Propose a new degradation call admission control（DCAC）scheme, which can be used in wideband code division multiple access communication system. So-called degradation is that non-real time call has the characteristic...Propose a new degradation call admission control（DCAC）scheme, which can be used in wideband code division multiple access communication system. So-called degradation is that non-real time call has the characteristic of variable bit rate, so decreasing its bit rate can reduce the load of the system, consequently the system can admit new call which should be blocked when the system is close to full load, therefore new call＇s access probability increases. This paper brings forward design project and does system simulation, simulation proves that DCAC can effectively decrease calls＇ blocking probability and increase the total number of the on-line users.展开更多
The structure and performance of space-time multiuser detection receiver at base stations of WCDMA system is analyzed, in which smart antenna is employed. WCDMA uplink signal model is established in this paper. Space-...The structure and performance of space-time multiuser detection receiver at base stations of WCDMA system is analyzed, in which smart antenna is employed. WCDMA uplink signal model is established in this paper. Space-time multiuser receiver presented in this paper combines 2D-RAKE with parallel interference cancellation (PIC), and the improved parallel interference cancellation methods are given. A novel space-time multiuser detection scheme, 2DRAKE-GPPIC is proposed. This scheme employs smart antenna to suppress unexpected DOA (Direction Of Arrival) signal, uses RAKE receiver to combine different delays of expected signal, and utilizes grouped partial parallel interference cancellation (GPPIC) algorithm to suppress further the interference signal in the main lobe of array antennas. The simulation results reveal that the scheme of space-time multiuser detection presented in this paper has better performance for WCDMA system.展开更多
In this paper bit error rate (BER) performance is analyzed for multiple input-multiple output (MIMO) communications systems using antenna selection in the transmitter, maximal ratio combining (MRC) and linear de-corre...In this paper bit error rate (BER) performance is analyzed for multiple input-multiple output (MIMO) communications systems using antenna selection in the transmitter, maximal ratio combining (MRC) and linear de-correlating detector (LDD) in the receiver in wide band code division multiple access (WCDMA) downlink channels with correlated Nakagami fading. The MRC maximizes signal to noise ratio of the received signal, then the LDD cancels out multiple access interference (MAI). Theoretical results are validated using computer simulations. Moreover, a pilot based estimation method is proposed to jointly estimate the channel gains and the rows of the LDD operator. Simulation results show that using this proposed method, diversity order is maintained in the receiver. Furthermore, our analysis shows the spectral efficiency degradation due to the pilot based strategy is negligible.展开更多
Traffic modeling is a crucial element in WCDMA system levelsimulations. A clear understanding of the nature of traffic in theWCDMA system and subsequent selection of an appropriate randomtraffic model are critical to ...Traffic modeling is a crucial element in WCDMA system levelsimulations. A clear understanding of the nature of traffic in theWCDMA system and subsequent selection of an appropriate randomtraffic model are critical to the success of the modeling enterprise.The resultant performance will evidently be of a function that ourdesign has been well adapted to the traffic, channel and usermobility models, and these models are also accurate. In this article,our attention will be focused on modeling voice and WWW data trafficwith the SBBP model and Victor model respectively.展开更多
In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF li...In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF link so as to suppress the out-of-band spurious spectrum and improve the transmission performance.The experimental results show that the out-of-band emission due to existence of the third-order Inter-Modulation Distortion (IMD3) is obviously sup-pressed by these two DPD.An Adjacent Channel Power Ratio (ACPR) improvement of 8 dB is ob-tained for a single-carrier WCDMA signal transmission.These two DPD have equal ability in lin-earization of the ROF system for a three-carrier WCDMA signal transmission.There is no apparent memory effects exist in the ROF link.展开更多
Smart antenna has been regarded as one promising technology to enhance the performance of CDMA mobile communication systems. However, when applied to 3G systems, the performance of traditional adaptive arrays may degr...Smart antenna has been regarded as one promising technology to enhance the performance of CDMA mobile communication systems. However, when applied to 3G systems, the performance of traditional adaptive arrays may degrade due to code and time multiplexing in dedicated physical channels. A novel semiblind adaptive array approach is proposed to solve this problem. It overcomes the selfinterfering problem by introducing a quasidespreading technique for the control channel, and contains a timemultipexed structure to utilize both pilot symbols and unknown control symbols within the control channel. The blind part of the proposed approach is based on the competition of two parallel branches with different reference sequences. Simulation results show significant improvement can be achieved by the proposed approach in a fastfading WCDMA environment.展开更多
In this paper,a novel radio-over-fiber(ROF) scheme to simultaneously generate and transmit wideband code division multiple access(WCDMA) and millimeter-wave(MMW) signals by using a single dual-electrode Mach-Zehnder m...In this paper,a novel radio-over-fiber(ROF) scheme to simultaneously generate and transmit wideband code division multiple access(WCDMA) 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,the highly transparent fiber-wireless networks,which are ideal for multi-standard wireless system operation,can be realized.展开更多
文摘Propose a new degradation call admission control（DCAC）scheme, which can be used in wideband code division multiple access communication system. So-called degradation is that non-real time call has the characteristic of variable bit rate, so decreasing its bit rate can reduce the load of the system, consequently the system can admit new call which should be blocked when the system is close to full load, therefore new call＇s access probability increases. This paper brings forward design project and does system simulation, simulation proves that DCAC can effectively decrease calls＇ blocking probability and increase the total number of the on-line users.
文摘The structure and performance of space-time multiuser detection receiver at base stations of WCDMA system is analyzed, in which smart antenna is employed. WCDMA uplink signal model is established in this paper. Space-time multiuser receiver presented in this paper combines 2D-RAKE with parallel interference cancellation (PIC), and the improved parallel interference cancellation methods are given. A novel space-time multiuser detection scheme, 2DRAKE-GPPIC is proposed. This scheme employs smart antenna to suppress unexpected DOA (Direction Of Arrival) signal, uses RAKE receiver to combine different delays of expected signal, and utilizes grouped partial parallel interference cancellation (GPPIC) algorithm to suppress further the interference signal in the main lobe of array antennas. The simulation results reveal that the scheme of space-time multiuser detection presented in this paper has better performance for WCDMA system.
文摘In this paper bit error rate (BER) performance is analyzed for multiple input-multiple output (MIMO) communications systems using antenna selection in the transmitter, maximal ratio combining (MRC) and linear de-correlating detector (LDD) in the receiver in wide band code division multiple access (WCDMA) downlink channels with correlated Nakagami fading. The MRC maximizes signal to noise ratio of the received signal, then the LDD cancels out multiple access interference (MAI). Theoretical results are validated using computer simulations. Moreover, a pilot based estimation method is proposed to jointly estimate the channel gains and the rows of the LDD operator. Simulation results show that using this proposed method, diversity order is maintained in the receiver. Furthermore, our analysis shows the spectral efficiency degradation due to the pilot based strategy is negligible.
文摘Traffic modeling is a crucial element in WCDMA system levelsimulations. A clear understanding of the nature of traffic in theWCDMA system and subsequent selection of an appropriate randomtraffic model are critical to the success of the modeling enterprise.The resultant performance will evidently be of a function that ourdesign has been well adapted to the traffic, channel and usermobility models, and these models are also accurate. In this article,our attention will be focused on modeling voice and WWW data trafficwith the SBBP model and Victor model respectively.
基金Supported by the National Natural Science Foundation of China (No. 60972064)
文摘In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF link so as to suppress the out-of-band spurious spectrum and improve the transmission performance.The experimental results show that the out-of-band emission due to existence of the third-order Inter-Modulation Distortion (IMD3) is obviously sup-pressed by these two DPD.An Adjacent Channel Power Ratio (ACPR) improvement of 8 dB is ob-tained for a single-carrier WCDMA signal transmission.These two DPD have equal ability in lin-earization of the ROF system for a three-carrier WCDMA signal transmission.There is no apparent memory effects exist in the ROF link.
文摘Smart antenna has been regarded as one promising technology to enhance the performance of CDMA mobile communication systems. However, when applied to 3G systems, the performance of traditional adaptive arrays may degrade due to code and time multiplexing in dedicated physical channels. A novel semiblind adaptive array approach is proposed to solve this problem. It overcomes the selfinterfering problem by introducing a quasidespreading technique for the control channel, and contains a timemultipexed structure to utilize both pilot symbols and unknown control symbols within the control channel. The blind part of the proposed approach is based on the competition of two parallel branches with different reference sequences. Simulation results show significant improvement can be achieved by the proposed approach in a fastfading WCDMA environment.
基金supported by the National Natural Science Foundation of China(No.61371061)Ningbo Natural Science Foundation(Nos.2013A610123 and 2013A610116)Scientific Research Fund of Zhejiang Provincial Education Department(No.Y201224026)
文摘In this paper,a novel radio-over-fiber(ROF) scheme to simultaneously generate and transmit wideband code division multiple access(WCDMA) 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,the highly transparent fiber-wireless networks,which are ideal for multi-standard wireless system operation,can be realized.
