SENSORS: Cooperative Diversity for Wireless Sensor Networks

0329908Anders host-Madseni夏威夷大学这个项目考虑无线传感器网络中传感器之间的通信。这种无线传感器网络的容量受到不同传输之间的干扰和无线信道的损害(例如衰落)的限制。本课题研究利用协作分集来克服无线通信的局限性。协作分集承诺的收益是巨大的，对无线传感器网络的设计可能会产生相当大的影响。简单形式的协作分集可以在短期内相对容易地构建到无线传感器网络中，而随着技术的发展，更高级的形式可以融入到未来的无线网络中。合作分集还可以对军事网络产生重大影响，包括通信网络和传感器-执行器网络。在协作分集中，多个节点组成一种联盟来帮助彼此进行传输。信源通过交换消息，共同起到多天线发射阵列的作用，目的地起到多天线接收阵列的作用。这样做有三个优点：分集，因为不同的路径可能独立衰落；通过波束成形获得功率增益；以及通过在消息传输上进行合作来减少干扰。从协作分集获得的收益既是通过遍历容量衡量的速率的增加，也是通过中断或中断容量衡量的分集。初步结果已经显示了非常大的收益，同时仍然暗示通过最佳信令可以获得进一步的可观收益。本课题计划的工作是：1)推导衰落信道中协作分集香农容量的上下界。2)开发协作分集的近最佳信令方法。3)开发简单的信令方法，即使是简单的传感器也可以使用。

0329908Anders Host-MadsenUniversity of HawaiiThis project considers the communication between sensors in a wireless sensor network. The capacity of such wireless sensor networks is limited both by the interference between different transmissions and by the impairments of the wireless channel, such as fading. This project investigates using cooperative diversity to overcome the limitations of the wireless communication. The gains promised by cooperative diversity are substantial, and the impact on the design of wireless sensor networks could be considerable. Simple forms of cooperative diversity can be build into wireless sensor networks in the near term relatively easily, while more advanced forms can be incorporated in future wireless networks as technology develops. Cooperative diversity can also have a large impact on military networks, both communications networks and sensor-actuator networks. In cooperative diversity, several nodes form a kind of coalition to assist each other with the transmission. The sources jointly act like a multi-antenna transmit array, and the destinations act like a multi-antenna receive array through interchange of messages. There are three advantages from this: diversity, since different paths might fade independently, a power gain through beamforming, and interference mitigation through cooperation on messages transmission. The gain from cooperative diversity is both an increase in rate, measured by ergodic capacity, and diversity, measured by outage or outage capacity. Preliminary results already show very large gains while still hinting at the further considerable gains that can be obtained by optimum signaling. The work planned in this project is 1) Deriving upper and lower bounds for the Shannon capacity of cooperative diversity in fading channels. 2) Developing near-optimum signaling methods for cooperative diversity. 3) Developing simple signaling methods that can be utilized by even simple sensors.