Zheng Liang is currently pursuing his PhD degree in the State Key Laboratory of Advanced Optical Communication Systems and Networks, as the student of Prof. Shilin Xiao. His research interests lie in the areas of stochastic process, queuing theory, and all optical buffering and switching. His work focuses on the performance evaluation of optical packet switching networks, including:|
- Quantized Delay Buffer (QDB) Model
He proposed the QDB model as a theoretical prototype for infinite quantized delay buffer. Discrete delay of contending packet in switching node becomes one key issue in performance analysis of optical buffer. Considering the delay quantization, delay time and waiting time of buffering packets are differentiated in detail. Then the Lindley integral equation is modified and used to study the performance of quantized delay buffer.
- Performance analysis for practical optical buffer systems
He presented an approximate analytic approach to evaluate the performance of practical optical buffer systems. Since exact performance analysis of such finite system is rather difficult and complex, he first studied two semi-finite system models, say, FCID (finite capacity and infinite delay) and ICFD (infinite capacity and finite delay) models, respectively by means of delay time generating function and virtual waiting time approaches. Then the practical finite system can be analyzed by means of these two semi-finite system models.
- Cyclic Fiber Delay Line buffer
He proposed a wheel-like cyclic fiber delay line buffer for providing flexible delay (small granularity) together with large buffer capacity. Conventional fiber loop buffer is implemented by only one fiber delay line, so the delay granularity is equal to the fiber length. The modified loop buffer is constructed by a number of shorter fiber delay lines so that the delay granularity can be much smaller. When utilizing multi-stage structure, the buffer capacity can be enlarged efficiently with no need to increase the total length of fiber delay lines.