Update or Wait: How to Keep Your Data Fresh

In this paper, we study how to optimally manage the freshness of information updates sent from a source node to a destination via a channel. A proper metric for data freshness at the destination is the age-of-information, or simply age, which is defined as how old the freshest received update is, since the moment that this update was generated at the source node (e.g., a sensor). A reasonable update policy is the zero-wait policy, i.e., the source node submits a fresh update once the previous update is delivered, which achieves the maximum throughput and the minimum delay. Surprisingly, this zero-wait policy does not always minimize the age. This counter-intuitive phenomenon motivates us to study how to…

• NS
  National Science Foundation

  Awards: CNS-1446582, CNS-1422988, CNS-1054738, CNS-1518829, CNS-1514260, CNS-1409336
• DT
  Defense Threat Reduction Agency

  Award: HDTRA1-14-1-0058
• AR
  Army Research Office

  Award: W911NF-14-1-0368