In term of the features of 3G system, a novel AMR link adaptation strategy for 3G system is proposed. The impacts of AMR codec modes and power control on traffic quality of service are taken into account in the strate...In term of the features of 3G system, a novel AMR link adaptation strategy for 3G system is proposed. The impacts of AMR codec modes and power control on traffic quality of service are taken into account in the strategy at the same time. By synthetically comparing the signal-to-interference ratio value with the switching threshold and comparing the transmission power with its threshold, radio resource management can always keep each link on its proper codec mode with the corresponding optimal power level to achieve both robust speech quality and link capacity enhancement. Based on the WCDMA FDD uplink link-level simulation platform, AMR link adaptation platform is constructed. Simulation results show that the algorithm can track the fast change of channel conditions and select the most robust codec mode, thus the synthetic speech quality of AMR is better than that of signal mode during a wide range of channel conditions. The result will provide a reference strategy for AMR link adaptation of 3G system.展开更多
Estimation of Rayleigh fading channels using time multiplexed pilot symbols in W CDMA (FDD) is considered. Method of interpolation on a second order curve using the instantaneous channel estimation of two contiguous...Estimation of Rayleigh fading channels using time multiplexed pilot symbols in W CDMA (FDD) is considered. Method of interpolation on a second order curve using the instantaneous channel estimation of two contiguous slots based on least square method (SOLSM) is presented. It is demonstrated by computer simulations that the channel distortion on data symbols in a slot can be estimated effectively compared to the method using simple linear interpolation, and the performance of the Rake combiner is improved effectively especially in fast moving cases.展开更多
The emergence of third generation mobile system (3G) makes video transmission in wireless environment possible, and the latest 3GPP/3GPP2 standards require 3G terminals support H.264/AVC. Due to high packet loss rate ...The emergence of third generation mobile system (3G) makes video transmission in wireless environment possible, and the latest 3GPP/3GPP2 standards require 3G terminals support H.264/AVC. Due to high packet loss rate in wireless envi- ronment, error resilience for 3G terminals is necessary. Moreover, because of the hardware restrictions, 3G mobile terminals support only part of H.264/AVC error resilience tool. This paper analyzes various error resilience tools and their functions, and presents 2 error resilience strategies for 3G mobile streaming video services and mobile conversational services. Performances of the proposed error resilience strategies were tested using off-line common test conditions. Experiments showed that the proposed error resilience strategies can yield reasonably satisfactory results.展开更多
Blind Adaptive Step-size Constant Modulus Algorithm (AS-CMA) for multiuser detection in DS-CDMA systems is presented. It combines the CMA and the concept of variable step-size, uses a second LMS algorithm for the step...Blind Adaptive Step-size Constant Modulus Algorithm (AS-CMA) for multiuser detection in DS-CDMA systems is presented. It combines the CMA and the concept of variable step-size, uses a second LMS algorithm for the step size. It adjusts the step-size according to the minimum output-energy principle within a specified range, thus overcomes the problems of bad effect of fixed step-size LMS algorithm. Compared with Adaptive Step-size LMS (AS-LMS) algoritilrn, through simulations, this algorithm can adapt the changes of the environment, suppress multiple access interference in the dynamic environment and the stability of Signal to Interference Ratio (SIR) is superior to that of AS-LMS.展开更多
This paper proposes a novel zero Intermediate Frequency (IF) receiver for Multi-Carrier (MC) Direct-Sequence Code-Division Multiple Access (DS-CDMA) based on multicar-rier mode of cdma2000 system. The proposed receive...This paper proposes a novel zero Intermediate Frequency (IF) receiver for Multi-Carrier (MC) Direct-Sequence Code-Division Multiple Access (DS-CDMA) based on multicar-rier mode of cdma2000 system. The proposed receiver employs direct RF-to-baseband down-conversion, sampling at a rate equal to the bandwidth of the baseband multicarrier signal and complex-valued coefficient FIR filters. This receiver avoids the need for arrays of high Q analog bandpass filters, has a much lower sampling rate half of that of conventional receiver and offers significant savings in hardware implementation. Analytic and simulation results show that the presented receiver performs well for both the AWGN channel and Rayleigh fading channel.展开更多
A novel radio-over-fiber(ROF) scheme to simultaneously generate and transmit the 3rd generation telecommunication(3G) and millimeter-wave(MMW) signals by using a single dual-electrode Mach-Zehnder modulator(MZM) is pr...A novel radio-over-fiber(ROF) scheme to simultaneously generate and transmit the 3rd generation telecommunication(3G) and millimeter-wave(MMW) signals by using a single dual-electrode Mach-Zehnder modulator(MZM) is proposed.There is no apparent nonlinearity induced by the ROF system.By employing this analog ROF signal transmission technique,highly transparent fiber-wireless convergence networks can be realized,which are ideal for multi-standard wireless system operation.展开更多
文摘In term of the features of 3G system, a novel AMR link adaptation strategy for 3G system is proposed. The impacts of AMR codec modes and power control on traffic quality of service are taken into account in the strategy at the same time. By synthetically comparing the signal-to-interference ratio value with the switching threshold and comparing the transmission power with its threshold, radio resource management can always keep each link on its proper codec mode with the corresponding optimal power level to achieve both robust speech quality and link capacity enhancement. Based on the WCDMA FDD uplink link-level simulation platform, AMR link adaptation platform is constructed. Simulation results show that the algorithm can track the fast change of channel conditions and select the most robust codec mode, thus the synthetic speech quality of AMR is better than that of signal mode during a wide range of channel conditions. The result will provide a reference strategy for AMR link adaptation of 3G system.
文摘Estimation of Rayleigh fading channels using time multiplexed pilot symbols in W CDMA (FDD) is considered. Method of interpolation on a second order curve using the instantaneous channel estimation of two contiguous slots based on least square method (SOLSM) is presented. It is demonstrated by computer simulations that the channel distortion on data symbols in a slot can be estimated effectively compared to the method using simple linear interpolation, and the performance of the Rake combiner is improved effectively especially in fast moving cases.
基金Project supported by the National Natural Science Foundation of China (Nos. 60473106 and 60333010), China Ministry of Education(No. 20030335064), and China Ministry of Science and Technology(No. 2003AA4Z1020)
文摘The emergence of third generation mobile system (3G) makes video transmission in wireless environment possible, and the latest 3GPP/3GPP2 standards require 3G terminals support H.264/AVC. Due to high packet loss rate in wireless envi- ronment, error resilience for 3G terminals is necessary. Moreover, because of the hardware restrictions, 3G mobile terminals support only part of H.264/AVC error resilience tool. This paper analyzes various error resilience tools and their functions, and presents 2 error resilience strategies for 3G mobile streaming video services and mobile conversational services. Performances of the proposed error resilience strategies were tested using off-line common test conditions. Experiments showed that the proposed error resilience strategies can yield reasonably satisfactory results.
基金Supported by the National Natural Science Fundation of China(No.60172018)
文摘Blind Adaptive Step-size Constant Modulus Algorithm (AS-CMA) for multiuser detection in DS-CDMA systems is presented. It combines the CMA and the concept of variable step-size, uses a second LMS algorithm for the step size. It adjusts the step-size according to the minimum output-energy principle within a specified range, thus overcomes the problems of bad effect of fixed step-size LMS algorithm. Compared with Adaptive Step-size LMS (AS-LMS) algoritilrn, through simulations, this algorithm can adapt the changes of the environment, suppress multiple access interference in the dynamic environment and the stability of Signal to Interference Ratio (SIR) is superior to that of AS-LMS.
基金Supported by the National Natural Science Founation of China(No.69725001)
文摘This paper proposes a novel zero Intermediate Frequency (IF) receiver for Multi-Carrier (MC) Direct-Sequence Code-Division Multiple Access (DS-CDMA) based on multicar-rier mode of cdma2000 system. The proposed receiver employs direct RF-to-baseband down-conversion, sampling at a rate equal to the bandwidth of the baseband multicarrier signal and complex-valued coefficient FIR filters. This receiver avoids the need for arrays of high Q analog bandpass filters, has a much lower sampling rate half of that of conventional receiver and offers significant savings in hardware implementation. Analytic and simulation results show that the presented receiver performs well for both the AWGN channel and Rayleigh fading channel.
基金supported by the National Natural Science Foundation of China(No.61371061)the Zhejiang Provincial Natural Science Foundation of China(Nos.LY12F01010 and LQ13F010007)the Open Fund of the Information and Communication Engineering of Top Key Discipline of Zhejiang Province
文摘A novel radio-over-fiber(ROF) scheme to simultaneously generate and transmit the 3rd generation telecommunication(3G) and millimeter-wave(MMW) signals by using a single dual-electrode Mach-Zehnder modulator(MZM) is proposed.There is no apparent nonlinearity induced by the ROF system.By employing this analog ROF signal transmission technique,highly transparent fiber-wireless convergence networks can be realized,which are ideal for multi-standard wireless system operation.
