Pub Date : 2009-10-08DOI: 10.1109/APCC.2009.5375673
B. Da, C. Ko
As the number of users increases, the amount of required feedback Channel State Information (CSI) at the base station becomes huge and prohibits the feasibility of conventional adaptive resource allocation algorithms in fairness-aware downlink OFDMA systems. Thus, this paper presents a novel mechanism making use of multi-user diversity to greatly reduce the feedback CSI while maintaining almost the same system performance. Some simulation results are given to verify this partial feedback mechanism.
{"title":"Fairness-aware resource allocation in downlink OFDMA systems with partial feedback CSI","authors":"B. Da, C. Ko","doi":"10.1109/APCC.2009.5375673","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375673","url":null,"abstract":"As the number of users increases, the amount of required feedback Channel State Information (CSI) at the base station becomes huge and prohibits the feasibility of conventional adaptive resource allocation algorithms in fairness-aware downlink OFDMA systems. Thus, this paper presents a novel mechanism making use of multi-user diversity to greatly reduce the feedback CSI while maintaining almost the same system performance. Some simulation results are given to verify this partial feedback mechanism.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115205839","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 : 2009-10-08DOI: 10.1109/APCC.2009.5375630
Sujun Zhang, J. Ping, Hao-jian Yan, Tingting Han1
Investigations of planetary atmospheres, ionospheres, rings, and magnetic fields using radio science techniques have been conducted by almost every planetary mission, and are planned for many future projects. Changes in the frequency, phase, amplitude and polarization of spacecraft radio signal, caused by passage through the atmosphere and ionosphere of the planet, were observed in rising and descending planet occultation events. Utilizing one inversion method, we can get the refractivity profiles of the atmosphere, density, temperature and pressure profiles of the neutral atmosphere, and the electron density profile of the ionosphere. Principles of the planetary radio occultation technique, physical backgrounds and module specifications of the YH-1 ground-based planetary atmosphere occultation processing system are described in this paper.
{"title":"Planetary radio occultation technique and inversion method for YH-1 Mars mission","authors":"Sujun Zhang, J. Ping, Hao-jian Yan, Tingting Han1","doi":"10.1109/APCC.2009.5375630","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375630","url":null,"abstract":"Investigations of planetary atmospheres, ionospheres, rings, and magnetic fields using radio science techniques have been conducted by almost every planetary mission, and are planned for many future projects. Changes in the frequency, phase, amplitude and polarization of spacecraft radio signal, caused by passage through the atmosphere and ionosphere of the planet, were observed in rising and descending planet occultation events. Utilizing one inversion method, we can get the refractivity profiles of the atmosphere, density, temperature and pressure profiles of the neutral atmosphere, and the electron density profile of the ionosphere. Principles of the planetary radio occultation technique, physical backgrounds and module specifications of the YH-1 ground-based planetary atmosphere occultation processing system are described in this paper.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124288215","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 : 2009-10-08DOI: 10.1109/APCC.2009.5375469
Yi-Mao Hsiao, Ming-Jen Chen, Yu-Jen Hsiao, Hui-Kai Su, Y. Chu
With the rapid development of the Internet applications and the explosion of end users, IP address has been exhausted and routing lookup speed is the bottleneck of router design. In addition TCAM is widely used for implementation fast IP forwarding table lookup. However, the need to maintain a sorted list incremental updates may slow the lookup speed in a TCAM. In this paper, a fast TCAM update scheme is proposed for TCAM-Based IPv6 routing lookup architecture. Based on the characteristic of prefix distribution, we design a TCAM-Based router architecture for IPv6 routing lookup. As simulation result shows more than 90% update do not need any memory movement in updating operation. The worse case is (D-2)/2, where D is the length of chain.
{"title":"A fast update scheme for TCAM-based IPv6 routing lookup architecture","authors":"Yi-Mao Hsiao, Ming-Jen Chen, Yu-Jen Hsiao, Hui-Kai Su, Y. Chu","doi":"10.1109/APCC.2009.5375469","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375469","url":null,"abstract":"With the rapid development of the Internet applications and the explosion of end users, IP address has been exhausted and routing lookup speed is the bottleneck of router design. In addition TCAM is widely used for implementation fast IP forwarding table lookup. However, the need to maintain a sorted list incremental updates may slow the lookup speed in a TCAM. In this paper, a fast TCAM update scheme is proposed for TCAM-Based IPv6 routing lookup architecture. Based on the characteristic of prefix distribution, we design a TCAM-Based router architecture for IPv6 routing lookup. As simulation result shows more than 90% update do not need any memory movement in updating operation. The worse case is (D-2)/2, where D is the length of chain.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124667448","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 : 2009-10-08DOI: 10.1109/APCC.2009.5375681
J. Hwang, Jong Seok Park, J. Kim
In this paper, sensing algorithms to select the available sub-bands in the cognitive UWB system are proposed; grouped time division sensing technique and decision methods for sub-channel selection. We employ energy detection method for spectrum sensing, which has low complexity in the wide spectrum sensing. Grouped time division sensing technique is proposed to transmit training symbols and to measure the interference level of sub-bands efficiently. It simplifies the procedure of spectrum sensing, because this scheme requires less number of sensing blocks in receiver. Finally, the decision methods, hard and soft decision, are proposed and compared. Proposed sensing algorithms in this paper can provide wider application of cognitive UWB system and smarter service in coexisting with other wireless system.
{"title":"The spectrum sensing algorithm using the soft decision algorithm in cognitive UWB system","authors":"J. Hwang, Jong Seok Park, J. Kim","doi":"10.1109/APCC.2009.5375681","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375681","url":null,"abstract":"In this paper, sensing algorithms to select the available sub-bands in the cognitive UWB system are proposed; grouped time division sensing technique and decision methods for sub-channel selection. We employ energy detection method for spectrum sensing, which has low complexity in the wide spectrum sensing. Grouped time division sensing technique is proposed to transmit training symbols and to measure the interference level of sub-bands efficiently. It simplifies the procedure of spectrum sensing, because this scheme requires less number of sensing blocks in receiver. Finally, the decision methods, hard and soft decision, are proposed and compared. Proposed sensing algorithms in this paper can provide wider application of cognitive UWB system and smarter service in coexisting with other wireless system.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128997256","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 : 2009-10-08DOI: 10.1109/APCC.2009.5375609
J. Oliver, R. Aravind, K. Prabhu
We consider the problem of pilot-aided accurate least squares (LS) channel estimation in the presence of carrier frequency offset (CFO). We first formulate the mean square error (MSE) of the LS channel estimator in the presence of CFO and then show how to select the pilot sequence (with element values constrained to plus or minus one) that minimizes the MSE. Our main conclusion is that, in the presence of CFO accurate channel estimates can be obtained by transmitting identical pilot symbol on all subcarriers. We demonstrate our results via computer simulations.
{"title":"Improved channel estimation in OFDM systems in the presence of CFO","authors":"J. Oliver, R. Aravind, K. Prabhu","doi":"10.1109/APCC.2009.5375609","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375609","url":null,"abstract":"We consider the problem of pilot-aided accurate least squares (LS) channel estimation in the presence of carrier frequency offset (CFO). We first formulate the mean square error (MSE) of the LS channel estimator in the presence of CFO and then show how to select the pilot sequence (with element values constrained to plus or minus one) that minimizes the MSE. Our main conclusion is that, in the presence of CFO accurate channel estimates can be obtained by transmitting identical pilot symbol on all subcarriers. We demonstrate our results via computer simulations.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127971658","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 : 2009-10-08DOI: 10.1109/APCC.2009.5375577
Y. Tang, X. Hong, X. Cao, Z. Zhao, L. Zhao, W. Wang, J. Wu, J. Lin
Fast tunable wavelength converter based on a GCSR laser and a digital driver is demonstrated in this paper. The wavelength coverage of the GCSR laser is over 40 nm. Hopping-mode wavelengths generated during tuning process are suppressed. Experimental results show that the shortest tuning time is within 6 ns of wavelength coverage 6.6 nm and the suppression ratio of the hopping-mode is 40 dB.
{"title":"Fast tunable wavelength converter with hopping-mode suppression based on GCSR laser and fine digital driver","authors":"Y. Tang, X. Hong, X. Cao, Z. Zhao, L. Zhao, W. Wang, J. Wu, J. Lin","doi":"10.1109/APCC.2009.5375577","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375577","url":null,"abstract":"Fast tunable wavelength converter based on a GCSR laser and a digital driver is demonstrated in this paper. The wavelength coverage of the GCSR laser is over 40 nm. Hopping-mode wavelengths generated during tuning process are suppressed. Experimental results show that the shortest tuning time is within 6 ns of wavelength coverage 6.6 nm and the suppression ratio of the hopping-mode is 40 dB.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130273790","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 : 2009-10-08DOI: 10.1109/APCC.2009.5375585
Guiling Wu, Ming Li, Pan Guo, Xinwan Li, Jianping Chen
A multi-wavelength space multiplexing photonic A/D converters is proposed which combines the WDM and space division multiplexing and enables higher sampling rate with the low loss and completely passive demultiplexing feature. The key technologies and progress are discussed.
{"title":"Multi-wavelength space multiplexing photonic A/D converters","authors":"Guiling Wu, Ming Li, Pan Guo, Xinwan Li, Jianping Chen","doi":"10.1109/APCC.2009.5375585","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375585","url":null,"abstract":"A multi-wavelength space multiplexing photonic A/D converters is proposed which combines the WDM and space division multiplexing and enables higher sampling rate with the low loss and completely passive demultiplexing feature. The key technologies and progress are discussed.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122864813","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 : 2009-10-08DOI: 10.1109/APCC.2009.5375641
M. Kim, Min-Cheol Hong
The purpose of this paper is to improve allocation of the number of bits without skipping the frame by accurately estimating the target bits in H.264/AVC rate control. In our scheme, we propose an enhancement method of the target frame rate based H.264/AVC bit allocation. The enhancement uses a frame complexity estimation to improve the existing mean absolute difference (MAD) complexity measurement. Bit allocation to each frame is not just computed by target frame rate but also adjusted by a combined frame complexity measure. Using the statistical characteristic, we obtain change of occurrence bit about QP to apply the bit amount by QP from the video characteristic and applied in the estimated bit amount of the current frame. Simulation results show that the proposed rate control scheme achieves time saving of more than 99% over existing rate control algorithm. Nevertheless, PSNR and bit rate were almost same as the performances.
{"title":"Adaptive real-time rate control for H.264","authors":"M. Kim, Min-Cheol Hong","doi":"10.1109/APCC.2009.5375641","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375641","url":null,"abstract":"The purpose of this paper is to improve allocation of the number of bits without skipping the frame by accurately estimating the target bits in H.264/AVC rate control. In our scheme, we propose an enhancement method of the target frame rate based H.264/AVC bit allocation. The enhancement uses a frame complexity estimation to improve the existing mean absolute difference (MAD) complexity measurement. Bit allocation to each frame is not just computed by target frame rate but also adjusted by a combined frame complexity measure. Using the statistical characteristic, we obtain change of occurrence bit about QP to apply the bit amount by QP from the video characteristic and applied in the estimated bit amount of the current frame. Simulation results show that the proposed rate control scheme achieves time saving of more than 99% over existing rate control algorithm. Nevertheless, PSNR and bit rate were almost same as the performances.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125668049","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 : 2009-10-08DOI: 10.1109/APCC.2009.5375664
Kazuki Takeda, F. Adachi
The bit error rate (BER) performance improvement of single-carrier signal transmissions using one-tap frequency-domain pre-equalization (pre-FDE) is limited by the residual inter-symbol interference (ISI). Recently, we proposed a joint Tomlinson-Harashima precoding (THP) and pre-FDE (called joint THP/pre-FDE) to improve the BER performance by removing the residual ISI. In this paper, to further improve the BER performance, we optimize THP based on the minimum mean square error (MMSE) criterion and propose a joint MMSE-THP/pre-FDE. The achievable BER and throughput are evaluated by computer simulation.
{"title":"Performance of joint MMSE-THP/Pre-FDE for single-carrier transmissions in a frequency-selective channel","authors":"Kazuki Takeda, F. Adachi","doi":"10.1109/APCC.2009.5375664","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375664","url":null,"abstract":"The bit error rate (BER) performance improvement of single-carrier signal transmissions using one-tap frequency-domain pre-equalization (pre-FDE) is limited by the residual inter-symbol interference (ISI). Recently, we proposed a joint Tomlinson-Harashima precoding (THP) and pre-FDE (called joint THP/pre-FDE) to improve the BER performance by removing the residual ISI. In this paper, to further improve the BER performance, we optimize THP based on the minimum mean square error (MMSE) criterion and propose a joint MMSE-THP/pre-FDE. The achievable BER and throughput are evaluated by computer simulation.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126786650","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 : 2009-10-08DOI: 10.1109/APCC.2009.5375572
Xiaoliang Wang, Xiaohong Jiang, S. Horiguchi
The lack of optical buffer is still one of the main problems that hinder the development of all optical network. The current works on this topic mainly focus on the emulation of optical buffers by using bufferless switch fabric and fiber delay line (SDL). Recent advances have shown the feasibility of emulating many kinds of optical buffers, such as First In First Out (FIFO) buffer, priority buffer etc. The Last In First Out (LIFO) buffer is another important network component that can be used for congestion control and providing quality of service guarantee in the network. In [1] Huang et al. introduced a recursive construction of LIFO buffer with buffer size B by using no less than 9 log B delay lines. In this paper, we explore a more effective construction of optical LIFO buffer from SDL and the feedback switch architecture. Based on such an architecture, a scheduling algorithm is proposed to emulate the LIFO buffer of size B with 2 log B delay lines.
{"title":"Packets scheduling for optical SDL LIFO buffers","authors":"Xiaoliang Wang, Xiaohong Jiang, S. Horiguchi","doi":"10.1109/APCC.2009.5375572","DOIUrl":"https://doi.org/10.1109/APCC.2009.5375572","url":null,"abstract":"The lack of optical buffer is still one of the main problems that hinder the development of all optical network. The current works on this topic mainly focus on the emulation of optical buffers by using bufferless switch fabric and fiber delay line (SDL). Recent advances have shown the feasibility of emulating many kinds of optical buffers, such as First In First Out (FIFO) buffer, priority buffer etc. The Last In First Out (LIFO) buffer is another important network component that can be used for congestion control and providing quality of service guarantee in the network. In [1] Huang et al. introduced a recursive construction of LIFO buffer with buffer size B by using no less than 9 log B delay lines. In this paper, we explore a more effective construction of optical LIFO buffer from SDL and the feedback switch architecture. Based on such an architecture, a scheduling algorithm is proposed to emulate the LIFO buffer of size B with 2 log B delay lines.","PeriodicalId":217893,"journal":{"name":"2009 15th Asia-Pacific Conference on Communications","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114231822","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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