Pub Date : 2013-10-24DOI: 10.1109/ISCIT.2013.6645934
Y. H. Chye, E. Dutkiewicz, R. Vesilo, R. Liu
The emerging technology of cognitive radio (CR) allows secondary users (SUs) to gain access to radio spectrum which is licensed to but temporarily unoccupied by primary users (PUs). Apart from spectrum sensing, dynamic spectrum access (DSA) is an important processing task for CR networks (CRNs). Its aim is to allocate spectrum for SUs dynamically without causing any harm to PUs. CRNs may support different traffic types that may have different quality of service (QoS) requirements. In order to meet these QoS requirements, channel states, queue states and traffic types should be taken into account in designing DSA schemes. However, traffic types handled by SUs are treated equally in most existing DSA schemes. We propose a cross-layer scheduling scheme by incorporating DSA, packet scheduling and a channel sharing policy to achieve efficient QoS support for SUs with different traffic types. QoS performance of the proposed scheduling scheme is evaluated in terms of average throughput, average packet delay and packet dropping probability for SUs with different traffic types. Simulation results show that the proposed scheduling scheme outperforms the conventional scheduling scheme by providing more efficient QoS support for SUs and higher throughput fairness among SUs as the PU's activity factor increases.
{"title":"A QoS-aware cross-layer scheduling scheme for multiuser mixed-traffic cognitive radio networks","authors":"Y. H. Chye, E. Dutkiewicz, R. Vesilo, R. Liu","doi":"10.1109/ISCIT.2013.6645934","DOIUrl":"https://doi.org/10.1109/ISCIT.2013.6645934","url":null,"abstract":"The emerging technology of cognitive radio (CR) allows secondary users (SUs) to gain access to radio spectrum which is licensed to but temporarily unoccupied by primary users (PUs). Apart from spectrum sensing, dynamic spectrum access (DSA) is an important processing task for CR networks (CRNs). Its aim is to allocate spectrum for SUs dynamically without causing any harm to PUs. CRNs may support different traffic types that may have different quality of service (QoS) requirements. In order to meet these QoS requirements, channel states, queue states and traffic types should be taken into account in designing DSA schemes. However, traffic types handled by SUs are treated equally in most existing DSA schemes. We propose a cross-layer scheduling scheme by incorporating DSA, packet scheduling and a channel sharing policy to achieve efficient QoS support for SUs with different traffic types. QoS performance of the proposed scheduling scheme is evaluated in terms of average throughput, average packet delay and packet dropping probability for SUs with different traffic types. Simulation results show that the proposed scheduling scheme outperforms the conventional scheduling scheme by providing more efficient QoS support for SUs and higher throughput fairness among SUs as the PU's activity factor increases.","PeriodicalId":356009,"journal":{"name":"2013 13th International Symposium on Communications and Information Technologies (ISCIT)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115614943","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 : 2013-10-24DOI: 10.1109/ISCIT.2013.6645947
Korakoch Kongsombut, R. Chaisricharoen
Problem in the orchid industry's production is caused by the lack of efficient technical knowledge and timely nursery environmental monitoring. Due to the constraints that the nurserymen have in accessing information, they suffered the hardship in managing the orchid care practices. Therefore, we propose a real-time advisory service by utilizing mobile application for mobility, cloud computing technology for scalability, and push notification service for early notification. The service manages to improve nurserymen decision making in orchid care management, reduce cost and time, and enhance their expertise in orchid production.
{"title":"Real-time advisory service for orchid care","authors":"Korakoch Kongsombut, R. Chaisricharoen","doi":"10.1109/ISCIT.2013.6645947","DOIUrl":"https://doi.org/10.1109/ISCIT.2013.6645947","url":null,"abstract":"Problem in the orchid industry's production is caused by the lack of efficient technical knowledge and timely nursery environmental monitoring. Due to the constraints that the nurserymen have in accessing information, they suffered the hardship in managing the orchid care practices. Therefore, we propose a real-time advisory service by utilizing mobile application for mobility, cloud computing technology for scalability, and push notification service for early notification. The service manages to improve nurserymen decision making in orchid care management, reduce cost and time, and enhance their expertise in orchid production.","PeriodicalId":356009,"journal":{"name":"2013 13th International Symposium on Communications and Information Technologies (ISCIT)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114176217","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 : 2013-10-24DOI: 10.1109/ISCIT.2013.6645878
A. López-Martín, R. Carvajal, J. Ramírez-Angulo
The optimal choice of output stages in CMOS transconductors in the presence of nonideal effects is analyzed. It is shown that current folding employing source-coupled differential pairs is advantageous versus the conventional approach based on current mirrors. Two versions of a CMOS transconductor, each one using one of the mentioned approaches, have been fabricated in a 0.5μm CMOS technology and tested. Measurement results confirm the linearity improvements of current folding at the output stage.
{"title":"On the optimal choice of the output stage in CMOS transconductors","authors":"A. López-Martín, R. Carvajal, J. Ramírez-Angulo","doi":"10.1109/ISCIT.2013.6645878","DOIUrl":"https://doi.org/10.1109/ISCIT.2013.6645878","url":null,"abstract":"The optimal choice of output stages in CMOS transconductors in the presence of nonideal effects is analyzed. It is shown that current folding employing source-coupled differential pairs is advantageous versus the conventional approach based on current mirrors. Two versions of a CMOS transconductor, each one using one of the mentioned approaches, have been fabricated in a 0.5μm CMOS technology and tested. Measurement results confirm the linearity improvements of current folding at the output stage.","PeriodicalId":356009,"journal":{"name":"2013 13th International Symposium on Communications and Information Technologies (ISCIT)","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123705431","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 : 2013-10-24DOI: 10.1109/ISCIT.2013.6645909
Chen Meng, Mohammed Raad, R. Raad
This paper describes an extension to Vector Base Amplitude Panning (VBAP) [7]. An audience targeting vector is introduced to the VBAP model to adjust the audio playback system according to the position of the audience. With this modification, it is possible to create virtual sound sources at positions that are better suited for the location of the target audience. Mobile applications such as mobile teleconferencing can take advantage of the surround sound technology to enhance the audio quality for users. In mobile surround, surround sound is produced by mobile telephone handsets, the locations of both the handsets and the audiences may vary during the play back. Therefore, we developed this vector based approach to allow us to move the loudspeakers and the audience independently from each other.
{"title":"Modified Vector Base Amplitude Panning implementation on smart devices","authors":"Chen Meng, Mohammed Raad, R. Raad","doi":"10.1109/ISCIT.2013.6645909","DOIUrl":"https://doi.org/10.1109/ISCIT.2013.6645909","url":null,"abstract":"This paper describes an extension to Vector Base Amplitude Panning (VBAP) [7]. An audience targeting vector is introduced to the VBAP model to adjust the audio playback system according to the position of the audience. With this modification, it is possible to create virtual sound sources at positions that are better suited for the location of the target audience. Mobile applications such as mobile teleconferencing can take advantage of the surround sound technology to enhance the audio quality for users. In mobile surround, surround sound is produced by mobile telephone handsets, the locations of both the handsets and the audiences may vary during the play back. Therefore, we developed this vector based approach to allow us to move the loudspeakers and the audience independently from each other.","PeriodicalId":356009,"journal":{"name":"2013 13th International Symposium on Communications and Information Technologies (ISCIT)","volume":"158 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122503815","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 : 2013-10-24DOI: 10.1109/ISCIT.2013.6645812
Yang Zhang, Zheng Zhou, Yuhang Jia, Bin Li, Zhichao Qin
We present an efficient codeword search algorithm for limited feedback MIMO beamforming systems. Given a predefined codebook, identifying the best beamforming codeword may easily become inefficient in terms of computational complexity. To reduce the computational complexity during the codeword searching process, we propose a novel (off-line) preprocessing scheme, which specifies the feasible condition for efficient searching. By exploiting the triangle inequality principle for distance, we develop a promising kick-out condition to avoid computing the chordal distance in the presence of non-optimal codewords of the input vector. Numerical experimental results have shown that the computational burden of our proposed algorithm has been significantly reduced compared with the traditional exhaustive search.
{"title":"Efficient codeword search algorithm for limited feedback MIMO beamforming systems","authors":"Yang Zhang, Zheng Zhou, Yuhang Jia, Bin Li, Zhichao Qin","doi":"10.1109/ISCIT.2013.6645812","DOIUrl":"https://doi.org/10.1109/ISCIT.2013.6645812","url":null,"abstract":"We present an efficient codeword search algorithm for limited feedback MIMO beamforming systems. Given a predefined codebook, identifying the best beamforming codeword may easily become inefficient in terms of computational complexity. To reduce the computational complexity during the codeword searching process, we propose a novel (off-line) preprocessing scheme, which specifies the feasible condition for efficient searching. By exploiting the triangle inequality principle for distance, we develop a promising kick-out condition to avoid computing the chordal distance in the presence of non-optimal codewords of the input vector. Numerical experimental results have shown that the computational burden of our proposed algorithm has been significantly reduced compared with the traditional exhaustive search.","PeriodicalId":356009,"journal":{"name":"2013 13th International Symposium on Communications and Information Technologies (ISCIT)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129825768","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 : 2013-10-24DOI: 10.1109/ISCIT.2013.6645828
Y. Marye, Rong Sun, Hua-An Zhao
Cooperative communications is a very important mechanism to provide diversity for devices that are incapable of harboring multiple antennae by emulating MIMO system. Different strategies of cooperation exist such as amplify-and-forward (AF) and decode-and-forward (DF). Although cooperation is a viable means of fighting multi path fading, it inherently induces a reduction in spectral efficiency which is against the need for increased data rate of wireless networks. In this paper, adaptive modulation is applied on existing cooperative protocols (AF and DF) as an approach to compensate for spectral efficiency loss while cooperating. In addition, an approach based on the previously existing ones called CSI directed estimate and forward (CDEF) strategy that utilizes CSI better and results in better BER performance with improved spectral efficiency is proposed. Simulation results also confirm the improvements, highlighting a promising approach to satisfy high data rate demands by current and future wireless networks.
{"title":"CSI assisted and modulation adaptive wireless cooperation for increased spectral efficiency","authors":"Y. Marye, Rong Sun, Hua-An Zhao","doi":"10.1109/ISCIT.2013.6645828","DOIUrl":"https://doi.org/10.1109/ISCIT.2013.6645828","url":null,"abstract":"Cooperative communications is a very important mechanism to provide diversity for devices that are incapable of harboring multiple antennae by emulating MIMO system. Different strategies of cooperation exist such as amplify-and-forward (AF) and decode-and-forward (DF). Although cooperation is a viable means of fighting multi path fading, it inherently induces a reduction in spectral efficiency which is against the need for increased data rate of wireless networks. In this paper, adaptive modulation is applied on existing cooperative protocols (AF and DF) as an approach to compensate for spectral efficiency loss while cooperating. In addition, an approach based on the previously existing ones called CSI directed estimate and forward (CDEF) strategy that utilizes CSI better and results in better BER performance with improved spectral efficiency is proposed. Simulation results also confirm the improvements, highlighting a promising approach to satisfy high data rate demands by current and future wireless networks.","PeriodicalId":356009,"journal":{"name":"2013 13th International Symposium on Communications and Information Technologies (ISCIT)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129261225","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 : 2013-10-24DOI: 10.1109/ISCIT.2013.6645843
Soumaya Dahi, S. Tabbane
This paper investigates the issue of determining an appropriate utility function to model the Secondary User (SU) preference toward spectrum holes on the basis of their duration. A Sigmoid shaped utility function is proposed and a proper tuning is discussed to improve the representation of SU preference and to involve the radio quality on the access decision process. The performance and the suitability of the proposed utility function is investigated within an access model whose purpose is to reduce handoff process related to PU activity.
{"title":"Sigmoid utility function formulation for handoff reducing Access model in cognitive radio","authors":"Soumaya Dahi, S. Tabbane","doi":"10.1109/ISCIT.2013.6645843","DOIUrl":"https://doi.org/10.1109/ISCIT.2013.6645843","url":null,"abstract":"This paper investigates the issue of determining an appropriate utility function to model the Secondary User (SU) preference toward spectrum holes on the basis of their duration. A Sigmoid shaped utility function is proposed and a proper tuning is discussed to improve the representation of SU preference and to involve the radio quality on the access decision process. The performance and the suitability of the proposed utility function is investigated within an access model whose purpose is to reduce handoff process related to PU activity.","PeriodicalId":356009,"journal":{"name":"2013 13th International Symposium on Communications and Information Technologies (ISCIT)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129776991","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 : 2013-10-24DOI: 10.1109/ISCIT.2013.6645831
Masathune Ishihara, N. Sasaoka, I. Yoshio, J. Okello
We propose a blind equalization system using an all-pass filter for de-mixing orthogonal frequency division multiplexing (OFDM) symbols in multiple-input multiple-output (MIMO) - OFDM system. In a conventional blind MIMO equalization, there is a possibility that originally transmitted streams are permutated, resulting in being unable to retrieve desired signals at the receiver. In order to solve the problem, each transmitted stream of the proposed MIMO-OFDM system is pre-filtered by a unique all-pass filter. The filter is referred to as Transmit tagging filter (TT-Filter) in this paper. At a receiver, an inverse filter of the TT-filter is used to blindly equalize a MIMO channel without any permutation. The system was originally designed for constant modulus symbol such as PSK signal. This paper evaluates the performance of a QAM Transmission which is non-constant.
{"title":"MCMA equalization without signal permutation for MIMO-OFDM systems using M-QAM","authors":"Masathune Ishihara, N. Sasaoka, I. Yoshio, J. Okello","doi":"10.1109/ISCIT.2013.6645831","DOIUrl":"https://doi.org/10.1109/ISCIT.2013.6645831","url":null,"abstract":"We propose a blind equalization system using an all-pass filter for de-mixing orthogonal frequency division multiplexing (OFDM) symbols in multiple-input multiple-output (MIMO) - OFDM system. In a conventional blind MIMO equalization, there is a possibility that originally transmitted streams are permutated, resulting in being unable to retrieve desired signals at the receiver. In order to solve the problem, each transmitted stream of the proposed MIMO-OFDM system is pre-filtered by a unique all-pass filter. The filter is referred to as Transmit tagging filter (TT-Filter) in this paper. At a receiver, an inverse filter of the TT-filter is used to blindly equalize a MIMO channel without any permutation. The system was originally designed for constant modulus symbol such as PSK signal. This paper evaluates the performance of a QAM Transmission which is non-constant.","PeriodicalId":356009,"journal":{"name":"2013 13th International Symposium on Communications and Information Technologies (ISCIT)","volume":"150 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130946211","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 : 2013-10-24DOI: 10.1109/ISCIT.2013.6645851
Zuo Zhao, Shengbing Zhang
The introduction of the full paper discusses that the influence of weak ties to Information Spreading in online social network are different according to different online social network type. In the information exchanged social networks, removing the weak ties have little influence on the information spreading, while in the relationship social network, removing the weak ties have significant influence on the information spreading. An efficient weak ties evaluation algorithm can more accurately find the weak ties in a social network to improve the control effect of information spreading. We study the weak ties evaluation algorithm, use the concept of clustering coefficient between two friends and the global evolution to optimize the initial algorithm, in order to solve some existed problem in the initial algorithm. Analysis and experiences proved that the new algorithm perform better than the initial algorithm and the weak ties are more effective on the information spreading in online social network, but the new algorithm still has little influence on the information spreading in the information exchanged social networks.
{"title":"Research on influence of weak ties to information spreading in online social networks","authors":"Zuo Zhao, Shengbing Zhang","doi":"10.1109/ISCIT.2013.6645851","DOIUrl":"https://doi.org/10.1109/ISCIT.2013.6645851","url":null,"abstract":"The introduction of the full paper discusses that the influence of weak ties to Information Spreading in online social network are different according to different online social network type. In the information exchanged social networks, removing the weak ties have little influence on the information spreading, while in the relationship social network, removing the weak ties have significant influence on the information spreading. An efficient weak ties evaluation algorithm can more accurately find the weak ties in a social network to improve the control effect of information spreading. We study the weak ties evaluation algorithm, use the concept of clustering coefficient between two friends and the global evolution to optimize the initial algorithm, in order to solve some existed problem in the initial algorithm. Analysis and experiences proved that the new algorithm perform better than the initial algorithm and the weak ties are more effective on the information spreading in online social network, but the new algorithm still has little influence on the information spreading in the information exchanged social networks.","PeriodicalId":356009,"journal":{"name":"2013 13th International Symposium on Communications and Information Technologies (ISCIT)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131502509","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 : 2013-10-24DOI: 10.1109/ISCIT.2013.6645868
A. Suadet, V. Kasemsuwan
A compact class-AB bulk-driven quasi-floating gate current mirror is proposed. The circuit is based on an active class-A current mirror using bulk-driven quasi-floating gate (BD-QFG) MOS transistors and low voltage bulk-input pseudo-differential amplifier. The circuit can operate from a supply voltage as low as VT+VDSAT. The performance of the circuit is verified by SPECTRE, using a standard 0.18 μm CMOS process with a 0.5 V supply voltage. The circuit demonstrates low input impedance (934 Ω) and relatively high output impedance (1.13 MΩ). The circuit can drive the output current 8 times larger than the quiescent current. The power dissipation under quiescent condition is 8.2 μW.
{"title":"A compact class-AB bulk-driven quasi-floating gate current mirror for low voltage applications","authors":"A. Suadet, V. Kasemsuwan","doi":"10.1109/ISCIT.2013.6645868","DOIUrl":"https://doi.org/10.1109/ISCIT.2013.6645868","url":null,"abstract":"A compact class-AB bulk-driven quasi-floating gate current mirror is proposed. The circuit is based on an active class-A current mirror using bulk-driven quasi-floating gate (BD-QFG) MOS transistors and low voltage bulk-input pseudo-differential amplifier. The circuit can operate from a supply voltage as low as VT+VDSAT. The performance of the circuit is verified by SPECTRE, using a standard 0.18 μm CMOS process with a 0.5 V supply voltage. The circuit demonstrates low input impedance (934 Ω) and relatively high output impedance (1.13 MΩ). The circuit can drive the output current 8 times larger than the quiescent current. The power dissipation under quiescent condition is 8.2 μW.","PeriodicalId":356009,"journal":{"name":"2013 13th International Symposium on Communications and Information Technologies (ISCIT)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126569821","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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