Hitachi patent partially invalid in GER: code distribution for mobile communication

Hitachi patent was partially declared invalid for DE and remains valid in auxiliary version: it is about the patent ‘code distribution for mobile communication’. The case about the Hitachi patent is interesting because of the relevant topic for mobile communication – and because the patent has already expired.

The European patent “Mobile communication arrangement with code distribution multiple access method” (No. 0 957 594) of Hitachi Ltd. is declared invalid with effect for the territory of the Federal Republic of Germany partly with respect to the attacked patent claims 3, 7 and 9, and with respect to the attacked patent claims 1 and 8 as far as it goes beyond the version according to auxiliary request B.6′.

This ruling of the BPatG (6 Ni 1/17 (EP), combined with 6 Ni 12/17 (EP), combined with 6 Ni 27/18 (EP)) is interesting on the one hand because of the – still relevant today – topic of code distribution for mobile communication, but furthermore also because the actions against this Hitachi patent are admissible despite the expiration of the patent in suit on February 26, 2019. Also an interesting aspect: auxiliary request B.6′, filed at the oral proceedings on February 19, 2020, was not rejected as being out of time (Sec. 83 (4) Patent Act) despite the applicants’ objection.

The facts of the case

Three plaintiffs seek to have European patent 0 957 594 declared invalid with effect for the territory of the Federal Republic of Germany to the extent of patent claims 1, 3, 7, 8, and 9; corresponding nullity actions were filed in December 2016, February 2017, and April 2018. Prior to that, in July 2016, Hitachi Ltd. had commenced infringement actions against the plaintiffs arising from patent claims 1 and 8 of the patent in suit.

In a written statement dated January 20, 2020, the first plaintiff extended its attack to patent claims 3, 4, 7 and 9 and declared its attack on patent claim 12 to be settled. By written statement of January 20, 2020, the second plaintiff extended its attack to claims 3, 7, and 9. The defendant agreed to the extensions of the invalidity claims as well as to the declaration of partial settlement.

Shortly thereafter, the three plaintiffs again demanded the invalidity of the patent in suit to the extent of claims 1, 3, 7, 8, and 9; patent owner Hitachi demanded the dismissal of the claims, or at least the dismissal of the claims under one of the auxiliary versions, including auxiliary claim B.6′ from the oral proceedings of February 19, 2020.

The Hitachi Patent: Code Distribution for Mobile Communication

Hitachi’s patent in suit is entitled “Code division multiple access mobile communication system”. The patent in suit relates to the synchronization of a mobile terminal with a base station of a CDMA mobile radio system.

Hitachi, originally known primarily as a well-known company for construction machinery and automotive electronics, has also been established for decades as a supplier of memory solutions and storage media (computer chips and computer drives).

The Hitachi patent in suit is about improved synchronization of time windows in code distribution for mobile communications, which is characterized by a spreading factor of the predetermined short time code having a lower value than a spreading factor of the first short time code.

Was this novel enough to be patentable? The applicants cited various printed materials in rebuttal.

Mobile CDMA communication systems

In principle, mobile CDMA communication systems (according to feature 1 in the patent in suit) were already known on the priority date. However, while the chip rate in a mobile CDMA communication system is fixed, the spreading factor is changed as required during operation on the individual traffic channels according to feature 4, thus allowing variable symbol rates to be realized. In this respect, the above-described spreading of each symbol to be transmitted by the long code and the first short code is a concretization of the “mapping” of these codes, the BPatG explained.

It was also argued by the applicants that patent claim 1 as granted in the patent in suit was not patentable over the TDD mode shown in the ARIB standard or over the ARIB TDD mode in combination with the Higuchi_IEEE print font.

And above all, the Nakamura_IEEE publication is contrary to the patentability of the patent in suit in the version according to auxiliary request B.6′; the mobile CDMA communication system proposed therein is similar to that of the ARIB standard.

Invalid in granted version, but valid in auxiliary version

The BPatG declared the Hitachi patent invalid as granted, but valid in the version according to auxiliary request B.6′. In the granted version, patent claim 1 goes beyond the content of the European patent application as originally filed, the court explained, in particular with reference to the disclosure EP 0 957 594 A2.

Therefore, the granted version is not subject to the grounds of invalidity of the inadmissible extension according to Art. II § 6(1)(3) IntPatÜG, Art. 138(1)(c) EPC and also the lack of an extension. c) EPC and also the lack of patentability under Art. II Sec. 6 (1) No. 1 IntPatÜG, Art. 138 (1) (a) in conjunction with Art. 52, 54 EPC.

Hitachi patent: protectable according to auxiliary request B.6′

However, the BPatG ruled that the Hitachi patent was protectable in the version according to auxiliary request B.6′. In particular, the Nakamura_IEEE publication does not prevent this, since it does not contain any information on the spreading factor. A person skilled in the art would, however, precisely because of the lack of a specific definition, take from the ARIB standard for the TDD mode a predetermined short code of length 1 symbol (= 256 chips) for the two chip rates 8.192 and 16.384 Mcps.
The subject-matter of claim 1 according to auxiliary claim B.6′ was therefore not affected by any of the variants disclosed in the ARIB standard in a manner detrimental to novelty, the court explained. And features 4 and 2.3.1 of the subject-matter of claims 1 and 8 according to auxiliary request B.6′ were not known either. Anyway, the Hitachi patent claims a priority date that is a few days before the publication of the Nakamura_IEEE publication.

83 (4) German Patent Act : Auxiliary request B.6′ filed late?

The applicants basically objected to auxiliary request B.6 as being filed late, since it was not filed until the oral proceedings on February 19, 2020. Normally, according to § 83 (4) Patent Act, late submissions are to be rejected.

But the BPatG nevertheless did not reject the auxiliary request. The application of § 83 (4) Patent Act requires that the submission is made in default of the time limit set under § 83 (2) Patent Act, moreover, that the party concerned did not sufficiently excuse the delay and that the consideration of the new submission would have required an adjournment of the date for oral proceedings. But that was not the case here; there had been no delays in the hearings and, moreover, the plaintiffs had continued to argue the case on the merits without complaint, the BPatG stated.

Hitachi patent expired since 2019 – lawsuits nevertheless admissible

Another interesting aspect in this case is that the Hitachi patent has expired since 2019, but the BPatG nevertheless classifies lawsuits as admissible. Thus, the BPatG is in line with the BGH case law according to ‘Signal Transmission’ of July 2020 (X ZR 90/18): lawsuits are admissible despite the expiration of the patent – if the plaintiff has reason to fear that he might still be exposed to claims based on past acts even after the expiration of the term of protection.

This should not be judged by too strict standards, the Federal Patent Court added. If an action for revocation is to serve as a preventive defense against claims, it is not decisive whether these have already been asserted or even announced, the BPatG explained.