European Transactions on Telecommunications最新文献_第3页

A routing algorithm with precomputation for Multiprotocol Label Switching Traffic Engineering 一种多协议标签交换流量工程中带预计算的路由算法

European Transactions on Telecommunications Pub Date : 2011-10-01 DOI: 10.1002/ett.1481

Tao He, Suoping Wang

引用次数: 2

Real-time bandwidth measurements over mobile connections 实时带宽测量移动连接

European Transactions on Telecommunications Pub Date : 2011-10-01 DOI: 10.1002/ett.1474

Erik Bergfeldt, S. Ekelin, J. Karlsson

{"title":"Real-time bandwidth measurements over mobile connections","authors":"Erik Bergfeldt, S. Ekelin, J. Karlsson","doi":"10.1002/ett.1474","DOIUrl":"https://doi.org/10.1002/ett.1474","url":null,"abstract":"The first study that investigates the characteristics of received probe packets and the reliability of bandwidth estimates when actively measuring the available bandwidth over radio interfaces in mobile communication networks is presented. Knowledge of available bandwidth is very useful in various contexts, e.g. in network management and adaptive streaming applications. Bandwidth measuring tools have so far primarily been designed for and evaluated in wired networks. However, such tools should also be examined in wireless networks since the use of, e.g., mobile broadband is rapidly increasing. The properties of wired and wireless links differ substantially, which affect the performance of the tools. We have made active-probing experiments over a high-speed downlink shared channel, which is used for High-Speed Downlink Packet Access (HSDPA) in the mobile communication technology UMTS, and over a forward traffic channel in CDMA2000 1xEV-DO. Both experiments were performed over commercial networks. They show that one cannot always expect uniform per-packet processing over the radio channel in mobile networks, which is expected by many probing tools. This reduces the reliability of the available-bandwidth estimates, however we suggest how this can be handled. Finally, the mobile-network measurements are compared to experiments performed in an IEEE 802.11 wireless LAN, where the radio channel does not create the same packet-processing behaviour. We also discuss the possibility of using the probe traffic for the purpose of identifying the communication technology at the bottleneck of the network path, assumed this is a wireless broadband link, by mapping specifications of standardised communication technologies to observed probe-traffic characteristics. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"1 1","pages":"255-267"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79034122","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}

引用次数: 5

Spectral and power efficiency of IEEE802.11n MIMO-OFDM WLAN systems using space-multimode-polarization diversity compact stacked circular microstrip antenna arrays 使用空间多模极化分集紧凑堆叠圆形微带天线阵列的IEEE802.11n MIMO-OFDM WLAN系统的频谱和功率效率

European Transactions on Telecommunications Pub Date : 2011-08-01 DOI: 10.1002/ett.1499

A. Yavanoglu, Ö. Ertug

{"title":"Spectral and power efficiency of IEEE802.11n MIMO-OFDM WLAN systems using space-multimode-polarization diversity compact stacked circular microstrip antenna arrays","authors":"A. Yavanoglu, Ö. Ertug","doi":"10.1002/ett.1499","DOIUrl":"https://doi.org/10.1002/ett.1499","url":null,"abstract":"Recent developments in wireless communication systems in indoor environments require high data rates and high transmission qualities especially for multimedia applications in wireless local area network (WLAN) systems. The support of high data rate multiple-input multiple-output (MIMO) spatial-multiplexing communication in orthogonal frequencydivision multiplexing WLAN systems conforming to IEEE802.11n standard requires the use of compact antennas with low correlation ports. In this paper, we analyse a MIMO array consisting of higher-order space-multimode-polarization diversity stacked circular microstrip patch uniform linear antenna arrays (SMP-SCP-ULAs) to exploit SMP diversity for use in WLAN systems. Using higher number of antenna ports in lower space and low cross-polar discrimination values between each transmit and receive antenna, SMP-SCP-ULA yields higher multiplexing gain and satisfies more restrictive size constraints in clustered MIMO systems. The performance gains of higher-order modal SMP-SCP-ULA are presented in terms of modal correlation, ergodic spectral efficiency, average bit error rate and compactness gain with respect to dipole and circular microstrip patch uniform linear arrays. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"10 1","pages":"231-239"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79413324","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}

引用次数: 9

Linear combination-based energy detection algorithm in low signal-to-noise ratio for cognitive radios 基于线性组合的认知无线电低信噪比能量检测算法

European Transactions on Telecommunications Pub Date : 2011-08-01 DOI: 10.1002/ett.1470

Shibing Zhang, Zhihua Bao

引用次数: 8

MAP channel estimation with turbo processing for orthogonal space-time block coded MISO systems 基于turbo处理的正交空时分组编码MISO系统MAP信道估计

European Transactions on Telecommunications Pub Date : 2011-08-01 DOI: 10.1002/ett.1473

I. Kammoun, M. Siala

{"title":"MAP channel estimation with turbo processing for orthogonal space-time block coded MISO systems","authors":"I. Kammoun, M. Siala","doi":"10.1002/ett.1473","DOIUrl":"https://doi.org/10.1002/ett.1473","url":null,"abstract":"In this paper, we investigate fast time-varying channel estimation for two orthogonal space–time block-coded systems with either two or three transmit antennas and with one receive antenna. We propose an iterative expectation–maximisation-based maximum a posteriori (MAP) semi-blind algorithm for the estimation of the discrete propagation channels seen from the transmit antennas. This algorithm requires a convenient representation of the channel using a discrete version of the Karhunen-Loeve expansion theorem. It incorporates the coded structure of each block in a turbo-processing fashion and uses the MAP training-based channel estimation algorithm for its optimum initialisation. The transmit antennas are assumed to be spatially correlated for the system with two transmit antennas and spatially uncorrelated for the three-antenna system. The validity of the proposed algorithm is highlighted by simulation results. The performance of the proposed receivers, based on MAP channel estimation, for the two systems approaches that of the perfect channel state information receiver, even for very time selective fading channels. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"209 1","pages":"218-230"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77762536","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}

引用次数: 2

Carrier sense adaptation with enhanced fairness in IEEE 802.15.4 WPAN IEEE 802.15.4 WPAN中增强公平性的载波感知自适应

European Transactions on Telecommunications Pub Date : 2011-08-01 DOI: 10.1002/ett.1467

Kyung-Joon Park, Kwanhee Jeong, Hyuk Lim, Daeyoung Park

引用次数: 5

TCP flow aware adaptive path switching in diffserv enabled MPLS networks 支持diffserv的MPLS网络中TCP流感知自适应路径交换

European Transactions on Telecommunications Pub Date : 2011-08-01 DOI: 10.1002/ett.1468

O. Alparslan, N. Akar, Ezhan Karasan

{"title":"TCP flow aware adaptive path switching in diffserv enabled MPLS networks","authors":"O. Alparslan, N. Akar, Ezhan Karasan","doi":"10.1002/ett.1468","DOIUrl":"https://doi.org/10.1002/ett.1468","url":null,"abstract":"We propose an adaptive flow-level multi-path routing-based traffic engineering solution for an IP backbone network carrying TCP/IP traffic. Incoming TCP flows are switched between two explicitly routed paths, namely the primary and secondary paths (PP and SP), for resilience and potential goodput improvement at the TCP layer. In the proposed architecture, PPs receive a preferential treatment over SPs using differentiated services mechanisms. The reason for this choice is not for service differentiation but for coping with the detrimental knock-on effect stemming from theuse of longer SP that is well known for conventional network load balancing algorithms. Moreover, both paths are congestion-controlled using Explicit Congestion Notification marking at the core and Additive Increase Multiplicative Decrease rate adjustment at the ingress nodes. The delay difference between PP and SP is estimated using two per-egress rate-controlling buffers maintained at the ingress nodes for each path, and this delay difference is used to determine the path over which a new TCP flow will be routed. We perform extensive simulations using ns-2 in order to demonstrate the viability of the proposed distributed adaptive multi-path routing method in terms of per-flow TCP goodput. The proposed solution consistently outperforms the single-path routing policy and provides substantial per-flow goodput gains under poor PP conditions. Moreover, highest goodput improvements under the proposed scheme are achieved by flows that receive the lowest goodputs with single-path routing, while the performance of the flows with high goodputs with single-path routing does not deteriorate with the proposed path switching technique. Copyright # 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"80 1","pages":"185-199"},"PeriodicalIF":0.0,"publicationDate":"2011-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86832341","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}

引用次数: 2

On fair rate adaption in interference-limited systems 限制干扰系统中的公平速率自适应

European Transactions on Telecommunications Pub Date : 2011-08-01 DOI: 10.1002/ett.1469

A. Schmeink

引用次数: 11

Common problems in delay-based congestion control algorithms: a gallery of solutions 基于延迟的拥塞控制算法中的常见问题:一系列解决方案

European Transactions on Telecommunications Pub Date : 2011-06-01 DOI: 10.1002/ett.1485

M. Rodríguez-Pérez, S. Herrería-Alonso, M. Fernández-Veiga, C. López-García

{"title":"Common problems in delay-based congestion control algorithms: a gallery of solutions","authors":"M. Rodríguez-Pérez, S. Herrería-Alonso, M. Fernández-Veiga, C. López-García","doi":"10.1002/ett.1485","DOIUrl":"https://doi.org/10.1002/ett.1485","url":null,"abstract":"Although delay-based congestion control protocols such as FAST Transmission Control Protocol (TCP) promise to deliver better performance than traditional TCP Reno, they have not yet been widely incorporated to the Internet. Several factors have contributed to their lack of deployment. Probably, the main contributing factor is that they are not able to compete fairly against loss-based congestion control protocols. In fact, the transmission rate in equilibrium of delay-based approaches is always less than their fair share when they share the network with traditional TCP Reno derivatives that employ packet losses as their congestion signal. There are also other performance impairments caused by the sensitivity to errors in the measurement of the congestion signal (queuing delay) that reduce the efficiency and the intra-protocol fairness of the algorithms. In this paper, we report, analyse and discuss some recent proposals in the literature to improve the dynamic behaviour of delay-based congestion control algorithms, FAST in particular. The coexistence of sources reacting differently to congestion, the identification of congestion appearance in the reverse path and the persistent congestion problem are the issues specifically addressed. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"15 1","pages":"168-179"},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73235589","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}

引用次数: 8

Traffic models for future backbone networks - a service-oriented approach 未来骨干网的流量模型——面向服务的方法

European Transactions on Telecommunications Pub Date : 2011-06-01 DOI: 10.1002/ett.1464

E. Palkopoulou, Christian Merkle, D. Schupke, C. Gruber, A. Kirstädter

{"title":"Traffic models for future backbone networks - a service-oriented approach","authors":"E. Palkopoulou, Christian Merkle, D. Schupke, C. Gruber, A. Kirstädter","doi":"10.1002/ett.1464","DOIUrl":"https://doi.org/10.1002/ett.1464","url":null,"abstract":"In this paper we present a novel approach to assess the impact of new and existing services on traffic volume in current and future backbone networks. Several proposals to model traffic load in access and backbone networks exist in the literature. These proposals consider current Internet traffic like http, smtp, ftp and Peer-to-Peer (P2P). We expect, however, that there will be a change in traffic load for future networks caused by services like IP Television (IPTV), Video on Demand (VoD) and Virtual Private Networks (VPN). Additionally, population-based models may no longer be applicable due to the widespread use of service-providers and hierarchical routing through network peering points. Therefore, it is important to reassess future traffic volumes and traffic patterns and to identify those services that have the most impact on the networks. We model today's traffic volume of each of the described services and estimate future traffic volumes taking peering points into account. To illustrate the different traffic flows and to characterise the traffic distribution we apply our results to a Germany reference network. Copyright © 2010 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"58 1","pages":"137-150"},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85096602","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}

引用次数: 26