Wireless Hotspots: Current Challenges and Future Directions

1. Wireless Hotspots: Current Challenges and Future Directions CSI5175 Wireless and Mobile Electronic Commerce Networks and their Applications Mao Zhang 2009.03.20

2. Content • Introduction • An example scenario • Technological challenges • Alternative approaches to connectivity • Conclusions

3. Introduction • Today, users access the Internet at a variety of places and environments where they spend a considerable amount of time outside private networks. • Wireless local area networks (WLANs) have emerged as a promising networking platform to extend network connectivity to these public places, or hotspots. • WISPs have established Wi-Fi hotspots in increasing numbers at public venues. • Several technological and deployment challenges remaining • Can roam anywhere? • Easy configuration? • A common way to authenticate? • Payment and billing? • Get bandwidth required? • Alternative network access technologies? • In summary, problems include authentication, security, coverage, management, location services, billing, and interoperability.

4. An example scenario • A scenario to motivate the vision of widespread Wi-Fi availability and to explore the various barriers • Kate needs to travel from San Diego to New York to attend a business meeting. • A presentation needs to send to colleagues before the departure • Register with the meeting venue’s Wi-Fi and get the location within the building to be guided to the meeting room • During the meeting, retrieve data from San Diego through VPN and then share with colleagues over an in-room ad hoc wireless network • Dinner time, CDMA 1xRTT card into Laptop to connect to the Internet to locate a good restaurant and get driving directions • Back to hotel, access emails using the hotel Wi-Fi network

5. Technological challenges – Authenticating to the hotspot provider • Sometimes, authentication is coupled with wireless-hop security where only authorized users receive network access. • Authentication helps the network to establish the users’ identity, while wireless-hop security ensures data privacy for authenticated users and protection for the network. • Repeat authentication at each hotspot location and the process might be configured differently. • Research questions: • Ease of access and mechanism • Authentication Latency: existing hardware mechanisms such as SIM-Card based authentication? • User Identity: existing identities such as those already through other services • 3rd party authenticators?

6. Technological challenges – Wireless-hop security • Security mechanisms provide data privacy to network users and also protect the network against malicious use. • Current approaches include per-user authentication, authorization of authenticated users through access keys, and access control, a number of schemes achieve security and provide authentication at MAC are being deployed in W-Lans • WEP is simple to manage in environment with known users. • Port-based network access control: ports are configured to block all traffic except authentication until the user identity is established.- IEEE 802.1X

7. Technological challenges – Wireless-hop security - Continued • Security challenges • Mutual Trust: e.g., implicit trust in the key distributor in WEP • Dynamic Key Management: simplified and transparent key exchange and renew • Hardware Approaches: Are there ways to provide the robustness of 802.1X through alternative hardware-based approaches? • Denial-of-Service: Current 802.11 Wi-Fi networks are highly susceptible to denial-of-service (DoS) attacks • Malicious Attacks: Hotspots are a comparatively open environment for malicious users

8. Technological challenges – Network performance and QoS • The ability to adequately provide capacity and coverage to handle dynamically-varying, location-dependent user load. • Understand the users’ behavior • Adapt to the changing resource availability or changing traffic characteristics which is not easy • Suggestion if adaptation is not possible • Questions for research • Measurement and Modeling • Monitoring (measurements of throughput, channel contention, packet errors, etc.) • QoS Enforcement: How can MAC protocols be designed to guarantee users a fair share of the wireless bandwidth and better channel utilization

9. Technological challenges – Location and context-awareness • Hotspots has the potential to make location and context-aware services more valuable and readily accessible to users • Requires a number of issues to be addressed • Application scenarios • Location Privacy and Anonymity: balance • Sensor Fusion: possibility to integrate multiple location sensing technologies • Location Granularity:absolute location vs. relative location • Location to Place: the capability to translate geographic location information into a more usable form

10. Technological challenges – Pricing model • Wi-Fi revenues are comparatively poor, the networks are at a disadvantage compared to their cellular counterpart due to the lack of widespread coverage. But it has the potential to offer users a higher bits/sec value. • Related challenges: • Subscription-based (prepaid) vs. pay-per-use model? • Central Billing Entity

11. Alternative approaches to connectivity - Multihophotspots • Multihopaccess increases the network diameter and allows clients out of range of access points to receive connectivity. • Challenges introduction: • Node Mobility: the number of active nodes in the ad hoc network, the network topology, and the volume of network traffic is constantly changing • Channel Interference: transmissions can cause interference at the access points, degrading effective throughput and the channel capacity. • Multiple Network Access: nodes in the multihop hotspot need: a wireless network adapter with more than one radio; or a wireless network adapter with the capability to multiplex connections from more than one network ; or more than one wireless adapter.

12. Alternative approaches to connectivity - Interoperation with WAN data services • Interoperation between cellular and hotspot networks is beneficial to both wireless carriers and hotspot operators. • Hardware support: for both services on mobile devices to migrate the connection across access technologies • Software ability through sensing to switch to the most resource-efficient mode of access • The establishment of roaming relationships and agreements between network operators for effective packet routing as users switch between them. TOGEWAnetAG offers a seamless integration of WLAN and GSM GPRS services and an integrated authentication, security, and billing over a common infrastructure:www.weroam.com • Handoff Mechanism • Location-assisted Roaming • System Support for Handoff: Is handoff initiated at the user device or by the network? • Billing

13. Conclusions • The continuing rollout of hotspot deployment is being fueled by the growing requirement for high-speed connectivity in public areas • A successful and viable hotspot business model will depend on the extent that it can provide value for all its stakeholders • End user: easy to use, economically attractive, and provides fast access • Hotspot network providers: reliable and robust third-party authenticating entity, establish peering agreements with other providers and accommodate the various resource and performance demands of the users. • Premise and building owners: establish business agreements with hotspot network providers to offer network access an everyday utility for the end user.