OFDMA系统多业务频谱切换策略的CPN建模及性能评价

The CPN Modeling and Performance Evaluation about Spectrum Handoff Strategies in OFDMA Multi-service Communication System

为保障用户的不同服务要求,对不同业务执行区分服务并实现频谱切换管理是通信系统亟需解决的主要问题之一.研究切换问题的传统方法是Markov建模,Markov模型具有无记忆特性,并且易于产生状态空间爆炸问题,这使得频谱切换策略的研究大多停留在单业务OFDMA系统.应用着色Petri网(colored petri nets,CPN)开发适用于多业务OFDMA系统的频谱切换策略,建立了4种兼顾切换用户和新到用户传输性能的频谱切换策略的CPN模型.仿真结果表明,CPN能够克服Markov模型的局限性,便于分析复杂系统,特别是到达规律服从多种数学分布的多业务系统频谱切换策略.

With the increasing diversified demand on communication system,the differentiation in multi-service is one of the major problems faced with the communication system on the premise of ensuring quality of service requirements of users. Markov model is the traditional way to study the switch problem,however,the memory- less quality and the state space explosion problem of the Markov model make the research about the spectrum handover strategies stay at the single business OFDMA system. This paper utilizes the Colored Petri Nets（ CPN） to develop the spectrum switching strategies suitable for multiple business OFDMA system. Four different spectrum strategies considering both the switching users and new users are discussed using CPN model in this paper. The results show that CPN can overcome the limitation of Markov,and facilitate the research of the spectrum handoff quality about the complex system,especially the multiple business system contenting several mathematical distributions for the users＇ arrival laws.