Realization of low power consumption wireless node using joint RF and baseband signal processing technique

本文提出了一种基于IEEE802.15.4标准的扩频接收机单射频分集方案。该方案采用了一个电子可控无源阵列辐射器（ESPAR）天线与周期性变化的方向性的符号率。IEEE 802.15.4关注低功耗短距离通信系统。然而，在严重的多径衰落环境中，误比特率性能不够好。分集是补偿由于多径衰落引起的性能下降的公知技术。然而，分集接收的复杂性是一个主要问题。在本文中，我们提出了一种新的单射频分集方案使用ESPAR天线与周期性变化的方向性。该方案能够在频率选择性衰落环境中获得分集增益，并解决了传统的基于ESPAR天线的分集方案收敛速度慢的问题。计算机仿真和理论分析表明，该方案具有分集增益。

This research reveils a single-RF diversity scheme for spread spectrum receiver based on IEEE 802.15.4 standard. The proposed scheme employs an Electronically Steerable Passive Array Radiator (ESPAR) antenna with periodically changing directivity at the symbol rate. IEEE 802.15.4 focuses on low power consumption short range communication systems. However, the bit error rate performance is not good enough in a severe multipath fading environment. Diversity is a well-known technique to compensate for the performance degradation due to multipath fading. However, the complexity for diversity reception is a major problem. In this paper, we propose a new single-RF diversity scheme using ESPAR antenna with periodically changing directivity. The proposed scheme is capable of obtaining the diversity gain in a frequency selective fading environment and it solves the slow convergence rate problem in the conventional ESPAR antenna based diversity scheme. Computer simulation result and theoretical analysis show that the proposed scheme gives diversity gain.