ETSI EN 300 113 V3.1.1 Receiver Performance Test Guidance

Key Details for Manufacturers

The evaluation of receivers in accordance with ETSI EN 300 113 can be quite challenging. The transmitter evaluation only requires the provision of means of generating test signals, either as continuous bit streams or as correctly coded signals; messages transmitted one by one, without gaps between them. The accuracy of the content of the transmitted signals used for testing is not one of the parameters assessed.

On the other hand, it places a great emphasis on the capability of the receiver to accurately retrieve the transmitted signal under various conditions. Therefore, the success rate of the received signal, through the comparison of the decoded message with the transmitted data, either in the shape of bit error ratio (BER) or successful message ratio, is the primary key performance indicator used for the assessment of all the receiver characteristics in the standard except for receiver spurious emissions.

Additionally, a lot more support is expected from the equipment manufacturer. The manufacturer should supply the means of generating the test signals, companion devices, and supporting test software application(s) for the performance of the tests. Further, the manufacturer should provide access to test points, either at the modulator/demodulator or the encoder/decoder or using a custom application to analyze the demodulated signals. The closer the test access point is to the air interface, the fewer variants that need to be tested since the measurement becomes less dependent on the application.

The receiver characteristics are evaluated using three formats of test signals according to the standard:

1. Continuous Bit Streams: Binary digits transferred sequentially without interruption.
2. Message: User data to be transferred in one or more packets during a session.
3. Packets: A block of contiguous stream of blocks sent by one transmitter to one particular receiver.

For each format, EN 300 113 describes specific procedures and criteria for determining the success ratio. In all cases, the manufacturer is expected to provide means of assessing the success rate.  The standard recommends using a bit measuring test set in the case of continuous bit streams, or a message measuring test set for messages or packets.  However, the efforts involved in collecting the information are not equivalent. More details are provided below.

Method of measurement with continuous bit streams:

The evaluation of continuous bit streams involves monitoring the bit error ratio of the demodulated data. For the Maximum Usable Sensitivity, for example, the specified bit error ratio is 10^-2.  That measurement is performed using a bit error ratio measuring device. Such a device allows the success ratio of the receiver to be observed instantaneously, thereby reducing the test time. Otherwise, the test method would be very time-consuming if performed manually.

Method of measurement with messages:

The evaluation of messages involves tracking the number of successful messages. For the Maximum Usable Sensitivity per example, the specified successful message ratio is 80%.  This test method requires issuing multiple correctly coded test signals, as defined above, to determine a message detection threshold leading to a successful message ratio of 80%. The message success ratio can be very time-consuming if the manufacturer does not provide an accompanying application.

Method of measurement with packets:

The evaluation with packets involves counting the number of successful packets within a message. For the Maximum Usable Sensitivity per example, the specified successful message ratio is 80%. This test method involves issuing multiple correctly coded test signals, as defined above, in the form of a message and assessing the ratio of the successful packets within the message. The message success ratio can be very time-consuming if the manufacturer does not provide an accompanying application.

Among all three test methods, using the continuous bit stream with a bit error ratio test set leads to the fewest iterations and cheaper testing costs. However, with the two other test methods, especially the measurement with messages, the number of trials to achieve the desired success ratio becomes significant; as a result, a manufacturer can expect a longer test duration and higher test costs.

In summary

EN 300 113 calls for the equipment manufacturers to assist the test facilities with the generation of the test signals, provide access to test points for the bit stream measurements and, supply application/hardware for the monitoring and analysis of the demodulated signals at the receiver. The choice of the method for measuring the data success rate at the receiver can significantly affect the testing time and costs.