This is a short Z2labs success story.
The project had an interesting angle where the issue reported simply could not be reproduced at our premises. The issue itself was measurably lower throughput than on the customer’s legacy product in the 868 MHz ISM band. Conducted RF performance tests on the HW did not reveal any issue. After a few iterations leading to no results a visit onsite and a few essential tests revealed that the radio environment was hugely different to ours which manifested itself in a 10 MHz wide rather high power LTE channel right above the application operating frequency generated by a base station close-by. This created a strong suspicion that the issue must be related to receiver blocking performance / linearity. Interesting that without the LTE blocker the issue would probably have never been spotted.
From this point on, the task became balancing dynamic range, linearity, selectivity and sensitivity of the receive chain by various configuration changes right on the RX IC without changing the PCB as the design was already in its finishing phase. We managed to arrive at a configuration that brought throughput on par with the legacy product without sacrificing too much in other performance metrics. The benchmark test was receiving test packets from the R&D premises generated by fellow engineers at various power levels and distances working on other products with the same protocol. By its nature this data collection was not controlled but could still provide a benchmark between parallel running solutions which we could leverage to tweak the configuration. The whole process took three days onsite until the solution was delivered.
