C-V2X is a very complex communication standard. It includes a very high number of different configuration and operation parameters. We would like to share our experience from a recent and very successful interoperability session conducted in China.

In the pre COVID-19 era, the major challenge of an interop or an expo event was to develop the required features in time. On-site installation, integration and debugging were a given; part of the planned activities. Complicated debug scenarios would require Wireless Radio experts, Hardware, Software and Customer Support experts along with local representatives who must be present on-site. The planning mostly involved selecting the personnel and coordinating the trips to the venue destination.

Now, when travel is limited, the challenges extend beyond development, but also require remote integration and remote debugging capabilities to be included in the product. For instance, creating sophisticated logging triggers that would record problematic situations in the field for quick offline analysis and resolution. At times, supporting the remote integration is so challenging, it exceeds the complexities of many aspects of the development itself.

Having a good team in place is a key to success

Based on Autotalks’ experience, the key to a successful international event is having regional technical experts. This has proven itself beneficial on numerous occasions in the past, but in times when travel restrictions are enforced, the necessity has increased tenfold. In addition to the cooperation with partners, local experts face the challenges of facilitating the debug process such as building the setup and installing the SW. In this year’s event, for instance, we supported several module vendors (integrating our chipset with different HW & SW) in parallel. Collaboration tools were heavily used, sharing screens of the regional expert and the engineering team at headquarters.

It is also worth noting that the engineering team’s spirit is also a major factor in a fast, successful issue resolution. The members of the engineering team must be flexible, available on short notice and at unconventional times. In the case of China, working at the event’s time zone meant starting at 4 AM.

Infrastructure preparation for remote debugging

A key concept in SW development is the turn-around time of a Design-Code-Test iteration. Remote debugging makes your turn-around time much longer. It takes a substantial amount of time to set a meeting with the remote engineer, explain the goal, details, tactics and then analyse and resolve the issue at hand, remotely. Interoperability events allocate only a few short slots, so it is required to be extremely efficient. Two aspects of the system can really help mitigate this challenge – configurability and verbosity.

Configurability means that you can easily configure your system in numerous useful ways. It also means that on-site representatives can easily try different scenarios in the field. There is no time for compilation. Instead this process should rely on command line parameters or configuration files. The trick is preparing the useful configurations in advance, trying to foresee what could come in handy during the integration on-site. For example, enabling configuration of parameters that require finetuning in the field.

Verbosity simply means that you have a comprehensive logging system. Such a system can give any amount of information, in different levels of detail, and from different modules, in a manageable way. Logging is crucial, since often the problems are not easily located. Debugging might utilize the logged radio signals, internal PHY state-machine states or even MAC decisions.

Analysing recorded signals remotely

One of the strongest capabilities is offline analysis of the logged scenario using simulation tools such as Matlab^©.This way, we can quickly come up with the resolution and even use playback to make sure that the issue is resolved. For instance, realizing the wrong type of frame numbering is used in the processing, via offline analysis of the recorded frame. In the field, such a problem could manifest as high packet error rate (PER) and could get in the way of device interoperability. Once the issue is found, it could be quite easy to fix, but it takes a lot of hard work and planning to prepare the infrastructure that would enable to quickly find such an issue without being in the field.

To summarize, this year’s interop event has brought out a lot of creativity, brainstorming for debug infrastructure ideas and team collaboration, with no regard to COVID-19, time zone or location. Extensive logging, simple configuration, analysis capabilities and excellent communication facilitated a successful remote interoperability event.