| 摘要: | 目前無線通訊和電子技術的發展，已經有能力做出體積小、低成本、低耗電、可作短距離傳輸的多功能無線感測網路節點，且每個節點皆具有感測、運算和通訊的功能。因此，無線感測網路的應用範圍將非常廣泛，例如：軍事、醫療、防災……等等；而針對不同之用途，僅須更換感測裝置和適度調整通訊模式便可達成目的。在軍事偵測用途方面，其可以快速佈建網路和容錯能力以利軍事監控和目標定位。醫療方面，醫師可以藉特製的無線感測網路節點放在病人的適當位置，以了解病情；其它方面如：對特定區域佈建無線感測網路，以利倉儲盤點、貨物品管、監控災害的防治等等。因此，相信在不久的將來，我們一定可以看到無線感測網路的大量應用。無線感測網路必須要考量的設計重點如：容錯性、可延展性、價格、硬體、拓撲型態、工作環境、省電等等；其有別於傳統無線網路之型態，所以勢必要再加以研究開發出其適合的軟硬體架構、通訊協定、應用程式…等。
一般無線感測網路在感測資料收集之後只是將資料傳回收集點自身並不多做判斷資料的動作，資料匯集中心便是基地台。在分散式自主性無線感測網路中有各種能力與感測性質不一的無線感測網路節點，在無基地台的環境中要取得網路環境資訊以及與其他節點交換訊息難度相對提高。在未明白網路拓撲的情況下使用搜尋方法找到節點的路徑因為實際網路輸入/輸出暫存器的大小等等影響，所以並不一定是最佳路徑，所以我們在搜尋目標時會重新建立一條路徑回去以保障雙向路徑都是最佳路徑，並且讓節點之前以點對點的方式通訊，每個節點都可以扮演基地台的角色，可以避免因為基地台發生錯誤而導致整個網路無法動彈的情況發生。
Recent advances in wireless communications and electronics have enabled the development of low cost, low power, and multifunctional sensor nodes that are small in size and communication untethered in short distances. These tiny sensor nodes, which consist of sensing, data processing, and communicating components, leverage the idea of wireless sensor networks. The sensor networks can be used for various application areas, e.g., health, military, and home. In military, for example, the rapid deployment, self-organization, and fault tolerance characteristics make them a very promising sensing technique for surveillance, reconnaissance, and targeting systems. In health, sensor nodes can also be deployed to monitor patients. Some other commercial applications include managing inventory, monitoring product quality, and monitoring disaster areas. In the future, this wide range of application areas will make wireless sensor networks to be integral parts of our lives. Realization of wireless sensor networks needs to satisfy the constraints introduced by factors such as fault tolerance, scalability, cost, hardware, topology change, environment, and power consumption.
Since above constraints are highly stringent and specific, new wireless ad hocnetworking techniques are required, e.g., the hardware and software architectures, communication protocols, application programs, etc. Our focus is not on the mechanical aspects of mobile sensor nodes – the sensor, power, motor, and wheels, etc. Instead, this integrated project focuses on designing and implementing the ADC/DAC circuit, baseband circuit, communication MAC protocols, routing strategies, embedded system, and so on, that are the core technologies of the wireless sensor network system.
When sensor nodes collect sensing data, they will send data to the sink node and don’t judge the data in Wireless Sensor Networks. All of the sensing data will send to Base Station (BS). It’s difficult to obtain the network information and exchange messages with other nodes in distributed self-origination Wireless Sensor Networks. People often use search or routing protocol to find nodes and paths. When we understand the network topology, the paths may not be the best paths. To solving this problem, the node which is found will rebuild a new path to the original node. After the path set up, the nodes use Peer-to-Peer method to communication. Every node can play the role of BS. It can avoid BS crashing. |
