【作者】 迟文升；

【导师】 李红艳；

【作者基本信息】 西安电子科技大学 ， 控制理论与控制工程， 2007， 硕士

【摘要】 无线通信的迅速发展,要求下一代的通信技术能够支持更高的信息传输速率和更高的用户移动速度,这对频谱利用率、抗多径干扰能力提出了更高的要求。以正交频分复用(OFDM)为代表的多载波调制技术被证明是最有前途的方案之一。在宽带无线接入领域采用OFDM是发展的趋势,它将成为未来移动通信系统的关键技术。本论文在分析OFDM的技术原理和性能优缺点的基础上,重点分析了OFDM的应用技术FLASH-OFDM及其改进技术Flexband的技术特点、网络性能;分析了FH-OFDMA蜂窝系统下行链路的用户容量问题;分析了Flexband系统蜂窝边缘处数据传输速率仍可提高的问题,提出了自适应载波调控策略。该策略能根据在蜂窝内分布的用户数,自适应调节蜂窝边缘处用户可用的子载波数。仿真表明,该方案可以提高蜂窝边缘处的数据吞吐率,增加蜂窝可支持的用户数。更多还原

【Abstract】 With the development of wireless communication, the next-generation communication technologies are required to support higher transmission rate and the higher rate of mobile users. They are also required to gain higher spectrum efficiency and have better ability against multi-path interference. Orthogonal frequency division multiplexing (OFDM) as the representative of the multi-carrier modulation technique proved to be one of the most promising. It is the development trend that OFDM will be used in the field of broadband wireless access. It will become a key technology for future mobile communication systems.Based on the analysis of the technological principles, advantages and disadvantages of OFDM, this paper focuses on the technical characteristics and network performance of FLASH-OFDM and Flexband of improved technology. It also does a research of the user capacity of downlink in the FH-OFDMA cellular system. And the problem is analyzed that the data transmission speed of cell edge in Flexband cellular system should be improved. To solve the problem of Flexband system, we propose an adaptive carrier allocation strategy, which can adaptively adjust the number of practicable subcarrier of the cell edge. The simulation results show that the method we presented can improve the sum-of-rates capacity of the cell edge and increase the number of users supported.更多还原