Research On Cross-layer Design In Mobile Communication

Mobile communication has been applied extensively in our daily life and it makes a great convenience for people to work and live. However, due to high needs on the freedom, mobility and bandwidth, mobile communication technology is challenged. Mobile communication environment is changing rapidly, but the design model based on hierarchical structure can not be flexibly adapt to changes in the wireless mobile environment, because each layer is independent of design or work, also layer interface is static, and restriction of each layer do not relate to its application. When designing the protocol stack, the system is assumed to work in the worst communications conditions. As a result, this method causes that protocol stacks can not effectively use the limited resources of spectrum and power resources, and can not combine parameters which distribute in each sub-layer of the network. To solve the problem, cross-layer design mechanism has been proposed. It coordinates each protocol stack's work through sharing specific information between layers, thus the system is compatible with the mobile communication environment and meet the different requirements of various applications. The core is to make the protocol stack realize the adaptive optimization according to the changes of communication environment.The concrete research context are as follows:1)The development of the third generation mobile communication and next generation mobile communication technology were introduced in detail. And the principle of cross-layer design was discussed based on studying the disadvantages of Open System Interconnection Reference Model, also cross-layer design mechanism of each protocol layer was analyzed.2)After analysing AMC and ARQ of link adaptation techniques, a cross-layer method which combines three layers was proposed. Using multi-layer (application layer included) design to meet the QoS requirements of the services, the scheme realized that a variety of multimedia services could be inserted to a physical frame. The simulation results prove that scheme is practicable.3)Using the cross-layer design strategy by combining AMC and HARQ techniques, three types of AMC thresholds' performances in the cross-layer were analyzed. The cross-layer design method was consisted of AMC, HARQ and queuing model based on embedded Markov chain. Through contrasting various parameters, detailed simulation diagrams of each parameter was gotten, and impact on cross-layer method by each parameter was analyzed. Finally, using cross-layer method to optimize system overall performance was realized.