Pub Date : 2004-05-14DOI: 10.1109/WTS.2004.1319543
S. Jitapunkul, K. Wutthipornpong, J. Songthanasak, S. Kunaruttanapruk
MC-CDMA is an attractive technique for achieving transmission in fading channels in high data rate mobile communications. However, it requires a high quality amplifier to cope with the large amplitude fluctuation at the transmitter side. The partial transmit sequences (PTS) scheme is one of the best methods to reduce peak to average power ratio (PAPR). A modified PTS scheme for uplink communications is proposed, in contrast to the original PTS, which is generally applied in the downlink in an OFDM system. While successfully reducing PAPR, PTS alters the code correlation property which affects bit error rate when applied to the MC-CDMA system uplink. Therefore, modified receivers to deal with this problem are also proposed.
{"title":"Peak to average power ratio reduction in MC-CDMA using partial transmit sequences","authors":"S. Jitapunkul, K. Wutthipornpong, J. Songthanasak, S. Kunaruttanapruk","doi":"10.1109/WTS.2004.1319543","DOIUrl":"https://doi.org/10.1109/WTS.2004.1319543","url":null,"abstract":"MC-CDMA is an attractive technique for achieving transmission in fading channels in high data rate mobile communications. However, it requires a high quality amplifier to cope with the large amplitude fluctuation at the transmitter side. The partial transmit sequences (PTS) scheme is one of the best methods to reduce peak to average power ratio (PAPR). A modified PTS scheme for uplink communications is proposed, in contrast to the original PTS, which is generally applied in the downlink in an OFDM system. While successfully reducing PAPR, PTS alters the code correlation property which affects bit error rate when applied to the MC-CDMA system uplink. Therefore, modified receivers to deal with this problem are also proposed.","PeriodicalId":242981,"journal":{"name":"2004 Symposium on Wireless Telecommunications","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121376358","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 : 2004-05-14DOI: 10.1109/WTS.2004.1319557
V. Bhat, D. Khati
The mobility management schemes of current cellular systems (e.g., GSM) use spatially static location areas (LA). The mapping of cells to location areas is performed infrequently using heuristics and aggregate statistics and resulting location areas apply to all the mobile subscribers. As all the subscribers do not have the same mobility patterns, these static and globally applicable location areas are far from optimal. The paper introduces a timer based dynamic location management algorithm, which uses the mobility of an individual subscriber and a timer for the user's current cell to form individualized location areas dynamically. An activity based mobility model is used to evaluate the performance of the proposed algorithm and to compare it with dynamic location management with variable size location area (Ajit Pal and Digvijay Singh Khati, Int. Conf. on Computer Networks and Mobile Computing, 2001). According to simulation results, the proposed algorithm incurs significantly lower location management cost as compared to dynamic location management with variable size LA.
{"title":"Timer based dynamic location management","authors":"V. Bhat, D. Khati","doi":"10.1109/WTS.2004.1319557","DOIUrl":"https://doi.org/10.1109/WTS.2004.1319557","url":null,"abstract":"The mobility management schemes of current cellular systems (e.g., GSM) use spatially static location areas (LA). The mapping of cells to location areas is performed infrequently using heuristics and aggregate statistics and resulting location areas apply to all the mobile subscribers. As all the subscribers do not have the same mobility patterns, these static and globally applicable location areas are far from optimal. The paper introduces a timer based dynamic location management algorithm, which uses the mobility of an individual subscriber and a timer for the user's current cell to form individualized location areas dynamically. An activity based mobility model is used to evaluate the performance of the proposed algorithm and to compare it with dynamic location management with variable size location area (Ajit Pal and Digvijay Singh Khati, Int. Conf. on Computer Networks and Mobile Computing, 2001). According to simulation results, the proposed algorithm incurs significantly lower location management cost as compared to dynamic location management with variable size LA.","PeriodicalId":242981,"journal":{"name":"2004 Symposium on Wireless Telecommunications","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115272369","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 : 2004-05-14DOI: 10.1109/WTS.2004.1319575
C. Wullems, K. Tham, H. Smith, M. Looi
The paper describes a trivial, but highly effective, denial of service attack based on commonly available IEEE 802.11 hardware and freely available software. The attack requires limited resources and is inexpensive to mount. The paper discusses the attack, its implementation, and provides an analysis of methods to achieve optimal denial of service results. While there is currently no defense against this type of attack, the paper also discusses possibilities for attack mitigation.
{"title":"A trivial denial of service attack on IEEE 802.11 direct sequence spread spectrum wireless LANs","authors":"C. Wullems, K. Tham, H. Smith, M. Looi","doi":"10.1109/WTS.2004.1319575","DOIUrl":"https://doi.org/10.1109/WTS.2004.1319575","url":null,"abstract":"The paper describes a trivial, but highly effective, denial of service attack based on commonly available IEEE 802.11 hardware and freely available software. The attack requires limited resources and is inexpensive to mount. The paper discusses the attack, its implementation, and provides an analysis of methods to achieve optimal denial of service results. While there is currently no defense against this type of attack, the paper also discusses possibilities for attack mitigation.","PeriodicalId":242981,"journal":{"name":"2004 Symposium on Wireless Telecommunications","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125932343","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 : 2004-05-14DOI: 10.1109/WTS.2004.1319574
Y. M. Erten, E. Tomur
We investigate the security aspects of wireless local area networks and discuss the weaknesses associated with various conventional 802.11 security protocols such as WEP (wired equivalent privacy) and 802.1x. We propose an architecture to control access to corporate 802.11 wireless networks, based on the privileges and location of users, using tested wired network components such as VPNs and firewalls. The presented architecture reduces the security risks in enterprise level deployment of wireless LANs.
{"title":"A layered security architecture for corporate 802.11 wireless networks","authors":"Y. M. Erten, E. Tomur","doi":"10.1109/WTS.2004.1319574","DOIUrl":"https://doi.org/10.1109/WTS.2004.1319574","url":null,"abstract":"We investigate the security aspects of wireless local area networks and discuss the weaknesses associated with various conventional 802.11 security protocols such as WEP (wired equivalent privacy) and 802.1x. We propose an architecture to control access to corporate 802.11 wireless networks, based on the privileges and location of users, using tested wired network components such as VPNs and firewalls. The presented architecture reduces the security risks in enterprise level deployment of wireless LANs.","PeriodicalId":242981,"journal":{"name":"2004 Symposium on Wireless Telecommunications","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130898628","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 : 2004-05-14DOI: 10.1109/WTS.2004.1319558
Hong, Doan Hoang, Phuong Man, Mirchandani
The interpretation by transmission control protocol (TCP) of loss of linkage as loss due to congestion causes significant inefficiency in a wireless network. Congestion that often occurs in a wireless LAN results in further reduced performance. The paper introduces a method of controlling congestion in a network via a feedback mechanism called fair intelligent congestion control (FICC) which is useful for improving TCP performance in such a network. FICC overcomes the inefficiency of TCP in misinterpreting the link loss as congestion loss. Simulation testing has demonstrated that, by eliminating buffer overflows caused by congestion, FICC provides desirable fairness, reduces delay variation and improves effective throughput.
{"title":"Introducing feedback congestion control to a network with IEEE 802.11 wireless LAN","authors":"Hong, Doan Hoang, Phuong Man, Mirchandani","doi":"10.1109/WTS.2004.1319558","DOIUrl":"https://doi.org/10.1109/WTS.2004.1319558","url":null,"abstract":"The interpretation by transmission control protocol (TCP) of loss of linkage as loss due to congestion causes significant inefficiency in a wireless network. Congestion that often occurs in a wireless LAN results in further reduced performance. The paper introduces a method of controlling congestion in a network via a feedback mechanism called fair intelligent congestion control (FICC) which is useful for improving TCP performance in such a network. FICC overcomes the inefficiency of TCP in misinterpreting the link loss as congestion loss. Simulation testing has demonstrated that, by eliminating buffer overflows caused by congestion, FICC provides desirable fairness, reduces delay variation and improves effective throughput.","PeriodicalId":242981,"journal":{"name":"2004 Symposium on Wireless Telecommunications","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127206358","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 : 2004-05-14DOI: 10.1109/WTS.2004.1319553
P. Mani, D. Petr
We aim to modify an existing mobile ad-hoc network (MANET) reactive routing protocol (ad-hoc on-demand distance vector, AODV) into a hybrid protocol by introducing adaptive, proactive behavior to improve its performance. Under our proposed scheme, route maintenance decisions are based on predicted values of 'link-breakage times' (when the next-hop node will move out of transmission range) obtained from a series of position/speed estimates of the next-hop node. These estimates are based on the power level of the received MAC frames. If a link is about to break, proactive discovery of new routes to all destinations using the next-hop node depends on the history of traffic to that destination. We simulated (using the ns2 simulator) numerous test conditions using CBR and TCP traffic and compared performance metrics for the original and modified versions of the protocol. We have achieved (1) a significant reduction in mean packet latency for CBR traffic and (2) a reduction in control overhead in TCP traffic, while incurring other small penalties for both types of traffic. Also, a comparison of some performance metrics for TCP and CBR traffic leads us to conclude that slight modifications in TCP can lead to its improved performance over MANETs.
{"title":"Development and performance characterization of enhanced AODV routing for CBR and TCP traffic","authors":"P. Mani, D. Petr","doi":"10.1109/WTS.2004.1319553","DOIUrl":"https://doi.org/10.1109/WTS.2004.1319553","url":null,"abstract":"We aim to modify an existing mobile ad-hoc network (MANET) reactive routing protocol (ad-hoc on-demand distance vector, AODV) into a hybrid protocol by introducing adaptive, proactive behavior to improve its performance. Under our proposed scheme, route maintenance decisions are based on predicted values of 'link-breakage times' (when the next-hop node will move out of transmission range) obtained from a series of position/speed estimates of the next-hop node. These estimates are based on the power level of the received MAC frames. If a link is about to break, proactive discovery of new routes to all destinations using the next-hop node depends on the history of traffic to that destination. We simulated (using the ns2 simulator) numerous test conditions using CBR and TCP traffic and compared performance metrics for the original and modified versions of the protocol. We have achieved (1) a significant reduction in mean packet latency for CBR traffic and (2) a reduction in control overhead in TCP traffic, while incurring other small penalties for both types of traffic. Also, a comparison of some performance metrics for TCP and CBR traffic leads us to conclude that slight modifications in TCP can lead to its improved performance over MANETs.","PeriodicalId":242981,"journal":{"name":"2004 Symposium on Wireless Telecommunications","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122798820","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 : 2004-05-14DOI: 10.1109/WTS.2004.1319559
Jul-Hung Yeh, Chi-Chen Lee, Jyh-cheng Chen
Energy conservation is critical for third generation (3G) cellular systems. In particular, future high-speed packet data services are expected to exhaust the energy of a mobile station rapidly. In 3GPP systems, the radio resource is mainly controlled by the radio resource control (RRC). This paper quantifies the energy consumption and the reconnection ratio for 3GPP systems based on the RRC state machine. Bursty and streaming packet data services are investigated. Through analytic models and comprehensive simulation with various traffic models, the impacts of diverse timer values on the RRC state machine are illustrated. In addition to quantifying energy consumption, appropriate timer values are suggested.
{"title":"Performance analysis of energy consumption in 3GPP networks","authors":"Jul-Hung Yeh, Chi-Chen Lee, Jyh-cheng Chen","doi":"10.1109/WTS.2004.1319559","DOIUrl":"https://doi.org/10.1109/WTS.2004.1319559","url":null,"abstract":"Energy conservation is critical for third generation (3G) cellular systems. In particular, future high-speed packet data services are expected to exhaust the energy of a mobile station rapidly. In 3GPP systems, the radio resource is mainly controlled by the radio resource control (RRC). This paper quantifies the energy consumption and the reconnection ratio for 3GPP systems based on the RRC state machine. Bursty and streaming packet data services are investigated. Through analytic models and comprehensive simulation with various traffic models, the impacts of diverse timer values on the RRC state machine are illustrated. In addition to quantifying energy consumption, appropriate timer values are suggested.","PeriodicalId":242981,"journal":{"name":"2004 Symposium on Wireless Telecommunications","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116724261","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 : 2004-05-14DOI: 10.1109/WTS.2004.1319544
Wentao Zhao, Mi Lu
We consider a distributed CDMA system in which mobiles are able to control their transmission rate and power based on their radio conditions. Each mobile is assumed to be myopic, that is, its solitary goal is to maximize the payoff, which is the difference between the effective throughput and the price that the system charges for the received power on behalf of the mobile. We prove that the distributed system converges to a Nash equilibrium such that users near the base station transmit in the full rate while farther users transmit at the full power. Our simulation results present a numerical view of this distributed scheme.
{"title":"Distributed rate and power control for CDMA uplink","authors":"Wentao Zhao, Mi Lu","doi":"10.1109/WTS.2004.1319544","DOIUrl":"https://doi.org/10.1109/WTS.2004.1319544","url":null,"abstract":"We consider a distributed CDMA system in which mobiles are able to control their transmission rate and power based on their radio conditions. Each mobile is assumed to be myopic, that is, its solitary goal is to maximize the payoff, which is the difference between the effective throughput and the price that the system charges for the received power on behalf of the mobile. We prove that the distributed system converges to a Nash equilibrium such that users near the base station transmit in the full rate while farther users transmit at the full power. Our simulation results present a numerical view of this distributed scheme.","PeriodicalId":242981,"journal":{"name":"2004 Symposium on Wireless Telecommunications","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130633974","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 : 2004-05-14DOI: 10.1109/WTS.2004.1319551
Huazhou Liu, Qing-An Zeng
We propose a novel mobile communication system which employs adaptive beamforming techniques. In the proposed system, the capacity is increased by reusing the same channel (frequency, time slot or code) in a cell. The QoS (quality of service) is improved by inherent properties of smart antennas, like reducing BER (bit error rate), multipath fading, etc. We provide an analytical model for the proposed system. The system is modeled and analyzed by a two-dimensional Markov chain. A new algorithm is derived to obtain the equilibrium state probabilities. We also investigate the QoS of the system in terms of the blocking probability of originating calls and the forced termination probability of handoff calls. As we expect, system capacity and performance are highly improved by employing smart antennas. We believe that the proposed system can be a candidate of future mobile communication systems to provide a service with high capacity and quality.
{"title":"Modeling and performance analysis of mobile communication systems using adaptive beamforming technique","authors":"Huazhou Liu, Qing-An Zeng","doi":"10.1109/WTS.2004.1319551","DOIUrl":"https://doi.org/10.1109/WTS.2004.1319551","url":null,"abstract":"We propose a novel mobile communication system which employs adaptive beamforming techniques. In the proposed system, the capacity is increased by reusing the same channel (frequency, time slot or code) in a cell. The QoS (quality of service) is improved by inherent properties of smart antennas, like reducing BER (bit error rate), multipath fading, etc. We provide an analytical model for the proposed system. The system is modeled and analyzed by a two-dimensional Markov chain. A new algorithm is derived to obtain the equilibrium state probabilities. We also investigate the QoS of the system in terms of the blocking probability of originating calls and the forced termination probability of handoff calls. As we expect, system capacity and performance are highly improved by employing smart antennas. We believe that the proposed system can be a candidate of future mobile communication systems to provide a service with high capacity and quality.","PeriodicalId":242981,"journal":{"name":"2004 Symposium on Wireless Telecommunications","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126012837","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 : 2004-05-14DOI: 10.1109/WTS.2004.1319552
M. Yang, P. Chong
The paper presents the performance analysis of a cellular system supporting two types of traffic with different reuse factors, using fixed channel allocation (FCA) and channel partitioning (CP), namely fixed channel partitioning (FCP). With CP, each cell is allocated two sets of channels and each set of channels supports different traffic, depending on the required reuse factor. The FCP system is modeled mathematically using queuing theory. A two-dimensional Markov chain model is developed to examine its performance. A scaling method is also proposed to deal with different call duration scenarios. As compared to the FCA system, we find that the FCP system can improve the system capacity depending on the traffic load fraction for each type of service. Analytical results are compared with the simulation results to verify our theoretical analysis.
{"title":"Performance analysis of a cellular system supporting two types of services with different reuse factors using channel partitioning","authors":"M. Yang, P. Chong","doi":"10.1109/WTS.2004.1319552","DOIUrl":"https://doi.org/10.1109/WTS.2004.1319552","url":null,"abstract":"The paper presents the performance analysis of a cellular system supporting two types of traffic with different reuse factors, using fixed channel allocation (FCA) and channel partitioning (CP), namely fixed channel partitioning (FCP). With CP, each cell is allocated two sets of channels and each set of channels supports different traffic, depending on the required reuse factor. The FCP system is modeled mathematically using queuing theory. A two-dimensional Markov chain model is developed to examine its performance. A scaling method is also proposed to deal with different call duration scenarios. As compared to the FCA system, we find that the FCP system can improve the system capacity depending on the traffic load fraction for each type of service. Analytical results are compared with the simulation results to verify our theoretical analysis.","PeriodicalId":242981,"journal":{"name":"2004 Symposium on Wireless Telecommunications","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114824324","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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