BER Measurement Using FEC Loopback to Compensate Back Channel Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As data rates increase, the loss in the back channel of Bit Error Ratio (BER) measurements becomes significant, making it difficult to achieve accurate measurements due to higher sensitivity requirements, leading to more expensive test equipment and less accurate results.
Innovation Solution
The implementation of forward error correction (FEC) encoding and decoding in the loopback mode of the device under test (DUT) to differentiate between errors introduced by the back channel and those caused by the receiver, allowing for a more reliable assessment of the BER by eliminating back channel-induced errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data rate is increased to meet higher bandwidth demands, then productivity is improved, but loss of information in the back channel increases
Solution Approach 1:
The patent introduces FEC encoding as an intermediary mechanism between the transmitter and receiver. The FEC encoder adds redundant bits to the data stream, creating a protected version that can compensate for errors introduced by back channel loss. This intermediary layer allows the system to maintain data integrity even when the back channel degrades at higher data rates.
Solution Approach 2:
The patent applies preliminary action by performing FEC encoding before the data traverses the vulnerable back channel. The redundant information is prepared in advance and embedded into the transmitted signal, so that when errors occur during transmission, the receiver can use the pre-added redundancy to correct the mistakes without needing retransmission.
2Measurement precision
If back channel loss increases due to higher data rates, then measurement precision deteriorates, but device complexity increases
Solution Approach 1:
The patent enables the DUT to perform self-service by incorporating FEC encoding and decoding capabilities within the device itself. The DUT's transmitter encodes the test pattern with FEC before sending it through the back channel, and the receiver decodes it upon reception. This self-contained approach allows the DUT to protect its own measurements without requiring complex external test equipment.
Solution Approach 2:
The patent extracts the FEC functionality from the test equipment and places it within the DUT itself. By taking out the encoding/decoding tasks from the external measurement system and embedding them in the device under test, the solution reduces the complexity requirements for expensive test equipment while maintaining measurement precision.
3Measurement precision
If higher sensitivity is required to compensate for back channel loss, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies preliminary action by pre-encoding the test data with FEC before it enters the back channel. This advance preparation of error correction information allows the receiver to correct errors without requiring excessive sensitivity in the measurement equipment. The redundant bits are already in place to handle potential corruption, reducing the need for high-sensitivity detection mechanisms.
Data Source
AI summary
A method of determining the bit error ratio (BER) of a device under test (DUT) includes transmitting a first signal of an original test bit pattern over a first channel to a receiver of the DUT, and forward error correction (FEC) encoding the original test bit pattern of the first signal transmitted to the receiver of the DUT in a loopback mode of the DUT to generate an FEC encoded test bit pattern. The method further includes transmitting a second signal of the FEC encoded test bit pattern from a transmitter of the DUT over a second channel, and FEC decoding the FEC encoded test bit pattern of the second signal to obtain a decoded test bit pattern and comparing the decoded test bit pattern with the original test bit pattern to determine a BER of the DUT.