This paper presents a study of the dynamic complexity of the Transmission Control Protocol (TCP) over mobile connections in the Universal Mobile Telecommunications System (UMTS) network. Using the concept of time-dependent exponent curves, the dynamic characteristics of TCP are studied and analysed from a simulation model of the UMTS network. Time-dependent exponent graphs have been used to test for chaotic behaviour in the traffic flow of wired communication networks. This paper fills the gap of studying the behavioural characteristics of TCP traffic flow inside the wireless UMTS network and additionally underlines the impact of this behaviour on the Quality of Service (QoS) offered by the network. An analysis of the results validates the existence of chaotic and random dynamics inside the traffic profile of the network. It is shown that in relation to traffic load, TCP exhibits from periodic to chaotic behaviour with relative levels of stochasticity. Based on these dynamics, it is shown that the occurrence of chaos, severely affects the QoS in the network.
{"title":"Dynamic Complexity of TCP in UMTS Networks and Performance Evaluation","authors":"I. Vasalos, R. Carrasco","doi":"10.1109/ICWMC.2008.63","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.63","url":null,"abstract":"This paper presents a study of the dynamic complexity of the Transmission Control Protocol (TCP) over mobile connections in the Universal Mobile Telecommunications System (UMTS) network. Using the concept of time-dependent exponent curves, the dynamic characteristics of TCP are studied and analysed from a simulation model of the UMTS network. Time-dependent exponent graphs have been used to test for chaotic behaviour in the traffic flow of wired communication networks. This paper fills the gap of studying the behavioural characteristics of TCP traffic flow inside the wireless UMTS network and additionally underlines the impact of this behaviour on the Quality of Service (QoS) offered by the network. An analysis of the results validates the existence of chaotic and random dynamics inside the traffic profile of the network. It is shown that in relation to traffic load, TCP exhibits from periodic to chaotic behaviour with relative levels of stochasticity. Based on these dynamics, it is shown that the occurrence of chaos, severely affects the QoS in the network.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121711451","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}
First, this paper describes a prediction of Rice factor (K factor) estimation for a high altitude platforms (HAPs) wireless channel. Estimation is based on experimental data which was collected from an object floating above the ground and carrying transmitter apparatus to perform as a HAPs. This experiment is intended to study multipath channel behaviour represented by K value for a wireless communication using HAPs. We use moment-based method estimator to characterize HAPs-channel in a wide interval of elevation angle. Secondly, the performance of WiMAX (IEEE802.16e) high speed transmission is simulated over the predicted HAPs channel. It is also shown how Doppler effect and K factor which is governed by elevation angle can contribute to the performance. We found that WiMAX services, which require high level requirement, fail to achieve an acceptable performance over HAPs channel if the elevation angle is lower than 40 degrees.
{"title":"Performance Evaluation of Broadband WiMAX Services over High Altitude Platforms (HAPs) Communication Channel","authors":"Iskandar, D.R. Putro","doi":"10.1109/ICWMC.2008.20","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.20","url":null,"abstract":"First, this paper describes a prediction of Rice factor (K factor) estimation for a high altitude platforms (HAPs) wireless channel. Estimation is based on experimental data which was collected from an object floating above the ground and carrying transmitter apparatus to perform as a HAPs. This experiment is intended to study multipath channel behaviour represented by K value for a wireless communication using HAPs. We use moment-based method estimator to characterize HAPs-channel in a wide interval of elevation angle. Secondly, the performance of WiMAX (IEEE802.16e) high speed transmission is simulated over the predicted HAPs channel. It is also shown how Doppler effect and K factor which is governed by elevation angle can contribute to the performance. We found that WiMAX services, which require high level requirement, fail to achieve an acceptable performance over HAPs channel if the elevation angle is lower than 40 degrees.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128356614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The anonymous mechanism of existing anonymous routing protocols in ad hoc networks significantly degraded their routing performances. To resolve the problem, this paper proposes a hierarchical pseudonym-based signature scheme and a self-generated pseudonym system based on the former. The signature scheme can be easily used to construct pseudonym system and non-interactively update private decryption keys. The self-generated pseudonym system features with following eminent characteristics: a node creates legal pseudonyms itself without participation of organization management center; there is unique pseudonym to be generated during the same period; the pseudonyms cannot be used up; nodes can independently authenticate each other with attaching less bytes than zero-knowledge protocol in classical pseudonym systems.
{"title":"Hierarchical Pseudonym-Based Signature Scheme and Self-Generated Pseudonym System in Ad Hoc Networks","authors":"Xiaojun Dang, Yang Zhang","doi":"10.1109/ICWMC.2008.19","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.19","url":null,"abstract":"The anonymous mechanism of existing anonymous routing protocols in ad hoc networks significantly degraded their routing performances. To resolve the problem, this paper proposes a hierarchical pseudonym-based signature scheme and a self-generated pseudonym system based on the former. The signature scheme can be easily used to construct pseudonym system and non-interactively update private decryption keys. The self-generated pseudonym system features with following eminent characteristics: a node creates legal pseudonyms itself without participation of organization management center; there is unique pseudonym to be generated during the same period; the pseudonyms cannot be used up; nodes can independently authenticate each other with attaching less bytes than zero-knowledge protocol in classical pseudonym systems.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130598224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sensor networks specifications are highly dependent on the application defined for the network. In this paper we tried to achieve adaptive method for decreasing over-covered areas using a simple selection algorithm in order to cover the desired percentage using a minimum number of active sensors and thus achieving to a higher life time for the whole network. The main advantage of this sensor-based algorithm is its selections that do not need a centralized coordination and thus increase the independence of each node from the whole network. In addition the networkpsilas robustness is increased and it becomes more resistant to unpredictable problems and network can adapt itself to different situations. Another advantage of the algorithm is that it does not need any sensor to locate the geographic location of each node. This algorithm leads finally to the possibility of more application and better usage of a presented wireless sensor network.
{"title":"Adaptive Method for Decreasing Over-covered Areas in Wireless Sensor Networks","authors":"M. Negahdar, M. Ardebilipour, M. Mapar","doi":"10.1109/ICWMC.2008.73","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.73","url":null,"abstract":"Sensor networks specifications are highly dependent on the application defined for the network. In this paper we tried to achieve adaptive method for decreasing over-covered areas using a simple selection algorithm in order to cover the desired percentage using a minimum number of active sensors and thus achieving to a higher life time for the whole network. The main advantage of this sensor-based algorithm is its selections that do not need a centralized coordination and thus increase the independence of each node from the whole network. In addition the networkpsilas robustness is increased and it becomes more resistant to unpredictable problems and network can adapt itself to different situations. Another advantage of the algorithm is that it does not need any sensor to locate the geographic location of each node. This algorithm leads finally to the possibility of more application and better usage of a presented wireless sensor network.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120960088","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}
While wireless LAN (WLAN) is very popular now a days, its performance deteriorates in the presence of other signals like Bluetooth (BT) signal that operate in the same band as WLAN. Present interference mitigation techniques in WLAN due to BT cancel interference in WLAN sub carrier where BT has hopped but do not cancel interference in the adjacent sub carriers. In this paper BT interference signal in all the OFDM sub carriers is estimated. That is, leakage of BT in other sub carriers including the sub carriers in which it has hopped is also measured. BT signals are estimated using the training signals of OFDM system. Simulation results in AWGN noise show that proposed algorithm agrees closely with theoretical results.
{"title":"Estimation of BT Interference in OFDM Sub Carriers with Training Signals","authors":"M. Roy, H. Jamadagni","doi":"10.1109/ICWMC.2008.11","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.11","url":null,"abstract":"While wireless LAN (WLAN) is very popular now a days, its performance deteriorates in the presence of other signals like Bluetooth (BT) signal that operate in the same band as WLAN. Present interference mitigation techniques in WLAN due to BT cancel interference in WLAN sub carrier where BT has hopped but do not cancel interference in the adjacent sub carriers. In this paper BT interference signal in all the OFDM sub carriers is estimated. That is, leakage of BT in other sub carriers including the sub carriers in which it has hopped is also measured. BT signals are estimated using the training signals of OFDM system. Simulation results in AWGN noise show that proposed algorithm agrees closely with theoretical results.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"41 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129703553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the bit error rate (BER) performance of conventional discrete Fourier transform (DFT) - OFDM system is compared with discrete wavelet transform (DWT)-OFDM system and discrete cosine transform (DCT)-OFDM system in an AWGN environment. Several wavelets such as Haar, Daubechie and Symlet are considered. We give the performance with two modulation format such as BPSK and QPSK. Simulation results show that Haar wavelet based scheme yields the lowest average bit error probability and the performance of DFT-OFDM and DWT (Haar)-OFDM with QPSK is better than BPSK modulation format.
{"title":"Performance Analysis of DFT-OFDM, DCT-OFDM, and DWT-OFDM Systems in AWGN Channel","authors":"D. Gupta, Torry Harris, Kamal K. Garg","doi":"10.1109/ICWMC.2008.66","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.66","url":null,"abstract":"In this paper, the bit error rate (BER) performance of conventional discrete Fourier transform (DFT) - OFDM system is compared with discrete wavelet transform (DWT)-OFDM system and discrete cosine transform (DCT)-OFDM system in an AWGN environment. Several wavelets such as Haar, Daubechie and Symlet are considered. We give the performance with two modulation format such as BPSK and QPSK. Simulation results show that Haar wavelet based scheme yields the lowest average bit error probability and the performance of DFT-OFDM and DWT (Haar)-OFDM with QPSK is better than BPSK modulation format.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116440076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The evolution of wireless sensor networks continues through the arrival of the Java development environment. More intuitive to a wider range of developers, and incorporating more powerful hardware; a number of residual research problems facing designers of wireless sensor networks have been addressed. The objective of this paper is to introduce and provide some exposure to the latest development environment available for wireless sensor networking, illustrate what achievements have already been made, and their immediate impact in the field. In particular, the problem of securing a potential deployment has been one of the major inhibitors to the widespread implementation of sensor networks; a problem which has been thoroughly addressed in the design of the Sun platform. This solution comes in the guise of a fully implemented and operational public key infrastructure. This paper critiques the security services provided; whilst considering current knowledge pertaining to the security of wireless sensor networks, in conjunction with the advantages of such a system and the opportunities it provides.
{"title":"The Impact of Java and Public Key Cryptography in Wireless Sensor Networking","authors":"D. Boyle, T. Newe","doi":"10.1109/ICWMC.2008.64","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.64","url":null,"abstract":"The evolution of wireless sensor networks continues through the arrival of the Java development environment. More intuitive to a wider range of developers, and incorporating more powerful hardware; a number of residual research problems facing designers of wireless sensor networks have been addressed. The objective of this paper is to introduce and provide some exposure to the latest development environment available for wireless sensor networking, illustrate what achievements have already been made, and their immediate impact in the field. In particular, the problem of securing a potential deployment has been one of the major inhibitors to the widespread implementation of sensor networks; a problem which has been thoroughly addressed in the design of the Sun platform. This solution comes in the guise of a fully implemented and operational public key infrastructure. This paper critiques the security services provided; whilst considering current knowledge pertaining to the security of wireless sensor networks, in conjunction with the advantages of such a system and the opportunities it provides.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134646268","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 we propose and assess the performance of virtual MIMO or relay-assisted cooperative schemes designed for the UL OFDMA based systems. We consider the use of an antenna array at the base station and a single antenna at both the mobile terminal and relay. The proposed cooperative schemes emulate a MIMO channel with 2 transmit and M receive antennas. Two types of relays are considered: amplify-and-forward and selective decode-and-forward. We derive the instantaneous normalized capacities and both the outage capacities and bit error rate are compared against the non-cooperative SISO and SIMO systems, considering different scenarios. The proposed relay-assisted schemes are suited for existing and for the future broadband wireless systems to increase the system capacity and coverage.
{"title":"Performance Evaluation of Virtual MIMO Schemes for the UL OFDMA Based Systems","authors":"A. Moço, S. Teodoro, A. Silva, A. Gameiro","doi":"10.1109/ICWMC.2008.61","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.61","url":null,"abstract":"In this paper we propose and assess the performance of virtual MIMO or relay-assisted cooperative schemes designed for the UL OFDMA based systems. We consider the use of an antenna array at the base station and a single antenna at both the mobile terminal and relay. The proposed cooperative schemes emulate a MIMO channel with 2 transmit and M receive antennas. Two types of relays are considered: amplify-and-forward and selective decode-and-forward. We derive the instantaneous normalized capacities and both the outage capacities and bit error rate are compared against the non-cooperative SISO and SIMO systems, considering different scenarios. The proposed relay-assisted schemes are suited for existing and for the future broadband wireless systems to increase the system capacity and coverage.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125869115","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 : 2008-07-27DOI: 10.1007/978-3-540-88011-0_14
L. D. Brito, L. Peralta
{"title":"Wireless Sensor Networks Applied to Museums' Environmental Monitoring","authors":"L. D. Brito, L. Peralta","doi":"10.1007/978-3-540-88011-0_14","DOIUrl":"https://doi.org/10.1007/978-3-540-88011-0_14","url":null,"abstract":"","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125878411","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 article presents a multi-column array and a beam forming circuit that produces two overlapping beams with high efficiency and adjustable beam patterns for wireless base station applications. The proposed antenna is an adjustable cylindrical sector array comprising of three separate columns of linear array. This structure allows forming of two overlapping beams with amplitude and phase excitations which can be implemented using a compact and low loss circuit. The adjustable offset displacement for the center column array allows refinement and adjustment of pattern characteristics of the two overlapping beams. This method results in beam split loss of less than 0.5 dB in comparison to a single beam case. Performance parameters such as the beam cross-over loss and pattern discrimination between beams can also be adjusted in-situ for optimum operation.
{"title":"Adjustable Dual Beam Wireless Base Station Antenna","authors":"S. Foo, B. Vassilakis","doi":"10.1109/ICWMC.2008.8","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.8","url":null,"abstract":"This article presents a multi-column array and a beam forming circuit that produces two overlapping beams with high efficiency and adjustable beam patterns for wireless base station applications. The proposed antenna is an adjustable cylindrical sector array comprising of three separate columns of linear array. This structure allows forming of two overlapping beams with amplitude and phase excitations which can be implemented using a compact and low loss circuit. The adjustable offset displacement for the center column array allows refinement and adjustment of pattern characteristics of the two overlapping beams. This method results in beam split loss of less than 0.5 dB in comparison to a single beam case. Performance parameters such as the beam cross-over loss and pattern discrimination between beams can also be adjusted in-situ for optimum operation.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123795585","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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