1. FUNDAMENTAL CROSS-LAYER APPROACH TO WIRELESS NETWORKS Prof. Edmund Yeh Jian Cao Yufang Xi Nov. 18, 2003

2. MAIN CHALLENGES IN WIRELESS COMMUNICATIONS Fading Multi-user interference Power/energy limitation Randomly varying traffic Distributed implementation

3. BASIC APPROACH Cohesive cross-layer framework Fundamental limits and insights Joint power control, rate allocation, routing, to maximize throughput and minimize delay

4. CELLULAR NETWORKS Base Station Uplink Downlink

5. RESOURCE ALLOCATION FOR UPLINK AND DOWNLINK Transmitter 1 Transmitter 2 Transmitter N Packets Fading State Queue State at time t R 1 (t), P 1 (t) R 2 (t), P 2 (t) R N (t), P N (t) Controller

6. MULTI-HOP WIRELESS NETWORKS Source 2 Destination 2 Source 1 Destination 1

7. RESOURCE ALLOCATION FOR MULTI-HOP WIRELESS NETWORKS 1 2 3 4 5 6 A 11 (t) A 12 (t) A 21 (t) A 31 (t) H 24 (t) H 12 (t) H 13 (t) H 36 (t) H 35 (t) V1V1 V2V2 A i1 (t) A i2 (t) A iK (t) p ij,r ij p im,r im

8. FUTURE DIRECTIONS Distributed implementations Multiple antennas Delay optimization