基于CDMA的水下传感器网络MAC协议设计

水下传感器网络( UWSN)中节点采用声波通信，水声信道的高误码率、长延迟、低带宽、多径效应、多普勒频散等技术，据此提出一种动态的、分布式的基于码分多址( CDMA)的水下传感器网络介质访问控制层( MAC)协议。该协议不但节能，还能够提高CDMA扩频码的重用率，并且能够适应网络拓扑的动态变化。同时，协议使用了功率控制机制，有效解决CDMA系统中普遍存在的“远-近”效应问题。仿真实验表明，与经典的静态编码分配协议和ALOHA相比，该协议在冲突率、交付率、端到端的延迟、能耗等方面具有更好的性能。

CDMA Based MAC Protocol for Underwater Sensor Networks

According to the characteristics that the sensor nodes in underwater sensor network ( UWSN) adopt acoustic communication, characterized by high error rate high delay, low bandwidth, multipath and Doppler shift, etc. , the current communication protocols designed for radio channels are unsuitable for underwater. So, a new dynamic and distribute code division multiple access ( CDMA)-based media ac-cess control ( MAC) protocol for UWSN was proposed. The protocol not only can save the limited energy of mobile nodes,but also increase the CDMA code reusability. The protocol can be adapted to the dynam-ic topology of UWSN. At the same time, the design of power control can minimize the near-far effect in-herit in CDMA. Simulation indicates that, compared with the static code assignment protocol and ALO-HA, the performance of the protocol mentioned above is satisfied on delivery ratio and end-to-end delay.