Multi-hop wireless networksFact or fiction?

Injong RheeDepartment of Computer Science

North Carolina State University

Status quo…

• Years of research in– Mobile ad hoc networks (MANETs)– Wireless mesh networks– Delay-tolerant networks (DTNs)

• But we are not seeing compelling business cases. – Why? – What went wrong?– What do we do?

No compelling business case, Why?

• Cost too much for wide network deployments?• Low performance for legacy Internet

applications?– We are still working on improving capacity and

“performance” (BW and Latency).• Perhaps, we may not be looking at the right

applications.– Too much emphasis on improving capacity (bits and

ms).– Not much research in developing and supporting

applications.

Many networked devices; just we don’t know how to get them to talk to each other

• Can we design applications that can use the existing deployment of networked devices?– Cellular networks– Mobile phones– APs in hot spots (restaurants, homes, groceries,

banks, offices)– Sensor networks

Suppose that all can talk to each other…….

• What are compelling multi-hop wireless applications?

• “Context-aware applications”– Location, location and location. – Higher abstractions: PLACES• Not longitude and latitude, but• Homes, Restaurants, Campuses, Meeting rooms,

Classrooms, Book stores, Coffee Shops, Parks, Shopping Centers, etc.

“Place”-aware applicationsOne of top commonly cited

killer mobile apps.– Personal agents– Social networking goes

hyper-local (e.g., Twinkle)

– Document your phote where they are taken.• Annotating and tagging

your contents (pictures and videos) with place information.

– Finding great places nearby.

– Address books with place information.

How to mine place information?This is where multi-hop wireless networks come in.

• GPS, faux-GPS (GSM) – it tells your coordinates not places.

• We have many more devices surrounding us.– APs and Ambience Sensors– Humans:User feedback

• Now we can post our sense of places to a wall “notepad” – devices happen to be in the same locations.– Sticky notes in the air (Romit Choudhury)

Can we share hints on the places?

superbsushi

Safe@ Nite?

Safe@ Nite?

One hop to another (being bulletin boards)

• Networking devices perhaps stand-alone or connected – they can be good places to attach a note.

• Mobile devices nearby you can be your place servers.– How others perceive the current locations can

provide hints on your sense of the current places.• In this sense, it is not traditional multi-hop

wireless routing.• But rather, one information travels from one hop

to another for ambience sensing.

Challenges

• No software and network architecture that allows devices to talk across domains– Can your cell-phones talk to each other?– Can your APs talk to your phones?– Can a sensor talk to your phones?

Conclusion

• Multi-hop wireless networks are hear; just we are not aware of it.

• We need to think outside the box of throughput and latency, but think more about applications, middleware, software and network architectures to leverage our networked devices.

• Then business cases will follow.