Minimizing the Age of Information in broadcast wireless networks

We consider a wireless broadcast network with a base station sending time-sensitive information to a number of clients. The Age of Information (AoI), namely the amount of time that elapsed since the most recently delivered packet was generated, captures the freshness of the information. We formulate a discrete-time decision problem to find a scheduling policy that minimizes the expected weighted sum AoI of the clients in the network. To the best of our knowledge, this is the first work to provide a scheduling policy that optimizes AoI in a wireless network with unreliable channels. The results are twofold: first, we show that a Greedy Policy, which transmits the packet with highest current age, is optimal for the case of symmetric networks. Then, for the general network case, we establish that the problem is indexable and obtain the Whittle Index in closed-form. Numerical results are presented to demonstrate the performance of the policies.

[1]  Tara Javidi,et al.  Optimality of myopic policy for a class of monotone affine restless multi-armed bandits , 2012, 2012 IEEE 51st IEEE Conference on Decision and Control (CDC).

[2]  Vivek S. Borkar,et al.  A Theory of QoS for Wireless , 2009, IEEE INFOCOM 2009.

[3]  J. Bather,et al.  Multi‐Armed Bandit Allocation Indices , 1990 .

[4]  Kevin D. Glazebrook,et al.  Multi-Armed Bandit Allocation Indices: Gittins/Multi-Armed Bandit Allocation Indices , 2011 .

[5]  Atilla Eryilmaz,et al.  Throughput-Optimal Scheduling Design With Regular Service Guarantees in Wireless Networks , 2015, IEEE/ACM Transactions on Networking.

[6]  N. L. Lawrie,et al.  Comparison Methods for Queues and Other Stochastic Models , 1984 .

[7]  P. Whittle.  Restless Bandits: Activity Allocation in a Changing World , 1988 .

[8]  Roy D. Yates,et al.  Real-time status: How often should one update? , 2012, 2012 Proceedings IEEE INFOCOM.

[9]  Vivek S. Borkar,et al.  Index Policies for Real-Time Multicast Scheduling for Wireless Broadcast Systems , 2008, IEEE INFOCOM 2008 - The 27th Conference on Computer Communications.

[10]  Roy D. Yates,et al.  Update or wait: How to keep your data fresh , 2016, IEEE INFOCOM 2016 - The 35th Annual IEEE International Conference on Computer Communications.

[11]  Elif Uysal-Biyikoglu,et al.  Age of information under energy replenishment constraints , 2015, 2015 Information Theory and Applications Workshop (ITA).

[12]  Dimitri P. Bertsekas,et al.  Dynamic Programming and Optimal Control, Two Volume Set , 1995 .

[13]  R. Weber,et al.  On an index policy for restless bandits , 1990, Journal of Applied Probability.

[14]  Anthony Ephremides,et al.  Optimal scheduling with strict deadlines , 1989 .

[15]  Xueying Guo,et al.  Index policies for optimal mean-variance trade-off of inter-delivery times in real-time sensor networks , 2015, 2015 IEEE Conference on Computer Communications (INFOCOM).

[16]  Marian Codreanu,et al.  On the Age of Information in Status Update Systems With Packet Management , 2015, IEEE Transactions on Information Theory.

[17]  Eytan Modiano,et al.  Optimal Transmission Scheduling in Symmetric Communication Models With Intermittent Connectivity , 2007, IEEE Transactions on Information Theory.

[18]  Qing Zhao,et al.  Indexability of Restless Bandit Problems and Optimality of Whittle Index for Dynamic Multichannel Access , 2008, IEEE Transactions on Information Theory.

[19]  Christian M. Ernst,et al.  Multi-armed Bandit Allocation Indices , 1989 .

[20]  Qing He,et al.  Optimizing freshness of information: On minimum age link scheduling in wireless systems , 2016, 2016 14th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt).

[21]  Eytan Modiano,et al.  Optimizing age-of-information in a multi-class queueing system , 2015, 2015 IEEE International Symposium on Information Theory (ISIT).

[22]  Eytan Modiano,et al.  Optimal scheduling of real-time traffic in wireless networks with delayed feedback , 2015, 2015 53rd Annual Allerton Conference on Communication, Control, and Computing (Allerton).