-12-30DOI: 10.1109/ISWCS.2008.4726113
M. Zahabi, V. Meghdadi, H. Meghdadi, J. Cances
A general method to develop Tanner graphs from tail-biting convolutional codes (CC) is proposed. Recursive systematic convolutional (RSC) and non-RSC codes are considered consistently and it is shown that the elimination of redundant states leads to a graph with low complexity. In addition the graphical representation is extended to derive the condition for which the tail-biting termination is valid. This analysis also leads to a unique graph applicable for decoding of both RSC and non-RSC codes. This graph is realized by exploiting the analog decoding scheme and MOS transistors. The circuit-level simulation is performed and the effect of important design parameters such as decoding latency, consumption and input dynamic range are considered.
{"title":"Analog decoding of tail-biting convolutional codes on graphs","authors":"M. Zahabi, V. Meghdadi, H. Meghdadi, J. Cances","doi":"10.1109/ISWCS.2008.4726113","DOIUrl":"https://doi.org/10.1109/ISWCS.2008.4726113","url":null,"abstract":"A general method to develop Tanner graphs from tail-biting convolutional codes (CC) is proposed. Recursive systematic convolutional (RSC) and non-RSC codes are considered consistently and it is shown that the elimination of redundant states leads to a graph with low complexity. In addition the graphical representation is extended to derive the condition for which the tail-biting termination is valid. This analysis also leads to a unique graph applicable for decoding of both RSC and non-RSC codes. This graph is realized by exploiting the analog decoding scheme and MOS transistors. The circuit-level simulation is performed and the effect of important design parameters such as decoding latency, consumption and input dynamic range are considered.","PeriodicalId":158650,"journal":{"name":"2008 IEEE International Symposium on Wireless Communication Systems","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128537724","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 : 2008-12-30DOI: 10.1109/ISWCS.2008.4726089
Zi-Tsan Chou, Ming-Luen Wu, Yu-Hsiang Lin, R. Jan
In an IEEE 802.11 ad hoc wireless LAN, the listen interval (LI) of a power-saving (PS) station should be fixed at one even there is no data traffic or its remaining battery power is low. However, if the value of LI is allowed more than two (in units of beacon interval), 802.11 power management may completely fail. In this paper, we propose a novel power management protocol, named OFPM, which not only equips a PS station with dynamic LI adjustment ability, but also conquers the following problems: (i) the possibly forever loss of ATIM frames, (ii) the waste of futile ATIM frames, and (iii) neighbor maintenance problem. Above all, OFPM has the following attractive features. (i) Given the maximum value of LI, Lmax, the number of tunable LIs is Lmax. (ii) For all LIs, the number of awake beacon intervals in an LI is minimal. (iii) The time complexity of OFPM neighbor maintenance is constant. (iv) By using our newly designed factor-hereditary quorum space technique, OFPM ensures that two PS neighbors can discover each other in finite time regardless of their offset and their individual LIs. (v) A closed-loop LI adjustment scheme is proposed such that a PS station can adaptively adjust its LI according to flow timeliness requirements. Via analyses and simulations, we show that OFPM significantly outperforms AQEC, the most energy-conserving protocol to date, in terms of adaptiveness, futile ATIM-frame ratio, and energy throughput.
{"title":"Optimal fully adaptive power management protocols for IEEE 802.11 ad hoc wireless LANs","authors":"Zi-Tsan Chou, Ming-Luen Wu, Yu-Hsiang Lin, R. Jan","doi":"10.1109/ISWCS.2008.4726089","DOIUrl":"https://doi.org/10.1109/ISWCS.2008.4726089","url":null,"abstract":"In an IEEE 802.11 ad hoc wireless LAN, the listen interval (LI) of a power-saving (PS) station should be fixed at one even there is no data traffic or its remaining battery power is low. However, if the value of LI is allowed more than two (in units of beacon interval), 802.11 power management may completely fail. In this paper, we propose a novel power management protocol, named OFPM, which not only equips a PS station with dynamic LI adjustment ability, but also conquers the following problems: (i) the possibly forever loss of ATIM frames, (ii) the waste of futile ATIM frames, and (iii) neighbor maintenance problem. Above all, OFPM has the following attractive features. (i) Given the maximum value of LI, Lmax, the number of tunable LIs is Lmax. (ii) For all LIs, the number of awake beacon intervals in an LI is minimal. (iii) The time complexity of OFPM neighbor maintenance is constant. (iv) By using our newly designed factor-hereditary quorum space technique, OFPM ensures that two PS neighbors can discover each other in finite time regardless of their offset and their individual LIs. (v) A closed-loop LI adjustment scheme is proposed such that a PS station can adaptively adjust its LI according to flow timeliness requirements. Via analyses and simulations, we show that OFPM significantly outperforms AQEC, the most energy-conserving protocol to date, in terms of adaptiveness, futile ATIM-frame ratio, and energy throughput.","PeriodicalId":158650,"journal":{"name":"2008 IEEE International Symposium on Wireless Communication Systems","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121877514","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 : 2008-12-30DOI: 10.1109/ISWCS.2008.4726008
Chunhui Liu, R. Mathar
In practice only imperfect channel state information (CSI) is available at the transmitter due to noisy and time-varying channel. In this paper, we consider optimal bit loading for orthogonal frequency division multiplexing (OFDM) with imperfect CSI subject to channel estimation. The frame length comes in as an important control parameter, while soft channel estimation and the Cramer-Rao bound are used to include the effect of channel estimation. We modify the conventional water-filling to take the maximal allowed rate on each subcarrier into account while considering CSI error. Its continuous output rates are optimally quantized by a non-iterative algorithm. Simulations show that the frame length is an important system parameter and that the computing time for the proposed algorithm linearly increases with the increasing number of subcarriers N.
{"title":"Optimal and efficient bit loading for OFDM in the presence of channel uncertainty","authors":"Chunhui Liu, R. Mathar","doi":"10.1109/ISWCS.2008.4726008","DOIUrl":"https://doi.org/10.1109/ISWCS.2008.4726008","url":null,"abstract":"In practice only imperfect channel state information (CSI) is available at the transmitter due to noisy and time-varying channel. In this paper, we consider optimal bit loading for orthogonal frequency division multiplexing (OFDM) with imperfect CSI subject to channel estimation. The frame length comes in as an important control parameter, while soft channel estimation and the Cramer-Rao bound are used to include the effect of channel estimation. We modify the conventional water-filling to take the maximal allowed rate on each subcarrier into account while considering CSI error. Its continuous output rates are optimally quantized by a non-iterative algorithm. Simulations show that the frame length is an important system parameter and that the computing time for the proposed algorithm linearly increases with the increasing number of subcarriers N.","PeriodicalId":158650,"journal":{"name":"2008 IEEE International Symposium on Wireless Communication Systems","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129508631","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 : 2008-12-30DOI: 10.1109/ISWCS.2008.4726080
Jing Wang, R. V. Prasad, I. Niemegeers
The booming multimedia applications are demanding multi-hop communications in high data rate millimeter wave radio WPANs (Wireless Personal Area Networks). However, unable to make use of space reuse, the IEEE 802.15.3 dependent piconet scheme shows its limit when the number of inter-connected piconet grows. In this paper, we introduce the concept of a bridging device - the via to setup multi-hop link across multiple piconets. A mini-superframe scheme, different switching strategies and a rendezvous scheme have been adopted and investigated. The simulation result shows this proposed approach has great potential to support the fast route discovery in high data rate multimedia applications.
{"title":"Enabling multi-hop on mmWave WPANs","authors":"Jing Wang, R. V. Prasad, I. Niemegeers","doi":"10.1109/ISWCS.2008.4726080","DOIUrl":"https://doi.org/10.1109/ISWCS.2008.4726080","url":null,"abstract":"The booming multimedia applications are demanding multi-hop communications in high data rate millimeter wave radio WPANs (Wireless Personal Area Networks). However, unable to make use of space reuse, the IEEE 802.15.3 dependent piconet scheme shows its limit when the number of inter-connected piconet grows. In this paper, we introduce the concept of a bridging device - the via to setup multi-hop link across multiple piconets. A mini-superframe scheme, different switching strategies and a rendezvous scheme have been adopted and investigated. The simulation result shows this proposed approach has great potential to support the fast route discovery in high data rate multimedia applications.","PeriodicalId":158650,"journal":{"name":"2008 IEEE International Symposium on Wireless Communication Systems","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129544192","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 : 2008-12-30DOI: 10.1109/ISWCS.2008.4726071
V. Jungnickel, T. Wirth, M. Schellmann, T. Haustein, W. Zirwas
We consider synchronization techniques required to enhance the cellular network capacity using base station cooperation. In the physical layer, local oscillators are disciplined by the global positioning system (GPS) and over the backbone network for outdoor and indoor base stations, respectively. In the medium access control (MAC) layer, the data flow can be synchronized by two approaches. The first approach uses so-called time stamps. The data flow through the user plane and through copies of it in each cooperative base station is synchronized using a timing protocol on the interconnects between the base stations. The second approach adds mapping information to the data after the user plane processing is almost finalized. Each forward-error encoded transport block, its modulation and coding scheme and the resources where it will be transmitted are multicast over the interconnect network. Interconnect latency is reduced below 1 ms to enable coherent interference reduction for mobile radio channels.
{"title":"Synchronization of cooperative base stations","authors":"V. Jungnickel, T. Wirth, M. Schellmann, T. Haustein, W. Zirwas","doi":"10.1109/ISWCS.2008.4726071","DOIUrl":"https://doi.org/10.1109/ISWCS.2008.4726071","url":null,"abstract":"We consider synchronization techniques required to enhance the cellular network capacity using base station cooperation. In the physical layer, local oscillators are disciplined by the global positioning system (GPS) and over the backbone network for outdoor and indoor base stations, respectively. In the medium access control (MAC) layer, the data flow can be synchronized by two approaches. The first approach uses so-called time stamps. The data flow through the user plane and through copies of it in each cooperative base station is synchronized using a timing protocol on the interconnects between the base stations. The second approach adds mapping information to the data after the user plane processing is almost finalized. Each forward-error encoded transport block, its modulation and coding scheme and the resources where it will be transmitted are multicast over the interconnect network. Interconnect latency is reduced below 1 ms to enable coherent interference reduction for mobile radio channels.","PeriodicalId":158650,"journal":{"name":"2008 IEEE International Symposium on Wireless Communication Systems","volume":"42 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120927324","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 : 2008-12-30DOI: 10.1109/ISWCS.2008.4726024
J. Prokopec, T. Fryza
The contribution describes a basic structure of the low rate wireless encoder and its application in domain of the video signal transmission. Also, the experimental results with real video sequences encoded by a three-dimensional discrete cosine transform coder will be presented. Finally, compress ratio and picture quality values will be published as well.
{"title":"Wireless transmission of video signal at very low bitrate","authors":"J. Prokopec, T. Fryza","doi":"10.1109/ISWCS.2008.4726024","DOIUrl":"https://doi.org/10.1109/ISWCS.2008.4726024","url":null,"abstract":"The contribution describes a basic structure of the low rate wireless encoder and its application in domain of the video signal transmission. Also, the experimental results with real video sequences encoded by a three-dimensional discrete cosine transform coder will be presented. Finally, compress ratio and picture quality values will be published as well.","PeriodicalId":158650,"journal":{"name":"2008 IEEE International Symposium on Wireless Communication Systems","volume":"214 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115502662","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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