Pub Date : 2008-03-05DOI: 10.1109/RWS.2008.4463462
E. McCune
It is becoming important to properly choose among the many semiconductor switch technologies available when designing efficient high-speed power switches, due to required circuit energy efficiency improvements. In a world of wide bandwidth and high frequency signals, the desirable operating frequency of switch-mode circuitry increases correspondingly. This paper proposes two figures of merit (FoM) combining FET channel ON resistance with gate-charge and gate-source voltage to perform such comparisons. Beyond just comparison, one FoM is shown to be useful in design and evaluation of high speed, high power switches and their drivers. Using these comparisons, silicon FETs are shown to have a huge disadvantage for high speed switching applications including RF power amplifiers.
{"title":"Process- and technology-independent power switching transistor figures of merit","authors":"E. McCune","doi":"10.1109/RWS.2008.4463462","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463462","url":null,"abstract":"It is becoming important to properly choose among the many semiconductor switch technologies available when designing efficient high-speed power switches, due to required circuit energy efficiency improvements. In a world of wide bandwidth and high frequency signals, the desirable operating frequency of switch-mode circuitry increases correspondingly. This paper proposes two figures of merit (FoM) combining FET channel ON resistance with gate-charge and gate-source voltage to perform such comparisons. Beyond just comparison, one FoM is shown to be useful in design and evaluation of high speed, high power switches and their drivers. Using these comparisons, silicon FETs are shown to have a huge disadvantage for high speed switching applications including RF power amplifiers.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"39 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":"114967883","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.2008.4463572
J. Frigon, C. Caloz, Yanyang Zhao
This paper presents a dynamic radiation pattern diversity (DRPD) MIMO wireless system where the antennas radiation patterns are electronically controlled in real-time. The adopted antenna elements are composite right/left-handed (CRLH) microstrip leaky-wave (LW) antennas for which the beam direction can be electronically scanned in a continuous manner from backfire to endfire and the beam shape can be controlled. This system offers a tremendous amount of flexibility in tuning the channel transfer matrix to increase the system performance. Based on this architecture, we propose two simple radiation pattern control algorithms. The first one requires no feedback and averages out the channel fades while the second one requires a simple feedback at the receiver to select the beam pattern maximizing the performance metric. The capacity of both algorithms is derived and analyzed using Monte Carlo simulations. The results show that these algorithms significantly improve the wireless link outage performance in a slow fading environment and increase the diversity gain of a MIMO system for a fixed multiplexing gain.
{"title":"Dynamic radiation pattern diversity (DRPD) MIMO using CRLH leaky-wave antennas","authors":"J. Frigon, C. Caloz, Yanyang Zhao","doi":"10.1109/RWS.2008.4463572","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463572","url":null,"abstract":"This paper presents a dynamic radiation pattern diversity (DRPD) MIMO wireless system where the antennas radiation patterns are electronically controlled in real-time. The adopted antenna elements are composite right/left-handed (CRLH) microstrip leaky-wave (LW) antennas for which the beam direction can be electronically scanned in a continuous manner from backfire to endfire and the beam shape can be controlled. This system offers a tremendous amount of flexibility in tuning the channel transfer matrix to increase the system performance. Based on this architecture, we propose two simple radiation pattern control algorithms. The first one requires no feedback and averages out the channel fades while the second one requires a simple feedback at the receiver to select the beam pattern maximizing the performance metric. The capacity of both algorithms is derived and analyzed using Monte Carlo simulations. The results show that these algorithms significantly improve the wireless link outage performance in a slow fading environment and increase the diversity gain of a MIMO system for a fixed multiplexing gain.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"16 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":"116791349","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.2008.4463632
D. Popescu, P. Yaddanapudi, N. Vallepalli, G. Raju
In this paper we present a side-by-side comparison between time-hopping (TH) impulse radios (IR) based on pulse amplitude modulation (PAM) and interference suppressing (IS) OFDM-based ultra wideband (UWB) systems in multi-user scenarios. For both systems we use minimum mean squared error (MMSE) receivers, and look at the raw bit error rate (BER) at the physical layer as performance criterion. This is evaluated using simulations for various scenarios that include additive white Gaussian noise (AWGN), multipath and/or multiple access interference, and narrowband interference. Numerical results indicate that in the presence of AWGN only, the two systems display similar performance, while for multipath propagation the TH-PAM IR system outperforms the IS-OFDM system. However, in the presence of narrowband interference the IS-OFDM system outperforms the TH-PAM IR system which displays poor performance in this case.
{"title":"A simulation comparison of time-hopping PAM and interference suppressing OFDM in multiuser ultra wideband communications systems","authors":"D. Popescu, P. Yaddanapudi, N. Vallepalli, G. Raju","doi":"10.1109/RWS.2008.4463632","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463632","url":null,"abstract":"In this paper we present a side-by-side comparison between time-hopping (TH) impulse radios (IR) based on pulse amplitude modulation (PAM) and interference suppressing (IS) OFDM-based ultra wideband (UWB) systems in multi-user scenarios. For both systems we use minimum mean squared error (MMSE) receivers, and look at the raw bit error rate (BER) at the physical layer as performance criterion. This is evaluated using simulations for various scenarios that include additive white Gaussian noise (AWGN), multipath and/or multiple access interference, and narrowband interference. Numerical results indicate that in the presence of AWGN only, the two systems display similar performance, while for multipath propagation the TH-PAM IR system outperforms the IS-OFDM system. However, in the presence of narrowband interference the IS-OFDM system outperforms the TH-PAM IR system which displays poor performance in this case.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"61 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":"125092649","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.2008.4463515
G. Baudoin
We present the exact calculation of phase noise due to dithering in a digitally controlled oscillator (DCO) whose output frequency is determined by the switching of elementary capacitors. The instantaneous possible frequency values depend on possible values of capacitors. Frequency resolution is improved by a dithering technique consisting in switching two capacitors values at a high frequency rate. The output frequency depends on the resulting average capacitor value that is function of time percentages during which each capacitor is selected. We give the exact expression of the output power spectral density (psd) and show that it decreases as 1/f4.
{"title":"Exact calculation of phase noise of RF digitally controlled oscillator with frequency resolution improved by dithering","authors":"G. Baudoin","doi":"10.1109/RWS.2008.4463515","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463515","url":null,"abstract":"We present the exact calculation of phase noise due to dithering in a digitally controlled oscillator (DCO) whose output frequency is determined by the switching of elementary capacitors. The instantaneous possible frequency values depend on possible values of capacitors. Frequency resolution is improved by a dithering technique consisting in switching two capacitors values at a high frequency rate. The output frequency depends on the resulting average capacitor value that is function of time percentages during which each capacitor is selected. We give the exact expression of the output power spectral density (psd) and show that it decreases as 1/f4.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"51 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":"123196172","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.2008.4463451
S. Winter, H. Ehm, A. Koelpin, R. Weigel
With an ideal model of a six-port communications receiver in mind, the optimal local oscillator (LO) power at the diode mixers for maximum signal-to-noise-ratio (SNR) at the baseband outputs is determined by simulations. The simulation setup contains the equivalent circuit for a diode mixer that has been used in a six-port communications receiver demonstrator [1]. By means of noise analysis and one tone harmonic balance simulations the SNR characteristics with respect to the LO power is derived in the presence of diode shot noise, and of diode shot noise combined with LO phase noise. The results show that a properly adjusted LO power is essential for the receiver performance.
{"title":"Six-port receiver local oscillator power selection for maximum output SNR","authors":"S. Winter, H. Ehm, A. Koelpin, R. Weigel","doi":"10.1109/RWS.2008.4463451","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463451","url":null,"abstract":"With an ideal model of a six-port communications receiver in mind, the optimal local oscillator (LO) power at the diode mixers for maximum signal-to-noise-ratio (SNR) at the baseband outputs is determined by simulations. The simulation setup contains the equivalent circuit for a diode mixer that has been used in a six-port communications receiver demonstrator [1]. By means of noise analysis and one tone harmonic balance simulations the SNR characteristics with respect to the LO power is derived in the presence of diode shot noise, and of diode shot noise combined with LO phase noise. The results show that a properly adjusted LO power is essential for the receiver performance.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"5 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":"123768095","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.2008.4463528
B. Sewiolo, M. Hartmann, B. Waldmann, R. Weigel
In this paper a new planar balun for UWB- applications has been developed using a two-stage Wilkinson divider for power splitting followed by two coupled line sections for plusmn90 phase shifting. Patterned ground shielding (PGS) is used to increase the even-mode and decrease the odd mode impedances. The compact balun structure covers an area of less than 5 mm2 and has been fabricated on a conventional double-layer printed circuit board to validate simulation results by measurement. The measured input and output return loss is below -10 dB from 3.5 to 10.5 GHz, so that a relative bandwidth of 100% is achieved. The measured insertion loss is about 0.5 dB by an acceptable phase imbalance over the operating frequency range. Measurements show a good agreement with the corresponding simulations.
{"title":"An ultra-wideband coupled-line balun using patterned ground shielding structures","authors":"B. Sewiolo, M. Hartmann, B. Waldmann, R. Weigel","doi":"10.1109/RWS.2008.4463528","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463528","url":null,"abstract":"In this paper a new planar balun for UWB- applications has been developed using a two-stage Wilkinson divider for power splitting followed by two coupled line sections for plusmn90 phase shifting. Patterned ground shielding (PGS) is used to increase the even-mode and decrease the odd mode impedances. The compact balun structure covers an area of less than 5 mm2 and has been fabricated on a conventional double-layer printed circuit board to validate simulation results by measurement. The measured input and output return loss is below -10 dB from 3.5 to 10.5 GHz, so that a relative bandwidth of 100% is achieved. The measured insertion loss is about 0.5 dB by an acceptable phase imbalance over the operating frequency range. Measurements show a good agreement with the corresponding simulations.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"223 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":"115556296","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.2008.4463616
L. Reyero, G. Delisle
New services in wireless communications are enforcing needs for accurate indoor and outdoor location technologies. Existing technologies are offering different coverage and accuracy, but none a pervasive location service. This paper first assesses the coverage and accuracy of the fundamental positioning technologies - GPS, WLAN-based, and GSM-based (Cell-ID and Trilateration) - by systematic measurements in various environments both indoor and outdoor. Then, an Always Best Located (ABL) algorithm is introduced and experimental performance results obtained in real situations are presented.
{"title":"Positioning technologies for implementation of the always best located algorithm","authors":"L. Reyero, G. Delisle","doi":"10.1109/RWS.2008.4463616","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463616","url":null,"abstract":"New services in wireless communications are enforcing needs for accurate indoor and outdoor location technologies. Existing technologies are offering different coverage and accuracy, but none a pervasive location service. This paper first assesses the coverage and accuracy of the fundamental positioning technologies - GPS, WLAN-based, and GSM-based (Cell-ID and Trilateration) - by systematic measurements in various environments both indoor and outdoor. Then, an Always Best Located (ABL) algorithm is introduced and experimental performance results obtained in real situations are presented.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"22 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":"116393566","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.2008.4463596
M. Scardelletti, G. Ponchak, S. Merritt, John S. Minor, A. Christian, Zorman
This paper presents an electrically small, coplanar waveguide fed, folded slot antenna that uses capacitive loading. Several antennas are fabricated with and without capacitive loading to demonstrate the ability of this design approach to reduce the resonant frequency of the antenna, which is analogous to reducing the antenna size. The antennas are fabricated on Cu-clad Rogers DuriodTM 6006 with multilayer chip capacitors to load the antennas. Simulated and measured results show close agreement, thus, validating the approach. The electrically small antennas have a measured return loss greater than 15 dB and a gain of 5.4, 5.6, and 2.7 dBi at 4.3, 3.95, and 3.65 GHz, respectively.
{"title":"Electrically small folded slot antenna utilizing capacitive loaded slot lines","authors":"M. Scardelletti, G. Ponchak, S. Merritt, John S. Minor, A. Christian, Zorman","doi":"10.1109/RWS.2008.4463596","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463596","url":null,"abstract":"This paper presents an electrically small, coplanar waveguide fed, folded slot antenna that uses capacitive loading. Several antennas are fabricated with and without capacitive loading to demonstrate the ability of this design approach to reduce the resonant frequency of the antenna, which is analogous to reducing the antenna size. The antennas are fabricated on Cu-clad Rogers DuriodTM 6006 with multilayer chip capacitors to load the antennas. Simulated and measured results show close agreement, thus, validating the approach. The electrically small antennas have a measured return loss greater than 15 dB and a gain of 5.4, 5.6, and 2.7 dBi at 4.3, 3.95, and 3.65 GHz, respectively.","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":"122926533","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.2008.4463593
P. Prakasam, M. Kulkarni, X. Chen, S. Hoyos, B. Sadler
Transform domain (TD) sampling is presented as an inexpensive and feasible solution for software defined receivers that operate on a very wide frequency spectrum. TD receivers expand the received signal over a basis set, and then operate on the basis coefficients. An analog computation of the basis coefficients efficiently parallelizes the signal for digital processing, relaxing the sampling requirements and enabling parallel digital processing at a much lower rate. Frequency domain (FD) sampling, as a special case of transform-domain sampling, has been proposed to parallelize the sampling process in wideband receivers. The proposed receiver makes use of a windowed integrator to perform charge sampling, which provides inherent anti-aliasing. More complex decimation filters with stronger attenuation of the unwanted channels are easily obtained from the simple integrator and can be exploited in designing a multi-standard receiver. The flexibility and scalability of TD receivers allow for the design of software radios that can operate on a large range of narrowband and wideband communications standards. A "dreamed software- defined-radio" TD receiver design example is provided which is capable of processing GSM, Bluetooth, IEEE802.11b/g, WiMax and UWB in a single reconfigurable frontend.
{"title":"Emerging technologies in software defined receivers","authors":"P. Prakasam, M. Kulkarni, X. Chen, S. Hoyos, B. Sadler","doi":"10.1109/RWS.2008.4463593","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463593","url":null,"abstract":"Transform domain (TD) sampling is presented as an inexpensive and feasible solution for software defined receivers that operate on a very wide frequency spectrum. TD receivers expand the received signal over a basis set, and then operate on the basis coefficients. An analog computation of the basis coefficients efficiently parallelizes the signal for digital processing, relaxing the sampling requirements and enabling parallel digital processing at a much lower rate. Frequency domain (FD) sampling, as a special case of transform-domain sampling, has been proposed to parallelize the sampling process in wideband receivers. The proposed receiver makes use of a windowed integrator to perform charge sampling, which provides inherent anti-aliasing. More complex decimation filters with stronger attenuation of the unwanted channels are easily obtained from the simple integrator and can be exploited in designing a multi-standard receiver. The flexibility and scalability of TD receivers allow for the design of software radios that can operate on a large range of narrowband and wideband communications standards. A \"dreamed software- defined-radio\" TD receiver design example is provided which is capable of processing GSM, Bluetooth, IEEE802.11b/g, WiMax and UWB in a single reconfigurable frontend.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"182 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":"114140312","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.2008.4463595
A. Moustafa, E. Abdallah, E. Hashish
This paper presents compact circular N-shaped antenna which is designed for wireless LAN (IEEE 802.11a) and other wireless communication systems using the 5.15-5.35 GHz frequency range. The reduction in its size is achieved by perturbing the surface current path on the edge of a circular patch antenna by two triangular slots which will form the N- shape. The proposed antenna is designed and fabricated on two-layered (air, Duriod 5880) and has equivalent performance with about 62% reduction in size with respect to the conventional circular antenna on Duriod 5880. The maximum measured bandwidth is approximately 240 MHz or 4.6%, which meets the requirements of WLAN (5.15-5.35 GHz) systems. A comprehensive parametric study has been carried out to understand the effect of various dimensional parameters and to optimize the performance of the antenna.
{"title":"Novel compact circular N-shaped patch antenna for 5.2 GHz wireless communications","authors":"A. Moustafa, E. Abdallah, E. Hashish","doi":"10.1109/RWS.2008.4463595","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463595","url":null,"abstract":"This paper presents compact circular N-shaped antenna which is designed for wireless LAN (IEEE 802.11a) and other wireless communication systems using the 5.15-5.35 GHz frequency range. The reduction in its size is achieved by perturbing the surface current path on the edge of a circular patch antenna by two triangular slots which will form the N- shape. The proposed antenna is designed and fabricated on two-layered (air, Duriod 5880) and has equivalent performance with about 62% reduction in size with respect to the conventional circular antenna on Duriod 5880. The maximum measured bandwidth is approximately 240 MHz or 4.6%, which meets the requirements of WLAN (5.15-5.35 GHz) systems. A comprehensive parametric study has been carried out to understand the effect of various dimensional parameters and to optimize the performance of the antenna.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"7 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":"129038620","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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