5 May
2021

Federal Circuit highlights limitations to claim construction when essential structure is only found in preamble

Co-published

The Federal Circuit has ruled on an important issue surrounding the claim construction of a preamble of a patent claim in Simo Holdings Inc v Hong Kong Ucloudlink Network Technology Ltd (2019-2411 (5 January 2021)). The key takeaway is that, in addition to being limiting when a claim preamble serves as an antecedent basis for a claim term appearing in the body of the claim, a preamble can also be limiting when it supplies “essential structure” and the body of the claim does not define “a structurally complete invention”.

The patent at issue, US Patent 9,736,689 (the ’689 patent), owned by SIMO Holdings Inc, describes apparatuses and methods for reducing roaming charges on cellular networks outside a home territory. SIMO sued Hong Kong uCloudlink Network Technology Limited and uCloudlink (America), Ltd (collectively, uCloudlink) for infringement. Four of uCloudlink’s products were alleged to infringe Claim 8 of the ’689 patent, which recites the following preamble followed by a list of functional steps:

8.         A wireless communication client or extension unit comprising a plurality of memory, processors, programs, communication circuitry, authentication data stored on a subscribed identify module (SIM) card and/or in memory and non-local calls database, at least one of the plurality of programs stored in the memory comprises instructions executable by at least one of the plurality of processors for: …”

enabling an initial setting of the wireless communication client or the extension unit and a remote administration system;

establishing a data communication link to transmit information among the wireless communication client or the extension unit, and the remote administration system;

establishing a local authentication information request in response to a local authentication request by a local cellular communication network, wherein the local authentication information request comprises information regarding the local authentication request for local authentication information received by the foreign wireless communication client or the extension unit from the local cellular communication network, and wherein the data communication link is distinct from the local cellular communication network;

relaying the local authentication information request to the remote administration system via the data communication link and obtaining suitable local authentication information from the remote administration system via the data communication link;

establishing local wireless services provided by the local cellular communication network to the wireless communication client or the extension unit by sending the local authentication information obtained from the remote administration system to the local cellular communication network over signal link; and

providing a communication service to the wireless communication client or the extension unit according to the established local wireless services.

’689 patent, col. 25, lines 4-40 (emphasis added).

The district court granted summary judgment on infringement in favour of SIMO Holdings. Even though the court held that the preamble is limiting, its decision to rule in favour of SIMO holdings rested on claim construction of the term ‘non-local calls database’. The district court reasoned that the preamble does not require a non-local calls database and therefore uCloudlink’s accused products meet all of the claim limitations.

The Federal Circuit agreed with the district court’s finding, in particular with the listed components, which typically indicates the end of the preamble. Even SIMO Holdings did not argue that part of the preamble is limiting but instead held that the non-local calls database should be excluded because it is not necessary to perform the functions recited in the body of the claim.

The Federal Circuit followed the canon that because the preamble supplies the only structure of the claimed device, with the non-local calls database being intertwined with the rest of preamble, it must be understood as part of the claimed invention and therefore is a required element for infringing Claim 8.

The Federal Circuit’s decision was in part based on the claim construction of the term ‘a plurality of’, which the district court found to require “at least two members” selected from a list of “memory, processors, programs, communication circuitry, authentication data stored on a subscribed identify module (SIM) card and/or in memory and non-local calls database”. It corrected the definition of ‘a plurality of’ in the context of Claim 8, to require “at least two of each” of the listed components. As for the non-local calls database, the Federal Circuit reasoned that there is no preceding article to negate the applicability of ‘a plurality of’ to a non-local calls database. Second, Claim 8 continues to read “at least one of the plurality of programs stored in the memory comprises instructions executable by at least one of the plurality of processors for:”. This indicates that the phrase ‘the plurality of’ applies “individually to at least some items in the list”. And given the list being “a bit of a mess grammatically”, reciting a “mix of plural, singular, and mixed-up forms” favours the reading of the “non-local calls database” included as an item in the list.

Having concluded that Claim 8 requires a plurality of non-local calls databases, the Federal Circuit reversed the district court’s grant of summary judgment in favour of SIMO Holdings, wiping out the $8 million awarded to SIMO Holdings.

Comment

Claim drafting and prosecution takeaways from the Federal Circuit decision in SIMO Holdings can be summarised as follows:

  • Avoid long, grammatically nested and complicated preamble language. Keep it short and simple.
  • The term ‘a plurality of’ followed by a list of components can be interpreted as at least two of eac’ of the listed components that follows and not a selective subset of the listed components. Therefore the consequences of using the phrase should be examined carefully in order to avoid unnecessarily limiting the scope of a claim.
  • At the drafting stage of a patent application, appropriate boilerplate language should be included in the specification to explicitly state what a plurality of should be interpreted as. For example, a plurality of a list of A, B and C should be interpreted as at least two elements from the list (eg, A and B, A and C, B and C, and/or A, B and C). 

For further information contact:

Joanna Chen
Polsinelli
View website

Babak Monajemi
Polsinelli
View website

This is a co-published article whose content has not been commissioned or written by the IAM editorial team, but which has been proofed and edited to run in accordance with the IAM style guide.