1. Mobile Computing and Wireless Communication Pisa 26 November 2002 Roberto Baldoni University of Roma “La Sapienza”

2. Motivation Towards Pervasive Computing within mostly invisible mobile computing infrastructure Convergence of enabling technologies Mobile devices PDA, Notebooks, sensors, …… till smart dust Cellular Communication (already pervasive) Wireless Networking Cheap, high bandwidth with limited range

3. Activity Domains One-hop mobile networks Ad-hoc (or multi-hop) mobile Networks Sensor networks Communication Internetworking Middleware Large body of research Emerging research aspects Technology Available Security Availability -Awareness Adaptability ………………

4. Common Characteristics Dynamic environment Location is a key notion Self-Organization Hot topic in industry (IBM, ATT, Microsoft) Results from MANETs research can be applied to autonomous systems and generally to reduce administration costs Interaction between mobile and fixed infrastructure

5. What is really missing? Glue existing results in an unique framework Development of a coherent set of theories and rigorous methos passes through....... Defining a “system model” for mobile computing capturing Networks Ad-hoc, one-hop etc. Mobility Mobility patterns, mobility behaviour (voluntary vs involuntary disconnections) Awarness Power-awareness, Location-Awareness Failure model

6. Research Themes: Communication Efficient communication is stil an open issue e.g. smart dust protocols in sensors networks, time Bounded Medium Access Control in ad-hoc, handover in single hop Is layering the right stack protocol architecture? TCP needs to look into the data-link/routing Caching has to look at routing table to do a good object placement and routing has to know where cached copies are to do a good routing Smart token-based algorithms can be done by using network layer information A bundled approach

7. Research Themes: Internetworking Ensuring Caching of fresh routes in manet Selecting next hop in sensor netwoks K-clustering

8. Research Themes: Middleware Services Necessary for enabling application Not defined and available yet Which services should be available in most mobile middleware systems? Data agregation, distributed hash-tables, persistent messaging, garbage collection, spacial data management Completelty decentralized vs core-based solutions vs hybrid solutions

9. V- Research themes: -Awareness Location-awareness How to describe, store, rate and use location information Common formats/interfaces? Energy-awareness Common interfaces? Context-awareness As a generalization of previous bullets Infrastructure awareness Execution environement awarness

10. V - Research themes: Security Current data link technologies do not provide enough protection Security features are not built-in in any routing protocol Energy efficient key management Authentication

11. V- Research Themes: Availability Group communication would not work well in Mobile Setting desptite many work on adaptability Lack of –awareness (power, location, context) Network Partition is a matter of life Group membership determined by proximity constraints Caching Placing proxies in an optimal location Collaborative caching Adaptability vs dependability

12. Other Research Themes Programming and application models Location based programming Consistency models Is eventual consistency the right answer? Do we need to support lots of models at the same time? Mobility patterns coordination To maximize connectivity Overlay Networks vs Mobile Networks Formal specification for getting rigorous design

13. Applications Identify relevant applications Ambient intelligence Rescue Augmented reality Social issues Health care.........

14. Conclusions Enabling platform is forthcoming!! Lots of open difficult problems (Horizontal and Vertical) Both practical and theoretical