PTAB did not err in finding mobile phone call handover patent obvious


July 07, 2017

The Patent Trial and Appeal Board (PTAB) in inter partes review proceedings did not err in determining that certain claims of a patent describing a method for handing over a mobile phone call from one base station to another base station were disclosed by prior art, the U.S. Court of Appeals for the Federal Circuit has ruled. However, the Board’s finding on the "arrangement for reactivating the link" means-plus-function limitation was reversed and remanded (IPCom GmbH & Co. v. HTC Corporation, July 7, 2017, Chen, R.).

IPCom GmbH & Co. is the owner of U. S. Patent No. 6,879,830 ("the ’830 patent"), which describes and claims a method and system for handing over a mobile phone call from one base station to another base station. After IPCom filed suit against HTC for infringing the ’830 patent, the PTAB granted inter partes review petitions from HTC, challenging claims 1, 5-26, and 28-37 of the ’830 patent.

The reexamination went through two rounds of review by the Examiner and the PTAB. In the first round, the Examiner concluded that the claims were patentable; however, on appeal, the Board issued a new ground for rejection for claims 1 and 5-30. In the second round, although IPCom amended the claims, the Board found the amended claims were obvious in view of four prior art references: U. S. Patent No. 5,222,248 (McDonald); U. S. Patent No. 6,088,590 (Anderson); digital cellular communications system (GSM); and American National Standard for Telecommunications-Personal Access Communications System Air Interface Standard (PACS). IPCom appealed.

Claim construction. The PTAB failed to conduct a proper claim construction of the "arrangement for reactivating the link" claim limitation, according to the court. The ’830 patent describes a method for performing handover of a cellular telephone or mobile station in a cellular telephone network from a first base station to a second base station, and describes forward and forced handover techniques, including a feature for reactivating the link when the handover to a second base station is unsuccessful. The claim limitation "an arrangement for reactivating the link with the first base station in the ’830 patent is a means-plus-function limitation described in the court’s prior opinion in HTC Corp. v. IPCom GmbH & Co., 667 F. 3d 1270 (Fed. Cir. 2012).

Although the Board recognized the prior ruling, it rejected IPCom’s proposed three-step algorithm for performing the function and failed to identify what it believed to be the correct algorithm from the ’830 patent specification, the court explained. The Board was required to perform a two-step analysis: (1) to identify the particular claimed function and (2) to look to the specification and identify the corresponding structure that performs that function. The PTAB’s analysis was erroneous because it never specified what it believed was the actual algorithm disclosed in the ’830 patent for performing the "arrangement for reactivating the link" function. Because that algorithm was not identified, the Board also erred by failing to evaluate whether the prior art disclosed that algorithm. Thus, the Board’s claim construction and finding of obviousness of claims 1, 18, 30, and 34 was vacated and remanded.

Obviousness. However, the PTAB did not err in finding that the other claim limitations—forced handover request message, handover query, and rejection message—which are recited in claims 18, 30, and 34, were disclosed by the prior art (PACS). IPCom conceded that PACS discloses a "forced handover request message" by describing a PERFORM_ALT message that is transmitted from the network to a mobile station and failed to challenge on appeal HTC’s arguments that PACS discloses the "handover query" and "rejection message," the court explained.

Additionally, there was no error in the Board’s analysis of the "informing the mobile station" limitation. According to the court, substantial evidence supported the finding that the combination of Anderson and McDonald teaches the recited limitation—Anderson teaches successful handover and McDonald describes cases in which handover is unsuccessful by using a busy OSW signal. Under the broadest reasonable construction, a combined system that can indicate either a successful handover using the features of Anderson or that no handover is possible using the features of McDonald was sufficient to meet the requirements of the claims.

There was also substantial evidence to support the Board’s finding that GSM teaches the claim limitations for the use of different generations of radio communications standards recited in claims 23 and 25. GSM discloses using a mobile station that can communicate with both GMS/2G and GPRS/2.5G base stations. Claims 23 and 25 do not require that the base stations be incapable of communicating with each other. Instead, the claims simple require that the first and second base stations operating "using different generations of radio communications standards for radio communications with the mobile station." The specification’s example of base stations incapable of communicating among themselves to facilitate handover should not be imported into claims 23 and 25, the court noted.

Finally, the Board’s motivation to combine McDonald, Anderson, GSM, and PACS was supported by substantial evidence. According to the court, both Anderson and McDonald teach solutions for resolving the problem of an unsuccessful handover in a cellular telephone network and a means of returning to a first base station after a failed handover attempt. A person of ordinary skill in the art would have been motivated to combine these teachings to solve a common problem of unsuccessful handovers, the court concluded.

The case is No. 2016-1474.

Attorneys: Mitchell G. Stockwell (Kilpatrick Townsend & Stockton LLP) for IPCom GmbH & Co. Michael A. Oblon (Perkins Coie, LLP) for HTC Corp.

Companies: IPCom GmbH & Co.; HTC Corp.

MainStory: TopStory Patent FedCirNews

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