160 likes | 191 Views
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. Outline. Introduction System model Optimal Scheduling Policy Simulation Result Short-term Performance
E N D
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
Outline • Introduction • System model • Optimal Scheduling Policy • Simulation Result • Short-term Performance • Conclusion
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
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
System Model(1) • Time-slotted system • {Uik} be a stochastic process associated with user i at time k • The better the channel condition of user i,the larger the value of Uik
System Model(2) • Performance measure • Throughput • SINR • Value of throughput - cost of power consumption
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.
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
Optimal Scheduling Policy(3) • The problem can be stated formally as follows: E( ) • E( )=E( ) • if A occurs =1 else =0
Optimal Scheduling Policy(4) • there exists a that satisfies P{ }= ,where the opportunistic policy is defined as
Short-term Performance(1) • be the number of time slots assigned to user i from ki to k • b the number of time slots should be assigned to user i
Conclusion • Computation • This scheduling algorithm has low computational burden • Related problems • Resource allocation • Scheduling schemes • Short-term performance • Delay requirement for certain user