Uncovering Killer Prior Art for a 5G Technology Patent

In the dynamic world of 5G technology and Standard Essential Patents (SEPs), we often encounter unique challenges that test our expertise. One such challenge was when we took on an invalidation case related to a 5G technology patent. Our client's goal was clear: find the closest prior art to invalidate a critical patent. The technology at the heart of the patent revolved around "numerology," specifically Subcarrier Spacing. To embark on this prior-art search effectively, understanding the core concept behind the patent was essential. This included grasping key inventors, assignees, critical classifications, and relevant keywords—a crucial step to ensure a productive search.

Our journey began with a deep dive into the intricacies of 5G technology, specifically the concept of numerology, which is defined as Subcarrier Spacing in 5G. Unlike 4G, 5G introduced multiple types of numerology or subcarrier spacings. Having unraveled the subject patent's essence, we honed in on the prosecution history and focused on the unique elements of the independent claim: A novel numerology design involving slot composition with distinct symbol lengths. Symbols within the first and second numerologies having varying symbol lengths. Our initial search using a spider search strategy yielded no fruitful results. We then explored 3GPP domain meetings, a vital resource for wireless communication patent projects, which led us to a potential reference. However, this reference (R1-164692) was published just five days after the patent's priority date, rendering it ineligible. Our quest continued into 3GPP email discussions, right before the cut-off date. Despite thorough exploration, we found nothing of relevance. Undeterred, we delved into patents, deploying various search strategies such as keywords, CPC, IPC, US & F-term classification, and inventor- and assignee-based searches. The objective was clear: identify a prior-art document published before the cut-off date. Yet, our patent search yielded no valuable results. Time was running out as we approached our submission deadline to the client. While some patent references had priority dates before the cut-off date, they were filed or published later. We meticulously scrutinized each one, searching for the novel aspect. Finally, we struck gold.

Our relentless pursuit culminated in the discovery of a patent (US20160352551A1) that disclosed the same concept as the subject patent, as well as the content identified in the 3GPP meeting document (R1-164692). This reference had four priority documents, with two filed before the priority date of the subject patent. However, the pertinent text was missing in these two priority documents. Our diligent analysis revealed the novel element of the target patent. We found a table that disclosed different subcarriers. This table turned out to be the key to solving the puzzle: The table revealed that the symbol length of the first numerology equaled the sum of the symbol lengths of two symbols of the second numerology, confirming the first novel element. Furthermore, it indicated that a symbol of the first numerology or second numerology had a symbol length different from that of other symbols of the same numerology, affirming the second novel element. Our client was ecstatic with the outcome, and the feedback we received was exceptional.
At Expertlancing, prior-art searching is an art that requires continuous innovation and a keen eye for detail. This case reinforced the importance of thoroughly analyzing every facet of a reference, including priority documents that may not initially seem promising. The treasure of prior art can often be found hidden within the text, tables, or figures of a priority document. Our experts at Expertlancing specialize in locating killer prior art for all types of prior-art searches. Please reach out to us for more information on how we can assist you with your intellectual property needs.