PRIN2005 – Women Kick-off Meeting

1. PRIN2005 – WomenKick-off Meeting University of Florence Research Unit Rome, Italy

2. Research Group • Romano Fantacci • Daniele Tarchi • Leonardo Maccari • Simone Menci • Andrea De Cristofaro Rome, Italy

3. Research Activity • WP3 Space division multiple access for QoS guaranteed wide-band connection • T3.1 Link adaptation • T3.2 Hybrid ARQ Techniques • T3.3 Optimized scheduling procedures • WP5 Secure applications, development and trials • T5.1 Security protocols for multi-hop wireless networks • T5.2 Authentication and identity management Rome, Italy

4. Resource management • The SOFDMA technique allows the allocation of different numbers of sub-carriers to the users basing on available resource and channel state. • The network operator has more flexibility in bandwidth and power management with an efficient resource utilization: • Adaptive Modulation and Coding • Adaptive carriers allocation • Power control Rome, Italy

5. Modulation and coding scheme variation • The so-called Adaptive Modulation and Coding (AMC) techniques have been proposed in order to choose the most efficient scheme basing on the channel state. • Choice of Modulation & Coding Scheme basing on required service. • Minimum QoS level (BER, FER, Delay) or throughput maximization. Rome, Italy

6. Dynamic carriers and/or power allocation • Basing on the same principle is possible to manage dynamically subcarriers and transmitting power. • The SOFDMA access scheme allows the dynamic allocation of sub-carriers to different users • Is also possible to manage the transmitting power for: • Mitigate the shadowing effect • Mitigate the interference Rome, Italy

7. LLC Protocols • In this topic the effort will be concentrated mainly on the hybrid ARQ (H-ARQ) techniques • Differently from classical ARQ techniques they are based on the joint use of FEC and ARQ techniques • In particular two schemes will be used: • Type I: when the two technique are used jointly • Type II: when the two techniques are optimized jointly Rome, Italy

8. Soft Output Combining H-ARQ • The last packet replica is recombined with a soft metric at the output of the decoder, maximizing the Euclidean distance between codeword; • Effective for SISO decoder (turbo codes) • The recombination schemes can use a diversity technique: • Maximum Ratio Combining (MRC); • Equal Gain Combining (EGC); • Weighted Gain Combining (WGC). • Both diversity and decoding gain are considered Rome, Italy

9. Quality of Service The QoS management involves all that transmitting parameters that have influences on the link performance and that, after defining them, have to be maintained Main parameters: Throughput Bandwidth wastage Delay Packet-loss Techniques for QoS control and dynamic resource management (scheduling policy): Packet Fair Queueing (PFQ): at each queue is assigned a weight that determines the resource allocation. It includes the the techniques based on Round Robin as the Packet Based Round Robin (PBRR) Earliest Deadline First (EDF): at each queue a priority is assigned basing on the deadline of the first packet to be transmitted Rome, Italy

10. Quality of Service – Application to WiMAX Mnaged traffic types: UGS, rtPS, nrtPS, BES BS Scheduler Priority: 1 = Max 4 = Min Strict semi-preemptive priority UGS rtPS nrtPS BES 1 2 3 4 PFQ Type Connection IDentifier PBRR EDF Priority Enhanced WFQ CID CID CID CID CID CID Rome, Italy

11. Heterogeneous network interworking • Allow the interoperability with the existing networks • Increment the WiMAX coverage in indoor environment • Based on standardized network to allow users and operator interoperability • Allow a soft-handoff in order to achieve a total coverage Rome, Italy

12. Application scenario PmP topology 2 transmitting WLAN Wi-Fi 2 receiving WLAN Wi-Fi WLAN rate equal to 11 Mbit/s WiMAX link in both uplink and downlink with rate equal to 5.5, 9, 11, 22 Mbit/s. Rome, Italy

13. Security in 802.16-2004 • The 802.16-2004 standard had lots of drawbacks ins security management: • Weak ciphering algorithms (DES with keys with wide validity) • No packet authentication • Inadeguated access control (RSA algorithm not well implemented) • No authentication from the base station Rome, Italy

14. Security in IEEE 802.16e • A lot of improvements… • More robust algorithms • Packet authentication • Access control with IEEE 802.1X model • Mutual authentication between base station and subscriber stations • ... At the price of more complex algorithms. • Performance degradation in mobility Rome, Italy

15. Security analysis on802.16 networks • Security analysis of 802.16-2004 • Security analysis of 802.16e • Integration in 802.11i / 802.1X environment • Mesh mode security verification • Topics to be verified: • Effective and useless algorithms • QoS under attacks • Denial of Service (DoS) replication • Authentication management in mesh networks and WiFi/WiMAX networks Rome, Italy

16. Analysis and development of authentication protocols • Authentication development in WiFi/WiMax networks • Authentication in both mesh and infrastructure environment • Verify and development of protocols: • Direct/empiric analysis and development • Analysis and development with formal verification tools Rome, Italy

17. Rome, Italy

18. Handoff in 802.1X mesh networks • The 802.1X networks foresee a centralized authentication model with the use of an authentication server that includes the user credentials. Each authentication is repeated with this server. • The authentication protocols increase delays during handoff procedures Rome, Italy