The role of Ad hoc networks in mobility

The role of Ad hoc networks in mobility BT Technology Journal Vol. 21 No. 3, July 2003 授課老師：潘仁義教授　　　 修課學生：郭姵妤 報告日期： 2003 -12 -23

Outline § Ad hoc Network § Applications of ad hoc network § Community-based networks § Free Networks § Share cost Networks § Commercial alternatives § Conclusions

Definition and expectation

Simple Scenarios § EX 1: extra revenue and marginal cost of email by using a fixed line is zero, no cheaper alternative (X)

Simple Scenarios § Ex 2: Send an e-mail to somebody who lives some distance away (X) § Ex 3: Internet user wants to download a big file from a web site on the other side of the world (X)

Simple Scenarios § Ex 4: Internet user wants to share a large file with neighbors (O)

Ad hoc Extension

Factors § Motivation § reason to co-operate with each other § Get access to connectivity § Negotiate for better connectivity § Because it’s there

Factors § Technically possible § It may not offer the quality of service network operators normally provide but it is good enough for many purpose

Factors § Cost effective § People do something as a hobby, the cost in time and money is less of an issue § Becomes a mass-market service, it must be cheap and easy to deploy

• Ideal Broadband – is FTTH and UWB (ultra-wideband) within home • if the number of ad hoc network grows faster than that of fiber rolling out • Ownership of the last mile • Ad hoc network might allow its user to hop to the best network or connection point or share network connection-part of management of how the network is used will move to the edge of the network

Simple Scenarios § EX 5: An internet user allows other internet users to share their always-on but not alwaysin-user internet connection § In use from 9. 00 am to 5. 00 pm Mon. to Fri. user decides to make its internet connection available during the evenings and at weekends § The rise of WARChalking

Hobo Signs & Symbols http: //www. slackaction. com/signroll. htm

War Chalking http: //www. warchalking. org/

Simple Scenarios § EX 6: A group of internet users pool their always-on but no always-in-use internet connection § Each user has fixed line internet access and arrange to manage their (joint) traffic

Simple Scenarios § EX 7: A group of internet user get together to buy and share a high bandwidth internet connection § Possible only when there is no fixed line broadband service available. § Fixed line network operator is losing control over the last mile § Ex 8: WISP sets up business in an area offering higher bandwidth § The fixed line network operator will lose revenue and end up having a large customer.

Form of ad hoc network § the most common form of ad hoc network will be a community-based network § In a area that is not served by fixed line broadband operators § i. e. group of people working together § Already a large number of community-based network § 14 in Australia, 18 in Europe, 30 in North America

Form of ad hoc network § Free Networks – Share network access with those who do not – Possible to apply from government or interested parties – It will end up spoiling it (bandwidth hogs) or cease operation if key person leaves the group § ARWAIN – provide free access for these group by utilizing bandwidth that others have paid for but are not using for young, sick, elderly, unemployed and disadvantages – Possible in small scale but not possible in large scale

Shared cost networks § Community outsource the management of the network to a commercial company § First-line technical support; No need of large advertising and marketing budgets § Retaining control of the network, community makes sure that the resource is not abused § Main driver-absence of fixed-line broadband operators or slower fixed line service § ex: Carnet has a limit of 30 Gbit/s per month usage.

Shared cost networks – Cheaper and faster connectivity – Community networks –global, • ex: member of one yacht club is normally welcome to use the facilities of another yacht as a visitor • User can gain access to the facilities in another location

Commercial alternatives • WISP – Single account, multiple network – Pass the risk of running hop-spot to business hot-spot Cafe Virtual WISP Airport Hotel

Commercial alternatives -3 G § 3 G mobile operators – WLAN is a threat to 3 G • 3 G not suitable for data-rich service • WLAN offers unmetered usage • WLAN offers faster data speed but not supportive for user moving with high speed § 3 G not suitable for service requiring broadband – Bigger as they have to compatible with GSM – Heavier than GSM handset and the battery is also heavier otherwise the battery life is limited

Commercial alternatives -3 G • • Unclear what sort of mobile device people prefer – Small mobile telephone just for voice – ‘Singing and all dancing’ mobile device that has a bigger , better screen even a small keyboard – If the latter, the devices may work better with a WLAN that offer more bandwidth than 3 G Research found – Laptop is preferred device- for access data-rich service for large screen and keyboard to get the full benefit

Capacity • • Ad hoc networks often have greater capacity than fixed line internet access Give 3 G tough competition, similar service can be provided more cheaply over WLAN

Conclusion § Collected bandwidth can be used in other wireless network.