Challenges in WSNs: Wireless Networks Wireless communication faces a variety of challenges Attenuation limits radio range ° Multi-hop communication increased latency increased failure/error probability complicated by use of duty cycles
Challenges in WSNs: Wireless Networks • Wireless communication faces a variety of challenges • Attenuation: • limits radio range • Multi-hop communication: • increased latency • increased failure/error probability • complicated by use of duty cycles Pr µ Pt d 2
Challenges in WSNs: Decentralization Centralized management(e. g at the base station) of the network often not feasible to due large scale of network and energy constraints Therefore, decentralized ( or distributed)solutions often preferred, though they may perform worse than their centralized counterparts Example: routing Centralized: Bs collects information from all sensor nodes BS establishes " optimal routes(e.g. in terms of energy) BS informs all sensor nodes of routes Can be expensive, especially when the topology changes frequently Decentralized Each sensors makes routing decisions based on limited local information Routes may be nonoptimal, but route establishment/management can be much cheaper
Challenges in WSNs: Decentralization • Centralized management (e.g., at the base station) of the network often not feasible to due large scale of network and energy constraints • Therefore, decentralized (or distributed) solutions often preferred, though they may perform worse than their centralized counterparts • Example: routing • Centralized: • BS collects information from all sensor nodes • BS establishes “optimal” routes (e.g., in terms of energy) • BS informs all sensor nodes of routes • Can be expensive, especially when the topology changes frequently • Decentralized: • Each sensors makes routing decisions based on limited local information • Routes may be nonoptimal, but route establishment/management can be much cheaper
Challenges in WSNs: Design Constraints Many hardware and software limitations affect the overall system design ° Examples include Low processing speeds (to save energy Low storage capacities (to allow for small form factor and to save energy) Lack of 1/0 components such as GPS receivers(reduce cost, size energy Lack of software features such as multi-threading(reduce software complexity
Challenges in WSNs: Design Constraints • Many hardware and software limitations affect the overall system design • Examples include: • Low processing speeds (to save energy) • Low storage capacities (to allow for small form factor and to save energy) • Lack of I/O components such as GPS receivers (reduce cost, size, energy) • Lack of software features such as multi-threading (reduce software complexity)
Challenges in WSNs: Security Sensor networks often monitor critical infrastructure or carry sensitive information, making them desirable targets for attacks Attacks may be facilitated by: Remote and unattended operation Wireless communication Lack of advanced security features due to cost, form factor, or energy Conventional security techniques often not feasible due to their computational communication, and storage requirements As a consequence sensor networks require new solutions for intrusion detection, encryption key establishment and distribution, node authentication and secrecy
Challenges in WSNs: Security • Sensor networks often monitor critical infrastructure or carry sensitive information, making them desirable targets for attacks • Attacks may be facilitated by: • Remote and unattended operation • Wireless communication • Lack of advanced security features due to cost, form factor, or energy • Conventional security techniques often not feasible due to their computational, communication, and storage requirements • As a consequence, sensor networks require new solutions for intrusion detection, encryption, key establishment and distribution, node authentication, and secrecy
Comparison Traditional networks Wireless sensor networks General-purpose design; serving many Single-purpose design; serving one specific applications application Typical primary design concerns are network Energy is the main constraint in the design of performance and latencies; energy is not a all node and network components primary concern Networks are designed and engineered Deployment, network structure, and resource according to plans use are often ad-hoc without planning Devices and networks operate in controlled sensor networks often operate in and mild environments environments with harsh conditions Maintenance and repair are common and Physical access to sensor nodes is ofter networks are typically easy to access difficult or even impossible Component failure is addressed through Component failure is expected and addressed maintenance and repair in the design of the network Obtaining global network knowledge is Most decisions are made localized without typically feasible and centralized the support of a central manager management is possible
Comparison Traditional Networks Wireless Sensor Networks General-purpose design; serving many applications Single-purpose design; serving one specific application Typical primary design concerns are network performance and latencies; energy is not a primary concern Energy is the main constraint in the design of all node and network components Networks are designed and engineered according to plans Deployment, network structure, and resource use are often ad-hoc (without planning) Devices and networks operate in controlled and mild environments Sensor networks often operate in environments with harsh conditions Maintenance and repair are common and networks are typically easy to access Physical access to sensor nodes is often difficult or even impossible Component failure is addressed through maintenance and repair Component failure is expected and addressed in the design of the network Obtaining global network knowledge is typically feasible and centralized management is possible Most decisions are made localized without the support of a central manager