Pub Date : 2013-12-01DOI: 10.1587/TRANSFUN.E96.A.2405
Tien Due Nguyen, T. Fujino, X. Tran
Lattice reduction aided (LRA) has been introduced recently by Yao and Wornell as a new type of MIMO detector. However, the quantization step of LRA detector is only suboptimal. In this paper, we propose a list quantization scheme to reduce the effect of quantization error. The method is to generate a list of candidate symbols from the original LRA estimated symbol. The simulation shows that improved performance can be obtained while additional complexity is reasonable small. The performance of LRA-MMSE with list quantization is shown to be very close to ML performance in both case, 4-QAM and 16-QAM modulation.
{"title":"An improved quantization scheme for lattice-reduction aided MIMO detection","authors":"Tien Due Nguyen, T. Fujino, X. Tran","doi":"10.1587/TRANSFUN.E96.A.2405","DOIUrl":"https://doi.org/10.1587/TRANSFUN.E96.A.2405","url":null,"abstract":"Lattice reduction aided (LRA) has been introduced recently by Yao and Wornell as a new type of MIMO detector. However, the quantization step of LRA detector is only suboptimal. In this paper, we propose a list quantization scheme to reduce the effect of quantization error. The method is to generate a list of candidate symbols from the original LRA estimated symbol. The simulation shows that improved performance can be obtained while additional complexity is reasonable small. The performance of LRA-MMSE with list quantization is shown to be very close to ML performance in both case, 4-QAM and 16-QAM modulation.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125419318","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 : 2007-12-12DOI: 10.1109/CANET.2007.4401687
Gang Yang, Zhengjie Yang, Jianhua Xu
A new tone reservation (TR) scheme for the Peak-to-average power ratio (PAPR) reduction in the orthogonal frequency division multiplexing (OFDM) system is proposed. Different from the conventional TR scheme, the cancellation signals are generated by using FFT/IFFT iteration. Simulation results show that the new TR scheme based on FFT/IFFT has a perfect PAPR reduction performance and the number of iteration is significantly reduced.
{"title":"PAPR reduction in the OFDM system employing Tone Reservation based on FFT/IFFT","authors":"Gang Yang, Zhengjie Yang, Jianhua Xu","doi":"10.1109/CANET.2007.4401687","DOIUrl":"https://doi.org/10.1109/CANET.2007.4401687","url":null,"abstract":"A new tone reservation (TR) scheme for the Peak-to-average power ratio (PAPR) reduction in the orthogonal frequency division multiplexing (OFDM) system is proposed. Different from the conventional TR scheme, the cancellation signals are generated by using FFT/IFFT iteration. Simulation results show that the new TR scheme based on FFT/IFFT has a perfect PAPR reduction performance and the number of iteration is significantly reduced.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114378779","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 : 2007-12-04DOI: 10.1109/ISCIT.2007.4392250
Fangmin Xu, W. Liu, Luyong Zhang, Zheng Zhou
In this paper, a novel frequency coded orthogonal IR-UWB (Impulse Radio UWB) pulse design method based on orthogonal carriers and ternary PN (Pseudo Noise) code is presented. The basic idea of the new approach is that the frequency-shifted sub-pulses are used to generate the orthogonal pulses by coding with PN sequence in frequency domain. Because the orthogonal carriers and PN codes are introduced into IR-UWB, the new method not only has the advantages of both the traditional IR-UWB and Multi-banded OFDM UWB, but also improves the efficiency of the instantaneous spectrum and energy of the transmitting UWB signal. Furthermore, the Auto-correlation and Cross-correlation characteristic of the proposed pulses are better than those of other conventional pulses. In addition, by the aid of Cognitive Radio technology, it can be guaranteed the transmitting signal in accordance with FCC spectral mask and coexistence, interference avoidance with other traditional narrow band system. And simulation results show the unique characters of the proposed pulse.
{"title":"A novel frequency coded orthogonal cognitive UWB pulse and modulation","authors":"Fangmin Xu, W. Liu, Luyong Zhang, Zheng Zhou","doi":"10.1109/ISCIT.2007.4392250","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392250","url":null,"abstract":"In this paper, a novel frequency coded orthogonal IR-UWB (Impulse Radio UWB) pulse design method based on orthogonal carriers and ternary PN (Pseudo Noise) code is presented. The basic idea of the new approach is that the frequency-shifted sub-pulses are used to generate the orthogonal pulses by coding with PN sequence in frequency domain. Because the orthogonal carriers and PN codes are introduced into IR-UWB, the new method not only has the advantages of both the traditional IR-UWB and Multi-banded OFDM UWB, but also improves the efficiency of the instantaneous spectrum and energy of the transmitting UWB signal. Furthermore, the Auto-correlation and Cross-correlation characteristic of the proposed pulses are better than those of other conventional pulses. In addition, by the aid of Cognitive Radio technology, it can be guaranteed the transmitting signal in accordance with FCC spectral mask and coexistence, interference avoidance with other traditional narrow band system. And simulation results show the unique characters of the proposed pulse.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116943889","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 : 2007-12-04DOI: 10.1109/ISCIT.2007.4392105
Golam Sawar, Emmanuel Lochin, R. Boreli
We present experimental results for the performance over satellite and long range wireless (WiMax) links of the new TCP-Friendly Rate Control (TFRC) congestion control mechanism from the Datagram Congestion Control Protocol (DCCP) proposed for use with real-time traffic. We evaluate the performance of the standard DCCP/CCID3 algorithm and identify two problem areas: the measured DCCP/CCID3 rate is inferior to the rate achievable with standard TCP and a significant rate oscillation continuously occurs making the resulting rate variable even in the short term. We analyse the links and identify the potential causes, i.e. long and variable delay and link errors. As a second contribution, we propose a change in the DCCP/CCID3 algorithm in which the number of feedback messages is increased from the currently standard of at least one per return trip time. Although it is recognised that the increase in control traffic may decrease the overall efficiency, we demonstrate that the change results in higher data rates which are closer to what is achievable with TCP on those networks and that the overhead introduced remains acceptable.
{"title":"Experimental performance of DCCP over live satellite and long range wireless links","authors":"Golam Sawar, Emmanuel Lochin, R. Boreli","doi":"10.1109/ISCIT.2007.4392105","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392105","url":null,"abstract":"We present experimental results for the performance over satellite and long range wireless (WiMax) links of the new TCP-Friendly Rate Control (TFRC) congestion control mechanism from the Datagram Congestion Control Protocol (DCCP) proposed for use with real-time traffic. We evaluate the performance of the standard DCCP/CCID3 algorithm and identify two problem areas: the measured DCCP/CCID3 rate is inferior to the rate achievable with standard TCP and a significant rate oscillation continuously occurs making the resulting rate variable even in the short term. We analyse the links and identify the potential causes, i.e. long and variable delay and link errors. As a second contribution, we propose a change in the DCCP/CCID3 algorithm in which the number of feedback messages is increased from the currently standard of at least one per return trip time. Although it is recognised that the increase in control traffic may decrease the overall efficiency, we demonstrate that the change results in higher data rates which are closer to what is achievable with TCP on those networks and that the overhead introduced remains acceptable.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117216200","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 : 2007-12-04DOI: 10.1109/ISCIT.2007.4392112
J. Pedrasa, A. Seneviratne
Mobility management is one area where context-awareness can be of great use. However, most context-management systems have been developed for smart spaces and are not designed for highly mobile devices. We propose an architecture for context-aware mobility management that is both distributed and hierarchical. The architecture consists of a global context server, a number of local proxy and adaptation servers, and the mobile nodes. Our architecture is unique in that both the local servers and the mobile nodes make mobility decisions, instead of having all the intelligence reside on network side components or central servers only, as is the case in most context management systems.
{"title":"A proposed architecture for context-aware mobility management","authors":"J. Pedrasa, A. Seneviratne","doi":"10.1109/ISCIT.2007.4392112","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392112","url":null,"abstract":"Mobility management is one area where context-awareness can be of great use. However, most context-management systems have been developed for smart spaces and are not designed for highly mobile devices. We propose an architecture for context-aware mobility management that is both distributed and hierarchical. The architecture consists of a global context server, a number of local proxy and adaptation servers, and the mobile nodes. Our architecture is unique in that both the local servers and the mobile nodes make mobility decisions, instead of having all the intelligence reside on network side components or central servers only, as is the case in most context management systems.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125042444","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 : 2007-12-04DOI: 10.1109/ISCIT.2007.4392074
Seong Hwan Kim, B. Jung, D. Sung
We present an analytical framework to evaluate the system capacity of two cellular systems in an interference-limited environment: a single-user system with and without other-cell interference and a multiuser system with and without other-cell interference. In a multiuser system, we adopt the multiuser diversity scheme. We derive closed-form expressions of the system capacity for the above four cases. The analytical results agree well with simulation result. Other-cell interference with large variances increases the achievable throughput, while the averaged other-cell interference reduces the system capacity. In addition, we show that a fairness problem arising between inner cells and outer cells in the cellular network can be improved by using other-cell interference in the multiuser system. Therefore, the multiuser diversity scheme can be a good candidate for future cellular networks.
{"title":"Effect of other-cell interference on multiuser diversity in cellular networks","authors":"Seong Hwan Kim, B. Jung, D. Sung","doi":"10.1109/ISCIT.2007.4392074","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392074","url":null,"abstract":"We present an analytical framework to evaluate the system capacity of two cellular systems in an interference-limited environment: a single-user system with and without other-cell interference and a multiuser system with and without other-cell interference. In a multiuser system, we adopt the multiuser diversity scheme. We derive closed-form expressions of the system capacity for the above four cases. The analytical results agree well with simulation result. Other-cell interference with large variances increases the achievable throughput, while the averaged other-cell interference reduces the system capacity. In addition, we show that a fairness problem arising between inner cells and outer cells in the cellular network can be improved by using other-cell interference in the multiuser system. Therefore, the multiuser diversity scheme can be a good candidate for future cellular networks.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123785435","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 : 2007-12-04DOI: 10.1109/ISCIT.2007.4391978
S. Gjessing
An important challenge in Optical Burst Switching (OBS) is to reduce the burst loss caused by contention. In this paper we develop a new method that improves the burst loss probability by burst re-routing in case of contention. Our rerouting method guarantees that bursts (that are not discarded) are routed towards the egress on a loop-free path We have made a detailed discrete event simulation model of OBS networks and evaluated the performance of our new method by comparing it to popular deflection methods. We simulate several realistic network topologies and find that, for realistic loads, re-routing indeed improves burst loss probability and has clear advantages when compared to the discussed deflection methods.
{"title":"A novel method for re-routing in OBS networks","authors":"S. Gjessing","doi":"10.1109/ISCIT.2007.4391978","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4391978","url":null,"abstract":"An important challenge in Optical Burst Switching (OBS) is to reduce the burst loss caused by contention. In this paper we develop a new method that improves the burst loss probability by burst re-routing in case of contention. Our rerouting method guarantees that bursts (that are not discarded) are routed towards the egress on a loop-free path We have made a detailed discrete event simulation model of OBS networks and evaluated the performance of our new method by comparing it to popular deflection methods. We simulate several realistic network topologies and find that, for realistic loads, re-routing indeed improves burst loss probability and has clear advantages when compared to the discussed deflection methods.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125497334","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 : 2007-12-04DOI: 10.1109/ISCIT.2007.4392138
A. Weiss, J. Picard
Next generation mobile networks frequently offer services and applications that require the stations position. It is well known that adding nodes to an existing wireless network enhances the localization accuracy of the network nodes. We exploit a recent compact expression of the Cramer-Rao bound to identify the nodes whose localization is improved. Further, we define the exact conditions for error reduction. In particular, in a planar network, an additional node must have at least three connections, not all of them to anchors, to affect the accuracy. We also show that the accuracy improvement is limited by a bound, which is independent of the number of additional nodes. Finally, we provide numerical examples that shed some light on the accuracy improvement.
{"title":"Localization enhancement by additional nodes in wireless networks","authors":"A. Weiss, J. Picard","doi":"10.1109/ISCIT.2007.4392138","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392138","url":null,"abstract":"Next generation mobile networks frequently offer services and applications that require the stations position. It is well known that adding nodes to an existing wireless network enhances the localization accuracy of the network nodes. We exploit a recent compact expression of the Cramer-Rao bound to identify the nodes whose localization is improved. Further, we define the exact conditions for error reduction. In particular, in a planar network, an additional node must have at least three connections, not all of them to anchors, to affect the accuracy. We also show that the accuracy improvement is limited by a bound, which is independent of the number of additional nodes. Finally, we provide numerical examples that shed some light on the accuracy improvement.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126655137","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 : 2007-12-04DOI: 10.1109/ISCIT.2007.4391997
T. Soorapanth
This paper presents a systematic approach for gaining design insights in a variety of analog design problems. Unlike designers* intuition, this method provides both quantitative and qualitative insights. The method relies on formulating a design problem as a geometric program (GP). These nonlinear, constrained optimization problem can be transformed to convex optimization problems, and then solved (globally) very efficiently. Designers can analyze quantitatively trade-offs among different specifications as well as construct trade-off curves very quickly owing to the efficiency of the method.
{"title":"Gaining insights in analog design via geometric programming","authors":"T. Soorapanth","doi":"10.1109/ISCIT.2007.4391997","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4391997","url":null,"abstract":"This paper presents a systematic approach for gaining design insights in a variety of analog design problems. Unlike designers* intuition, this method provides both quantitative and qualitative insights. The method relies on formulating a design problem as a geometric program (GP). These nonlinear, constrained optimization problem can be transformed to convex optimization problems, and then solved (globally) very efficiently. Designers can analyze quantitatively trade-offs among different specifications as well as construct trade-off curves very quickly owing to the efficiency of the method.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122301414","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 : 2007-12-04DOI: 10.1109/ISCIT.2007.4392031
H. Suzuki, B. Murray, A. Grancea, R. Shaw, J. Pathikulangara, I. Collings
At CSIRO we are engaged in developing enabling technologies for future wireless data communication networks. We have developed a real-time signal processing hardware demonstrator which is suitable for flexible prototyping of new wireless signalling proposals using multiple transmitters and multiple receivers at each end of a communication link, known as multiple-input multiple-output (MIMO). Significant features of our demonstrator include the use of high quality radio components, which allows accurate wideband MIMO channel measurements, and a flexible digital hardware suitable not only for the wideband MIMO demonstrator but also for other applications, such as radio astronomy. This paper describes the design details of the demonstrator.
{"title":"Real-time wideband MIMO demonstrator","authors":"H. Suzuki, B. Murray, A. Grancea, R. Shaw, J. Pathikulangara, I. Collings","doi":"10.1109/ISCIT.2007.4392031","DOIUrl":"https://doi.org/10.1109/ISCIT.2007.4392031","url":null,"abstract":"At CSIRO we are engaged in developing enabling technologies for future wireless data communication networks. We have developed a real-time signal processing hardware demonstrator which is suitable for flexible prototyping of new wireless signalling proposals using multiple transmitters and multiple receivers at each end of a communication link, known as multiple-input multiple-output (MIMO). Significant features of our demonstrator include the use of high quality radio components, which allows accurate wideband MIMO channel measurements, and a flexible digital hardware suitable not only for the wideband MIMO demonstrator but also for other applications, such as radio astronomy. This paper describes the design details of the demonstrator.","PeriodicalId":331439,"journal":{"name":"2007 International Symposium on Communications and Information Technologies","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114045719","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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