Pub Date : 2008-03-05DOI: 10.1109/RWS.2008.4463539
J. Matyjas, M. Medley, M. Oxley, S. Reichhart
The objective of this work is the development of cross-layer network receiver designs for wireless CDMA communications with a special emphasis given to high-dimensional adaptive processing under small sample support (e.g. rapidly-changing environments). In this work, we propose a quadratically-constrained MVDR/MMSE filter in an effort to achieve superior filtering performance under limited sample support adaptations. The quadratically-constrained MVDR/MMSE filter estimator utilizes a parameterized estimate of the input covariance matrix that is given as a convex combination of the sample-average covariance matrix and a scalar multiple of its inverse. Selection methods based on the limited sample support are proposed for both the inverse matrix multiplicative scalar as well as the convex parameter, and they can be applied more generally to other adaptive decision techniques such as selection of the diagonally-loaded MVDR parameter.
{"title":"Convex optimization in wireless CDMA receiver design","authors":"J. Matyjas, M. Medley, M. Oxley, S. Reichhart","doi":"10.1109/RWS.2008.4463539","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463539","url":null,"abstract":"The objective of this work is the development of cross-layer network receiver designs for wireless CDMA communications with a special emphasis given to high-dimensional adaptive processing under small sample support (e.g. rapidly-changing environments). In this work, we propose a quadratically-constrained MVDR/MMSE filter in an effort to achieve superior filtering performance under limited sample support adaptations. The quadratically-constrained MVDR/MMSE filter estimator utilizes a parameterized estimate of the input covariance matrix that is given as a convex combination of the sample-average covariance matrix and a scalar multiple of its inverse. Selection methods based on the limited sample support are proposed for both the inverse matrix multiplicative scalar as well as the convex parameter, and they can be applied more generally to other adaptive decision techniques such as selection of the diagonally-loaded MVDR parameter.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126162569","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463614
M. Lehne, S. Raman
A prototype FFT processor IC that reduces linearity requirements of analog-to-digital converters in broadband orthogonal-frequency-division-multiplexing (OFDM) receivers is presented. The processor is based on a time-interleaving bank of sample-and-holds and a discrete- time analog multiplication based FFT. The circuit design of the prototype IC is presented and measurement results from the 0.13 mum test chip are shown. The FFT length-8 prototype successfully demodulates a complex OFDM signal at 1 GSps while drawing 25 milliwatts of power from a 1.2 Volt supply and achieving an error vector magnitude of 2.8%.
{"title":"A prototype analog/mixed-signal fast fourier transform processor IC for OFDM receivers","authors":"M. Lehne, S. Raman","doi":"10.1109/RWS.2008.4463614","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463614","url":null,"abstract":"A prototype FFT processor IC that reduces linearity requirements of analog-to-digital converters in broadband orthogonal-frequency-division-multiplexing (OFDM) receivers is presented. The processor is based on a time-interleaving bank of sample-and-holds and a discrete- time analog multiplication based FFT. The circuit design of the prototype IC is presented and measurement results from the 0.13 mum test chip are shown. The FFT length-8 prototype successfully demodulates a complex OFDM signal at 1 GSps while drawing 25 milliwatts of power from a 1.2 Volt supply and achieving an error vector magnitude of 2.8%.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126189468","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463460
P. Zampardi
GaAs HBT technologies currently dominate the wireless handset marketplace due to their proven RF performance, time-to-market, and size advantages compared to other technologies. As with any technology, new customer specifications and requirements drive the development of next generation processes. Some of the challenging customer requirements that will be, or already are, part of the future of handset power amplifiers are lower end-of-life battery voltage, lower/no reference voltage, improved mid-power efficiency performance, and the increasing number of band/modes used in the phone.
{"title":"GaAs technology status and perspectives for multi-band and multi-standard challenges in upcoming RF-frontends","authors":"P. Zampardi","doi":"10.1109/RWS.2008.4463460","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463460","url":null,"abstract":"GaAs HBT technologies currently dominate the wireless handset marketplace due to their proven RF performance, time-to-market, and size advantages compared to other technologies. As with any technology, new customer specifications and requirements drive the development of next generation processes. Some of the challenging customer requirements that will be, or already are, part of the future of handset power amplifiers are lower end-of-life battery voltage, lower/no reference voltage, improved mid-power efficiency performance, and the increasing number of band/modes used in the phone.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127268566","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463498
M. Hadi, S. Mahmoud
The Compact-FDTD method is optimized for modeling electrically large waveguiding structures by analyzing its dispersion relation and predicting dispersion-optimized model parameters. The resulting algorithm is used to efficiently model an electrically large earth tunnel. Using the dominant mode's quality factor as a benchmark which is a measure of the power leakage through the tunnel walls, it is demonstrated that errors of the order of 1% could be achieved using a very coarse mesh totaling just 200 FDTD cells. This successful numerical experiment paves the way towards modeling more general and realistic tunnels with minimal computing resources.
{"title":"Modeling wireless propagation in a rectangular tunnel with the Compact-FDTD method","authors":"M. Hadi, S. Mahmoud","doi":"10.1109/RWS.2008.4463498","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463498","url":null,"abstract":"The Compact-FDTD method is optimized for modeling electrically large waveguiding structures by analyzing its dispersion relation and predicting dispersion-optimized model parameters. The resulting algorithm is used to efficiently model an electrically large earth tunnel. Using the dominant mode's quality factor as a benchmark which is a measure of the power leakage through the tunnel walls, it is demonstrated that errors of the order of 1% could be achieved using a very coarse mesh totaling just 200 FDTD cells. This successful numerical experiment paves the way towards modeling more general and realistic tunnels with minimal computing resources.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129093608","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463635
T. Van Slyke, W. Kuhn, B. Natarajan
This paper presents quantitative interference measurements from a commercially available ultra-wide-band (UWB) transmitter in the global positioning system (GPS) LI band (1575.42 MHz) to investigate the possibility of co-locating UWB and GPS radios. Theoretical analysis shows that a single UWB transmitter conforming to the United States Federal Communications Commission (FCC) specifications could degrade the sensitivity of a GPS receiver by three decibels if both radios were separated by a distance of 1.33 meters. In this work, we measure radiation from the transmitting antenna and associated circuitry of a UWB (multi-band orthogonal frequency division multiplexing) based commercial USB device. Our measurements reveal that the circuitry associated with the UWB device is a significant source of interference while the interference due to antenna transmissions is minimal. Therefore, we believe that adequate shielding of UWB circuitry is necessary to allow a UWB transmitter and a GPS receiver to be co-located.
{"title":"Measuring interference from a UWB transmitter in the GPS L1 band","authors":"T. Van Slyke, W. Kuhn, B. Natarajan","doi":"10.1109/RWS.2008.4463635","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463635","url":null,"abstract":"This paper presents quantitative interference measurements from a commercially available ultra-wide-band (UWB) transmitter in the global positioning system (GPS) LI band (1575.42 MHz) to investigate the possibility of co-locating UWB and GPS radios. Theoretical analysis shows that a single UWB transmitter conforming to the United States Federal Communications Commission (FCC) specifications could degrade the sensitivity of a GPS receiver by three decibels if both radios were separated by a distance of 1.33 meters. In this work, we measure radiation from the transmitting antenna and associated circuitry of a UWB (multi-band orthogonal frequency division multiplexing) based commercial USB device. Our measurements reveal that the circuitry associated with the UWB device is a significant source of interference while the interference due to antenna transmissions is minimal. Therefore, we believe that adequate shielding of UWB circuitry is necessary to allow a UWB transmitter and a GPS receiver to be co-located.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130912141","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463526
W. Fathelbab, F. Khoury, J. Kellar, K. W. White
A new approach for the design of UWB hairpin-comb filters is presented. The filters can be designed to possess broad upper stopband characteristics by controlling the overall size of their resonators. The measured frequency characteristics of implemented UWB filters show potential first spurious passbands centered at about six times the fundamental passband center frequencies.
{"title":"Ultra-wideband (UWB) Hairpin-Comb filters with broad stopband performances","authors":"W. Fathelbab, F. Khoury, J. Kellar, K. W. White","doi":"10.1109/RWS.2008.4463526","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463526","url":null,"abstract":"A new approach for the design of UWB hairpin-comb filters is presented. The filters can be designed to possess broad upper stopband characteristics by controlling the overall size of their resonators. The measured frequency characteristics of implemented UWB filters show potential first spurious passbands centered at about six times the fundamental passband center frequencies.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"1990 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125504379","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 : 2008-03-05DOI: 10.1109/CHINACOM.2008.4685188
Po-Hao Chang, Li-Kai Ye, Jun-Ren Chen
Recently, mobile communication system has been required to provide quality of service and multimedia service. Since the radio frequency spectrum is a precious resource, wireless radio networks need to make efficient use of it by providing high capacity for the system of interest. Time-domain and Frequency-domain spread MC DS-CDMA (TF-domain spread MC DS-CDMA) is a capacity improvement transmission scheme. The advantage of this scheme is that it can support more users without using long spreading codes. Multiuser Detection (MUD) is a kind of technology that can eliminate multiple access interference and increase system capacity. In this paper, we use Genetic Algorithm to reduce computational complexity of optimum detector and apply it to TF-domain spread MC DS-CDMA to eliminate multiple access interference in order for system to support more users with better performance.
{"title":"Genetic algorithm based multiuser detection in multi-carrier DS-CDMA system","authors":"Po-Hao Chang, Li-Kai Ye, Jun-Ren Chen","doi":"10.1109/CHINACOM.2008.4685188","DOIUrl":"https://doi.org/10.1109/CHINACOM.2008.4685188","url":null,"abstract":"Recently, mobile communication system has been required to provide quality of service and multimedia service. Since the radio frequency spectrum is a precious resource, wireless radio networks need to make efficient use of it by providing high capacity for the system of interest. Time-domain and Frequency-domain spread MC DS-CDMA (TF-domain spread MC DS-CDMA) is a capacity improvement transmission scheme. The advantage of this scheme is that it can support more users without using long spreading codes. Multiuser Detection (MUD) is a kind of technology that can eliminate multiple access interference and increase system capacity. In this paper, we use Genetic Algorithm to reduce computational complexity of optimum detector and apply it to TF-domain spread MC DS-CDMA to eliminate multiple access interference in order for system to support more users with better performance.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126025109","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463420
Khiam-Boon Png, Xiaoming Peng, S. Chattong, H.T. Francis, F. Chin
In this paper, a novel joint carrier and sampling frequency offset estimation scheme for multi-band orthogonal frequency division multiplexing (MB-OFDM) ultra wideband (UWB) system is introduced. We investigate the relationship between carrier and sampling frequency offset when they have a common error source and derive the joint estimation scheme. The proposed scheme consists of two stages. In the first stage, a robust estimation of the frequency offset is carried out using preamble symbols. In the second stage, pilot subcarriers within OFDM symbols is used to track the phase distortion caused by the presence of estimation error, if any, in the first stage. Extensive simulation is carried out and the results show that when coupled with the appropriate compensation algorithms, the proposed scheme is effective in limiting the MB-OFDM system performance degradation due to frequency offset to within 0.5 dB.
{"title":"Joint carrier and sampling frequency offset estimation for MB-OFDM UWB system","authors":"Khiam-Boon Png, Xiaoming Peng, S. Chattong, H.T. Francis, F. Chin","doi":"10.1109/RWS.2008.4463420","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463420","url":null,"abstract":"In this paper, a novel joint carrier and sampling frequency offset estimation scheme for multi-band orthogonal frequency division multiplexing (MB-OFDM) ultra wideband (UWB) system is introduced. We investigate the relationship between carrier and sampling frequency offset when they have a common error source and derive the joint estimation scheme. The proposed scheme consists of two stages. In the first stage, a robust estimation of the frequency offset is carried out using preamble symbols. In the second stage, pilot subcarriers within OFDM symbols is used to track the phase distortion caused by the presence of estimation error, if any, in the first stage. Extensive simulation is carried out and the results show that when coupled with the appropriate compensation algorithms, the proposed scheme is effective in limiting the MB-OFDM system performance degradation due to frequency offset to within 0.5 dB.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"173 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121052707","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463570
M. Chang
For a multiple-input multiple output (MIMO) communication system, the optimal detection is by the maximum-likelihood (ML) approach, which, however, has complexity that increases exponentially with the number of transmit antennas. In this paper, we propose a novel algorithm that implements the MIMO ML detection with reduced complexity. Our algorithm is developed based on a branch-and-bound (BB) principle. We apply a new type of cost function and give an efficient calculation algorithm. The initial reference data vector could be obtained by efficient MMSE-based algorithms. We also observe the impacts of initial reference data vectors.
{"title":"A novel branch-and-bound based maximum-likelihood MIMO detection algorithm","authors":"M. Chang","doi":"10.1109/RWS.2008.4463570","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463570","url":null,"abstract":"For a multiple-input multiple output (MIMO) communication system, the optimal detection is by the maximum-likelihood (ML) approach, which, however, has complexity that increases exponentially with the number of transmit antennas. In this paper, we propose a novel algorithm that implements the MIMO ML detection with reduced complexity. Our algorithm is developed based on a branch-and-bound (BB) principle. We apply a new type of cost function and give an efficient calculation algorithm. The initial reference data vector could be obtained by efficient MMSE-based algorithms. We also observe the impacts of initial reference data vectors.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116218361","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463490
H. Papadopoulos, C. Sundberg
In this paper we consider space-time coded wideband transmission from multiple base-stations. These systems can provide improved resistance to shadowing and extended range. An inherent challenge with these systems, however, is asynchronous reception of the signal elements. We describe three full space diversity approaches for wideband transmission from non-collocated antennas, with throughput, diversity, receiver-complexity trade-offs. Common to all systems are OFDM-type signaling, bit interleaved coded modulation, and iterative decoding. The lowest data-rate lowest complexity system employs an inner orthogonal space- time block code with embedded OFDM transmission, while the highest data-rate highest complexity scheme does not employ an inner code. The latter scheme can provide even higher data rates at reduced space diversity.
{"title":"Wideband space-time coded systems with non-collocated antennas","authors":"H. Papadopoulos, C. Sundberg","doi":"10.1109/RWS.2008.4463490","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463490","url":null,"abstract":"In this paper we consider space-time coded wideband transmission from multiple base-stations. These systems can provide improved resistance to shadowing and extended range. An inherent challenge with these systems, however, is asynchronous reception of the signal elements. We describe three full space diversity approaches for wideband transmission from non-collocated antennas, with throughput, diversity, receiver-complexity trade-offs. Common to all systems are OFDM-type signaling, bit interleaved coded modulation, and iterative decoding. The lowest data-rate lowest complexity system employs an inner orthogonal space- time block code with embedded OFDM transmission, while the highest data-rate highest complexity scheme does not employ an inner code. The latter scheme can provide even higher data rates at reduced space diversity.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122398994","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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