Jin Nan Zhang

Adaptive Polarization Mode Dispersion Compensation with DPSO Algorithm

Dithering particle swarm optimization (DPSO) algorithm is introduced into adaptive polarization mode dispersion (PMD) compensation in optical communication system. The DPSO algorithm has the merits of rapid convergence to the global optimum, without being trapped in local sub-optima, and good robustness to noise. How to implement DPSO as a component of a control algorithm in adaptive polarization mode dispersion compensation is described. Performance comparisons between PSO and DPSO were carried out theoretically and experimentally.

BER Performance Analysis of MIMO-CPolSK Using on Free-Space Optical Communications

Enslaved by atmospheric turbulence and transmission power, performance of Free-space Optical Communication (FSO) fluctuates greatly. A new communication system of MIMO-CPolSK combined the MIMO system and CPolSK modulation is proposed in this paper. According to the strength of turbulence, different mathematical models of atmospheric channel are adopted. The BER calculating formula of SISO-CPolSK is proposed at first, then the BER performance of MISO-CPolSK and MIMO-CPolSK system is presented. The result of numerical simulation shows that BER performance is greatly promoted in MIMO system and compared to OOK modulation, the SNR of receiving in CPolSK modulation is reduced about 3dB when the system has the same BER performance under the same condition.

A Polarization Stabilization Control System Based on DSP

A polarization stabilization control system based on digital signal processor (DSP) is proposed in this paper. The system uses low frequency radio frequency (RF) power as control signal for polarization stabilization, and it does not need high-speed circuit to track fast polarization change. Modified particle swarm optimization algorithm is utilized and the effectiveness of polarization stabilization control is experimentally verified.

The Design and Implementation of USB Mass Storage and CCID Composite Device

USB disk and UKEY are common applications of USB Mass Storage and CCID protocol and used widely in our daily life, but they are always deployed on different kinds of devices such as USB disk and UKEY. A potential application that integrates the functions of these two protocols into one device is discovered by us. In this way, we can regard a single device as a mass storage and an UKEY as well. According to this discovery, a new Mass Storage and CCID composite device is developed on IS8U192A development board. After this, several tests are made with some test tools to ensure the newly developed device is able to function well and the Mass Storage and CCID protocols are accurately implemented.

Performance Analysis of Coherent Atmospheric Optical Communications with Soft-decision Forward Error Correction

Performance of coherent atmospheric optical communication system with heterodyne detection and LDPC codes was evaluated over atmospheric channel attenuations of which are about 20-30 dB/km. To reduce bit error and enhance the system performance LDPC code was implemented in system. Combining coherent detection and LDPC codes could reduce the received power requirement ~4 dBm at the BER of 10-9.

Application of a Novel Modulation Scheme of PS-RZ-QPSK Signal in High-speed Optical Transmission System

Modulation principle of dual-polarization quadratu-re phase shift keying signal and polarization-switched QPSK signal are demonstrated and advantages of PS-QPSK are proved in theoretically. A novel modulation scheme of PS-RZ-QPSK signal is proposed in this paper. The scheme reduces transmitter cost by less use of Mach-Zehnder modulator, but also presents similar performance as traditional structure for PS-RZ-QPSK. The simulate result indicates PS-RZ-QPSK can achieve a better transmission performance than DP-RZ-QPSK at the same bit rate (84Gb/s) and baud rate (28GBd), and proves showing the feasibility of novel modulation scheme.

An application of LDPC code for wireless coherent-light commutation in atmospheric channel

Low Density Parity Check code is more and more taken seriously in high-speed transmission. In this article we represent a LDPC coder and decoder which based on IEEE802.16e and realize the coder and decoder with Virtex-5 FPGA. By using Matlab to make an off-line system simulation, we analyzed and compared the LDPC performance under the different length of code for LDPC coder then analyzed the influence of different iteration to the LDPC BER performance of decoder.

Design and Implementation of Buffer Control in EoS System

We propose an optimization approach to EoS (Ethernet over SDH) buffer control which the objective is to dynamically adjust the EoS buffer management registers. We will present the improved model of the traffic buffer management based on embedded MCU to control the SDRAM of the EoS chip, and setup the end-to-end system to illustrate the feasibility and advantage of the solution in buffer management when the data transport rate suddenly exceed the bandwidth of Ethernet port.

Design and Realization of 10Gbps DPSK System for Free Space Optical Communication

The performance of atmospheric communication system is limited by the atmospheric turbulence. In this paper, we present a practical 10Gbps DPSK transmission system for free space optical (FSO) communication with low error probability and wide-opening eye diagram. Compared to OOK modulation, DPSK format is a more effective way to resist the atmospheric turbulence. In addition, we designed parameters of this modulation system to be varied as the channel situation changed to achieve an optimized performance. The experiment results show that such a DPSK system could greatly overcome the atmospheric turbulence.

Design and Implementation of New Embedded Network Management and Monitoring System

Embedded devices are confined to be agents although they have been deployed in network management system for decades. We shed light on this situation by designing and implementing a new full-featured embedded network management system. On one hand, this system can still be an agent; on the other hand, this system provides a friendly GUI and I/O devices such as mouse and keyboard, which allows administrators to conveniently monitor and configure the managed equipment. The new system is developed on ARM with Linux using multithreading method, and it is deployed on ROADM equipment in optical network. SNMP is applied to be the network management protocol.