Research On Electromagnetic Compatibility Of Multi-Mode Mobile Terminal

In the future, the mobile station will comprise a wide range access technology (RAT) providing user with a flexible and efficient access to the multimedia service and high data rate communication. Although much work has been done for coexistence analysis between different systems base station (BS), most of them have not addressed the interference within multimode terminal. Hence, to fill this gap, this paper deals with coexistence of multi-mode mobile terminal under mutual interference. We constructed the two scenarios separately with DCS1800+TD-LTE and with WCDMA+TD-LTE in order to research on multi-mode terminal radio frequency mutual interference. After introducing the definition and kinds of interference between two systems within the terminal, we use the reduction of receiver sensitivity to measure the impact of the interference. Then we simulated and evaluated the influence of such interference on bit error rate (BER). The results show that the interference calls for additional isolation over22dB for the coexistence of DCS1800and TD-LTE and5dB for the coexistence of WCDMA and TD-LTE at transceiver port.Based on the research above, some solutions are proposed in this paper to solve the problem of the multi-mode terminal interference. The solution of space isolation improves the system performance by increasing the distance between transceivers. The method of installing filter on the receiver can mitigate the overloading interference effectively. And setting the guard band between the systems can be used to weaken the interference from adjacent channel. The optimization of PCB board can solve the problem of radiation interference from the bottom. With the limit space of terminal, the design of antennas with no common ground may be more effect the space isolation. The practical application of these methods needs further research and validation.