In this work, we propose a novel medium access scheme named Smart-CSMA with piggybacking that can effectively solve the collision problem and enhance the throughput and access delay performance as well as the quality-of-service support for a high-speed WLAN in the infrastructure topology. Smart-CSMA with piggybacking combines the advantages of the standard PCF and DCF modes. It can efficiently supports the quality-of-service requirements like in the PCF access mode while relying on the simple on- demand CSMA channel access mechanism like in the DCF mode. In the proposed scheme, every station employs the standard CSMA mechanism with a slightly modified backoff procedure. A master station is responsible for scheduling backoff timers for all client stations. It shall send the backoff timer information together with the frames destined to each client station. The client station then uses the received backoff timer value to start the backoff procedure associated with the current transmission in the queue. If the client station has not obtained the backoff schedule from the master station due to any reason, it then uses a random backoff value to start the backoff procedure. A generic algorithm is provided for the master station to allocate arbitrary slots for each client station. Furthermore, a piggybacking frame exchange mechanism is proposed to enhance capacity of the system. Numerical results show that the proposed scheme significantly outperforms the standard IEEE 802.11 DCF and PCF schemes, and the superior performance is not sensitive to the number of active and inactive client stations in the network.
{"title":"Improving CSMA for WLANs via Piggybacking and Scheduled Backoff Mechanisms","authors":"S. Siwamogsatham","doi":"10.1109/FGCN.2007.149","DOIUrl":"https://doi.org/10.1109/FGCN.2007.149","url":null,"abstract":"In this work, we propose a novel medium access scheme named Smart-CSMA with piggybacking that can effectively solve the collision problem and enhance the throughput and access delay performance as well as the quality-of-service support for a high-speed WLAN in the infrastructure topology. Smart-CSMA with piggybacking combines the advantages of the standard PCF and DCF modes. It can efficiently supports the quality-of-service requirements like in the PCF access mode while relying on the simple on- demand CSMA channel access mechanism like in the DCF mode. In the proposed scheme, every station employs the standard CSMA mechanism with a slightly modified backoff procedure. A master station is responsible for scheduling backoff timers for all client stations. It shall send the backoff timer information together with the frames destined to each client station. The client station then uses the received backoff timer value to start the backoff procedure associated with the current transmission in the queue. If the client station has not obtained the backoff schedule from the master station due to any reason, it then uses a random backoff value to start the backoff procedure. A generic algorithm is provided for the master station to allocate arbitrary slots for each client station. Furthermore, a piggybacking frame exchange mechanism is proposed to enhance capacity of the system. Numerical results show that the proposed scheme significantly outperforms the standard IEEE 802.11 DCF and PCF schemes, and the superior performance is not sensitive to the number of active and inactive client stations in the network.","PeriodicalId":254368,"journal":{"name":"Future Generation Communication and Networking (FGCN 2007)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128554311","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}
Load balancing is an important problem for the efficient operation of peer-to-peer(P2P) networks. A key issue for dynamic load balancing in self-organizing networks is to identify overloaded nodes and reassign their loads to others. Recently, most of researchers have concentrated on developing strategies to the design of balanced structured P2P networks. However, none of these strategies is suitable for unstructured P2P networks. This paper proposes a novel routing based algorithm for load balancing in heterogeneous, dynamic unstructured P2P networks. Our algorithm does not need the global information and hence is resilient to dynamic node arrivals, departures, and failures. Experimental results indicate that our algorithm outperforms existing load balancing algorithms in terms of load transfer.
{"title":"Routing Based Load Balancing for Unstructured P2P Networks","authors":"Ming Xu, J. Guan","doi":"10.1109/FGCN.2007.197","DOIUrl":"https://doi.org/10.1109/FGCN.2007.197","url":null,"abstract":"Load balancing is an important problem for the efficient operation of peer-to-peer(P2P) networks. A key issue for dynamic load balancing in self-organizing networks is to identify overloaded nodes and reassign their loads to others. Recently, most of researchers have concentrated on developing strategies to the design of balanced structured P2P networks. However, none of these strategies is suitable for unstructured P2P networks. This paper proposes a novel routing based algorithm for load balancing in heterogeneous, dynamic unstructured P2P networks. Our algorithm does not need the global information and hence is resilient to dynamic node arrivals, departures, and failures. Experimental results indicate that our algorithm outperforms existing load balancing algorithms in terms of load transfer.","PeriodicalId":254368,"journal":{"name":"Future Generation Communication and Networking (FGCN 2007)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129256876","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 work, we develop an analytical model for the integration of real time and elastic traffic in a system supporting both UMTS R99 and HSDPA/HSUPA channels. We first develop models for the powers and throughputs, and then use them to study the dynamic evolution of the system by a Markovian model. We also study the impact of the interaction between uplink and downlink caused by the TCP ACKs carried by dedicated or shared channels. We apply our model to dimension the system for different traffic scenarios. In particular, we show how to determine the number of carriers that must be assigned to a base station in order to meet some blocking requirements, and whether they will be shared between R99 and HSPA or dedicated to one system.
{"title":"HSUPA/HSDPA Systems: Capacity and Dimensioning","authors":"A. Baroudy, S. Elayoubi","doi":"10.1109/FGCN.2007.145","DOIUrl":"https://doi.org/10.1109/FGCN.2007.145","url":null,"abstract":"In this work, we develop an analytical model for the integration of real time and elastic traffic in a system supporting both UMTS R99 and HSDPA/HSUPA channels. We first develop models for the powers and throughputs, and then use them to study the dynamic evolution of the system by a Markovian model. We also study the impact of the interaction between uplink and downlink caused by the TCP ACKs carried by dedicated or shared channels. We apply our model to dimension the system for different traffic scenarios. In particular, we show how to determine the number of carriers that must be assigned to a base station in order to meet some blocking requirements, and whether they will be shared between R99 and HSPA or dedicated to one system.","PeriodicalId":254368,"journal":{"name":"Future Generation Communication and Networking (FGCN 2007)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116373852","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}
When the fast Fourier transform (FFT) is executed using an in-place method, the input or output data must be accessed in a digit-reversed order. The previous digit reversal circuits, which are based on a binary counter, require complex multiplexers. This paper proposes a new digit reversal circuit based on two-bit counter modules for the variable-length radix-4 FFT. This circuit can be designed with minimal multiplexers, and thus can efficiently generate digit-reversed sequences compared with digit reversal circuits based on a binary counter.
{"title":"A Digit Reversal Circuit for the Variable-Length Radix-4 FFT","authors":"Seung-Ho Ok, Byungin Moon","doi":"10.1109/FGCN.2007.7","DOIUrl":"https://doi.org/10.1109/FGCN.2007.7","url":null,"abstract":"When the fast Fourier transform (FFT) is executed using an in-place method, the input or output data must be accessed in a digit-reversed order. The previous digit reversal circuits, which are based on a binary counter, require complex multiplexers. This paper proposes a new digit reversal circuit based on two-bit counter modules for the variable-length radix-4 FFT. This circuit can be designed with minimal multiplexers, and thus can efficiently generate digit-reversed sequences compared with digit reversal circuits based on a binary counter.","PeriodicalId":254368,"journal":{"name":"Future Generation Communication and Networking (FGCN 2007)","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116742249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper investigates the survivable routing in backbone optical transport networks with shared-risk link groups (SRLG) constraints, and proposes a new risk-level disjoint protection (RLDP) algorithm for provide different service level for different connection request. Compared with the conventional SRLG- disjoint protection (SDP) algorithm, RLDP performs better resource utilization and blocking probability. Simulation results are shown to be promising.
{"title":"Survivable Routing with Risk-Level Disjoint in WDM Optical Networks","authors":"Lei Guo, Xingwei Wang, Cunqian Yu","doi":"10.1109/FGCN.2007.209","DOIUrl":"https://doi.org/10.1109/FGCN.2007.209","url":null,"abstract":"This paper investigates the survivable routing in backbone optical transport networks with shared-risk link groups (SRLG) constraints, and proposes a new risk-level disjoint protection (RLDP) algorithm for provide different service level for different connection request. Compared with the conventional SRLG- disjoint protection (SDP) algorithm, RLDP performs better resource utilization and blocking probability. Simulation results are shown to be promising.","PeriodicalId":254368,"journal":{"name":"Future Generation Communication and Networking (FGCN 2007)","volume":"199 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116151012","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}
To improve the flexibility and accuracy of link adaptation (LA) of LDPC coded OFDM system, the classical exponential effective-SNR mapping (EESM) link quality model is extended to LDPC codes. Theoretical analysis and simulation results indicate that by selecting proper modulation and coding adjusting factors, the EESM model is precise for LDPC codes, both in terms of complexity and accuracy for various modulation and coding schemes (MCS), sub- channel states and coding block lengths. Therefore it can be treated as an accurate link to system (L2S) interface for LDPC coded multi-carrier system. To verify it, a new LA scheme based on LDPC codes specified in IEEE802.16e standard is presented. Based on the EESM model, the link-level performance of BPSK over additional white Gaussian noise (AWGN) channel is used to predict the throughput performances of the LA scheme, which match the simulation results very well.
{"title":"Link Adaptation of LDPC Codes Based on Exponential Effective-SNR Mapping Link Quality Model","authors":"Wei Sun, Xiang Chen, Zesong Fei, Jingming Kuang","doi":"10.1109/FGCN.2007.160","DOIUrl":"https://doi.org/10.1109/FGCN.2007.160","url":null,"abstract":"To improve the flexibility and accuracy of link adaptation (LA) of LDPC coded OFDM system, the classical exponential effective-SNR mapping (EESM) link quality model is extended to LDPC codes. Theoretical analysis and simulation results indicate that by selecting proper modulation and coding adjusting factors, the EESM model is precise for LDPC codes, both in terms of complexity and accuracy for various modulation and coding schemes (MCS), sub- channel states and coding block lengths. Therefore it can be treated as an accurate link to system (L2S) interface for LDPC coded multi-carrier system. To verify it, a new LA scheme based on LDPC codes specified in IEEE802.16e standard is presented. Based on the EESM model, the link-level performance of BPSK over additional white Gaussian noise (AWGN) channel is used to predict the throughput performances of the LA scheme, which match the simulation results very well.","PeriodicalId":254368,"journal":{"name":"Future Generation Communication and Networking (FGCN 2007)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114768976","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 the ubiquitous environments, smart cards as an ubiquitous computing device provide several services to pervasive computing and ubiquitous services. In 2006, Shieh-Wang pointed out the weakness of Juang's remote mutual authentication scheme using smart card and further proposed a novel remote user authentication scheme using smart card. The current paper, however, demonstrates that Shieh-Wang's scheme does not provide perfect forward secrecy and is vulnerable to a privileged insider's attack.
{"title":"Two Security Problems of Efficient Remote Mutual Authentication and Key Agreement","authors":"Eunjun Yoon, K. Yoo","doi":"10.1109/FGCN.2007.225","DOIUrl":"https://doi.org/10.1109/FGCN.2007.225","url":null,"abstract":"In the ubiquitous environments, smart cards as an ubiquitous computing device provide several services to pervasive computing and ubiquitous services. In 2006, Shieh-Wang pointed out the weakness of Juang's remote mutual authentication scheme using smart card and further proposed a novel remote user authentication scheme using smart card. The current paper, however, demonstrates that Shieh-Wang's scheme does not provide perfect forward secrecy and is vulnerable to a privileged insider's attack.","PeriodicalId":254368,"journal":{"name":"Future Generation Communication and Networking (FGCN 2007)","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125265170","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 an algorithm to realize a power-aware network topology in wireless sensor networks. The algorithm creates a multicast tree connecting all sensor nodes. In the multicast tree, a sink node should be a root node, and all the data sensed in the sensor nodes are transferred to the sink node using the tree connection. The relay nodes aggregate the received data, and transfer the aggregated data to the sink at an appropriate timing so as to avoid packet collisions. To do this, all the sensor nodes are grouped in clusters. Here, each cluster has a head node, which is automatically selected from among the nodes in the cluster. In addition, our algorithm has an autonomous mechanism that can change the cluster head dynamically based on the remaining energy of each sensor node and the communication quality among the sensor nodes, which are obtained by periodical information exchange between the sensor nodes. This mechanism contributes to extending the lifetime of the sensor network. After describing the algorithm, some experimental results are shown to prove its effectiveness and robustness.
{"title":"An Autonomous Multicast-tree Creation Algorithm for Wireless Sensor Networks","authors":"K. Onodera, T. Miyazaki","doi":"10.1109/FGCN.2007.58","DOIUrl":"https://doi.org/10.1109/FGCN.2007.58","url":null,"abstract":"In this paper, we propose an algorithm to realize a power-aware network topology in wireless sensor networks. The algorithm creates a multicast tree connecting all sensor nodes. In the multicast tree, a sink node should be a root node, and all the data sensed in the sensor nodes are transferred to the sink node using the tree connection. The relay nodes aggregate the received data, and transfer the aggregated data to the sink at an appropriate timing so as to avoid packet collisions. To do this, all the sensor nodes are grouped in clusters. Here, each cluster has a head node, which is automatically selected from among the nodes in the cluster. In addition, our algorithm has an autonomous mechanism that can change the cluster head dynamically based on the remaining energy of each sensor node and the communication quality among the sensor nodes, which are obtained by periodical information exchange between the sensor nodes. This mechanism contributes to extending the lifetime of the sensor network. After describing the algorithm, some experimental results are shown to prove its effectiveness and robustness.","PeriodicalId":254368,"journal":{"name":"Future Generation Communication and Networking (FGCN 2007)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126623288","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 sparse matrix decompositions for DFT matrix and DCT matrix are proposed. Based on these propositions, we develop a fast hybrid DFT and DCT architecture for OFDM. In addition, we address the OFDM based on DFT or DCT in Cognitive Radio system. An adaptive OFDM based on DFT or DCT in Cognitive Radio system has the capacity to nullify individual carriers to avoid interference to the licensed users. Therefore, there could be a considerably large number of zero-valued inputs/outputs for the IDFT/DFT or IDCT/DCT on the OFDM transceiver. Hence, the standard methods of DFT and DCT are no longer efficient due to the wasted operations on zero. Based on this observation, we present a transform decomposition on two dimensional (2-D) systolic array for IDFT/DFT and IDCT/DCT, this algorithm can achieve an efficient computation for OFDM in Cognitive Radio system.
{"title":"Fast Hybrid DFT/DCT Architecture for OFDM in Cognitive Radio System","authors":"Zhu Chen, M. Lee, Chang-Joo Kim","doi":"10.1109/FGCN.2007.124","DOIUrl":"https://doi.org/10.1109/FGCN.2007.124","url":null,"abstract":"In this paper, the sparse matrix decompositions for DFT matrix and DCT matrix are proposed. Based on these propositions, we develop a fast hybrid DFT and DCT architecture for OFDM. In addition, we address the OFDM based on DFT or DCT in Cognitive Radio system. An adaptive OFDM based on DFT or DCT in Cognitive Radio system has the capacity to nullify individual carriers to avoid interference to the licensed users. Therefore, there could be a considerably large number of zero-valued inputs/outputs for the IDFT/DFT or IDCT/DCT on the OFDM transceiver. Hence, the standard methods of DFT and DCT are no longer efficient due to the wasted operations on zero. Based on this observation, we present a transform decomposition on two dimensional (2-D) systolic array for IDFT/DFT and IDCT/DCT, this algorithm can achieve an efficient computation for OFDM in Cognitive Radio system.","PeriodicalId":254368,"journal":{"name":"Future Generation Communication and Networking (FGCN 2007)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127008692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes the rapid multimedia encryption method (fast encryption algorithm for multimedia FEA-M) and the evolutions of encryption, decryption structure. In present paper the method to analyze and explain for the latest encryption laws has already been advanced. This paper presents an improved way to increase strength and toughness to improve the security of encryption to make it difficult to break through such attacks. In addition, this paper will refer to the background utilized by FEA-M over the years and its attack methodologies and enhancements.
本文介绍了快速多媒体加密方法(fast encryption algorithm for multimedia FEA-M)以及加密、解密结构的演变。本文提出了对最新加密规律进行分析和解释的方法。本文提出了一种提高加密强度和韧性的改进方法，以提高加密的安全性，使其难以突破此类攻击。此外，本文还将介绍多年来有限元分析所利用的背景及其攻击方法和改进。
{"title":"Security Cryptanalysis in High-Order Improved Fast Encryption Algorithm for Multimedia","authors":"Shiuh-Jeng Wang, Hung Hsuan Chen, Pin-You Chen, Yuh-Ren Tsai","doi":"10.1109/FGCN.2007.199","DOIUrl":"https://doi.org/10.1109/FGCN.2007.199","url":null,"abstract":"This paper describes the rapid multimedia encryption method (fast encryption algorithm for multimedia FEA-M) and the evolutions of encryption, decryption structure. In present paper the method to analyze and explain for the latest encryption laws has already been advanced. This paper presents an improved way to increase strength and toughness to improve the security of encryption to make it difficult to break through such attacks. In addition, this paper will refer to the background utilized by FEA-M over the years and its attack methodologies and enhancements.","PeriodicalId":254368,"journal":{"name":"Future Generation Communication and Networking (FGCN 2007)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126118788","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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