Proposed Use Case & Improve ad-hoc mode for 802.11ah/a/b/g/n

1. September 2011 doc.: IEEE 802.11-11/1138r0 Proposed Use Case & Improve ad-hoc mode for 802.11ah/a/b/g/n Date: 2011-08-20 Authors: Slide Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission

2. doc.: IEEE 802.11-11/1138r0 The Future Holds Surprises • The unpredictable nature of the future, especially when it relates to technology, is possibly the ONE thing we can predict with absolute certainty. However, there are many things that we can use to determine probable outcomes. • No-one could have foreseen the huge explosion in not only mobile phones, but other mobile devices. The use of these devices has also been surprising, with not only cellular network usage, but wireless use of smartphones growing exponentially. Slide 2 Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission

3. doc.: IEEE 802.11-11/1138r0 The Medium needs to cope with the Message(s) • The rise of the use of mobile communications technology (including tablet devices using programs such as Skype & Facetime for business and personal communication) has shown that people embrace the notion of communication anywhere, anytime. • Cellular networks are becoming rapidly overwhelmed. There also needs to be a solution that provides alternatives to them in rural and regional locations, countries with high poverty rates, developing and third world communities, and areas hit by emergency or disaster scenarios. Slide Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission

4. September 2011 doc.: IEEE 802.11-11/1138r0 ServalProject.org as Example Use-Case • Fully-distributed telephony, messaging and file-transfer for disaster, rural/remote and developing country use. • Large-scale ad-hoc mesh networks (but possibly only local direct reachability) • High-mobility of nodes • Protocols under continuous development • Using 802.11a/b/g/n as current transport, but not ideal, because ... Slide Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission

5. September 2011 doc.: IEEE 802.11-11/1138r0 Limitations of Ad-Hoc 802.11a/b/g/n • Cell-splitting / BSSID synchronization / interface hangs problems / outright device incompatibility: partly due to poor implementation of ad-hoc in WiFi drivers, partly due to complexity of ad-hoc specification. • Purpose of SSID and BSSID is to separate traffic. For ad-hoc mesh networks we want to prevent separation. • Beacons deplete available bandwidth, and not required for ad-hoc networks. • Indoor range of 802.11b/g/n on cell phone is ~ house: need several house range to form suburban meshes. • Outdoor range of 802.11b/g/n on cell phone is ~village: need several km to form rural/remote meshes. Slide Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission

6. September 2011 doc.: IEEE 802.11-11/1138r0 Proposal: S1G Packet Radio WiFi • Operate simultaneous with existing managed and AP modes so that mesh can co-exist with infrastructure. • Ignore BSSID, only channel and SSID should separate packet-radio traffic. • Take advantage of natural advantages of radio: all frames are broadcast. • Beacons not required, because there is no cell coordination as everything is broadcast. • Low bit-rate under sender control are useful (think Twitter, HAM) • Cellular baseband radio is a compelling resource. Slide Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission

7. doc.: IEEE 802.11-11/1138r0 Leave Mesh Routing in Software (or Why 802.11s Isn’t The Only Solution) • Standards process timelines match hardware development, but lag software development. • Mesh routing protocols under continuous development. • Goal should be to remove barriers to innovation where possible. Slide Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission

8. doc.: IEEE 802.11-11/1138r0 Variable & Low Bit-Rates Are Useful • Mesh networks often have variable node density. • High Bit-Rates for High-Density / Short-Range ... • ... But Low-Density (e.g., Rural) meshes require longer range, and so Low Bit-Rates are an attractive option. • 10kbits half-duplex is enough to carry a full-duplex phone call • +20db versus 1mbit = ~10x range versus 1mbit • Need to get rid of beacons to make low bit rates feasible Slide Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission

9. doc.: IEEE 802.11-11/1138r0 Wifi over Baseband Processor • Every cell phone has a baseband processor which is prime near the ISM915/ISM868 bands, even the cheapest ones. • No increase in bill of materials, but adds compelling advantage. Slide Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission

10. doc.: IEEE 802.11-11/1138r0 Other projects There are many other mesh networking projects out there needing robust adhoc mesh networking. • Village Telco build low-cost community telephone network hardware and software that can be set up in minutes anywhere in the world. • Digitata is a body intent on sharing education resources and access to the Internet via mesh networking to African children • OpenMeshProject.org has tasked itself with developing the best open source technologies, while simultaneously partnering with existing technologies, to create a private, citizen-owned communications infrastructure, such as would be used in situations such as citizen based political reform Slide Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission

11. September 2011 doc.: IEEE 802.11-11/1138r0 References • Village Telco http://villagetelco.org/ • Projects using Mesh Networking http://emergentbydesign.com/2011/02/11/16-projects-initiatives-building-ad-hoc-wireless-mesh-networks/ • Performance of Urban Mesh Networks http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.90.3623&rep=rep1&type=pdf • IEEE 802.11n-2009 http://en.wikipedia.org/wiki/IEEE_802.11n-2009 Slide Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc. Submission