Throughput KPI & Latency KPI in LTE- RF Optimization Part I
Integrity in LTE Network- Throughput KPI & Latency KPI in LTE
LTE IP throughput is the measure of the data payload that was successfully transmitted over the amount of time required to transmit the data.
Because of the bursty nature of data, and to be independent of file size, the specification requires that the determination of transmission time does not include idle TTIs when the buffer was not empty.
As shown in the figure, only the time samples when data is present in the buffer are used to determine transmission time.
The calculation of the total transferred data volume defined in the 3GPP specification reference is shown i.e. only the data that is successfully transmitted (i.e., acknowledged by the UE) while the data buffer was not empty used to determine data volume.
Data that had to re-transmitted, or the of data in the last transmission (which emptied the buffer), is not used the calculate data volume.
LTE IP latency is defined as the amount of time an IP packet resides in the eNB buffer before it is transmitted over the air.
As shown in the figure, only IP packets that enter an empty buffer are considered. The numerator is the summation of time when the packet enters the empty buffer until the first block is sent to the Uu interface. The denominator is simply the number of measurement samples taken.