This paper investigates the deployment of single frequency terrestrial DVB networks in terms of their carbon footprint. A network optimization tool is presented that is based on evolution optimisation method, the genetic algorithm. The target of the investigation is to design the network considering the minimization of its carbon emissions. For the purpose of the investigation a real mountainous area is examined. The field computations are based on accurate multiple slope uniform theory of diffraction (UTD) approximations. Simulation results show a great reduction of CO2 emissions when carbon footprint is included in the optimization process.
{"title":"Low carbon network planning","authors":"G. Koutitas","doi":"10.1109/EW.2010.5483502","DOIUrl":"https://doi.org/10.1109/EW.2010.5483502","url":null,"abstract":"This paper investigates the deployment of single frequency terrestrial DVB networks in terms of their carbon footprint. A network optimization tool is presented that is based on evolution optimisation method, the genetic algorithm. The target of the investigation is to design the network considering the minimization of its carbon emissions. For the purpose of the investigation a real mountainous area is examined. The field computations are based on accurate multiple slope uniform theory of diffraction (UTD) approximations. Simulation results show a great reduction of CO2 emissions when carbon footprint is included in the optimization process.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"12 8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126273782","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}
We investigate the use of a timing synchronization technique within cooperative multi-hop networks with and without direct transmission between the source and destination nodes. In particular, we employ a parallel interference cancellation (PIC) technique to combat the effect of timing misalignment of the received signal at both the relay and the destination nodes. We compare the advantage in using direct transmission (DT) to assist in reducing the end-to-end bit-error-rate (BER) at the receiver with using multiple level cooperation among all nodes of each hop without direct transmission. Using 8-PSK constellation signals, our simulation results show that increased cooperation among neighboring nodes delivers improved end-to-end BER as compared to direct transmission assisted cooperation.
{"title":"Cooperative multi-hop wireless network with robustness to asynchronism","authors":"A. Elazreg, S. Kassim, J. Chambers","doi":"10.1109/EW.2010.5483499","DOIUrl":"https://doi.org/10.1109/EW.2010.5483499","url":null,"abstract":"We investigate the use of a timing synchronization technique within cooperative multi-hop networks with and without direct transmission between the source and destination nodes. In particular, we employ a parallel interference cancellation (PIC) technique to combat the effect of timing misalignment of the received signal at both the relay and the destination nodes. We compare the advantage in using direct transmission (DT) to assist in reducing the end-to-end bit-error-rate (BER) at the receiver with using multiple level cooperation among all nodes of each hop without direct transmission. Using 8-PSK constellation signals, our simulation results show that increased cooperation among neighboring nodes delivers improved end-to-end BER as compared to direct transmission assisted cooperation.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131073028","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 presents a performance model for dynamic resource allocation in cellular deployments of IEEE 802.16e-like systems. More specifically, we derive a framework which allows to quantify the number of VoIP calls that can be supported in downlink of such systems purely based on the average SINR per terminal. The major difficulty to overcome is to predict the impact of dynamic resource allocations on the system performance in the presence of interference. We show that dynamic resource allocations perform a transformation of subcarrier SINR PDFs and derive an approximate, closed-form representation of these SINR PDFs. Based on these derivations, we derive rate PMFs which predicts system performance up to a gap of about 25% compared to optimal system performance. Furthermore, the model allows for detailed investigation of dynamic resource allocation in interference-limited scenarios. We show that the average SINR is not a valid metric to predict system performance from, but instead the received power of the signal of interest is much more important (together with the received interference power). To the best of our knowledge, such performance models are novel while the presented insights have significant consequences for network design and network self-optimization.
{"title":"How bad is interference in IEEE 802.16e systems?","authors":"Farshad Naghibi, J. Gross","doi":"10.1109/EW.2010.5483384","DOIUrl":"https://doi.org/10.1109/EW.2010.5483384","url":null,"abstract":"This paper presents a performance model for dynamic resource allocation in cellular deployments of IEEE 802.16e-like systems. More specifically, we derive a framework which allows to quantify the number of VoIP calls that can be supported in downlink of such systems purely based on the average SINR per terminal. The major difficulty to overcome is to predict the impact of dynamic resource allocations on the system performance in the presence of interference. We show that dynamic resource allocations perform a transformation of subcarrier SINR PDFs and derive an approximate, closed-form representation of these SINR PDFs. Based on these derivations, we derive rate PMFs which predicts system performance up to a gap of about 25% compared to optimal system performance. Furthermore, the model allows for detailed investigation of dynamic resource allocation in interference-limited scenarios. We show that the average SINR is not a valid metric to predict system performance from, but instead the received power of the signal of interest is much more important (together with the received interference power). To the best of our knowledge, such performance models are novel while the presented insights have significant consequences for network design and network self-optimization.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"338 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133923454","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}
Quality of service (QoS) differentiation is one of the keys to success for WiMAX (Worldwide Interoperability for Microwave Access) networks. Although the IEEE 802.16 standard issued some guidelines to design a QoS architecture, for the most part implementation details are left to manufacturers. Focus in this paper is on channel-aware scheduling policies to be implemented in the WiMAX Base Station for the delivery of downlink data traffic to fixed subscriber stations in a point-to-multipoint topology. This paper investigates on the effect of adaptive modulation and coding (AMC) schemes on the performance of the designed schedulers. Evaluation of the scheduling techniques will be based on their ability to provide QoS differentiation among traffic classes and fairness in the treatment of data flows in the same class. We expect that although AMC can be effectively used to dynamically adapt to variable channel conditions, it is not sufficient to guarantee inter-class traffic differentiation and intra-class fairness unless the scheduler also accounts for compensation of lost transmission opportunities of each single data flow.
{"title":"AMC and channel-awareness for QoS-based scheduler design in WiMAX networks","authors":"S. Pizzi, A. Molinaro, A. Iera","doi":"10.1109/EW.2010.5483452","DOIUrl":"https://doi.org/10.1109/EW.2010.5483452","url":null,"abstract":"Quality of service (QoS) differentiation is one of the keys to success for WiMAX (Worldwide Interoperability for Microwave Access) networks. Although the IEEE 802.16 standard issued some guidelines to design a QoS architecture, for the most part implementation details are left to manufacturers. Focus in this paper is on channel-aware scheduling policies to be implemented in the WiMAX Base Station for the delivery of downlink data traffic to fixed subscriber stations in a point-to-multipoint topology. This paper investigates on the effect of adaptive modulation and coding (AMC) schemes on the performance of the designed schedulers. Evaluation of the scheduling techniques will be based on their ability to provide QoS differentiation among traffic classes and fairness in the treatment of data flows in the same class. We expect that although AMC can be effectively used to dynamically adapt to variable channel conditions, it is not sufficient to guarantee inter-class traffic differentiation and intra-class fairness unless the scheduler also accounts for compensation of lost transmission opportunities of each single data flow.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"49 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132640347","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}
Under an average delay constraint, we investigate the energy-efficient scheduling problem in multi-access wireless sensor networks. With the objective to minimize the transmission energy cost under average packet delay constraint, we formulate the problem as a constrained stochastic dynamic programming problem, and compute the constrained optimal policies. Superior to the existing strategies, the proposed scheduling does not require any noncausal information. It determines the scheduled sensor node as well as the transmission duration of the scheduled packet only by current backlogs at the sensor nodes. We also present the simulation results to analyze the proposed scheduling for different transmission scenarios.
{"title":"Energy efficient scheduling in multi-access wireless sensor networks: A stochastic dynamic programming method","authors":"Xiaomao Mao, Peiliang Qiu","doi":"10.1109/EW.2010.5483395","DOIUrl":"https://doi.org/10.1109/EW.2010.5483395","url":null,"abstract":"Under an average delay constraint, we investigate the energy-efficient scheduling problem in multi-access wireless sensor networks. With the objective to minimize the transmission energy cost under average packet delay constraint, we formulate the problem as a constrained stochastic dynamic programming problem, and compute the constrained optimal policies. Superior to the existing strategies, the proposed scheduling does not require any noncausal information. It determines the scheduled sensor node as well as the transmission duration of the scheduled packet only by current backlogs at the sensor nodes. We also present the simulation results to analyze the proposed scheduling for different transmission scenarios.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132892976","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 routing paths of vehicular ad-hoc network (VANET) in a city environment consists of many possible paths and junctions. Shortest path routing is not viable because each path has to be populated with vehicles. A scalable multi-hop routing protocol which adapts well to the city environment even with rapidly changing network topologies and lots of disconnected, sparse and dense network conditions is sought after. Here, we propose a new position-based routing protocol i.e. JARR, which will address the shortcomings of the current protocols by estimating the density of paths to be used. Packets are also routed from one junction to another and the direction and position of next hops are pre-considered with different ratios depending on the estimated density of the path. Simulation works were performed to compare JARR routing protocol with an existing protocol which uses the shortest path strategy.
{"title":"A novel routing protocol — Junction based Adaptive Reactive Routing (JARR) for VANET in city environments","authors":"Clarence Augustine T. H. Tee, A. Lee","doi":"10.1109/EW.2010.5483386","DOIUrl":"https://doi.org/10.1109/EW.2010.5483386","url":null,"abstract":"The routing paths of vehicular ad-hoc network (VANET) in a city environment consists of many possible paths and junctions. Shortest path routing is not viable because each path has to be populated with vehicles. A scalable multi-hop routing protocol which adapts well to the city environment even with rapidly changing network topologies and lots of disconnected, sparse and dense network conditions is sought after. Here, we propose a new position-based routing protocol i.e. JARR, which will address the shortcomings of the current protocols by estimating the density of paths to be used. Packets are also routed from one junction to another and the direction and position of next hops are pre-considered with different ratios depending on the estimated density of the path. Simulation works were performed to compare JARR routing protocol with an existing protocol which uses the shortest path strategy.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131909696","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 use the spatial dimension of spectrum sharing to allow the re-use of a radio frequency spectrum, first licensed to a primary user, by several secondary or cognitive users, while providing an outage performance to the primary user. In particular, we consider a primary receiver in the center of an exclusive region (or no-talk zone) and a guard band, within which there is no secondary transmitter, in order to protect the primary transmission against strong interference. Outside the exclusive region and the guard band, N cognitive transmitters are distributed randomly. Moreover, the primary service is protected by an outage constraint making the primary rate to be greater, most of the time, than a minimal necessary rate C0. We study the effects of shadowing and path-loss exponent on the primary exclusive region.
{"title":"Impact of shadowing on the primary exclusive region in cognitive networks","authors":"Abdoulaye Bagayoko, P. Tortelier, I. Fijalkow","doi":"10.1109/EW.2010.5483402","DOIUrl":"https://doi.org/10.1109/EW.2010.5483402","url":null,"abstract":"In this paper we use the spatial dimension of spectrum sharing to allow the re-use of a radio frequency spectrum, first licensed to a primary user, by several secondary or cognitive users, while providing an outage performance to the primary user. In particular, we consider a primary receiver in the center of an exclusive region (or no-talk zone) and a guard band, within which there is no secondary transmitter, in order to protect the primary transmission against strong interference. Outside the exclusive region and the guard band, N cognitive transmitters are distributed randomly. Moreover, the primary service is protected by an outage constraint making the primary rate to be greater, most of the time, than a minimal necessary rate C0. We study the effects of shadowing and path-loss exponent on the primary exclusive region.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126051176","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}
P. Serrano, C. Bernardos, Antonio de la Oliva, I. Soto
A lot of attention has been given to multihop wireless networks lately, but further research is needed. This attention has motivated an increase in the number of 802.11-based deployments, both indoor and outdoor. These testbeds are used to run measurements in order to analyze and understand the limitation and differences between analytical or simulation-based figures and the results from real-life experimentation. In this paper we describe the lessons learned from the deployment of a wireless multihop testbed under the false floor of a laboratory in our Computer Science building. We assess the radio shielding provided by the false floor panels, and run exhaustive and controlled experiments to analyze the performance limits of commercial off-the-shelf hardware. The results obtained confirm that experimental measurements can severely deviate from the expected theoretical values.
{"title":"Lessons learned from the deployment of a multihop IEEE 802.11g testbed using COTS devices","authors":"P. Serrano, C. Bernardos, Antonio de la Oliva, I. Soto","doi":"10.1109/EW.2010.5483471","DOIUrl":"https://doi.org/10.1109/EW.2010.5483471","url":null,"abstract":"A lot of attention has been given to multihop wireless networks lately, but further research is needed. This attention has motivated an increase in the number of 802.11-based deployments, both indoor and outdoor. These testbeds are used to run measurements in order to analyze and understand the limitation and differences between analytical or simulation-based figures and the results from real-life experimentation. In this paper we describe the lessons learned from the deployment of a wireless multihop testbed under the false floor of a laboratory in our Computer Science building. We assess the radio shielding provided by the false floor panels, and run exhaustive and controlled experiments to analyze the performance limits of commercial off-the-shelf hardware. The results obtained confirm that experimental measurements can severely deviate from the expected theoretical values.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127296832","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}
Weighted ergodic sum-rate maximization in OFDMA uplink is investigated. A finite set of achievable rates is assumed. The problem is formulated as a convex optimization problem. An analytical solution is derived using the Lagrangian dual decomposition. Numerical results show that the weights can be adjusted to increase the fairness in the system or to increase the priority of certain users.
{"title":"Ergodic sum-rate maximization in OFDMA uplink with discrete rates","authors":"E. Yaacoub, Ahmad M. El-Hajj, Z. Dawy","doi":"10.1109/EW.2010.5483394","DOIUrl":"https://doi.org/10.1109/EW.2010.5483394","url":null,"abstract":"Weighted ergodic sum-rate maximization in OFDMA uplink is investigated. A finite set of achievable rates is assumed. The problem is formulated as a convex optimization problem. An analytical solution is derived using the Lagrangian dual decomposition. Numerical results show that the weights can be adjusted to increase the fairness in the system or to increase the priority of certain users.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129164222","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 IEEE 802.16 standard for fixed and mobile broadband wireless access systems specifies a group of Medium Access Control (MAC) procedures among which the handover (HO) is one of the crucial contributions, especially significant for the mobility requirement. The HO procedure defines numerous parameters which need a fine tuning in order to achieve satisfactory communication performance. This paper presents the impact of handover parameters value and an error-prone radio channel over the IEEE 802.16e CDMA-based handover procedure performance. We analytically analyzed the handover latency and connection dropping probability. The results were compared with the experimental measurements conducted on a protocol prototype specially developed for this purpose by using Specification and Description Language. The following parameters were investigated: value of the contention window minimal and maximal size, number of transmission allocations per frame, number of available CDMA ranging codes, timers and maximum retransmission limits used in the processes of ranging, basic capabilities negotiation and registration. We have found that all these parameters need to be carefully adjusted in accordance to the following conditions: number of stations performing handover at a same time, WiMAX physical layer working parameters and frame-error rate in the uplink and downlink radio channel.
{"title":"Analysis of IEEE 802.16e contention-based handover in erroneous channel","authors":"P. Latkoski, B. Popovski","doi":"10.1109/EW.2010.5483491","DOIUrl":"https://doi.org/10.1109/EW.2010.5483491","url":null,"abstract":"The IEEE 802.16 standard for fixed and mobile broadband wireless access systems specifies a group of Medium Access Control (MAC) procedures among which the handover (HO) is one of the crucial contributions, especially significant for the mobility requirement. The HO procedure defines numerous parameters which need a fine tuning in order to achieve satisfactory communication performance. This paper presents the impact of handover parameters value and an error-prone radio channel over the IEEE 802.16e CDMA-based handover procedure performance. We analytically analyzed the handover latency and connection dropping probability. The results were compared with the experimental measurements conducted on a protocol prototype specially developed for this purpose by using Specification and Description Language. The following parameters were investigated: value of the contention window minimal and maximal size, number of transmission allocations per frame, number of available CDMA ranging codes, timers and maximum retransmission limits used in the processes of ranging, basic capabilities negotiation and registration. We have found that all these parameters need to be carefully adjusted in accordance to the following conditions: number of stations performing handover at a same time, WiMAX physical layer working parameters and frame-error rate in the uplink and downlink radio channel.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128952212","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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