Pub Date : 2011-11-01DOI: 10.1109/ISWCS.2011.6125360
R. Zakhour, S. Hanly
In [1], we considered base station (BS) cooperation in the form of coordinated beamforming, focusing on min-max fairness in the power usage subject to target SINR constraints: optimal beamforming strategies were characterized, and it was shown that in the asymptotic regime where the number of antennas at each BS and that of users in each cell both grow large with their ratios held constant, the dimensionality of the optimization is greatly reduced. In the present paper, we focus on the two cell case, for which feasibility conditions are established and the asymptotic problem solution is reduced to a simple single parameter search.
{"title":"Min-max fair coordinated beamforming via large systems analysis: The two-cell case","authors":"R. Zakhour, S. Hanly","doi":"10.1109/ISWCS.2011.6125360","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125360","url":null,"abstract":"In [1], we considered base station (BS) cooperation in the form of coordinated beamforming, focusing on min-max fairness in the power usage subject to target SINR constraints: optimal beamforming strategies were characterized, and it was shown that in the asymptotic regime where the number of antennas at each BS and that of users in each cell both grow large with their ratios held constant, the dimensionality of the optimization is greatly reduced. In the present paper, we focus on the two cell case, for which feasibility conditions are established and the asymptotic problem solution is reduced to a simple single parameter search.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114208195","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125339
B. Coll-Perales, J. Gozálvez
Traditional single-hop cellular architectures fail to provision high and homogeneous quality of service (QoS) levels throughout a cell area. In addition, the performance and optimization of handover mechanisms poses significant challenges due to degraded channel conditions at the cell boundaries. In this context, multi-hop cellular networking technologies have been identified as an attractive solution to overcome traditional cellular limitations and improve the performance in handover areas. This paper discusses a novel handover process using multi-hop cellular networks with mobile relays (MCN-MR), and illustrates the benefits of this approach over traditional cellular handovers through field tests.
{"title":"On the capability of multi-hop cellular networks with mobile relays to improve handover performance","authors":"B. Coll-Perales, J. Gozálvez","doi":"10.1109/ISWCS.2011.6125339","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125339","url":null,"abstract":"Traditional single-hop cellular architectures fail to provision high and homogeneous quality of service (QoS) levels throughout a cell area. In addition, the performance and optimization of handover mechanisms poses significant challenges due to degraded channel conditions at the cell boundaries. In this context, multi-hop cellular networking technologies have been identified as an attractive solution to overcome traditional cellular limitations and improve the performance in handover areas. This paper discusses a novel handover process using multi-hop cellular networks with mobile relays (MCN-MR), and illustrates the benefits of this approach over traditional cellular handovers through field tests.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126311537","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125320
Michele Rondinone, J. Gozálvez
Recent vehicular routing proposals dynamically select forwarding paths based on real-time traffic information, mostly the vehicular density, and route the packets to the final destination using the sender-based forwarding approach. However, estimating the vehicular density can require a significant communications overhead, and the adoption of sender-based forwarding can increase the presence of unreliable radio links in multi-hop transmissions. In this context, this paper presents a novel contention-based forwarding protocol that dynamically selects routing paths based on their multi-hop connectivity. The paper outlines the design of the proposal, and the optimization of some its design parameters. The obtained results show that the technique proposed in this paper achieves high packet delivery ratios, while reducing the overhead and efficiently managing the communications channel.
{"title":"Exploiting multi-hop connectivity for dynamic routing in VANETs","authors":"Michele Rondinone, J. Gozálvez","doi":"10.1109/ISWCS.2011.6125320","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125320","url":null,"abstract":"Recent vehicular routing proposals dynamically select forwarding paths based on real-time traffic information, mostly the vehicular density, and route the packets to the final destination using the sender-based forwarding approach. However, estimating the vehicular density can require a significant communications overhead, and the adoption of sender-based forwarding can increase the presence of unreliable radio links in multi-hop transmissions. In this context, this paper presents a novel contention-based forwarding protocol that dynamically selects routing paths based on their multi-hop connectivity. The paper outlines the design of the proposal, and the optimization of some its design parameters. The obtained results show that the technique proposed in this paper achieves high packet delivery ratios, while reducing the overhead and efficiently managing the communications channel.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126352068","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125436
Rafael Reinhold, R. Kays
Comprehensive and well-founded knowledge of the wireless indoor channel is fundamental in order to enable realistic modeling of the dynamic channel characteristics. Many modeling approaches are available in the literature. However, the usage of a single representative channel model is desirable to ensure scientific reproducibility and a common basis for system design. In this paper, the often cited channel model of the IEEE 802.11n task group (TGn) is analyzed in comparison to a large number of channel measurements in home environments. A non-negligible deviation between both approaches can be noticed. In order to overcome this divergence, parameter modifications for the IEEE 802.11n model are proposed to match the measurement results.
{"title":"Channel models for the design of OFDM-based wireless indoor transmission","authors":"Rafael Reinhold, R. Kays","doi":"10.1109/ISWCS.2011.6125436","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125436","url":null,"abstract":"Comprehensive and well-founded knowledge of the wireless indoor channel is fundamental in order to enable realistic modeling of the dynamic channel characteristics. Many modeling approaches are available in the literature. However, the usage of a single representative channel model is desirable to ensure scientific reproducibility and a common basis for system design. In this paper, the often cited channel model of the IEEE 802.11n task group (TGn) is analyzed in comparison to a large number of channel measurements in home environments. A non-negligible deviation between both approaches can be noticed. In order to overcome this divergence, parameter modifications for the IEEE 802.11n model are proposed to match the measurement results.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127935788","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125309
S. Görtzen, Lars Schiefler, A. Schmeink
In this paper, we show that arbitrary hierarchical pulse amplitude modulation (PAM) schemes can be fully described by generalized Cantor sets. Generalized Cantor sets are modified versions of the Cantor ternary set, a famous mathematical construct known for its set-theoretical properties. The fractal nature of generalized Cantor sets allow for a natural reinterpretation as a modulation scheme. The resulting Cantor set description of one-dimensional hierarchical modulation schemes covers the constellation points as well as the boundary points of the decision regions. Furthermore, we derive simple formulas for the average signal power as well as for iterative demodulation. All results can be extended to two dimensions and hierarchical quadrature amplitude modulation (QAM) schemes. As such, this paper offers a novel perspective on the classification and parametrization of practical hierarchical modulation schemes.
{"title":"Hierarchical generalized Cantor set modulation","authors":"S. Görtzen, Lars Schiefler, A. Schmeink","doi":"10.1109/ISWCS.2011.6125309","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125309","url":null,"abstract":"In this paper, we show that arbitrary hierarchical pulse amplitude modulation (PAM) schemes can be fully described by generalized Cantor sets. Generalized Cantor sets are modified versions of the Cantor ternary set, a famous mathematical construct known for its set-theoretical properties. The fractal nature of generalized Cantor sets allow for a natural reinterpretation as a modulation scheme. The resulting Cantor set description of one-dimensional hierarchical modulation schemes covers the constellation points as well as the boundary points of the decision regions. Furthermore, we derive simple formulas for the average signal power as well as for iterative demodulation. All results can be extended to two dimensions and hierarchical quadrature amplitude modulation (QAM) schemes. As such, this paper offers a novel perspective on the classification and parametrization of practical hierarchical modulation schemes.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130720266","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125447
H. Tabassum, F. Yilmaz, Z. Dawy, Mohamed-Slim Alouini
In this paper, we introduce a new methodology to model the uplink inter-cell interference (ICI) in wireless cellular networks. The model takes into account both the effect of channel statistics (i.e., path loss, shadowing, fading) and the resource allocation scheme in the interfering cells. Firstly, we derive a semi-analytical expression for the distribution of the locations of the allocated user in a given cell considering greedy resource allocation with maximum signal-to-noise ratio (SNR) criterion. Based on this, we derive the distribution of the uplink ICI from one neighboring cell. Next, we compute the moment generating function (MGF) of the cumulative ICI observed from all neighboring cells and discuss some examples. Finally, we utilize the derived expressions to evaluate the outage probability in the network. In order to validate the accuracy of the developed semi-analytical expressions, we present comparison results with Monte Carlo simulations. The major benefit of the proposed mechanism is that it helps in estimating the distribution of ICI without the knowledge of instantaneous resource allocations in the neighbor cells. The proposed methodology applies to any shadowing and fading distributions. Moreover, it can be used to evaluate important network performance metrics numerically without the need for time-consuming Monte Carlo simulations.
{"title":"On the statistics of uplink inter-cell interference with greedy resource allocation","authors":"H. Tabassum, F. Yilmaz, Z. Dawy, Mohamed-Slim Alouini","doi":"10.1109/ISWCS.2011.6125447","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125447","url":null,"abstract":"In this paper, we introduce a new methodology to model the uplink inter-cell interference (ICI) in wireless cellular networks. The model takes into account both the effect of channel statistics (i.e., path loss, shadowing, fading) and the resource allocation scheme in the interfering cells. Firstly, we derive a semi-analytical expression for the distribution of the locations of the allocated user in a given cell considering greedy resource allocation with maximum signal-to-noise ratio (SNR) criterion. Based on this, we derive the distribution of the uplink ICI from one neighboring cell. Next, we compute the moment generating function (MGF) of the cumulative ICI observed from all neighboring cells and discuss some examples. Finally, we utilize the derived expressions to evaluate the outage probability in the network. In order to validate the accuracy of the developed semi-analytical expressions, we present comparison results with Monte Carlo simulations. The major benefit of the proposed mechanism is that it helps in estimating the distribution of ICI without the knowledge of instantaneous resource allocations in the neighbor cells. The proposed methodology applies to any shadowing and fading distributions. Moreover, it can be used to evaluate important network performance metrics numerically without the need for time-consuming Monte Carlo simulations.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130929788","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125284
Dong Fang, A. Burr
In this paper, we investigate a novel Estimate-and-Forward (EF) scheme based on quantization for Turbo coded Physical layer network coding (PLNC) on the two-way relay channel (TWRC). The network coded soft information is estimated as soft bits, which are then transmitted in quantized form. According to the different importance of different bits of the quantization index, unequal error protection (UEP) is then applied using multilevel coding (MLC). The simulation results indicate that the Bit Error Rate (BER) performance of the proposed scheme is superior to that of the traditional Estimate-and-Forward scheme.
{"title":"Quantization based Estimate-and-Forward with unequal error protection for Turbo coded Physical layer network coding on the TWRC","authors":"Dong Fang, A. Burr","doi":"10.1109/ISWCS.2011.6125284","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125284","url":null,"abstract":"In this paper, we investigate a novel Estimate-and-Forward (EF) scheme based on quantization for Turbo coded Physical layer network coding (PLNC) on the two-way relay channel (TWRC). The network coded soft information is estimated as soft bits, which are then transmitted in quantized form. According to the different importance of different bits of the quantization index, unequal error protection (UEP) is then applied using multilevel coding (MLC). The simulation results indicate that the Bit Error Rate (BER) performance of the proposed scheme is superior to that of the traditional Estimate-and-Forward scheme.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132276271","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125404
Pranav Sakulkar, Adrish Banerjee
In this paper, we describe a new method for improving cooperative spectrum sensing in cognitive radio. We introduce a new block based on belief propagation algorithm in the conventional structure of cooperative spectrum sensing. The belief propagation block allows propagation of correct beliefs over a network of secondary users and thus in turn improves the primary user detection. We consider the network of secondary users as Tanner graph [1] and propose a scheme based on belief propagation over these graphs to improve the local decisions at the secondary users before sending the decisions to the fusion center. We demonstrate the improvement in probability of detection, Pd using our belief propagation block by simulating the performance of cooperative spectrum sensing using energy detection over Rayleigh fading channels. The proposed scheme provides improvement over conventional cooperative spectrum sensing for both soft combination and hard combination schemes.
{"title":"Improved cooperative spectrum sensing using belief propagation algorithm and energy detection","authors":"Pranav Sakulkar, Adrish Banerjee","doi":"10.1109/ISWCS.2011.6125404","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125404","url":null,"abstract":"In this paper, we describe a new method for improving cooperative spectrum sensing in cognitive radio. We introduce a new block based on belief propagation algorithm in the conventional structure of cooperative spectrum sensing. The belief propagation block allows propagation of correct beliefs over a network of secondary users and thus in turn improves the primary user detection. We consider the network of secondary users as Tanner graph [1] and propose a scheme based on belief propagation over these graphs to improve the local decisions at the secondary users before sending the decisions to the fusion center. We demonstrate the improvement in probability of detection, Pd using our belief propagation block by simulating the performance of cooperative spectrum sensing using energy detection over Rayleigh fading channels. The proposed scheme provides improvement over conventional cooperative spectrum sensing for both soft combination and hard combination schemes.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132629066","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125441
S. Kayat, M. Ali, Mohd Khairul Mohd Salleh
This paper presents a novel design of a reconfigurable microstrip antenna with a slotted patch. The proposed design was based on the structure of an aperture coupled microstrip antenna using FR-4 substrate at dual operating frequency. Two types of slot (horizontal and vertical) were introduced and three ideal switches were integrated into the horizontal slot to achieve frequency reconfigurability. The design was simulated using CST Microwave Studio Suite 2009 at operating frequency of 2–6GHz. The effects of two different slots and switch configurations were studied and the results were analyzed and discussed in terms of x-axis spacing, slot length, return loss and gain. The simulation results were presented and the proposed antenna is able to operate at dual operating frequency of 2.36 GHz and 5.67GHz.
本文提出了一种新颖的带开槽贴片的可重构微带天线设计。提出了一种基于FR-4基片的双工作频率孔径耦合微带天线结构的设计方案。引入了两种槽型(水平槽型和垂直槽型)，并在水平槽中集成了三个理想的交换机，实现了频率的可重构性。利用CST Microwave Studio Suite 2009在2-6GHz工作频率下对该设计进行了仿真。研究了两种不同槽位和开关配置对系统性能的影响，并从x轴间距、槽位长度、回波损耗和增益等方面对结果进行了分析和讨论。仿真结果表明，该天线能够在2.36 GHz和5.67GHz双工作频率下工作。
{"title":"A reconfigurable microstrip antenna with a slotted patch at dual frequency","authors":"S. Kayat, M. Ali, Mohd Khairul Mohd Salleh","doi":"10.1109/ISWCS.2011.6125441","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125441","url":null,"abstract":"This paper presents a novel design of a reconfigurable microstrip antenna with a slotted patch. The proposed design was based on the structure of an aperture coupled microstrip antenna using FR-4 substrate at dual operating frequency. Two types of slot (horizontal and vertical) were introduced and three ideal switches were integrated into the horizontal slot to achieve frequency reconfigurability. The design was simulated using CST Microwave Studio Suite 2009 at operating frequency of 2–6GHz. The effects of two different slots and switch configurations were studied and the results were analyzed and discussed in terms of x-axis spacing, slot length, return loss and gain. The simulation results were presented and the proposed antenna is able to operate at dual operating frequency of 2.36 GHz and 5.67GHz.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115460217","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125429
Xiang Xu, M. Reyer, Florian Schröder, A. Engels, R. Mathar
Among current physical channel models, deterministic models, such as ray-launching, are accurate but site-specific. Geometry-based stochastic models are flexible, however, cannot benefit if site information is available. In this work, a semi-stochastic MIMO channel model is proposed. It integrates results from deterministic models into stochastic models, merging the advantages of both approaches.
{"title":"A semi-stochastic radio propagation model for wireless MIMO channels","authors":"Xiang Xu, M. Reyer, Florian Schröder, A. Engels, R. Mathar","doi":"10.1109/ISWCS.2011.6125429","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125429","url":null,"abstract":"Among current physical channel models, deterministic models, such as ray-launching, are accurate but site-specific. Geometry-based stochastic models are flexible, however, cannot benefit if site information is available. In this work, a semi-stochastic MIMO channel model is proposed. It integrates results from deterministic models into stochastic models, merging the advantages of both approaches.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115543154","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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