Consider a multicast network, which is a finite directed
Abstract: Freshness of information is of importance to achieve real-time control among networked devices and applications. This letter considers the age-of-information (AoI) that characterizes how long it elapses until the reception of the latest information at the destination from its generation. Particularly, we examine the peak AoI, i.e., the maximum of AoI, just before the latest information is received for D/G/1 queuing systems, in which the information (or packet) is periodically generated. We obtain an approximate closed-form expression for the outage probability that the peak AoI exceeds a certain threshold. Numerical results for D/Geo/1/1 and D/M/1/1 systems show that our approximation is tight. Existing system: In, some optimal information update policies to minimize the average age penalty per unit time under various constraints are considered. Furthermore, Champati et al. studied the violation probability that AoI is greater than or equal to a certain age limit (or threshold) for D/G/1 queue in [8]. Note that their expression in is based on the infinite sum of the probabilities that a (partial) sum of v service times is greater than a certain threshold. It thus requires v times convolutions of service time
distributions as v ! 1, whereas some truncation on v is considered. Our characterization however uses a single parameter called quality of service (QoS) exponent of AoI based on large deviation. Compared to, this work investigates the probability. Proposed system: DEVICES (or sensors) in a variety of real-time applications are asked to report a measurement or update to a destination in the Internet-of-Things (IoT) and machine-to machine (M2M) communications. It is thus important through the networks to deliver the information to the destination by keeping it fresh so that real-time interactions and control become feasible. To this end, the age-ofinformation (AoI) , which is defined as the elapsed time for the information delivered to the destination once it has been produced, has been considered to measure the freshness of data or information. As previous work, the average AoI is obtained for queuing systems such as M/M/1, M/D/1, and D/M/1 with first-come first- serve (FCFS) policy. For M/M/1 systems with queue length of one or two, the average AoI and peak AoI are studied. Advantages: In, some optimal information update policies to minimize the average age penalty per unit time under various constraints are considered. Furthermore, Champati et al. studied the violation probability that AoI is greater than or equal to a certain age limit (or threshold) for D/G/1 queue. Note that their expression in is based on the infinite sum of the probabilities that a (partial) sum of v service times is greater than a certain threshold. It thus requires v times convolutions of service time distributions as v ! 1, whereas some truncation on v is considered. Our characterization however uses a single parameter called quality of service (QoS) exponent of AoI based on large deviation. Disadvantages: It is thus important through the networks to deliver the information to the destination by keeping it fresh so that real-time interactions and control become feasible. To this end, the age-of-information (AoI), which is defined as the elapsed
time for the information delivered to the destination once it has been produced, has been considered to measure the freshness of data or information. As previous work, the average AoI is obtained for queuing systems such as M/M/1, M/D/1, and D/M/1 with first-come first- serve (FCFS) policy. For M/M/1 systems with queue length of one or two, the average AoI and peak AoI are studied. Notice that the peak AoI is the maximum value of age achieved just before an update is received. The impact of buffer size on AoI is analyzed with packet deadline control. Modules: Destination in the Internet – Of – Things: DEVICES (or sensors) in a variety of real-time applications are asked to report a measurement or update to a destination in the Internet-of-Things (IoT) and machine-to machine (M2M) communications. It is thus important through the networks to deliver the information to the destination by keeping it fresh so that real-time interactions and control become feasible. To this end, the age-ofinformation (AoI) , which is defined as the elapsed time for the information delivered to the destination once it has been produced, has been considered to measure the freshness of data or information. As previous work, the average AoI is obtained for queuing systems such as M/M/1, M/D/1, and D/M/1 with first-come first- serve (FCFS) policy. For M/M/1 systems with queue length of one or two, the average AoI and peak AoI are studied. Notice that the peak AoI is the maximum value of age achieved just before an update is received. The impact of buffer size on AoI is analyzed with packet deadline control. Quality of service: In, some optimal information update policies to minimize the average age penalty per unit time under various constraints are considered. Furthermore, Champati et al. studied the violation probability that AoI is greater than or equal to a certain age limit (or threshold) for D/G/1 queue. Note that their expression in is based on the infinite sum of the probabilities that a (partial) sum of v service times is greater than a certain threshold. It thus requires v times convolutions of service time distributions as v ! 1, whereas some truncation on v is considered. Our
characterization however uses a single parameter called quality of service (QoS) exponent of AoI based on large deviation. Compared to, this work investigates the probability. Outage probability: Level, while depict how much tightly the outage probability of peak AoI can be guaranteed. For, we can see that the probability that the queue length is greater than, or equal to three is much less than 0:005, i.e., a short queue length. Even for such a moderate low utilization, the approximations on the outage probability of AoI are tight. When the queue length would be limited by 14 with, it is expected that the packet loss can be less than and we guarantee that the probability that the peak AoI violates 45 (sec) is less than. To this end, the mean service time of 3.5 should be provided. As expected, as increases, the outage probability of speak AoI also increases. At the same, the performances in D/M/1/1 are slightly worse than those.