from the United States Patent and Trademark Office, Patent
Trial and Appeal Board in No. 95/001, 192.
Mitchell G. Stockwell, Kilpatrick Townsend & Stockton
LLP, Atlanta, GA, argued for appellant. Also represented by
Michael S. Pavento, David A. Reed.
Michael A. Oblon, Perkins Coie, LLP, Washington, DC, argued
for appellee. Also represented by TYLER R. Bowen, Jonathan M.
James, Phoenix, AZ; Dan L. Bagatell, Hanover, NH.
Prost, Chief Judge, Clevenger and Chen, Circuit Judges.
GmbH & Co. (IPCom) is the owner of U.S. Patent No. 6,
879, 830 ('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 sued
HTC Corporation (HTC) for infringing the '830 patent, HTC
requested that the U.S. Patent and Trademark Office (PTO)
conduct inter partes reexamination of claims 1, 5-26, and
28-37 of the '830 patent, which the PTO granted. The
reexamination went through two rounds of review by the
Examiner and the Patent Trial and Appeal Board (Board). In
the first round, the Examiner concluded that the claims were
patentable, but HTC appealed to the Board, which issued a new
ground of rejection for claims 1 and 5-30. In the second
round, IPCom amended claims 1, 5-26, and 28-37,
 but the Board found that these
amended claims were obvious under 35 U.S.C. § 103 in
view of various combinations of McDonald,  Anderson,
GSM,  and PACS.
appeal, IPCom alleges that, even though it had amended the
scope of claims 31-37 during its second round before the
Examiner, the Board lacked jurisdiction to review the
Examiner's patentability determination of these amended
claims in the Board decision now on appeal. IPCom also argues
that the Board's obviousness rejections were based on a
flawed claim construction, because the Board never identified
the structure in the patent specification that corresponds to
the "arrangement for reactivating the link"
means-plus-function claim limitation. IPCom also appeals the
Board's factual findings for several other claim
limitations and the motivation to combine the prior art
references in the manner claimed by the '830 patent.
conclude that, under the circumstances of this case, the
Board properly had the authority to consider the
patentability of claims 31-37 and thus reject IPCom's
procedural challenge to the Board's rejection of these
claims. But we agree with IPCom that the Board failed to
conduct a proper claim construction of the "arrangement
for reactivating the link" claim limitation, and we
vacate and remand the obviousness rejections based on that
limitation. We affirm the Board's findings in all other
'830 patent describes a method for performing handover
(or handoff) of a cellular telephone or mobile station (MS)
in a cellular telephone network from a first base station
(BSl) to a second base station (BS2). '830 patent col. 1
ll. 14-62. Mobile stations communicate with a network by
exchanging signals with a base station, where the base
station is part of a wired network of base stations, fixed
lines, and switching units. Id. col. 2 1. 64-col. 3
1. 3. Handover occurs in a network when the mobile station
switches from one base station to another. Id. col.
1 ll. 25-28.
'830 patent describes forward and forced handover
techniques. Id. col. 5 ll. 10-15, 61-64. A forward
handover is one in which the mobile station, rather than the
first base station, determines a handover is necessary, and
seeks out the second base station. Id. col. 1 ll.
37-38. A forced handover is one in which the first base
station initiates the handover, e.g., by sending a message to
the mobile station instructing the mobile station to perform
a handover to a second base station. Id. col. 1 ll.
53-56, col. 2 ll. 24-31.
reduce the chance of interrupted service when a mobile
station must perform a handover, the claimed invention calls
for the first base station to maintain, for a period of time,
the link data for the mobile station as well as hold in
reserve link resources required to maintain a link between
the mobile station and the first base station. When a
handover of the mobile station to a second base station is
unsuccessful, the mobile station reactivates the link with
the first base station, e.g., by continuing to maintain the
link. Id. col. 2 ll. 38-40, col. 5 ll. 10-15, 61-64,
col. 6 ll. 13-53. By providing this feature, if the mobile
station cannot establish a link with a second base station,
the mobile station's link with the first base station can
be maintained without the mobile base station having to
resend link information to the first base station.
Id. col. 5 ll. 24-26, col. 6 ll. 40-52. This feature
is claimed in the "arrangement for reactivating the
link" limitation in independent claims 1, 18, 30, and
34. J.A. 12565-74. Claim 1 is reproduced below:
1. (Unamended) A mobile station for use with a network
including a first base station and a second base station that
achieves a handover from the first base station to the second
base station by:
storing link data for a link in a first base station,
holding in reserve for the link resources of the first base
when the link is to be handed over to the second base
initially maintaining a storage of the link data in the first
initially causing the resources of the first base station to
remain held in reserve, and
at a later timepoint determined by a fixed period of time
predefined at a beginning of the handover, deleting the link
data from the first base station and freeing up the resources
of the first base station, the mobile station comprising:
an arrangement for reactivating the link with the first
base station if the handover is unsuccessful.
J.A. 12565 (emphasis added). Independent claims 18, 30, and
34 also recite three additional limitations of (1) a
"forced handover request message" from the first
base station to the mobile station; (2) a "handover
query" from the mobile station to a second base station;
and (3) a "rejection message" from the second base
station if the second base station cannot support the mobile
station. Appellant Br. 10-11; J.A. 12570-74.
'830 patent also describes a flexible type of handover,
in which a handover is handled in different ways, depending
on whether a network can support handover by transferring
"link data" directly between the first and second
base stations, or whether that information must be
communicated directly from the mobile station to the second
base station. '830 patent col. 2 ll. 32-38, col. 3 ll.
10-16. This feature is the "informing the mobile
station" limitation recited in independent claims 5, 12,
and 16. J.A. 12566-70. Claim 5, for example, recites
"informing the mobile station whether the network is
capable of transferring the link data from the first base
station to the second base station." J.A. 12567. The
last relevant limitation in the challenged claims covers a
network using different generations of radio communication
standards and is recited in claims 23 and 25. J.A. 12571-72.
These claims recite that "the first base station and the
second base station operate in respective parts of the
network using different generations of radiocommunications
standards for radio communication with the mobile
station." J.A. 12571-72.
purposes of this appeal, the challenged claims can be
separated into five categories. First, independent claims 1,
18, 30, and 34 recite the "arrangement for reactivating
the link" means-plus-function limitation. Second,
independent claims 18, 30, and 34 recite the "forced
handover request message, " "handover query, "
and "rejection message" limitations. Third,
independent claims 5, 12, and 16 recite the "informing
the mobile station" limitation. Fourth, dependent claims
23 and 25 recite using different generations of radio
communications standards. Fifth, claims 31-37 are challenged
based on jurisdiction.
noted, the Board considered four prior art references.
McDonald describes a technique for dealing with failed
handovers. When a mobile station moves from one cell to a
neighboring cell in a cellular telephone network, the mobile
station searches for a second base station in the neighboring
cell and sends an inbound signaling word (ISW) message to
inquire whether a handover is possible. McDonald col. 1 ll.
30-33, col. 2 1. 66-col. 3 1. 9. If the second base station
cannot support a handover, the network sends the mobile
station a busy outbound signaling word (OSW) rejection
message. Id. col. 1 ll. 42-46, col. 2 ll. 1-3). The
"busy OSW" signal informs the mobile station that
the network cannot transfer link data from the first base
station to the second base station. J.A. 7. The mobile
station "can then choose to return" to the first
base station by "deregister[ing]" from the second
base station, "inform[ing]" the network that it is
"returning to the previous channel, " and
"attempting] to receive" at the first base station.
McDonald col. 3 ll. 14-21.
describes "mobile directed" or "mobile
centric" handover techniques. Anderson col. 17 ll.
45-52. Anderson describes integrating multiple cellular
network technologies, including GSM (prior art reference
described infra at Background Part III) into a
single network. Id. col. 4 ll. 40-61. It also
describes several types of successful handovers, including a
"make before break" handover. Id. col. 15
l. 25-col. 18 l. 25. In this handover, the mobile station
initiates a handover attempt based on a drop in link quality
below a predetermined threshold level between the mobile
station and a first base station. Id. col. 16 ll.
26-33. To initiate the handover, the mobile station scans for
potential new base stations and measures the received signal
quality from the potential new base stations to identify a
base station with the highest signal quality (the second base
station). Id. col. 16 ll. 6-30. The mobile station
then sends a handover request message to the second base
station and waits for a response. Id. col. 16 ll.
26-33. If the second base station accepts the mobile
station's handover request, the second base station sends
a response requesting transfer of the link data from the
first base station to the second base station, and the
network transfers the link data. Id. col. 16 ll.
36-60. By transferring the link data from the first base
station to the second base station, the network informs the
mobile station that the network can transfer the link data.
also describes a "break before make" embodiment to
prevent interrupted service. Anderson col. 18 ll. 16-21. In
this embodiment, a mobile station that suddenly loses its
connection with a first base station can quickly reacquire
the first base station, or acquire a different base station
(even if no information is available after the link with the
first base station is lost). Id. col. 18 ll. 16-21.
Global System for Mobile (GSM) Communications
Global System for Mobile (GSM) communications standard was
developed by the European Telecommunications Standards
Institute (ETSI) to standardize telecommunications protocols.
J.A. 13225. GSM describes reactivating a link with a first
base station when a handover attempt to a second base station
is unsuccessful. The mobile station sends a "channel
request" message to a second base station, which
responds, in some circumstances, with an "immediate
assignment reject" message. J.A. 13303. The mobile
station then sends a "handover failure" message to
the first base station and "resumes normal operation as
if no handover attempt had occurred." Id. GSM
also describes the use of base stations that can operate
using different generations of radio communications standards
because it discloses a mobile station ...