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Wireless location algorithm using digital broadcasting signals based on neural network 被引量:1
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作者 柯炜 吴乐南 殷奎喜 《Journal of Southeast University(English Edition)》 EI CAS 2010年第3期394-398,共5页
In order to enhance the accuracy and reliability of wireless location under non-line-of-sight (NLOS) environments,a novel neural network (NN) location approach using the digital broadcasting signals is presented. ... In order to enhance the accuracy and reliability of wireless location under non-line-of-sight (NLOS) environments,a novel neural network (NN) location approach using the digital broadcasting signals is presented. By the learning ability of the NN and the closely approximate unknown function to any degree of desired accuracy,the input-output mapping relationship between coordinates and the measurement data of time of arrival (TOA) and time difference of arrival (TDOA) is established. A real-time learning algorithm based on the extended Kalman filter (EKF) is used to train the multilayer perceptron (MLP) network by treating the linkweights of a network as the states of the nonlinear dynamic system. Since the EKF-based learning algorithm approximately gives the minimum variance estimate of the linkweights,the convergence is improved in comparison with the backwards error propagation (BP) algorithm. Numerical results illustrate thatthe proposedalgorithmcanachieve enhanced accuracy,and the performance ofthe algorithmis betterthanthat of the BP-based NN algorithm and the least squares (LS) algorithm in the NLOS environments. Moreover,this location method does not depend on a particular distribution of the NLOS error and does not need line-of-sight ( LOS ) or NLOS identification. 展开更多
关键词 digital broadcasting signals neural network extended Kalman filter (EKF) backwards error propagation algorithm multilayer perceptron
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The Response Time Analysis of Digital Broadcasting System
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作者 WANGShuo ZHANGJiang-ling FENGDan 《Wuhan University Journal of Natural Sciences》 CAS 2005年第3期515-519,共5页
Digital broadcasting system has become a high-light of research on computer application. To respond to the changes of the playbill in the broadcasting system in real time, the response time of the system must be studi... Digital broadcasting system has become a high-light of research on computer application. To respond to the changes of the playbill in the broadcasting system in real time, the response time of the system must be studied. There is scarcely the research on this area currently. The influence factors in the response time are analyzed; the model on the response time of the system service is built; how the influence factors affect the response time of the system service is validated; and four improvement measures are proposed to minimize the response time of system service. 展开更多
关键词 Key words digital broadcasting system response time ANALYSIS REAL TIME
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Characteristics of Digital Broadcasting Technology and Its Development Research
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作者 Mo YANG 《International Journal of Technology Management》 2014年第11期7-9,共3页
Driven by the rapid development of agricultural science and technology, many techniques have been developed rapidly, especially the development of broadcasting technology which earth-shaking changes have taken place. ... Driven by the rapid development of agricultural science and technology, many techniques have been developed rapidly, especially the development of broadcasting technology which earth-shaking changes have taken place. The advent of digital broadcasting technology makes the broadcast technology enter a new stage. With its low energy consumption and large coverage area, digital broadcasting technology was widely welcomed by the broadcast television industry. This paper analyzes digital audio broadcasting, multimedia digital broadcasting and digital AM broadcasting, and further concretely elaborates the application prospects of digital broadcasting technology. 展开更多
关键词 shock digital broadcasting TECHNOLOGY CHARACTERISTICS APPLICATION
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A smartcard conditional access interface scheme for conditional access subsystem separation in digital TV broadcasting 被引量:2
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作者 XIE Qiang ZHENG Shi-bao YU Xiao-jing 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第6期1008-1017,共10页
Conditional access system (CAS) is a key technical component in digital TV broadcasting through which TV op-erators manage the appropriate rights of different subscribers in order to protect their commercial benefits.... Conditional access system (CAS) is a key technical component in digital TV broadcasting through which TV op-erators manage the appropriate rights of different subscribers in order to protect their commercial benefits. The normal digital TV receiver can only receive and decode the pay TV programs scrambled by one specific CAS. In this paper, the authors proposed a smartcard conditional access interface (SCAI) scheme in order to make the digital TV receiver be a common receiving platform independent of any specific CAS employed at the broadcasting head-end. As a result, it only needs to include a common condi-tional access software package (CCAP) without any requirement of hardware modification in the receiver. Comparison between the two mentioned DVB-CI-based schemes showed that the cost of such kind receiver is greatly reduced. The main design points of the proposed scheme and its reference implementation’s architecture are presented in this paper. This scheme is also one of the candidate national standards for Chinese digital TV broadcasting industry. 展开更多
关键词 digital TV broadcasting Conditional access subsystem separation Smartcard interface
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DIFFERENTIAL AMPLITUDE PHASE SHIFT KEYING: A NEW MODULATION METHOD FOR TURBO CODE IN DIGITAL RADIO BROADCASTING 被引量:2
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作者 Khalid H. Sayhood Wu Lenan (Radio Engineering Department, Southeast University, Nanjing 210096) 《Journal of Electronics(China)》 2003年第2期86-96,共11页
The multilevel modulation techniques nf M-Differential Amplitude Phase Shift Keying (DAPSK) have been proposed in combination with Turbo code scheme for digital radio broadcasting bands below 30 MHz radio channel. Com... The multilevel modulation techniques nf M-Differential Amplitude Phase Shift Keying (DAPSK) have been proposed in combination with Turbo code scheme for digital radio broadcasting bands below 30 MHz radio channel. Comparison of this modulation method with channel coding in an Additive White Gaussian Noise (AWGN) and multi-path fading channels has been presented. The analysis provides an iterative decoding of the Turbo code. 展开更多
关键词 DAPSK system Turbo code digital radio broadcasting
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Advanced Digital Techniques and Tendencies in the Development of Modem Digital Satellite Broadcasting
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作者 董荔真 《Journal of Beijing Institute of Technology》 EI CAS 1994年第2期170-175,共6页
The fundamental aspects of digital broadcasting are its service flexibility and power savings, which make all-digital satellite broadcasting a viable and economic propositon compared with analog broadcasting. Tendenci... The fundamental aspects of digital broadcasting are its service flexibility and power savings, which make all-digital satellite broadcasting a viable and economic propositon compared with analog broadcasting. Tendencies in the development of digital television broadcasting are: (1) Stereophonic or two-language sound transmission with television in existing analog TV system, (2) Digital direct satellite broadcasting (D-DBS); (3)Digital high definition television (HDTV) Broadcasting. 展开更多
关键词 satellite broadcasting television high-resolution TV stereophonic technique/ digital Satellite broadcasting
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Modulation for Digital Radio Broadcasting Using Amplitude Autocorrelation of Pseudo Random Noise Codes to Carry Information
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作者 Fabrício de Araújo Carvalho Fernando Walter 《Communications and Network》 2013年第3期57-64,共8页
The frequency bands used in mobile communications are allocated according to the type of application. With the need for more channels, the frequency spectrum has become a scarce natural resource. This study shows the ... The frequency bands used in mobile communications are allocated according to the type of application. With the need for more channels, the frequency spectrum has become a scarce natural resource. This study shows the results of a proposed modulation using a variation of the autocorrelation of pseudo-random codes to carry information. The work also presents the generation of multiple orthogonal axes to increase the bit rate thus improving the channel efficiency. 展开更多
关键词 digital Radio broadcasting Spectral Efficiency Pseudo Random Codes CDMA SDR
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Digital Radio Broadcasting for Community Radios Using Pseudo-random Codes
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作者 Fabrício de Araújo Carvalho Fernando Walter 《Communications and Network》 2013年第3期374-379,共6页
This paper aims to present a digital radio broadcasting system that explores the advantages of pseudo-random codes. In this context, a transmitter and its dual receiver are able to reuse frequency spectrum bands witho... This paper aims to present a digital radio broadcasting system that explores the advantages of pseudo-random codes. In this context, a transmitter and its dual receiver are able to reuse frequency spectrum bands without interfering on other existing communication systems. It is proposed a communication system that allows radio broadcasting with the following characteristics: lower transmission power, new communication channels and digital signal processing techinques to add positioning services in two dimensions. 展开更多
关键词 digital Radio broadcasting Software Defined Radio Spectral Efficiency Trilateration Positioning
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Equalization Reconstruction Algorithm Based on Reference Signal Frequency Domain Block Joint for DTMB-Based Passive Radar
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作者 Shuai Ma Zeqi Yang +2 位作者 Hua Zhang Yiheng Liu Xiaode Lyu 《Journal of Beijing Institute of Technology》 EI CAS 2024年第1期41-53,共13页
Channel equalization plays a pivotal role within the reconstruction phase of passive radar reference signals.In the context of reconstructing digital terrestrial multimedia broadcasting(DTMB)signals for low-slow-small... Channel equalization plays a pivotal role within the reconstruction phase of passive radar reference signals.In the context of reconstructing digital terrestrial multimedia broadcasting(DTMB)signals for low-slow-small(LSS)target detection,a novel frequency domain block joint equalization algorithm is presented in this article.From the DTMB signal frame structure and channel multipath transmission characteristics,this article adopts a unconventional approach where the delay and frame structure of each DTMB signal frame are reconfigured to create a circular convolution block,facilitating concurrent fast Fourier transform(FFT)calculations.Following equalization,an inverse fast Fourier transform(IFFT)-based joint output and subsequent data reordering are executed to finalize the equalization process for the DTMB signal.Simulation and measured data confirm that this algorithm outperforms conventional techniques by reducing signal errors rate and enhancing real-time processing.In passive radar LSS detection,it effectively suppresses multipath and noise through frequency domain equalization,reducing false alarms and improving the capabilities of weak target detection. 展开更多
关键词 passive radar frequency domain equalization reference signal reconstruction digital terrestrial multimedia broadcasting(DTMB)
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High Robust Broadcasting over DTMB-A with Low-rate LDPC Codes 被引量:2
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作者 Chao Zhang Kewu Peng +2 位作者 Zhitong He Yonglin Xue Hui Yang 《China Communications》 SCIE CSCD 2022年第3期192-201,共10页
As the 2nd generation digital terrestrial television broadcasting(DTTB)standard,digital terrestrial/television multimedia broadcasting-advanced(DTMB-A)can provide higher spectrum efficiency and transmission reliabilit... As the 2nd generation digital terrestrial television broadcasting(DTTB)standard,digital terrestrial/television multimedia broadcasting-advanced(DTMB-A)can provide higher spectrum efficiency and transmission reliability by adopting flexible frame structure and advanced forward error correction coding compared with the 1 st generation DTTB systems.In order to increase the flexibility and robustness of the DTTB network,the frequency reuse scheme of factor one(reuse-1)is proposed,where the same RF channel is used by different stations covering the adjacent service areas.However,it demands a very low carrier-tonoise ratio(C/N)threshold below 0 dB at the DTTB physical layer.In this paper,a robust broadcasting technique is proposed based on DTMB-A with newly designed low-rate low density parity check(LDPC)codes.By adopting quasi-cyclic(QC)Raptor-like structure and progressive lifting method,the high performance low-rate LDPC codes are designed supporting multiple code lengths.Both density-evolution analyses and laboratory measurements demonstrate that DTMB-A with low-rate coding can complete the demodulation reliably with the C/N threshold below0 d B,which is one important necessary condition to support frequency reuse-1 scheme. 展开更多
关键词 digital terrestrial/television multimedia broadcasting-advanced(DTMB-A) digital terrestrial television broadcasting(DTTB) low-rate low density parity check(LDPC)code
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Cooperative DVB-SH Satellite Broadcasting Systems with Rotated Signal Constellations
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作者 Nikos C.Sagias Stylianos Papaharalabos P.Takis Mathiopoulos 《China Communications》 SCIE CSCD 2015年第6期59-72,共14页
In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) wi... In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) with fixed installment,which acts as a relay.Moreover and in the context of the digital video broadcasting-satellite-to-handheld(DVB-SH) standard,the performance improvements offered by the rotated constellations method are investigated,where prior transmission,a phase rotation of the transmitted symbols by a fixed angle is applied followed by a random component interleaver.Turbo codes with soft decision decoding and appropriate random channel interleavers are also considered.We present analytical expressions for the bit log-likelihood ratios(LLRs)that are needed for soft decision decoding at the MT turbo decoder,while the code combining technique is adapted to improve the end-to-end(E2E) performance.Then,we obtain through extensive computer simulations the average bit error probability(ABEP) of quadrature phase-shift keying(QPSK) signals received over pure land-mobile satellite(LMS)and pure CGS links for coding rates 1/3 and6/7.Moreover,the optimal rotation angles are obtained for both links.E2 E ABEP results are then presented assuming cooperation between GEO and CGS,while the power allocation issue is investigated under fixed total transmission power.Our performance evaluation results show that by using the constellation rotation technique,a performance gain can be achieved for high coding rates. 展开更多
关键词 broadcasting code combining constellation rotation coding rate comple-mentary ground system (CGS) coopera-tion digital video broadcasting satellite-to-hand-held (DVB-SH) DECODE-AND-FORWARD log-likelihood ratio (LLR) quadrature phase-shift keying (QPSK) orthogonal frequency-di-vision multiplexing (OFDM) relays satellitecommunications soft-decision decoding tur-bo codes random interleavers
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A NOVEL ALGORITHM FOR SIDE PEAKS SUPPRESSION OF AMBIGUITY FUNCTION FOR PASSIVE RADAR BASED ON CHINESE DTTB SIGNAL 被引量:5
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作者 Li Jichuan Lu Xiaode Zhao Yaodong 《Journal of Electronics(China)》 2012年第6期485-492,共8页
The ambiguity function of Chinese standard Digital Television Terrestrial Broadcasting (DTTB) signals for passive radar contains one main peak and many side peaks. The side peaks may cause the false alarms. The relati... The ambiguity function of Chinese standard Digital Television Terrestrial Broadcasting (DTTB) signals for passive radar contains one main peak and many side peaks. The side peaks may cause the false alarms. The relative positions and the reasons for the side peaks are analyzed and a new algorithm for side peaks suppression is proposed in this paper. The algorithm, in consideration of the characteristics of the structure of the frame, can eliminate the side peaks completely in the valid Doppler observation interval by setting the reference signals to zero at equal intervals. Both the simulative and experimental results show that this algorithm can improve the performance of target detection of the passive radar based on DTTB signal. 展开更多
关键词 Passive radar digital Television Terrestrial broadcasting (DTTB) Ambiguity Function (AF) Side peaks suppression
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Efficient Priority Packet Recovery Based on Network Coding in DVB-IPDC System
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作者 WANG Lian PENG Daiyuan LIANG Hongbin 《China Communications》 SCIE CSCD 2015年第7期167-178,共12页
In DVB-IPDC system, due to the constraints of handheld devices and the broadcast nature of wireless network, packet loss is inevitable. ECDR-NC proposed is a retransmission encoding packet selection algorithm based on... In DVB-IPDC system, due to the constraints of handheld devices and the broadcast nature of wireless network, packet loss is inevitable. ECDR-NC proposed is a retransmission encoding packet selection algorithm based on the dynamic information updating, which can find the current most effective complete decoding packet. ECDR-NC can not only avoid the redundant encoding packets due to the overlapping among encoding packets, but also reduce the computational complexity compared with the traditional encoding schemes. Furthermore, the retransmission upper bound of ECDR-NC is fully controlled. In time-sensitive applications, to maximize the aggregate number of recovery packets while minimizing the total number of discarded packets due to the time limit according to the priority preference, the adaptive priority scheme EPNC is formulized, and the weighted relation graph is constructed to find the maximum-weighted encoding packets sequence according to the decoding gains. In the same network environment, the performances comparisons between PNC and EPNC show that EPNC is more efficient and more rational, and the average discarded packets ratios ofEPNC can be reduced about 18%~27%. The main contributions of this paper are an effective retransmission encoding packet selection algorithm ECDR-NC proposed, and a new adaptive priority recovery scheme EPNC introduced into DVB-IPDC system. 展开更多
关键词 digital video broadcasting(DVB) RETRANSMISSION network coding(NC) longterm evolution(LTE) wireless network
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AN EFFICIENT APPROACH FOR DVB-H HANDOVER IN DVB-H/UMTS HYBRID NETWORKS
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作者 Liu Cong Liao Jianxin +2 位作者 Zhu Xiaomin Zhang Huiyuan Ni Ping 《Journal of Electronics(China)》 2008年第5期689-696,共8页
Handover in Digital Video Broadcasting for Handhelds(DVB-H) aims to provide continuous mobile broadcasting services when a user is traveling through cell boundaries.A good handover control can improve the power effici... Handover in Digital Video Broadcasting for Handhelds(DVB-H) aims to provide continuous mobile broadcasting services when a user is traveling through cell boundaries.A good handover control can improve the power efficiency and gain much better reception quality.This letter provides a novel approach for DVB-H handover based on DVB-H/Universal Mobile Telecommunications System(UMTS) hybrid network,which moves the main handover function from the terminals to the networks,so that it reduces the operation complexity of the terminals and increases the power saving.When the terminal can not receive the DVB-H signal in the transmission shadow areas or because of some other reasons,the UMTS networks may offer the same service to users to make the service continuous.As the UMTS networks have the topology of the DVB-H networks,by communicating with the terminals,the UMTS networks can help the terminals to predict the handover,and avoid unnecessary handover. 展开更多
关键词 digital Video broadcasting for Handhelds (DVB-H) Universal Mobile Telecommunications System (UMTS) HANDOVER MOBILE
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A continuously and widely tunable analog baseband chain with digital-assisted calibration for multi-standard DBS applications 被引量:1
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作者 李松亭 李建成 +1 位作者 谷晓忱 王宏义 《Journal of Semiconductors》 EI CAS CSCD 2013年第6期143-151,共9页
This paper presents a continuously and widely tunable analog baseband chain with a digital-assisted calibration scheme implemented on a 0.13μm CMOS technology.The analog baseband is compliant with several digital bro... This paper presents a continuously and widely tunable analog baseband chain with a digital-assisted calibration scheme implemented on a 0.13μm CMOS technology.The analog baseband is compliant with several digital broadcasting system(DBS) standards,including DVB-S,DVB-S2,and ABS-S.The cut-off frequency of the baseband circuit can be changed continuously from 4.5 to 32 MHz.The gain adjustment range is from 6 to 55.5 dB with 0.5 dB step.The calibration includes automatic frequency tuning(AFT) and automatic DC offset calibration (DCOC) to achieve less than 6%cut-off frequency deviation and 3 mV residual output offset.The out-of-band IIP2 and IIP3 of the overall chain are 45 dBm and 18 dBm respectively,while the input referred noise(IRN) is 17.4 nV/√Hz.All circuit blocks are operated at 2.8 V from LDO and consume current of 20.4 mA in the receiving mode. 展开更多
关键词 analog baseband continuously and widely tunable LPF digital broadcasting system digital-assisted DC offset calibration digital-assisted automatic frequency tuning
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