Study on Adaptive Radio Resource, Access and Transmission Control Technologies for Wireless Communication Systems under Severe Electromagnetic Interference Conditions

在本研究中，我们针对严重电磁干扰和有限频谱资源条件下的无线通信系统，开发了自适应无线资源、接入和传输控制技术。具体地说，我们开发了以下四种技术，(1)即使在严重的电磁干扰条件下也支持稳定的无线通信链路的自适应传输控制技术，(2)减少输入到接收器的干扰的干扰抑制技术，(3)其中自适应地分配每个终端的无线电资源以最小化干扰的自适应无线电资源管理技术，以及(4)其中根据电磁和业务条件自适应地选择接入方案的自适应接入控制技术。特别是对于基于时分多址(TDMA)的系统，我们提出了一种用于正交频分复用/TDMA(ofdm/TDMA)系统的自适应子载波选择技术，其中自适应地选择干扰较少的子载波，并自适应地控制所选子载波的调制参数，从而极大地简化了基于动态信道分配(DCA)的TDMA系统的信道分配过程。根据这些结果，我们得出结论：TDMA和码分多址都不是万能的，而是应该根据电磁和业务条件自适应地选择。我们还得出结论，自适应无线电传输控制和自适应无线电资源管理技术对于缓解动态变化的信道和干扰条件的影响非常有用。

In this research, we have developed adaptive radio resource, access and transmission control technologies for wireless communication systems under severe electromagnetic interference and limited spectrum resource conditions. Specifically, we have developed the following four technologies, (1) adaptive transmission control techniques to support stable wireless communication links even under severe electromagnetic interference conditions, (2) interference suppression techniques to reduce interference input to the receiver, (3) adaptive radio resource management techniques in which radio resource for each terminal is adaptively assigned so as to minimize interference, and (4) adaptive access control techniques in which an access scheme is adaptively selected according to the electromagnetic and traffic conditions. Especially for time division multiple access (TDMA) based systems, we have developed an adaptive subcarrier selection techniques for orthogonal frequency division multiplexing/TDMA (OFDM/TDMA) systems in which less interfered subcarriers are adaptively selected and modulation parameters for the selected subcarrier is adaptively controlled, thereby dynamic channel assignment (DCA) based channel assignment process for TDMA is extremely simplified. With these results, we have concluded that both TDMA and code division multiple access (CDMA) are not almighty, rather each of them should be adaptively selected according to the electromagnetic and traffic conditions. We have also concluded that the adaptive radio transmission control and adaptive radio resource management technologies are very useful to mitigate the effect of dynamically varying channel as well as interference conditions.