By: Caldwell

Rights and Challenges

Is owning a patent enough? Even with the rights granted to an individual to protect their patents, the infringement process allows a defendant tools to counter and invalidate the patent owner’s claims.

1. Legal Tools in the Battle for Patent Rights

One of the most important rights any patent owner possesses is the ability to enforce their patent rights in District Court against infringement. However, bringing or threatening such enforcement actions may prompt a defendant (or alleged patent infringer) to try to invalidate the asserted patent(s) on grounds based on prior art by filing a petition for inter partes review (“IPR”) at the PTAB. As discussed in previous posts, the standard for instituting an inter partes review as set forth in 35 U.S.C. § 314(a) provides that an inter partes review may not be instituted “unless there is a reasonable likelihood that the petitioner would prevail with respect to at least one of the claims challenged in the petition.” Once the petitioner files a petition, the patent owner has three months to file an optional patent owner preliminary response (“POPR”)1, which can address reasons why the Board should decline to institute review of the challenged patent. The POPR may raise procedural challenges to the petition and substantive responses to the petitioner’s asserted prior art, proposed claim constructions, and asserted grounds of unpatentability. A Patent Owner can “win” in an inter partes review in either of two ways: 1). The petition is not instituted or, if instituted 2) the PTAB issues a decision stating that the challenged claims are valid. This synopsis captures two IPRs where the Caldwell IP Team successfully assisted in protecting a patent owner’s efforts against institution of an IPR. 

2. Inter Partes Threat – IPR2020-01430 

Petitioner John Mezzalingua Associates (“Petitioner”) filed a petition against patent owner Dali Wireless, Inc (“Patent Owner”) seeking institution of inter partes review of claims 1-19 of U.S. Patent No. 10,334,499 (“the ‘499 patent”) 

The ’499 patent discloses systems and methods that improve wireless capacity at the front end (i.e., at the digital remote units (“DRUs”)) in a distributed antenna system (“DAS”). For instance, users of wireless devices may gravitate to an office cafeteria during lunchtime, which may overload remote units in the cafeteria. The ’499 patent claims a “baseband unit” that is “configured to send a digital representation of a [first/second] set of radio resources” to a remote unit. The baseband unit of the ’499 patent allocates radio resources to digital remote units throughout a DAS to adapt to dynamic load conditions on a particular remote unit—i.e., the overloaded cafeteria remote unit at lunchtime. 

Petitioner sought institution on three grounds: under section 35 U.S.C § 102 as allegedly anticipated by Oh (US Patent 7,286,507); under section 35 U.S.C § 103 as allegedly obvious over Oh in view of Cannon (US Patent Publication 2010/0177760) and again under section 35 U.S.C § 103 as allegedly obvious over Oh in view of Fisher (US Patent Publication 2007/0008939)2 

Patent Owner, in response, challenged the institution of the IPR petition on the merits of the alleged prior art and also as redundant since the references asserted were considered during the prosecution of the ‘499 patent. On the merits, patent owner asserted that Oh did not disclose a “baseband,” a “baseband unit,” or communicating configuration information to a remote unit indicating which sets of “radio resources” to use. Patent owner asserted that petitioner referred to a DAS hub which was disclosed in Oh as the claimed “baseband unit,” but patent owner provided evidence that a DAS hub simply routed traffic using mapping data in a table for correlating a coverage segment of a respective base station to an IP address of a DAS antenna unit.3 In other words, DAS antenna units in Oh were merely pass-through devices with static configuration– as Oh did not disclose any adaptive adjustments to the antenna units at all, in contrast to the claimed baseband unit. No communication of configuration information to remote units existed in Oh that reconfigured them or indicates which sets of “radio resources” to use as in the claimed baseband unit.  

The PTAB agreed with patent owner’s argument. 4 Based on the PTAB’s claim construction of “radio resources,” Oh’s transmission of communication traffic to the DAS antenna units, which does not incorporate information used in the transmission of the radio resource from an antenna of the remote unit, did not disclose the sending of a digital representation of radio resources. The PTAB stated that petitioner failed to show how Oh disclosed “radio resources” being received by the DAS hub from the BTSs (first and second signal sources) and sent, in a digital representation, so those radio resources could be transmitted at the antenna of that unit. Oh disclosed only underlying data that arrived in the radio resource as included in the “incoming communication traffic” which was sent to the Oh DAS antenna units. 

Regarding the obviousness grounds, petitioner challenged the claims as obvious with Oh in view of two references: Cannon and Fisher. Patent owner challenged the motivation to combine the Cannon and Fisher references with Oh. The PTAB agreed that the petitioner failed to show a sufficient motivation to combine the references. 5 

As such, patent owner prevailed as institution of inter partes reviewed for claims 1-19 of the ‘499 patent was denied. 

3. Failed Inter Partes Institution – IPR2020-01432 

The second success story is a failed institution of an inter partes review on challenged claims 1-20 of (“the ‘171 patent”) 6 

The ’171 Patent discloses a DAS having a digital access unit (DAU) that provides reconfigurable routing and switching of signals to digital remote radio units (RRU) 1-N for communications with mobile devices. This reconfiguration of radio units enables “a high degree of flexibility to manage, control, re-configure, enhance and facilitate the radio resource efficiency, usage and overall performance of the distributed wireless network.”7 The claims recite translating signals to “baseband” and “reconfiguring” a remote radio unit that adaptively readjusts the radio capacity of one or more remote radio units by changing configuration parameters. 

As with the ‘499 patent, petitioner sought institution on three grounds: under section 35 U.S.C § 102 as allegedly anticipated by Oh (US Patent 7,286,507), under section 35 U.S.C § 103 as allegedly obvious over Oh in view of Cannon (US Patent Publication 2010/0177760), and again under section 35 U.S.C § 103 as allegedly obvious over Oh in view of Fisher (US Patent Publication 2007/0008939)8 

Petitioner referred to the DAS hub in Oh as the claimed “digital access unit” (DAU). However, patent owner asserted that Oh’s DAS hub simply distributed traffic using a mapping table to route traffic from coverage segments of respective base stations to IP addresses of DAS antenna units; in other words, patent owner argued that the DAS antenna units in Oh were pass-through devices having static configurations with no adjustments needed.9 Patent Owner further argued that petitioner failed to demonstrate where in Oh the DAS hub reconfigured any DAS antenna unit by changing configuration parameters of the DAS antenna unit.  

The PTAB agreed with patent owner that petitioner did not establish that Oh disclosed “reconfiguring each remote radio unit.” Referring to claim 1, Oh disclosed that configuring and modifying the mapping data altered distribution of RAN coverage among the various DAS antenna units.10 However, this modification of mapping data used to route traffic did not meet the claim limitation because it did not reconfigure (change) the DAS antenna units themselves.  

Furthermore, and similarly to the petition challenging the claims in the ‘499 patent, petitioner challenged the claims as obvious with Oh in view of two references: Cannon and Fisher. The PTAB stated that the record contained no evidence or argument that a decentralized system of Cannon could have been applicable to Oh with identified, predictable results.11 The PTAB reasoned that the petition did not sufficiently show either that the use of Cannon’s decentralized system would have been a design choice for one of ordinary skill in the art, or that one of ordinary skill would have been motivated to make the combination with a reasonable expectation of success. 

Accordingly, patent owner prevailed as institution of inter partes reviewed for claims 1-20 of the ‘171 patent was denied. 

4. Successful Defense Tactics

For a patent owner, getting served with a petition for institution of inter partes review can be a daunting experience, in which a successful defense can be indispensable. To succeed in defending against such a petition, it is crucial for a patent owner to pair with a partner that not only understands the technology, but also the practice at the PTAB. The right partner can help navigate the challenges of the inter partes review process.