Packet delivery ratio compares received packets with the defined number transmitted during a stated test interval and configuration.
Why this matters in the industry
Industrial teams need an observable outcome related to the application's reporting requirements.
The technical reasoning
Packet delivery ratio counts successful deliveries within a defined population and time window. Its meaning changes with retry policy, duplicate handling and deadline definition. Industrial applications may need both eventual delivery and on-time delivery because a late message can be operationally equivalent to a missing one.
Defining a communication outcome before counting it
Packet success depends on more than RF power. Payload length, timing, retries, receiver state and the application's arrival deadline influence the outcome. A packet-delivery fraction is an estimate from a specified sample; its confidence depends on sample size and whether observations can reasonably be treated as independent. Correlated fades or shared interference can make a long sequence less informative than the same number of independent trials.
How to structure the investigation
Define whether retries, duplicates and late arrivals count. Record packet size, interval, channel and operating conditions. Use enough observations for the intended comparison, and report the sample size rather than presenting an unqualified percentage.
Define a transmitted attempt, an acceptable arrival and treatment of duplicates or retries. Record the complete configuration and the number of observations at each condition. Compare repeated runs and preserve timestamps when timing matters. Under an independent Bernoulli approximation, the standard error of an estimated success fraction is approximately the square root of p times one minus p divided by n, but extreme values and correlated data need more careful treatment.
Worked example or engineering scenario
If 990 of 1,000 messages eventually arrive, delivery ratio is 99 percent. If only 950 arrive before a required deadline, on-time delivery is 95 percent; the first metric hides the timing gap.
Evidence to collect
| Record | Purpose |
|---|---|
| Attempt count | Defines the tested state and scope of the comparison. |
| Retry treatment | Makes the stimulus or route condition reproducible. |
| Arrival deadline | Supports interpretation of variation and possible confounding effects. |
| Test conditions | Connects the observation with the stated engineering decision. |
Trade-offs and common interpretation errors
A displayed 100% from a small sample is not a reliability guarantee. Pooling unlike configurations can also hide weak conditions. Report sample counts and the chosen criterion, and connect the measured outcome to the application's requirement rather than assuming every successful reception is timely or useful.
What the result can support
Specify the packet population, retry treatment and deadline when reporting delivery performance.
A measured ratio is not a guarantee of future delivery under different conditions.
Further technical reading
Related industry knowledge
- How to Separate Antenna Problems from IoT Radio Problems
- How to Test IoT Radios at Low Battery Voltage
Numerical scenarios are illustrative assumptions, not reported measurements of a supplied product or installation.