ETSI Email Archives: A secret ingredient to crack SEP Litigation

“More than 75% of SEP litigations involve 3GPP standards, including these days’ hot topic i.e. 5G standard and its predecessor i.e. 4G, 3G, and 2G”


The stakes in such high-profile litigations of the Telecom domain are so high that invalidating a SEP (Standard Essential Patent) becomes quite a challenge. A miss of a single document (or to say inability to connect dots) can make your client lose millions.

One good thing about challenging such SEPs is that the chances of finding a prior-art in 3GPP meeting archives (incl. draft/proposals/specs/CRs) are very high. This corresponds to the fact that usually the inventors of SEPs participate in 3GPP meetings and innovate around the topics being discussed in those meetings. So on exploring the 3GPP meetings, you may come across some close prior-arts notably from other companies. This is because delegates from different companies participate and contribute their ideas toward solving the work item defined for the 3GPP workgroup.

If you are an attorney who has worked previously on such high-profile SEP litigation, you might have witnessed the situation where you got hands on a very close art disclosing the idea briefly that you were looking for but missed on one or the other claim elements. The finish line is right there but you are out of fuel and you are just hanging around waiting for someone’s help to cross the line.

I found myself in a very similar situation — as a searcher — while I was working on a project that involved finding prior art for a Standard Essential Patent in litigation.  

Finding Prior Art for a SEP

Before I share what exactly I did, let me set the right context by explaining the concept that I was looking for (It would be just a brief as it’s highly confidential). We needed to find a specific MCS table in which a single index value is used to represent two Modulation schemes in two different configurations.

We know from experience that we could find solid leads from 3GPP meeting materials. With that thought, we started the search by exploring the RAN workgroup meetings. On exploring some meetings held before the cut-off date, I got a very close proposal from Vivo disclosing the novel idea i.e. single index value was being used to represent two Modulation schemes. However, the MCS table including details on code rate, spectral efficiency, etc was not there.

The Missing Feature

This one missing feature was tingling in my brain, as I was finding it to be very obvious for a skilled person to incorporate the novel idea (found in VIVO document) in a legacy MCS table defined standard having details on code rate, spectral efficiency, etc. I already had good supporting documents around that. 

Given the very high stakes in the project, I knew that I had to challenge our opponent with the best solution existing out there. So, I didn’t stop there and went on exploring the email archives of the VIVO’s researcher on the ETSI list server.

The ETSI List Server archives all the emails exchanged between 3GPP delegates. Over the emails, they sometimes exchange ideas, problems, comments, documents, etc. Moreover, all of the conversations and ideas talked about in these email discussions might not reach the 3GPP contributions. Some ideas may get dropped for being in the initial stage or some examples may be skipped. That makes email servers a source of exclusive content related to the telecom domain.

Diving into the ETSI archives

I knew that the smallest doubt in VIVO’s art can be diluted if a little information could be available in the initial conversation i.e. ETSI server from VIVO’s researcher. It could make our case eventually stronger.

I followed this hunch and started tracking down the email conversations in the ETSI platform. And voila! I discovered an email attachment having the exact same table that I was looking for. What more could I ask for?


The email discussions helped us make the case stronger. We shared the document with our client without thinking twice, that’s how sure we were about it. As anticipated, the client was super happy with the approach of finding prior art in the ETSI archives. With it, they were able to make strong grounds to challenge the SEP under question.

“Never ever lose hope”, we have heard and read this line so many times. At GreyB we live this line every day. If there is any slightest chance that the information exists and can solve a problem for our client, we will definitely find it. EVERY TIME. 

How do we do that? Well, to tell you In a nutshell, we align our approach to find different possible ways to crack the case. And we never lose hope. 😉

Authored by: Sayanee Saha, Prior Art

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