Pub Date : 2003-04-22DOI: 10.1109/VETECS.2003.1208897
M. Zorzi, R. Rao
In this paper, we consider a novel forwarding technique based on collision avoidance and on knowledge of the geographical location of the nodes involved. Selection of the relaying nodes is made randomly via contention among receivers. We consider a simplified performance analysis and provide analytical parameter optimization. Comparisons giving evidence of the accuracy of our approximate approach are also provided. The scheme is compared with STEM, and is shown to perform significantly better for sufficient node density.
{"title":"Exploring the energy-latency tradeoff of geographic random forwarding for ad hoc and sensor networks","authors":"M. Zorzi, R. Rao","doi":"10.1109/VETECS.2003.1208897","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1208897","url":null,"abstract":"In this paper, we consider a novel forwarding technique based on collision avoidance and on knowledge of the geographical location of the nodes involved. Selection of the relaying nodes is made randomly via contention among receivers. We consider a simplified performance analysis and provide analytical parameter optimization. Comparisons giving evidence of the accuracy of our approximate approach are also provided. The scheme is compared with STEM, and is shown to perform significantly better for sufficient node density.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114187535","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207572
M. Fiacco, N. Piercy
The nanoBTS/spl trade/ from ip.access is a GSM/GPRS distributed base station system specifically designed as an inexpensive and flexible solution for coverage of the indoor environment. Thanks to its low power consumption and ease of installation, these GSM-over-IP modules can be used as in-fills to provide extra coverage and capacity or as a PBX replacement where mobile traffic and signalling are routed through the corporate intranet. However, in order to increase the system trunking efficiency, more efficient channel allocation schemes need to be employed; these may not be required for other type of picocell architectures such as distributed antennas systems. This paper explores such algorithms, which are being used within the wireless in-building solution offered by ip.access. Simulation results show that by employing a load based allocation algorithm, the call blocking probability is substantially reduced when compared with mobile driven cell selection schemes.
{"title":"Enhancing GSM capacity in the indoor environment using the nanoBTS","authors":"M. Fiacco, N. Piercy","doi":"10.1109/VETECS.2003.1207572","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207572","url":null,"abstract":"The nanoBTS/spl trade/ from ip.access is a GSM/GPRS distributed base station system specifically designed as an inexpensive and flexible solution for coverage of the indoor environment. Thanks to its low power consumption and ease of installation, these GSM-over-IP modules can be used as in-fills to provide extra coverage and capacity or as a PBX replacement where mobile traffic and signalling are routed through the corporate intranet. However, in order to increase the system trunking efficiency, more efficient channel allocation schemes need to be employed; these may not be required for other type of picocell architectures such as distributed antennas systems. This paper explores such algorithms, which are being used within the wireless in-building solution offered by ip.access. Simulation results show that by employing a load based allocation algorithm, the call blocking probability is substantially reduced when compared with mobile driven cell selection schemes.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114592699","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207758
Y. Teng, T. Nagaosa, K. Mori, H. Kobayashi
This paper proposes an adaptive subchannel and bit allocation method for OFDMA (orthogonal frequency division multiple access) based wireless LAN systems. The proposed adaptive subchannel and bit allocation method combines the adaptive subchannel allocation technique and adaptive modulation technique to improve the channel capacity of OFDMA system. This paper presents computer simulation results to demonstrate that the proposed method can achieve the higher frequency bandwidth efficiency and excellent signal quality even under severe frequency selective fading environment for point-to-multipoint wireless LAN systems.
{"title":"Proposal of adaptive subchannel and bit allocation method for OFDM access wireless LAN systems","authors":"Y. Teng, T. Nagaosa, K. Mori, H. Kobayashi","doi":"10.1109/VETECS.2003.1207758","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207758","url":null,"abstract":"This paper proposes an adaptive subchannel and bit allocation method for OFDMA (orthogonal frequency division multiple access) based wireless LAN systems. The proposed adaptive subchannel and bit allocation method combines the adaptive subchannel allocation technique and adaptive modulation technique to improve the channel capacity of OFDMA system. This paper presents computer simulation results to demonstrate that the proposed method can achieve the higher frequency bandwidth efficiency and excellent signal quality even under severe frequency selective fading environment for point-to-multipoint wireless LAN systems.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129414129","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1208786
Hoon Kim, Jayong Koo, Keunyoung Kim, Youngnam Han
In wireless communication systems, channel estimation is required not only for the coherent demodulation but also for the higher layer resource utilization. In WCDMA/FDD (wideband code division multiple access frequency division duplexing), downlink channel estimation can be performed in both CPICH (common pilot channel) and DPCCH (dedicated physical control channel). In this paper, considering the different link quality between CPICH and DPCCH according to the location of a mobile station (MS), estimation schemes that use both channels are suggested and their performances are compared in terms of mean square error (MSE). Power control effect on DPCCH channel estimation is also investigated in the performance evaluation.
{"title":"Downlink channel estimation and power control in CDMA systems","authors":"Hoon Kim, Jayong Koo, Keunyoung Kim, Youngnam Han","doi":"10.1109/VETECS.2003.1208786","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1208786","url":null,"abstract":"In wireless communication systems, channel estimation is required not only for the coherent demodulation but also for the higher layer resource utilization. In WCDMA/FDD (wideband code division multiple access frequency division duplexing), downlink channel estimation can be performed in both CPICH (common pilot channel) and DPCCH (dedicated physical control channel). In this paper, considering the different link quality between CPICH and DPCCH according to the location of a mobile station (MS), estimation schemes that use both channels are suggested and their performances are compared in terms of mean square error (MSE). Power control effect on DPCCH channel estimation is also investigated in the performance evaluation.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129626910","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207649
K. J. Hwang, Sok-Kyu Lee, K. Chang
The MIMO system employing multiple antennas at both the transmitter and the receiver increases the spectral efficiency greatly. But the spectral efficiency of MIMO system depends on spatial channel characteristics. So some kind of adaptive transmission is required according to spatial channel conditions. In this paper, we propose adaptive rate MIMO system using space-time block mapping. The rate is controlled by effective number of spatial channels. The effective number of spatial channels is determined from spatial channel characteristics and is integer number from 1 to the minimum number of transmit and receive antennas. By switching the MIMO mode adaptively according to spatial channel conditions, throughput can be maximized.
{"title":"Adaptive rate MIMO system using space-time block mapping","authors":"K. J. Hwang, Sok-Kyu Lee, K. Chang","doi":"10.1109/VETECS.2003.1207649","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207649","url":null,"abstract":"The MIMO system employing multiple antennas at both the transmitter and the receiver increases the spectral efficiency greatly. But the spectral efficiency of MIMO system depends on spatial channel characteristics. So some kind of adaptive transmission is required according to spatial channel conditions. In this paper, we propose adaptive rate MIMO system using space-time block mapping. The rate is controlled by effective number of spatial channels. The effective number of spatial channels is determined from spatial channel characteristics and is integer number from 1 to the minimum number of transmit and receive antennas. By switching the MIMO mode adaptively according to spatial channel conditions, throughput can be maximized.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129748964","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207525
C. Bettstetter, Bastian Friedrich
Distributed mobility-adaptive clustering algorithms are used in multihop ad hoc networks to separate the nodes into logical groups and build up a hierarchical network architecture. This paper studies the convergence time and message complexity of Basagni's generalized DMAC clustering algorithm. Our results show how many time steps and signaling messages are typically needed after a single topology change to re-achieve a stable and valid cluster structure. Furthermore, we discuss chain reactions that can occur along a path if certain conditions are fulfilled. Finally, we regard a mobile scenario in order to analyze (a) the number of signaling messages per node and time step and (b) the percentage of time steps in which the cluster structure is invalid. Our results give a qualitative insight on the behavior of clustering in ad hoc networks. In particular, they show that tuning the density of clusterheads and employing a hysteresis parameter for cluster changes can significantly improve the performance.
{"title":"Time and message complexities of the generalized distributed mobility-adaptive clustering (GDMAC) algorithm in wireless multihop networks","authors":"C. Bettstetter, Bastian Friedrich","doi":"10.1109/VETECS.2003.1207525","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207525","url":null,"abstract":"Distributed mobility-adaptive clustering algorithms are used in multihop ad hoc networks to separate the nodes into logical groups and build up a hierarchical network architecture. This paper studies the convergence time and message complexity of Basagni's generalized DMAC clustering algorithm. Our results show how many time steps and signaling messages are typically needed after a single topology change to re-achieve a stable and valid cluster structure. Furthermore, we discuss chain reactions that can occur along a path if certain conditions are fulfilled. Finally, we regard a mobile scenario in order to analyze (a) the number of signaling messages per node and time step and (b) the percentage of time steps in which the cluster structure is invalid. Our results give a qualitative insight on the behavior of clustering in ad hoc networks. In particular, they show that tuning the density of clusterheads and employing a hysteresis parameter for cluster changes can significantly improve the performance.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129945613","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1208800
Seong‐Ho Son, S. Eom, S. Jeon
This paper describes a realization of a tracking phased array antenna system for the shipboard station in X-band satellite communication. This antenna system is necessary to accurately track a target satellite due to the narrow beamwidth. This developed antenna has Tx and Rx antenna beams as well as tracking beam. These beams are independently steered electronically in elevation and mechanically in azimuth. However, a Korean target satellite will be launched into geostationary orbit after a few years. We verified the real-time tracking performance by means of transmission and reception of television broadcasting signal between the developed antenna system and satellite transponder simulator under operation of ship motion simulator. In addition, the measured results of antenna system are presented and discussed.
{"title":"A novel tracking control realization of phased array antenna for mobile satellite communications","authors":"Seong‐Ho Son, S. Eom, S. Jeon","doi":"10.1109/VETECS.2003.1208800","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1208800","url":null,"abstract":"This paper describes a realization of a tracking phased array antenna system for the shipboard station in X-band satellite communication. This antenna system is necessary to accurately track a target satellite due to the narrow beamwidth. This developed antenna has Tx and Rx antenna beams as well as tracking beam. These beams are independently steered electronically in elevation and mechanically in azimuth. However, a Korean target satellite will be launched into geostationary orbit after a few years. We verified the real-time tracking performance by means of transmission and reception of television broadcasting signal between the developed antenna system and satellite transponder simulator under operation of ship motion simulator. In addition, the measured results of antenna system are presented and discussed.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128779753","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1208888
D. Garg, F. Adachi
Recently orthogonal frequency division multiplexing (OFDM) has gained a lot of attention in mobile radio communications because of its ability to allow high data rate transmission in a severe frequency selective fading channel. Rate compatible punctured turbo coded hybrid ARQ (RCPT HARQ) has been found to give improved throughput performance in a DS-CDMA system. However the extent to which the RCPT HARQ improves the throughput performance of the OFDM system has not been fully understood. In this paper we evaluate by computer simulations the performance of the RCPT HARQ for the OFDM system. It is found that the type II RCPT HARQ has the highest throughput when minimum amount of redundancy bits are transmitted with each retransmission, typical case is when the puncturing period for the parity sequences is 8. It was found that the OFDM system with RCPT HARQ outperforms the DS-CDMA system with RCPT HARQ in a frequency selective channel.
{"title":"Rate compatible punctured turbo-coded hybrid ARQ for OFDM in a frequency selective fading channel","authors":"D. Garg, F. Adachi","doi":"10.1109/VETECS.2003.1208888","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1208888","url":null,"abstract":"Recently orthogonal frequency division multiplexing (OFDM) has gained a lot of attention in mobile radio communications because of its ability to allow high data rate transmission in a severe frequency selective fading channel. Rate compatible punctured turbo coded hybrid ARQ (RCPT HARQ) has been found to give improved throughput performance in a DS-CDMA system. However the extent to which the RCPT HARQ improves the throughput performance of the OFDM system has not been fully understood. In this paper we evaluate by computer simulations the performance of the RCPT HARQ for the OFDM system. It is found that the type II RCPT HARQ has the highest throughput when minimum amount of redundancy bits are transmitted with each retransmission, typical case is when the puncturing period for the parity sequences is 8. It was found that the OFDM system with RCPT HARQ outperforms the DS-CDMA system with RCPT HARQ in a frequency selective channel.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129029814","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1208884
T. Hesse
The location methods time-of-arrival (TOA) and time-difference-of-arrival (TDOA) become essential for position computation in UMTS networks. During absence of line-of-sight (LOS) propagation, timing errors will occur when these methods are applied. Hence, presence or absence of an LOS connection must be identified. The proposed algorithm detects a LOS connection of a moving user terminal by utilizing the channel coefficients estimated in a UMTS receiver. From the time variations of the first and second path coefficients, measures of the corresponding Doppler bandwidths are calculated. The difference in bandwidth between a reflected path and an LOS path allows a distinction between LOS and non-LOS (NLOS) propagation of the first path. Computer simulations prove the proper operation of the proposed algorithm in typical propagation environments, leading to a reliable indicator for the presence of an LOS connection. Changes in propagation conditions from NLOS to LOS are also tracked quickly.
{"title":"Detection of a line-of-sight connection to a UMTS base station for increased location accuracy of user terminals","authors":"T. Hesse","doi":"10.1109/VETECS.2003.1208884","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1208884","url":null,"abstract":"The location methods time-of-arrival (TOA) and time-difference-of-arrival (TDOA) become essential for position computation in UMTS networks. During absence of line-of-sight (LOS) propagation, timing errors will occur when these methods are applied. Hence, presence or absence of an LOS connection must be identified. The proposed algorithm detects a LOS connection of a moving user terminal by utilizing the channel coefficients estimated in a UMTS receiver. From the time variations of the first and second path coefficients, measures of the corresponding Doppler bandwidths are calculated. The difference in bandwidth between a reflected path and an LOS path allows a distinction between LOS and non-LOS (NLOS) propagation of the first path. Computer simulations prove the proper operation of the proposed algorithm in typical propagation environments, leading to a reliable indicator for the presence of an LOS connection. Changes in propagation conditions from NLOS to LOS are also tracked quickly.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129290743","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 : 2003-04-22DOI: 10.1109/VETECS.2003.1207739
L. M. Davis, D. Garrett, G. Woodward, M. Bickerstaff, F. Mullany
Multiple-input multiple-output (MIMO) technology has been proposed for the high speed downlink packet access (HSDPA) extension to the 3GPP mobile wireless standard to achieve high data throughput with significantly increased spectral efficiency. Data is encoded, interleaved, spread and transmitted over multiple antennas. This paper presents an architecture for a baseband MIMO HSDPA receiver. The architecture is based on two prototype silicon devices that perform MIMO detection and turbo decoding. System simulations prove the high performance potential of the MIMO proposal for HSDPA. Furthermore, the acceptable complexity of both devices demonstrates the practicality of a single chip solution for an HSDPA MIMO receiver.
{"title":"System architecture and ASICs for a MIMO 3GPP-HSDPA receiver","authors":"L. M. Davis, D. Garrett, G. Woodward, M. Bickerstaff, F. Mullany","doi":"10.1109/VETECS.2003.1207739","DOIUrl":"https://doi.org/10.1109/VETECS.2003.1207739","url":null,"abstract":"Multiple-input multiple-output (MIMO) technology has been proposed for the high speed downlink packet access (HSDPA) extension to the 3GPP mobile wireless standard to achieve high data throughput with significantly increased spectral efficiency. Data is encoded, interleaved, spread and transmitted over multiple antennas. This paper presents an architecture for a baseband MIMO HSDPA receiver. The architecture is based on two prototype silicon devices that perform MIMO detection and turbo decoding. System simulations prove the high performance potential of the MIMO proposal for HSDPA. Furthermore, the acceptable complexity of both devices demonstrates the practicality of a single chip solution for an HSDPA MIMO receiver.","PeriodicalId":272763,"journal":{"name":"The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring.","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126816419","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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