SBER or single ended BER GSM test failed in CMU200

As we know BER is the short form of Bit Error Rate. BER test basically compares the data bits transmitted with decoded received data bits and take ratio of bits in error with the total number of bits transmitted.
Hence BER = Bits in Error/Total number of bits

For the loop back BER test, tester(CMU200) transmits pseudo random data sequence either PN9 or PN11 or any other pattern after physical layer processing as per wireless standard(e.g. GSM) to the UE(mobile) under test. Hence here CMU200 consists of physical layer transmitter part. The UE receives the GSM compliant signal and decodes the same. This decoded data is again passed to the uplink physical layer chain before looping back to the tester(i.e. CMU200).

The tester(CMU200) compares the transmitted PN sequence data with the looped back data and calculates the BER and displays on the screen. We can also refer this type of BER as double ended BER.

Unlike loop back BER, single ended BER(SBER) does not loop back the decoded data to uplink physical layer. It is the responsibility of the UE (Mobile) to compare the decoded data(B) with the original PN sequence set(A) in the tester (CMU200). The single ended BER result is reported back to the tester to display the same on the screen. CMU200 does not do any comparison of the data in this test with the reference PN sequence data.

This SBER test is ideal for testing the DUT's receiver sensitivity test without looping back the data. This test does not require tester to have uplink signal processing functionality. The tester equipment(here CMU200) need to have downlink physical layer signal processing chain which will be processed in the DUT.

The tester and DUT can be either GSM,CDMA or LTE compliant or it can be WLAN or WiMAX compliant device.

Test and Measurement Equipments

RF and Wireless Terminologies