Research Issues in Wireless Sensor Networks Prof. Xiaohua Jia Dept. of Computer Science City University of Hong Kong CS Dept, City Univ.
Characteristics of Sensor Networks • Low power and limited energy supply • Simple CPU (low speed, small memory) • Low network speed, unreliable data link, small transmission range • Large deployment and dynamic replacement • No infrastructure and self & dynamic organization CS Dept, City Univ.
Layered Structure of Sensor Networks Applications Database Queries Data Aggregation Routing Security Localization Time Synch Topology Cont’l OS / Network Hardware / MAC layer CS Dept, City Univ.
Localization / Time Synchronization • Localization of tagged and untagged objects • Finding locations of sensors without GPS • One-hop or multi-hop time synchronization (important for scheduling of sensor nodes) CS Dept, City Univ.
Topology Control Adjust transmission power of nodes or determine logical neighbors of nodes. • Achieving desirable connectivity / reducing interferences / increasing throughput • QoS topology control • Dynamic, distributed (localized), and efficient. CS Dept, City Univ.
Placement and Coverage Issues • Placement of sensor nodes for good coverage or network connectivity. • Placement of data-sinks for efficient data collection or network throughput. • Network connectivity (or area coverage) and node density. • Scheduling of nodes sleep / active for energy saving under desirable area coverage. CS Dept, City Univ.
Security of Sensor Networks • Light-weight cryptographic primitives • Light-weight security protocols for key distribution / key management / authentication • Intrusion detection / intrusion tolerance • Secured routing (lack of security infrastructure) CS Dept, City Univ.
Routing & Data Aggregation • Data centric routing (data push / pull / hybrid) • Backbone computation / clustering • Geographic routing (GPSR, etc) • QoS routing • Energy efficiency & real-time issues • Broadcasting / multicasting / anycasting • Data aggregation & query optimizations CS Dept, City Univ.
Data Query & Data Processing • Database systems for sensor networks • Application data processing / signal processing / pattern recognition • Location sensitive database / spatial database CS Dept, City Univ.
Applications of Sensor Networks • Environment monitoring • Agriculture • Manufacturing industries • Medicine • Disaster warning / prevention / relief operations • Military applications CS Dept, City Univ.
Concluding Remarks Strategic Research Directions of Sensor Networks: • Special-purposed hardware design (application tailored, low cost). • Security issues in sensor networks. • Sensor network applications. CS Dept, City Univ.