4.3.3 Meaning of the Result Graphs in PRIME
The meaning of each result graph in the spreadsheets is described in the table below. The name of each one refers to the DUT operation, position and kind of data.
| Graph Name | Description |
|---|---|
| RSSI (dBµV) | The rssi parameter is the Received Signal Strength Indication in dBuV |
| CINR (dB) | The cinr parameter is the Carrier to Interference plus Noise Ratio in dB. It is a measure of the signal quality. It has a correspondency with the EVM defined on the PRIME specification (CINR(dB) = - EVM(dB)). |
| SNR (dB) | The snr parameter is the Signal to Noise Ratio in dB. It is a measure of the signal quality (SNR (dB) ≃ CINR(dB) + 3). |
| EVM (%) | The evm parameter on the
graphs is the Error Vector Magnitud in % defined like the porcentage of
phase gap (from 0 to 90º) between the received samples and the expected
samples. It is a measure of the difference between the ideal (reference)
and the measured received samples on the modulation mapping. Depending
on the modulation, this error can reach the:
|
| EVM Header Avg (%) | This is the average of all the EVM
Header received. The EVM Header to average is the carrier’s phase error
that has more distortion (maximum EVM) in the two header symbols (four
symbols if we use the robust mode) for each received frame. As the PRIME header is always in BPSK with convolutional encoder, the maximum error that it is allowed will be 100%, but it is recommended to have a small error without noise and low attenuation in order to support high noise environments. |
| EVM Payload Avg (%) | This is the average of all the EVM
Payloads received (in BPSK, QPSK or 8-PSK). The EVM Payload to average
is the carrier’s phase error that has more distortion (maximum EVM) in
all the payload symbols for each received frame. This average is a
global measure that indicates how far (in average) we are of
transmitting in one or other modulation. Example: If we have an EVM Payload Average of 20%, we could transmit in 8PSK (without convolutional encoder) without problems, but if we are around 24% or more, we will have to think on more robust modulations. This is done automatically by the MAC layer on a real scenario. |
| EVM Payload Max (%) | It is the maximum of all the EVM
payloads received. It is the carrier with more distortion in all the payloads received. This value can imply that it could not possible to receive some messages in some modulations (without convolutional encoder).. |
| EVM Payload Acum Avg (%) | It is the
average of all the EVM Payload Accumulated received. The EVM Payload Accumulated received is the error average of all the carriers in all the payload symbols. This value is normally small because generally, the carriers that have more distortion are only a few. |
| BER soft | On the soft-decision decoding process, it correspond with the accumulated distance between the received symbols and the theoretical ones. The result must be as close as possible to 0 to guarantee the correct decoding. |
| Narrow Band Noise (%) | Percentage of carriers with detected narrow band noise |
| Impulsive Noise (%) | Percentage of symbols with detected impulsive noise |
| FER (%) | Frame Error Rate, percentage of lost frames against sent frames. |
- A gain of 3 dB between the modulations BPSK, QPSK, 8PSK.
- A gain of about 6 dB when using convolutional coding.
- Additional gain is obtained using robust modulation that adds more energy to each symbol.