Pub Date : 1997-09-01DOI: 10.1109/PIMRC.1997.631040
P. Kuganesan, K. Letaief, Yue Chen
A new modulation technique, known as multicode modulation, has previously been proposed to transmit high-speed data over multipath wireless links. In this paper, we investigate the use of various combinations of orthogonal codes and signature sequences in multicode modulation and propose a low-complexity receiver structure which uses a fast Walsh transform or fast Fourier transform. To further improve system performance, we also consider the use of antenna diversity and convolutional coding. Sample numerical results which illustrate the potential of multicode modulation over multipath Rayleigh fading links are also presented.
{"title":"Multicode modulation for high-speed wireless data transmission","authors":"P. Kuganesan, K. Letaief, Yue Chen","doi":"10.1109/PIMRC.1997.631040","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.631040","url":null,"abstract":"A new modulation technique, known as multicode modulation, has previously been proposed to transmit high-speed data over multipath wireless links. In this paper, we investigate the use of various combinations of orthogonal codes and signature sequences in multicode modulation and propose a low-complexity receiver structure which uses a fast Walsh transform or fast Fourier transform. To further improve system performance, we also consider the use of antenna diversity and convolutional coding. Sample numerical results which illustrate the potential of multicode modulation over multipath Rayleigh fading links are also presented.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114968020","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.631099
G. Pedersen, S. Widell, Torsten Østervall
The diversity gain obtained by employing antenna diversity on handheld phones are investigated for the two branch case in the presence of the human head. The envelope correlation coefficient is calculated from measurements of angular distributions of multipath field and complex radiation patterns. The mean effective gain (MEG) and diversity gain is calculated for a 360/spl deg/ rotation of the phone in the environments. The calculated correlation, MEG and diversity gain are compared to measured values in the same environments. It is demonstrated that low correlation and nearly equal branch powers can be obtained on small handhelds even when operated near the human head, and it is concluded that a high return can be expected from antenna diversity on realistic handhelds. Furthermore good agreements is shown between both measured correlation and MEGs and calculated values based on measured angular power densities and complex antenna patterns.
{"title":"Handheld antenna diversity evaluation in a DCS-1800 small cell","authors":"G. Pedersen, S. Widell, Torsten Østervall","doi":"10.1109/PIMRC.1997.631099","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.631099","url":null,"abstract":"The diversity gain obtained by employing antenna diversity on handheld phones are investigated for the two branch case in the presence of the human head. The envelope correlation coefficient is calculated from measurements of angular distributions of multipath field and complex radiation patterns. The mean effective gain (MEG) and diversity gain is calculated for a 360/spl deg/ rotation of the phone in the environments. The calculated correlation, MEG and diversity gain are compared to measured values in the same environments. It is demonstrated that low correlation and nearly equal branch powers can be obtained on small handhelds even when operated near the human head, and it is concluded that a high return can be expected from antenna diversity on realistic handhelds. Furthermore good agreements is shown between both measured correlation and MEGs and calculated values based on measured angular power densities and complex antenna patterns.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117195159","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.631058
J. Moss, A. M. Street, D. Edwards, K. Allen
This paper presents techniques for obtaining direction of arrival (DOA) information from both narrowband and wideband radio channel measurements, with the use of spatial diversity. The multipaths arriving at the receiver are presented in a photographic form, which may be directly compared with the surroundings. The use of wideband channel information allows time-gated measurements to be made of the impinging signals. This technique is ideally suited to the validation of radio cellular propagation tools.
{"title":"Radio imaging for the validation of propagation predictions","authors":"J. Moss, A. M. Street, D. Edwards, K. Allen","doi":"10.1109/PIMRC.1997.631058","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.631058","url":null,"abstract":"This paper presents techniques for obtaining direction of arrival (DOA) information from both narrowband and wideband radio channel measurements, with the use of spatial diversity. The multipaths arriving at the receiver are presented in a photographic form, which may be directly compared with the surroundings. The use of wideband channel information allows time-gated measurements to be made of the impinging signals. This technique is ideally suited to the validation of radio cellular propagation tools.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124702591","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.626988
R. Toy, J. Haartsen
This paper presents the results for interference simulations for the GSM-based home base station (HBS) system for a high-density urban scenario. In one possible HBS system, the HBS system is not frequency-coordinated with the overlaying macro cellular network. This paper investigates the impact of such a system on the macro cellular network by simulating the interference environment seen by both the macro cellular system and the HBS system. These simulations study the interference as a function of the HBS base station power and of the traffic load in the HBS system. The results show that such HBS systems can coexist with macro systems in high-density urban areas without producing noticeable interference to the macro cellular system and that the HBS system has good performance.
{"title":"Interference simulations for a home base station system","authors":"R. Toy, J. Haartsen","doi":"10.1109/PIMRC.1997.626988","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.626988","url":null,"abstract":"This paper presents the results for interference simulations for the GSM-based home base station (HBS) system for a high-density urban scenario. In one possible HBS system, the HBS system is not frequency-coordinated with the overlaying macro cellular network. This paper investigates the impact of such a system on the macro cellular network by simulating the interference environment seen by both the macro cellular system and the HBS system. These simulations study the interference as a function of the HBS base station power and of the traffic load in the HBS system. The results show that such HBS systems can coexist with macro systems in high-density urban areas without producing noticeable interference to the macro cellular system and that the HBS system has good performance.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123242605","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.624384
J. Casademont, J. Aspas, M. Carrillo
The Digital European Cordless Telecommunication System (DECT) is gaining acceptance in environments different to the ones the system has been designed for. In particular outdoors environments as the radio local loop (RLL) or public cordless terminal mobility (CTM). The main difference between indoors, where DECT was supposed to work, and outdoors is that for this latter environment the signal propagation is not limited between walls and further studies have to be performed to determine its capacity. In this paper a study of a CTM system in an urban environment is presented. Static or mobile users appear on a surface with a regular distribution of buildings and streets. An evaluation of the traffic capacity and related parameters of the system is performed by simulation. The main focus is on the influence of different base station locations on the static or mobile terminals.
{"title":"DECT capacity in an urban environment","authors":"J. Casademont, J. Aspas, M. Carrillo","doi":"10.1109/PIMRC.1997.624384","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.624384","url":null,"abstract":"The Digital European Cordless Telecommunication System (DECT) is gaining acceptance in environments different to the ones the system has been designed for. In particular outdoors environments as the radio local loop (RLL) or public cordless terminal mobility (CTM). The main difference between indoors, where DECT was supposed to work, and outdoors is that for this latter environment the signal propagation is not limited between walls and further studies have to be performed to determine its capacity. In this paper a study of a CTM system in an urban environment is presented. Static or mobile users appear on a surface with a regular distribution of buildings and streets. An evaluation of the traffic capacity and related parameters of the system is performed by simulation. The main focus is on the influence of different base station locations on the static or mobile terminals.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116540922","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.631076
H. Holma, A. Toskala, Tero Ojanperä
The coverage of a DS-CDMA cellular system in unloaded and in loaded cases is considered. The analysis is based on the noise limited range in the uplink. A medium bit rate data service (144 kbit/s) is used as an example service in this paper. A decrease in cell range is calculated when the network load is increased. The effect of base station multiuser detection in increasing the range in the loaded network is analyzed. Base station multiuser detection is also shown to lower the mobile station transmission power in a loaded network thus making uplink range and average mobile transmission power more insensitive to network load. The impact of inter-cell interference at the base station in different propagation environments is also analyzed in this paper. For actual network planning multiuser detection and the propagation environment must be taken into account.
{"title":"Cellular coverage analysis of wideband MUD-CDMA system","authors":"H. Holma, A. Toskala, Tero Ojanperä","doi":"10.1109/PIMRC.1997.631076","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.631076","url":null,"abstract":"The coverage of a DS-CDMA cellular system in unloaded and in loaded cases is considered. The analysis is based on the noise limited range in the uplink. A medium bit rate data service (144 kbit/s) is used as an example service in this paper. A decrease in cell range is calculated when the network load is increased. The effect of base station multiuser detection in increasing the range in the loaded network is analyzed. Base station multiuser detection is also shown to lower the mobile station transmission power in a loaded network thus making uplink range and average mobile transmission power more insensitive to network load. The impact of inter-cell interference at the base station in different propagation environments is also analyzed in this paper. For actual network planning multiuser detection and the propagation environment must be taken into account.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122891009","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.627022
M. Maeda, M. Nakagawa
Inter-vehicle communication (IVC) systems, where vehicles exchange information with each other, can decrease traffic accidents and promote smoother driving. To realize such systems, decentralized (i.e., base-station-less) network management is required because of the independent movement of vehicles. However, it is very difficult to achieve decentralized synchronization among unspecified vehicles. Therefore we propose an adaptive channel access protocol for an asynchronous communication using spread spectrum (SS), so synchronization is not required. Moreover by using the SS boomerang method, we can realize an IVC system which is adaptable to vehicle density. Such a system is very important for IVC because without an adaptable communication system, when there is high vehicle density some vehicles can not access the channel and transmit their packets reliably. From computer simulations, it was confirmed that the proposed protocol is effective in realizing adaptive communication and all vehicles can transmit their packets reliably.
{"title":"Adaptive channel access protocol for asynchronous inter-vehicle communication network using spread spectrum","authors":"M. Maeda, M. Nakagawa","doi":"10.1109/PIMRC.1997.627022","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.627022","url":null,"abstract":"Inter-vehicle communication (IVC) systems, where vehicles exchange information with each other, can decrease traffic accidents and promote smoother driving. To realize such systems, decentralized (i.e., base-station-less) network management is required because of the independent movement of vehicles. However, it is very difficult to achieve decentralized synchronization among unspecified vehicles. Therefore we propose an adaptive channel access protocol for an asynchronous communication using spread spectrum (SS), so synchronization is not required. Moreover by using the SS boomerang method, we can realize an IVC system which is adaptable to vehicle density. Such a system is very important for IVC because without an adaptable communication system, when there is high vehicle density some vehicles can not access the channel and transmit their packets reliably. From computer simulations, it was confirmed that the proposed protocol is effective in realizing adaptive communication and all vehicles can transmit their packets reliably.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123036627","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.630945
S. Gray, T. Kenney
When IS-95 CDMA mobiles are close to an AMPS base station, the radio frequency portion of the mobile often produces product signals in the baseband CDMA signal. In some cases, AMPS products will decrease the demodulation performance causing the IS-95 CDMA mobile to drop a call. To minimize the impact to existing mobile receiver designs, a technique is described for reducing intermodulation products by first detecting when the products are significant and then switching the low noise amplifier in the IS-95 CDMA mobile between a high and low gain state. This paper presents a detector for AMPS intermodulation products and the performance of this detector using data collected in CDMA networks in Los Angeles.
{"title":"A technique for detecting AMPS intermodulation distortion in an IS-95 CDMA mobile","authors":"S. Gray, T. Kenney","doi":"10.1109/PIMRC.1997.630945","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.630945","url":null,"abstract":"When IS-95 CDMA mobiles are close to an AMPS base station, the radio frequency portion of the mobile often produces product signals in the baseband CDMA signal. In some cases, AMPS products will decrease the demodulation performance causing the IS-95 CDMA mobile to drop a call. To minimize the impact to existing mobile receiver designs, a technique is described for reducing intermodulation products by first detecting when the products are significant and then switching the low noise amplifier in the IS-95 CDMA mobile between a high and low gain state. This paper presents a detector for AMPS intermodulation products and the performance of this detector using data collected in CDMA networks in Los Angeles.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121960543","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.630897
A. Åslundh, M. Frodigh, K. Wallstedt
Today there is growing demand for ubiquitous high-quality indoor wireless communication systems and many different proposals regarding such systems have been brought forward. This study investigates how three different indoor radio network concepts perform in time dynamic simulations when user mobility is introduced. In this new simulation environment a system based on a number of radio-ports connected to a centralized radio network controller is compared to a system based on small pico cells and a system based on distributed antennas. With this particular simulation set up the results indicate that the capacity of the centralized radio network controller is two times the capacity of the pico cellular concept and three times the capacity of the system comprised of distributed antennas. The capacity advantage found here for the centralized radio network controller compared to a distributed antenna solution is smaller than in a previous study. There it was found that the capacity of the centralized radio network controller is four times the capacity of a system with distributed antennas.
{"title":"A performance comparison of three indoor radio network concepts based on time dynamic simulations","authors":"A. Åslundh, M. Frodigh, K. Wallstedt","doi":"10.1109/PIMRC.1997.630897","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.630897","url":null,"abstract":"Today there is growing demand for ubiquitous high-quality indoor wireless communication systems and many different proposals regarding such systems have been brought forward. This study investigates how three different indoor radio network concepts perform in time dynamic simulations when user mobility is introduced. In this new simulation environment a system based on a number of radio-ports connected to a centralized radio network controller is compared to a system based on small pico cells and a system based on distributed antennas. With this particular simulation set up the results indicate that the capacity of the centralized radio network controller is two times the capacity of the pico cellular concept and three times the capacity of the system comprised of distributed antennas. The capacity advantage found here for the centralized radio network controller compared to a distributed antenna solution is smaller than in a previous study. There it was found that the capacity of the centralized radio network controller is four times the capacity of a system with distributed antennas.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117025742","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 : 1997-09-01DOI: 10.1109/PIMRC.1997.627077
V. Tarokh, A. Naguib, N. Seshadri, A. Calderbank
We consider the design of channel codes for improving the data rate and/or the reliability of communications using multiple transmit antennas over a fading channel. It is assumed that the transmitter does not know the channel but seeks to choose a codebook that guarantees a diversity gain of r/sub 1/ when there is no mobility and a diversity gain of r/sub 2//spl ges/r/sub 1/ when the channel is fast fading. A solution to this problem is unveiled in this paper. Here, the encoded data is split into n streams that are simultaneously transmitted using n transmit antennas. The signal received at each receive antenna is a superposition of the faded versions of the n transmitted signals. We derive performance criteria for designing codes having the aforementioned properties. Performance is shown to be determined by diversity advantage quantified by a rank/distance and coding advantage quantified by a determinant/product criterion. The criteria is used to design codes for both slow and rapid fading channels. The constructed codes have remarkable performance in low signal to noise ratios and are suitable for improving the frequency reuse factor under a variety of mobility conditions.
{"title":"Low-rate multi-dimensional space-time codes for both slow and rapid fading channels","authors":"V. Tarokh, A. Naguib, N. Seshadri, A. Calderbank","doi":"10.1109/PIMRC.1997.627077","DOIUrl":"https://doi.org/10.1109/PIMRC.1997.627077","url":null,"abstract":"We consider the design of channel codes for improving the data rate and/or the reliability of communications using multiple transmit antennas over a fading channel. It is assumed that the transmitter does not know the channel but seeks to choose a codebook that guarantees a diversity gain of r/sub 1/ when there is no mobility and a diversity gain of r/sub 2//spl ges/r/sub 1/ when the channel is fast fading. A solution to this problem is unveiled in this paper. Here, the encoded data is split into n streams that are simultaneously transmitted using n transmit antennas. The signal received at each receive antenna is a superposition of the faded versions of the n transmitted signals. We derive performance criteria for designing codes having the aforementioned properties. Performance is shown to be determined by diversity advantage quantified by a rank/distance and coding advantage quantified by a determinant/product criterion. The criteria is used to design codes for both slow and rapid fading channels. The constructed codes have remarkable performance in low signal to noise ratios and are suitable for improving the frequency reuse factor under a variety of mobility conditions.","PeriodicalId":362340,"journal":{"name":"Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117097386","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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