Pub Date : 2012-04-01DOI: 10.1109/WCNC.2012.6214357
Mikko V. J. Heikkinen, J. Nurminen
This paper studies the electricity consumption of mobile phone chargers. The charger's electricity consumption varies depending on its state. We measured the electricity consumption of various phone and charger models in different states. We also did panel studies on the recharging behavior of smartphone users. Based on these and other sources, we are able to estimate mobile phone recharging electricity consumption, cost, and CO2 emissions both in Europe and in the USA. Our analysis shows that the actual recharging of batteries consumes only 40% of the total energy; the rest is wasted mainly by unnecessarily plugged-in chargers consuming 55% of the total energy.
{"title":"Measuring and modeling mobile phone charger energy consumption and environmental impact","authors":"Mikko V. J. Heikkinen, J. Nurminen","doi":"10.1109/WCNC.2012.6214357","DOIUrl":"https://doi.org/10.1109/WCNC.2012.6214357","url":null,"abstract":"This paper studies the electricity consumption of mobile phone chargers. The charger's electricity consumption varies depending on its state. We measured the electricity consumption of various phone and charger models in different states. We also did panel studies on the recharging behavior of smartphone users. Based on these and other sources, we are able to estimate mobile phone recharging electricity consumption, cost, and CO2 emissions both in Europe and in the USA. Our analysis shows that the actual recharging of batteries consumes only 40% of the total energy; the rest is wasted mainly by unnecessarily plugged-in chargers consuming 55% of the total energy.","PeriodicalId":329194,"journal":{"name":"2012 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134598562","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 : 2012-04-01DOI: 10.1109/WCNC.2012.6214309
Konstantinos G. Tsiknas, G. Stamatelos
An important application for the IEEE 802.16 technology (also called WiMAX) it to provide high-speed access to the Internet where the transmission control protocol (TCP) is the core transport protocol. In this paper we study through extensive simulation scenarios, the performance characteristics of five representative TCP schemes, namely TCP New Reno, Vegas, Veno, Westwood and BIC, in WiMAX networks, under the conditions of correlated wireless errors, asymmetric end-to-end capabilities and link congestion. The target is to evaluate how the above conditions would affect the TCP congestion control, and suggest the best schemes to be employed in WiMAX Networks.
IEEE 802.16技术(也称为WiMAX)的一个重要应用是提供高速访问Internet，其中传输控制协议(TCP)是核心传输协议。本文通过广泛的仿真场景，研究了WiMAX网络中TCP New Reno、Vegas、Veno、Westwood和BIC五种具有代表性的TCP方案在相关无线误差、端到端能力不对称和链路拥塞等条件下的性能特征。目的是评估上述条件对TCP拥塞控制的影响，并提出在WiMAX网络中采用的最佳方案。
{"title":"Performance evaluation of TCP in IEEE 802.16 networks","authors":"Konstantinos G. Tsiknas, G. Stamatelos","doi":"10.1109/WCNC.2012.6214309","DOIUrl":"https://doi.org/10.1109/WCNC.2012.6214309","url":null,"abstract":"An important application for the IEEE 802.16 technology (also called WiMAX) it to provide high-speed access to the Internet where the transmission control protocol (TCP) is the core transport protocol. In this paper we study through extensive simulation scenarios, the performance characteristics of five representative TCP schemes, namely TCP New Reno, Vegas, Veno, Westwood and BIC, in WiMAX networks, under the conditions of correlated wireless errors, asymmetric end-to-end capabilities and link congestion. The target is to evaluate how the above conditions would affect the TCP congestion control, and suggest the best schemes to be employed in WiMAX Networks.","PeriodicalId":329194,"journal":{"name":"2012 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134608247","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 : 2012-04-01DOI: 10.1109/WCNC.2012.6214264
Holger Degenhardt, A. Klein
A multi-pair two-way relaying scenario with multi-antenna mobile stations is considered. The bidirectional communications between the mobile stations are supported by an intermediate non-regenerative multi-antenna relay station. It is assumed that the mobile stations can subtract the back-propagated self-interference. Different relay transceive filter design approaches which utilize the fact that the mobile stations can perform self-interference cancellation are introduced. First, a self-interference aware MMSE transceive filter is derived. Second, a multi-antenna MMSE extension of the zero-forcing block-diagonalization based approaches is proposed and an upper bound for these approaches is given. The proposed transceive filters require less antennas at the relay station and achieve higher sum rates compared to conventional relay transceive filter approaches which do not exploit the capability of the mobile stations to perform self-interference cancellation.
{"title":"Self-interference aware MIMO filter design for non-regenerative multi-pair two-way relaying","authors":"Holger Degenhardt, A. Klein","doi":"10.1109/WCNC.2012.6214264","DOIUrl":"https://doi.org/10.1109/WCNC.2012.6214264","url":null,"abstract":"A multi-pair two-way relaying scenario with multi-antenna mobile stations is considered. The bidirectional communications between the mobile stations are supported by an intermediate non-regenerative multi-antenna relay station. It is assumed that the mobile stations can subtract the back-propagated self-interference. Different relay transceive filter design approaches which utilize the fact that the mobile stations can perform self-interference cancellation are introduced. First, a self-interference aware MMSE transceive filter is derived. Second, a multi-antenna MMSE extension of the zero-forcing block-diagonalization based approaches is proposed and an upper bound for these approaches is given. The proposed transceive filters require less antennas at the relay station and achieve higher sum rates compared to conventional relay transceive filter approaches which do not exploit the capability of the mobile stations to perform self-interference cancellation.","PeriodicalId":329194,"journal":{"name":"2012 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130307371","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 : 2012-04-01DOI: 10.1109/WCNC.2012.6214254
Yejian Chen, S. Brink
A low-complexity detection algorithm is proposed for Multiple-Input Multiple-Output (MIMO) systems with many transmit and receive antennas. We involve QR Decomposition (QRD) to triangularize the effective MIMO channel matrix so that several MIMO sub-systems can be individually established, which allow detecting several (possibly overlapping) groups of data streams separately. This method is referred to as MIMO Overlapped Subspace Detection (OSD). Further, we propose an OSD based non-iterative (i.e., without feedback from an outer channel decoder) Interference Cancellation (IC) approach where some streams are cancelled out as reliable interference. Link layer simulations for an 8×8 configuration show that this algorithm not only inherits the feature of OSD, yielding a scalable performance/complexity trade-off, but can also closely approach the MIMO ergodic capacity.
{"title":"Enhanced MIMO subspace detection with interference cancellation","authors":"Yejian Chen, S. Brink","doi":"10.1109/WCNC.2012.6214254","DOIUrl":"https://doi.org/10.1109/WCNC.2012.6214254","url":null,"abstract":"A low-complexity detection algorithm is proposed for Multiple-Input Multiple-Output (MIMO) systems with many transmit and receive antennas. We involve QR Decomposition (QRD) to triangularize the effective MIMO channel matrix so that several MIMO sub-systems can be individually established, which allow detecting several (possibly overlapping) groups of data streams separately. This method is referred to as MIMO Overlapped Subspace Detection (OSD). Further, we propose an OSD based non-iterative (i.e., without feedback from an outer channel decoder) Interference Cancellation (IC) approach where some streams are cancelled out as reliable interference. Link layer simulations for an 8×8 configuration show that this algorithm not only inherits the feature of OSD, yielding a scalable performance/complexity trade-off, but can also closely approach the MIMO ergodic capacity.","PeriodicalId":329194,"journal":{"name":"2012 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130365534","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 : 2012-04-01DOI: 10.1109/WCNC.2012.6214012
Ayman Khalil, M. Crussiére, J. Hélard
In this paper, we investigate spectrum sharing and multiple access problems for the high-rate ultra-wideband (UWB) systems. Based on the use of the linear precoded orthogonal frequency division multiplexing (LP-OFDM) proposed as an evolution of the well known multi-band OFDM (MB-OFDM) solution supported by the WiMedia Alliance for future high-rate UWB systems, the objective of this paper is to study a multiuser optimization spectrum sharing scheme for LP-OFDM UWB systems. This optimization study leads to a novel multiple access solution for the high-rate UWB systems. Simulation results demonstrate the efficiency of the use of the LP-OFDM transmission technique in the multiuser spectrum sharing scheme. Besides, the novel LP-OFDM multiuser spectrum sharing solution shows its capacity to provide a good tradeoff between the QoS support of the high-priority users and the fairness between the competing users.
{"title":"Spectrum sharing optimization model for multiuser linear-precoded OFDM UWB systems","authors":"Ayman Khalil, M. Crussiére, J. Hélard","doi":"10.1109/WCNC.2012.6214012","DOIUrl":"https://doi.org/10.1109/WCNC.2012.6214012","url":null,"abstract":"In this paper, we investigate spectrum sharing and multiple access problems for the high-rate ultra-wideband (UWB) systems. Based on the use of the linear precoded orthogonal frequency division multiplexing (LP-OFDM) proposed as an evolution of the well known multi-band OFDM (MB-OFDM) solution supported by the WiMedia Alliance for future high-rate UWB systems, the objective of this paper is to study a multiuser optimization spectrum sharing scheme for LP-OFDM UWB systems. This optimization study leads to a novel multiple access solution for the high-rate UWB systems. Simulation results demonstrate the efficiency of the use of the LP-OFDM transmission technique in the multiuser spectrum sharing scheme. Besides, the novel LP-OFDM multiuser spectrum sharing solution shows its capacity to provide a good tradeoff between the QoS support of the high-priority users and the fairness between the competing users.","PeriodicalId":329194,"journal":{"name":"2012 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125666062","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 : 2012-04-01DOI: 10.1109/WCNC.2012.6213928
Nico Aerts, M. Moeneclaey
Cooperative communication is a promising technique that achieves spatial diversity without requiring multi-antenna receivers. In this paper we consider the cooperative Amplify-and-Forward protocol and assume the channel realizations to be unknown. We study several pilot-based channel estimation strategies at the relay and the destination. The obtained maximum-likelihood estimators are evaluated for transmission over Rice-fading channels, in terms of channel estimation accuracy and error performance.
{"title":"Pilot-based ML estimation in Amplify-and-Forward cooperative networks","authors":"Nico Aerts, M. Moeneclaey","doi":"10.1109/WCNC.2012.6213928","DOIUrl":"https://doi.org/10.1109/WCNC.2012.6213928","url":null,"abstract":"Cooperative communication is a promising technique that achieves spatial diversity without requiring multi-antenna receivers. In this paper we consider the cooperative Amplify-and-Forward protocol and assume the channel realizations to be unknown. We study several pilot-based channel estimation strategies at the relay and the destination. The obtained maximum-likelihood estimators are evaluated for transmission over Rice-fading channels, in terms of channel estimation accuracy and error performance.","PeriodicalId":329194,"journal":{"name":"2012 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115848966","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 : 2012-04-01DOI: 10.1109/WCNC.2012.6214127
N. Shahid, I. Naqvi, Saad B. Qaisar
Support-Vector Machines (SVM) have received a great interest in the machine learning community since their introduction, especially in Outlier Detection in Wireless Sensor Networks (WSN). The Quarter-Sphere formulation of One-Class SVM (QS-SVM), extends the main SVM ideas from supervised to unsupervised learning algorithms. The QS-SVM formulation is based only on Spatio-Temporal correlations between the sensor nodes (hence the name Spatio-Temporal Quarter-Sphere SVM, ST-QS-SVM). Thus, it has a non-ideal performance. This work presents a new One-Class Quarter-Sphere SVM formulation based on the novel concept of Attribute Correlations between the sensor nodes, hence the name, Spatio-Temporal-Attribute Quarter-sphere SVM (STA-QS-SVM) formulation. Online and partially online approaches to Outlier Detection in WSNs have been presented using this formulation. The results indicate a significant increase in the Outlier Detection rates and a remarkable reduction in the False Positive rates over the previous formulation (ST-QS-SVM). The results of this novel technique also suggest that the partially online approach is as efficient as the online approach, thereby conserving significant computational and communication complexity. Moreover very high Event Detection rates have been reported for STA-QS-SVM, which have not been reported by ST-QS-SVM.
{"title":"Quarter-Sphere SVM: Attribute and Spatio-Temporal correlations based Outlier & Event Detection in wireless sensor networks","authors":"N. Shahid, I. Naqvi, Saad B. Qaisar","doi":"10.1109/WCNC.2012.6214127","DOIUrl":"https://doi.org/10.1109/WCNC.2012.6214127","url":null,"abstract":"Support-Vector Machines (SVM) have received a great interest in the machine learning community since their introduction, especially in Outlier Detection in Wireless Sensor Networks (WSN). The Quarter-Sphere formulation of One-Class SVM (QS-SVM), extends the main SVM ideas from supervised to unsupervised learning algorithms. The QS-SVM formulation is based only on Spatio-Temporal correlations between the sensor nodes (hence the name Spatio-Temporal Quarter-Sphere SVM, ST-QS-SVM). Thus, it has a non-ideal performance. This work presents a new One-Class Quarter-Sphere SVM formulation based on the novel concept of Attribute Correlations between the sensor nodes, hence the name, Spatio-Temporal-Attribute Quarter-sphere SVM (STA-QS-SVM) formulation. Online and partially online approaches to Outlier Detection in WSNs have been presented using this formulation. The results indicate a significant increase in the Outlier Detection rates and a remarkable reduction in the False Positive rates over the previous formulation (ST-QS-SVM). The results of this novel technique also suggest that the partially online approach is as efficient as the online approach, thereby conserving significant computational and communication complexity. Moreover very high Event Detection rates have been reported for STA-QS-SVM, which have not been reported by ST-QS-SVM.","PeriodicalId":329194,"journal":{"name":"2012 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124369307","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 : 2012-04-01DOI: 10.1109/WCNC.2012.6214332
Jie Zhang, Tiejun Lv, Hui Gao, Yueming Lu
In this paper, we consider the resource allocation problem in the uplink transmission of an orthogonal frequency-division multiple access (OFDMA) based cognitive radio (CR) network. The resource allocation aims to maximize the uplink throughput of secondary users (SUs) in CR network under the constraints of the primary user (PU) interference and the transmit power limits of SUs. In general, the optimal joint power and subchannel allocation is known as NP-hard. To ease the computation complexity while maintain good performance, we propose a novel particle swarm optimization (PSO) based joint uplink power and subchannel allocation algorithm to solve this resource allocation problem. Due to the combinatorial nature of the resource allocation problem, our algorithm in which power continuously changes while the subchannel allocation strategy alters in the iteration process can obtain better performance than the existing decomposition based algorithm that subchannel assignment and power allocation are implemented separately. Simulation results show the effectiveness of the proposed algorithm.
{"title":"Joint uplink power and subchannel allocation in cognitive radio network","authors":"Jie Zhang, Tiejun Lv, Hui Gao, Yueming Lu","doi":"10.1109/WCNC.2012.6214332","DOIUrl":"https://doi.org/10.1109/WCNC.2012.6214332","url":null,"abstract":"In this paper, we consider the resource allocation problem in the uplink transmission of an orthogonal frequency-division multiple access (OFDMA) based cognitive radio (CR) network. The resource allocation aims to maximize the uplink throughput of secondary users (SUs) in CR network under the constraints of the primary user (PU) interference and the transmit power limits of SUs. In general, the optimal joint power and subchannel allocation is known as NP-hard. To ease the computation complexity while maintain good performance, we propose a novel particle swarm optimization (PSO) based joint uplink power and subchannel allocation algorithm to solve this resource allocation problem. Due to the combinatorial nature of the resource allocation problem, our algorithm in which power continuously changes while the subchannel allocation strategy alters in the iteration process can obtain better performance than the existing decomposition based algorithm that subchannel assignment and power allocation are implemented separately. Simulation results show the effectiveness of the proposed algorithm.","PeriodicalId":329194,"journal":{"name":"2012 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"347 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134259806","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 : 2012-04-01DOI: 10.1109/WCNC.2012.6214170
S. Djahel, Y. Ghamri-Doudane
In this paper, we address the beacon congestion issue in Vehicular Ad Hoc Networks (VANETs) due to its devastating impact on the performance of ITS applications. The periodic beacon broadcast may consume a large part of the available bandwidth leading to an increasing number of collisions among MAC frames, especially in case of high vehicular density. This will severely affect the performance of the Intelligent Transportation Systems (ITS) safety based applications that require timely and reliable dissemination of the event-driven warning messages. To deal with this problem, we propose an original solution that consists of three phases as follows; priority assignment to the messages to be transmitted /forwarded according to two different metrics, congestion detection phase, and finally transmit power and beacon transmission rate adjustment to facilitate emergency messages spread within VANETs. Our solution outperforms the existing works since it doesn't alter the performance of the running ITS applications unless a VANET congestion state is detected. Moreover, it ensures that the most critical and nearest dangers are advertised prior to the farther and less damaging events. The simulation results show promising results and validate our solution.
{"title":"A robust congestion control scheme for fast and reliable dissemination of safety messages in VANETs","authors":"S. Djahel, Y. Ghamri-Doudane","doi":"10.1109/WCNC.2012.6214170","DOIUrl":"https://doi.org/10.1109/WCNC.2012.6214170","url":null,"abstract":"In this paper, we address the beacon congestion issue in Vehicular Ad Hoc Networks (VANETs) due to its devastating impact on the performance of ITS applications. The periodic beacon broadcast may consume a large part of the available bandwidth leading to an increasing number of collisions among MAC frames, especially in case of high vehicular density. This will severely affect the performance of the Intelligent Transportation Systems (ITS) safety based applications that require timely and reliable dissemination of the event-driven warning messages. To deal with this problem, we propose an original solution that consists of three phases as follows; priority assignment to the messages to be transmitted /forwarded according to two different metrics, congestion detection phase, and finally transmit power and beacon transmission rate adjustment to facilitate emergency messages spread within VANETs. Our solution outperforms the existing works since it doesn't alter the performance of the running ITS applications unless a VANET congestion state is detected. Moreover, it ensures that the most critical and nearest dangers are advertised prior to the farther and less damaging events. The simulation results show promising results and validate our solution.","PeriodicalId":329194,"journal":{"name":"2012 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134311382","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 : 2012-04-01DOI: 10.1109/WCNC.2012.6214470
F. Tseng, Min-Yao Chang, Wen-Rong Wu
Most nonlinear transceiver designs in amplify-and-forward (AF) multiple-input-multiple-output (MIMO) relay systems assume that instantaneous perfect channel state informations (CSIs) are available. Transceiver design with imperfect CSIs have rarely been addressed. In this paper, we consider an AF MIMO system in which a Tomlinson-Harashima precoder (THP) is used at the source, a linear precoder at the relay, and a minimum-mean-squared-error (MMSE) receiver at the destination. With the imperfect CSIs, we propose a new robust transceiver design method. It is shown that the optimization problem for the design is difficult due to the fact that the objective function is a nonlinear function of the source and relay precoders and yet the constraints are coupled. To overcome the problem, we adopt the primal decomposition technique, decomposing the original optimization into a subproblem and a master problem. To facilitate the derivation of the solution, we propose cascading THP with a unitary precoder and using a lower bound of the objective function. In this way, we can translate the original matrix-valued optimization into the scalar-valued concave optimization. Using the Karush-Kuhn-Tucker (KKT) conditions, we can finally obtain the closed-form solutions for the relay and source precoders. Simulations show that the proposed design is effective against the imperfect CSIs.
{"title":"Robust MMSE transceiver design in amplify-and-forward MIMO relay system with Tomlinson-Harashima source precoding","authors":"F. Tseng, Min-Yao Chang, Wen-Rong Wu","doi":"10.1109/WCNC.2012.6214470","DOIUrl":"https://doi.org/10.1109/WCNC.2012.6214470","url":null,"abstract":"Most nonlinear transceiver designs in amplify-and-forward (AF) multiple-input-multiple-output (MIMO) relay systems assume that instantaneous perfect channel state informations (CSIs) are available. Transceiver design with imperfect CSIs have rarely been addressed. In this paper, we consider an AF MIMO system in which a Tomlinson-Harashima precoder (THP) is used at the source, a linear precoder at the relay, and a minimum-mean-squared-error (MMSE) receiver at the destination. With the imperfect CSIs, we propose a new robust transceiver design method. It is shown that the optimization problem for the design is difficult due to the fact that the objective function is a nonlinear function of the source and relay precoders and yet the constraints are coupled. To overcome the problem, we adopt the primal decomposition technique, decomposing the original optimization into a subproblem and a master problem. To facilitate the derivation of the solution, we propose cascading THP with a unitary precoder and using a lower bound of the objective function. In this way, we can translate the original matrix-valued optimization into the scalar-valued concave optimization. Using the Karush-Kuhn-Tucker (KKT) conditions, we can finally obtain the closed-form solutions for the relay and source precoders. Simulations show that the proposed design is effective against the imperfect CSIs.","PeriodicalId":329194,"journal":{"name":"2012 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133588629","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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