1. Opportunistic Transmission Scheduling With Resource-Sharing Constraints in Wireless Networks From IEEE JOURNAL ON SELECTED AREAS IN COMMUNCATIONS Presented by Wan-Hisu Kuo 2001/11/15

2. Outline Introduction System model Optimal Scheduling Policy Simulation Result Short-term Performance Conclusion

3. Introduction(1) User perceive time-varying service quality and/or quantity because channel conditions are time-varying Improve wireless resource efficiency by exploiting time-varying channel conditions,while at the same time control the levels of fairness among users

4. Introduction(2) Associated with each user is a number between 0 and 1 representing the long- term fraction of time to be assigned to the user

5. System Model(1) Time-slotted system {U i k } be a stochastic process associated with user i at time k The better the channel condition of user i,the larger the value of U i k

6. System Model(2) Performance measure Throughput SINR Value of throughput - cost of power consumption

7. Optimal Scheduling Policy(1) Let denote the time-fraction assigned to user i,where and N:number of users in the cell Let be the performance vector at time slot k,where is the performance value achieved by user i if time slot k is assigned to user i.

8. Optimal Scheduling Policy(2) Policy Q to be a mapping from the performance-vector space to the index set {1,2, …,N} If,then user i should use the time slot,and the system receives a performance “ reward ” of E( ) is the average system performance value associated with Policy Q

9. Optimal Scheduling Policy(3) The problem can be stated formally as follows: E( ) E( )=E( ) if A occurs =1 else =0

10. Optimal Scheduling Policy(4) there exists a that satisfies P{ }=,where the opportunistic policy is defined as

11. Optimal Scheduling Policy(5)

12. Simulation Results(1)

13. Simulation Results(2)

14. Short-term Performance(1) be the number of time slots assigned to user i from k i to k b the number of time slots should be assigned to user i

15. Short-term Performance(2)

16. Conclusion Computation This scheduling algorithm has low computational burden Related problems Resource allocation Scheduling schemes Short-term performance Delay requirement for certain user