2016/7/31 A Survey on Sensor Networks Ian F. Akyildiz, Weilian Su, Yogesh Sankarasubramaniam, and Erdal Cayirci Georgia Institute of Technology Report ： yan yi li From:IEEE Communications Magazine August 2002.

2016/7/32 大綱  Introduction  感測網路的通訊體系架構 Physical, Data link, Network, Transport, Application  結論

2016/7/33 Introduction  Application areas: Health, military, home, and commercial  The differences between sensor networks and ad hoc networks: The number of sensor nodes in a sensor network can be several orders of magnitude higher than the nodes in an ad hoc network. Density of deployment Probability of failure Change of topology Hardware constraint

2016/7/34 感測網路的通訊架構 感測器節點通常分散於感測領域 這些分散的每一個感測器節點都有能力去收集數據資 料並且回傳路由數據到接收端. 接收端可以通過網路或是衛星 和事件管理者做通訊.

2016/7/35 感測網路設計的影響因素  including fault tolerance  Scalability  production costs  operating environment  sensor network topology  hardware constraints  transmission media  power consumption

2016/7/36 硬體的限制

2016/7/37 感測網路通訊架構 Used by the sink and sensor nodes

2016/7/38 實體層  頻率選擇，載波頻率的產生，信號檢測，調變以及 數據加密  915 MHz ISM 頻帶已被廣泛提出的感測網路 Industrial, scientific,medical  追求的能量使用效率 二進制和多進制調變 ( 超寬頻 ) UWB 無線電脈衝 (IR)  基頻  不需要媒介或者是載波頻率  脈衝位置調變 (PPM)  較低的傳輸電力和簡單的收發器

2016/7/39 實體層  Open research issues: Modulation schemes  Simple and low-power Strategies to overcome signal propagation effects Hardware design  Tiny, low-power, low-cost  transceiver, sensing, and processing units  need to be designed.

2016/7/310 資料鏈結層  Responsibility: Multiplexing of data streams Data frame detection Medium access control Error control

2016/7/311 資料鏈結層  Open research issues: MAC for mobile sensor networks  SMACS and EAR Determination of lower bounds on the energy required for sensor network self- organization Error control coding schemes Power-saving modes of operation  Turn the transceiver off when idle  Using short data packets

2016/7/312 網路層  Designed according to the following principles: Power efficiency Data-centric No hinder the collaborative effort An ideal sensor network has attribute-based addressing and location awareness

2016/7/313 網路層  Route 1: Sink-A-B-T, total PA=4, total α=3  Route 2: Sink-A-B- C-T, total PA=6, total α=6  Route 3: Sink-D-T, total PA=3, total α=4  Route 4: Sink-E-F-T, total PA=5, total α=6  Maximum PA route: Route 4  Minimum energy (ME) route: Route 1  Minimum hop (MH) route: Route 3 Route 1: Sink-A-B-T, total PA=4, total α=3, Route 2: Sink-A-B-C-T, total PA=6, total α=6, Route 3: Sink-D-T, total PA=3, total α=4, Route 4: Sink-E-F-T, total PA=5, total α=6

2016/7/314 網路層  Flooding  Gossiping  Sensor protocols for information via negotiation (SPIN)  Directed diffusion ADVREQ DATA ADVREQDATA SourceSink Step 1: propagate interest Step 2: set up gradient Step 3: send data

2016/7/315 網路層  Open research issues Improved or new protocols to address higher topology changes and higher scalability.

2016/7/316 傳輸層  Need when system is planned to be accessed through the Internet or other external networks  Between sensor node and sink node: UDP  Between sink node and user: UDP or TCP TCP/UDP ?

2016/7/317 傳輸層  Open research issues Hardware constraints such as limited power and memory. Each sensor node cannot store large amounts of data like a server in the internet. may be needed where UDP-type protocols are used in the sensor network and TCP/UDP protocols in the internet or satellite network.

2016/7/318 應用層  Potential application layer protocols for sensor networks remains a largely unexplored region.  three possible application layer protocols Sensor management protocol (SMP) task assignment and data advertisement protocol (TADAP), Sensor query and data dissemination protocol (SQDDP)

2016/7/319 應用層  Open research issues Although SQTL is proposed, other application layer protocols still need to be developed to pride a greater level of services Research developments should also focus on TADAP and SQDDP

2016/7/320 Conclusion  Wide range of application areas  New sensor networking techniques are required  Intend to motivate a search for solutions to the open research issues