United States Court of Appeals 

for the Federal Circuit ______________________ 

AC TECHNOLOGIES S.A.,

Appellant

v.

AMAZON.COM, INC., BLIZZARD 

ENTERTAINMENT, INC.,

Appellees

______________________ 

2018-1433

______________________ 

Appeal from the United States Patent and Trademark 

Office, Patent Trial and Appeal Board in No. IPR2015-

01802.

______________________ 

Decided: January 9, 2019

______________________ 

MINGHUI YANG, Hardy Parrish Yang, LLP, Austin, 

TX, argued for appellant. Also represented by VICTOR G.

HARDY; ANDREW DINOVO, NICOLE E. GLAUSER, DiNovo, 

Price, Ellwanger & Hardy LLP. 

 DANIEL T. SHVODIAN, Perkins Coie, LLP, Palo Alto, 

CA, argued for appellees. Also represented by 

CHRISTOPHER LEE KELLEY, WING LIANG, VICTORIA Q.

SMITH; DAN L. BAGATELL, Hanover, NH. 

______________________ 
2 AC TECHS. v. AMAZON.COM

Before MOORE, SCHALL, and STOLL, Circuit Judges.

STOLL, Circuit Judge.

The Patent Trial and Appeal Board issued a final 

written decision ruling certain claims of AC Technologies 

S.A.’s U.S. Patent No. 7,904,680 unpatentable. On reconsideration, it invalidated the remaining claims based on a 

ground of unpatentability raised by Amazon.com, Inc. and 

Blizzard Entertainment, Inc. (collectively, “Amazon”) in 

their petition but not addressed in the final written 

decision. AC appeals, arguing that the Board exceeded its 

authority and deprived it of fair process by belatedly 

considering this ground. 

We disagree. Precedent mandates that the Board 

consider all grounds of unpatentability raised in an 

instituted petition. The Board complied with due process, 

and AC does not persuade us that the Board erred in 

either its claim construction or its ultimate conclusions of 

unpatentability. Accordingly, we affirm. 

BACKGROUND

I. The ’680 Patent

The ’680 patent relates generally to data access and 

management. As shown in Figure 1, clients, such as 

users’ (B) personal computers, may store data in or request data stored in clusters (C), each composed of one or 

more cells (Z), via a network (N). 
AC TECHS. v. AMAZON.COM 3

’680 patent col. 7 ll. 45–46, 53–56, col. 9 ll. 55–56. The 

patent teaches that storing copies of data across a network improves data integrity and reduces network lag. 

Id. at col. 1 l. 28–col. 2 l. 5, col. 2 ll. 21–31. To achieve 

this, the system copies data—either “the entire data GD 

or the fields [data subsets] F”—redundantly across the 

network. Id. at col. 7 ll. 1–3, col. 7 l. 65–col. 8 l. 2. The 

system determines when and where to copy and store 

particular data as a function of predetermined data 

transmission parameters. See, e.g., id. at col. 2 ll. 21–27. 

Representative claim 1 reads as follows: 

1. A data management system comprising:

at least two data storage units;
4 AC TECHS. v. AMAZON.COM

at least one computer unit that stores at least one 

complete file, each file including a plurality of individual pieces, the pieces containing parts of the 

files, wherein at least one piece is stored in a redundant manner in the at least two data storage 

units; 

a controller to enable data transmission between 

the data storage units and the computer unit;

wherein at least one of the data storage units and 

computer unit measures a data transmission performance between at least one of the data storage 

units and the computer unit, the at least one piece 

being stored by the computer unit in a redundant 

manner in the data storage units as a function of 

the measured data transmission performance, and 

the computer unit accessing the at least one of the 

data storage units as a function of the measured 

data transmission performance; and

wherein at least one of the at least two data storage units measures a data transmission performance between at least two of the at least two 

data storage units and the data storage units copy 

pieces that are redundantly stored in the system 

from one of the data storage units to another of 

the data storage units independently of an access 

of the computer unit based on the data transmission performance measured between the data 

storage units.

(emphases added to indicate limitations relevant to the 

parties’ disputes). Claim 2 depends from claim 1 and

further recites that the data storage units and computer 

unit “are connected over a wireless network.” Claims 4 

and 6 depend from claims similar to claim 1 and likewise 

require connection over a wireless network. 
AC TECHS. v. AMAZON.COM 5

II. Rabinovich

Amazon challenged the ’680 patent in an IPR. It 

based its unpatentability arguments on a single prior art 

reference: “Dynamic Replication on the Internet,” by 

Dr. Michael Rabinovich. See Michael Rabinovich, et al., 

AT&T Labs Research, Dynamic Replication on the Internet (1998) (J.A. 567–601). Figure 1 shows the Rabinovich

system, which, as relevant here, includes both a client (c), 

which requests files, and hosts (h and s), which maintain 

those files and service client requests. 

J.A. 573. To better manage client requests, Rabinovich 

defines an algorithm for making and placing file copies 

across hosts. Among other things, that algorithm considers both “cnt(s, xs),” defined as the total number of requests for file xs from a particular host (s) for a particular 

period of time, and “cnt(E, xs),” defined as the number of 

times those requests for file xs have passed an entity (E) 

as they pass from the client to host (s). J.A. 577–78. 
6 AC TECHS. v. AMAZON.COM

III. The IPR

Amazon’s petition for IPR presented three grounds. 

In Ground 1, Amazon argued that if “computer unit” were

construed narrowly and mapped to Rabinovich’s client, 

Rabinovich rendered all claims of the ’680 patent obvious. 

In Ground 2 and Ground 3, Amazon argued that if “computer unit” were instead construed broadly and mapped 

to Rabinovich’s host, it anticipated some claims

(Ground 2) and rendered remaining claims 2, 4, and 6 

obvious (Ground 3). 

At institution, the Board adopted the broad construction of “computer unit” and then instituted review of 

Grounds 1 and 2. See Amazon.com, Inc. v. AC Techs. S.A., 

No. IPR2015-01802, Paper 10 at 7–9, 23, 25 (P.T.A.B. 

Mar. 8, 2016). With respect to Ground 3, the Board stated 

that it had “addressed Petitioner’s contentions in our 

analysis above of Ground 1 and determined that Petitioner has established a reasonable likelihood of showing that 

claims 2, 4, and 6 are unpatentable as obvious over Rabinovich under our construction of ‘computer unit.’ As a 

result, this ground is moot.” Id. at 25. The Board concluded by instituting review of whether all claims of the 

’680 patent would have been obvious over Rabinovich and 

whether some claims were anticipated by Rabinovich. See 

id. at 26. 

The IPR proceeded, and AC filed a patent owner response. In it, AC argued that as properly construed, the 

claims require redundantly storing file pieces, not redundantly storing a complete file, and that Rabinovich failed 

to disclose this aspect of the claims. AC further argued 

that Rabinovich failed to disclose copying data “independently of an access of the computer unit” because 

Rabinovich’s replication algorithm relied on cnt(s, xs), 

entailing access of the client computers. At oral argument, AC added that Rabinovich’s reliance on cnt(E, xs) 

also violated the “independently of an access” limitation. 
AC TECHS. v. AMAZON.COM 7

In its final written decision, the Board rejected AC’s 

contention that the claims require storage of distinct 

individual pieces of the file. It reasoned that because the 

claims recite “at least one piece” and “pieces,” the claims 

contemplate and include copying and storing more than 

one piece of a file, including up to an entire file. And it 

noted that the claims do not limit how the system stores 

or copies the at least one file-piece(s). Amazon.com, Inc. v. 

AC Techs. S.A., No. IPR2015-01802, Paper 32 at 25–30 

(P.T.A.B. Mar. 6, 2017) (“Final Written Decision”). The 

Board also rejected AC’s contention that Rabinovich failed 

to teach copying data “independently of an access of the 

computer unit.” The Board agreed that if Rabinovich’s 

client corresponded to the claimed “computer unit,” Rabinovich did not render any claims obvious under Amazon’s 

Ground 1. At the same time, however, it found that if 

Rabinovich’s host corresponded to the claimed “computer 

unit,” as argued by Amazon in Ground 2, then Rabinovich 

anticipated every claim except claims 2, 4, and 6 because

neither of the cnt parameters cited by AC involved access 

of Rabinovich’s hosts. It found that cnt(s, xs) represented 

access of Rabinovich’s client, not the host. See id. at 18, 

33. And it credited Amazon’s expert’s unchallenged 

testimony that cnt(E, xs) measured possible future demand for a file and did not require access of the host. Id. 

at 34–36. 

The Board’s final decision did not address whether 

claims 2, 4, and 6 would have been obvious if the host

were treated as the “computer unit,” as Amazon had 

asserted in Ground 3. Pointing to that omission, Amazon 

promptly moved for reconsideration. Despite AC’s protest 

that Ground 3 had never been part of the IPR, the Board 

determined that it should reach the challenge. With the 

Board’s permission, both parties submitted additional 

arguments, expert declarations, and supporting exhibits. 

AC urged that under the Board’s claim constructions, the 

claims permitted only ad hoc wireless networks, with 
8 AC TECHS. v. AMAZON.COM

which Rabinovich would have been incompatible. But the 

Board determined that nothing in the claims or the specification limited the claimed wireless network to a particular type of network, and it held that Amazon had proven 

claims 2, 4, and 6 unpatentable. See Amazon.com, Inc. v. 

AC Techs. S.A., No. IPR2015-01802, Paper 55 at 7–8 

(P.T.A.B. Nov. 14, 2017) (“Rehearing Decision”). AC now 

appeals. 

DISCUSSION

Exclusive jurisdiction to review the Board’s final written decisions rests with this court. See 35 U.S.C. § 319; 

see also 28 U.S.C. § 1295(a)(4)(A). We enforce the limits

placed on the Board by statute and due process. See WiFi One, LLC v. Broadcom Corp., 878 F.3d 1364, 1374 

(Fed. Cir. 2018) (en banc) (“Enforcing statutory limits on 

an agency’s authority to act is precisely the type of issue 

that courts have historically reviewed.”); Belden Inc. v. 

Berk-Tek LLC, 805 F.3d 1064, 1080 (Fed. Cir. 2015)

(reviewing alleged denial of procedural due process rights 

by the Board). We consider de novo the Board’s legal 

conclusions. See PPC Broadband, Inc. v. Corning Optical 

Commc’ns RF, LLC, 815 F.3d 734, 739 (Fed. Cir. 2016). 

And we ensure that substantial evidence supports the 

Board’s factual findings. See Polaris Indus., Inc. v. Arctic 

Cat, Inc., 882 F.3d 1056, 1064 (Fed. Cir. 2018).

I 

AC argues that the Board erred procedurally when it 

invalidated claims 2, 4, and 6 based on a ground that it 

did not institute in its institution decision. AC claims 

that in doing so, the Board exceeded its statutory authority and fell short of the requirements of due process. We 

address these arguments in turn. 

A 

At institution, the Board determines “whether to institute an [IPR].” 35 U.S.C. § 314(b). The Supreme Court 
AC TECHS. v. AMAZON.COM 9

recently clarified that this statutory language “indicates a 

binary choice—either institute review or don’t.” SAS Inst.

Inc. v. Iancu, 138 S. Ct. 1348, 1355 (2018). If the Board 

institutes an IPR, it must issue a final written decision 

addressing all claims challenged by the petitioner. See id. 

at 1359–60; see also 35 U.S.C. § 318(a). And, we have 

held, if the Board institutes an IPR, it must similarly 

address all grounds of unpatentability raised by the 

petitioner. See Adidas AG v. Nike, Inc., 894 F.3d 1256, 

1258 (Fed. Cir. 2018) (remanding noninstituted grounds 

for review); BioDelivery Scis. Int’l, Inc. v. Aquestive Therapeutics, Inc., 898 F.3d 1205, 1208 (Fed. Cir. 2018) (“PostSAS cases have held that it is appropriate to remand to 

the PTAB to consider non-instituted claims as well as 

non-instituted grounds.”). 

This precedent forecloses AC’s argument that the 

Board exceeded its statutory authority when it reconsidered its final written decision and addressed noninstituted Ground 3. Indeed, it would have violated the 

statutory scheme had the Board not done so. See PGS 

Geophysical AS v. Iancu, 891 F.3d 1354, 1360 (Fed. Cir. 

2018) (“Equal treatment of claims and grounds for institution purposes has pervasive support in SAS.”). Contrary 

to AC’s arguments, see Appellant’s Br. 49–53, neither 

§ 314(b)’s timing requirements nor § 314(d)’s limits on 

appealability alter the Board’s statutory obligation to rule 

on all claims and grounds presented in the petition. See 

SAS, 138 S. Ct. at 1356 (explaining that an IPR must 

“proceed[] ‘[i]n accordance with’ or ‘in conformance to’ the 

petition” (second alteration in original) (quoting Pursuant, 

Oxford English Dictionary (3d ed. 2007), 

http://www.oed.com/view/Entry/155073)). 

B 

We recognize that SAS did not displace the Board’s 

responsibility to comply with due process. We have 

explained that due process dictates that parties before the 
10 AC TECHS. v. AMAZON.COM

Board must receive adequate notice of the issues the 

Board will decide as well as an opportunity to be heard on 

those issues. See Genzyme Therapeutic Prods. Ltd. P’ship 

v. Biomarin Pharm. Inc., 825 F.3d 1360, 1367–68

(Fed. Cir. 2016). 

No due process violation occurred here. As AC admits, after the Board decided to accept Amazon’s rehearing request and consider Ground 3, it permitted AC to 

take discovery and submit additional briefing and evidence on that ground. Though AC did not receive a 

hearing specific to Ground 3, it never requested one. Had 

AC desired a hearing, it should have made a request 

before the Board. See, e.g., Intellectual Ventures II LLC v. 

Ericsson Inc., 686 F. App’x 900, 905–06 (Fed. Cir. 2017) 

(finding no due process violation where party had notice 

and an opportunity to be heard and failed to request surreply or rehearing to address issue). 

II

On the merits, AC initially challenges the Board’s interpretation of the claim limitations reciting “piece(s).” 

We review the Board’s ultimate claim constructions de 

novo, see In re Man Mach. Interface Techs. LLC, 822 F.3d 

1282, 1285 (Fed. Cir. 2016), and we review any subsidiary 

factual findings involving extrinsic evidence for substantial evidence, see Teva Pharm. USA, Inc. v. Sandoz, Inc., 

135 S. Ct. 831, 841 (2015). The broadest reasonable 

interpretation standard applies to this IPR.1 Thus, the 

 

1 Per recent regulation, the Board applies the Phillips claim construction standard to petitions filed on or 

after November 13, 2018. See Changes to the Claim 

Construction Standard for Interpreting Claims in Trial 

Proceedings Before the Patent Trial and Appeal Board, 

83 Fed. Reg. 51,340 (Oct. 11, 2018) (to be codified at 

37 C.F.R. pt. 42). Because Amazon filed its petition before 
AC TECHS. v. AMAZON.COM 11

Board’s construction must be reasonable in light of the 

record evidence and the understanding of one skilled in

the art. See Microsoft Corp. v. Proxyconn, Inc., 789 F.3d 

1292, 1298 (Fed. Cir. 2015), overruled on other grounds by

Aqua Prods., Inc. v. Matal, 872 F.3d 1290 (Fed. Cir. 2017)

(en banc). 

The Board acknowledged that a file consists of pieces 

of data. The Board explained, however, that because the 

claims recite storing “at least one piece” and copying 

“pieces” of data, they permit copying and storing of “more 

than one piece, and thus all of the pieces of an entire file.” 

Final Written Decision, at 25–26. The Board further 

explained that the claims impose no limit on how the 

system stores or copies pieces and they do not require 

storing or copying pieces on an individual basis or prohibit storing or copying pieces “contiguously with other pieces 

of the same file.” Id. at 28–29. 

We conclude that the intrinsic evidence supports the 

Board’s view. The claims themselves specifically contemplate storage and copying of multiple pieces of a file. 

They recite storing “at least one piece” and copying “pieces 

that are redundantly stored in the system.” ’680 patent 

col. 25 l. 64–col. 26 l. 24 (emphases added). Though other 

claims recite “the received piece” of data, such claims each 

refer back to the “at least one piece” limitation for antecedent basis. See, e.g., id. at col. 27 ll. 36–37, 49–50, 

col. 28 ll. 25–26, 31–32; Oral Arg. at 11:45–59, 

http://oralarguments.cafc.uscourts.gov/default.aspx?fl=20

17-1999.MP3 (agreeing that “every time [the claim] 

refer[s] to a piece of data later in the claim, it refers back 

to ‘at least one piece’”). No claim limits how many pieces

the system may copy and store, and no claim limits how

the system copies and stores those pieces. Indeed, claim 1 

 

November 13, 2018, we apply the broadest reasonable 

interpretation standard.
12 AC TECHS. v. AMAZON.COM

requires storage of all pieces of a complete file as a complete file, at least on the computer unit. See ’680 patent 

col. 25 ll. 66–67 (“[A]t least one computer unit that stores 

at least one complete file, each file including a plurality of 

individual pieces . . . .”). 

The specification further supports the Board’s claim 

construction. It contemplates “distribution of the entire 

data,” not merely specific pieces. Id. at col. 7 l. 65–col. 8 

l. 2. And though it also describes the system separately 

storing pieces of data, it specifies that those disclosures 

relate to particular embodiments of the claimed invention

and never disclaims whole-file storage. See id. at col. 2 

l. 55–61 (“In another embodiment the data in the system 

is divided into data subsets, and . . . stored 

in . . . cells . . . .” (emphasis added)). The prosecution 

history contains no contrary statements. 

AC asserts that the Board’s construction conflicts 

with the invention’s purpose and that the specification 

compels a contrary construction. But it crafts that argument by ignoring—often through strategic use of ellipses—the disclosures noted above and by relying on an 

expert whose testimony the Board elsewhere characterized as “conclusory.” See Final Written Decision, at 7;

Appellant’s Br. 31, 37. Having broadly drafted its claims

to encompass both systems that copy and store individual 

pieces and those that copy and store multiple or all pieces 

of a file, AC cannot now read features from preferred 

embodiments into its claims to bolster its validity arguments. See In re Van Geuns, 988 F.2d 1181, 1184 

(Fed. Cir. 1993) (“[L]imitations are not to be read into the 

claims from the specification.”). For all of the above 

reasons, we see no error in the Board’s claim interpretation. 

III

AC also challenges the Board’s ultimate findings of 

anticipation and conclusions of obviousness. Specifically, 
AC TECHS. v. AMAZON.COM 13

AC disputes the Board’s finding that Rabinovich discloses 

copying “independently of an access of the computer unit,” 

as recited by the anticipated independent claims, and the 

Board’s conclusion that it would have been obvious to 

connect Rabinovich’s computer unit and data storage 

units over a wireless network, as recited by claims 2, 4, 

and 6. We address these arguments in turn.

A 

We review the Board’s finding that Rabinovich discloses copying “independently of an access of the computer 

unit,” a question of fact, for substantial evidence. See 

In re Gleave, 560 F.3d 1331, 1334–35 (Fed. Cir. 2009). 

The Board found that Rabinovich discloses this limitation 

because neither cnt(s, xs) nor cnt(E, xs) requires access of 

Rabinovich’s host, the element Amazon identified as the 

claimed computer unit. See Final Written Decision, at 32–

37. Substantial evidence supports the Board’s finding. 

Specifically, Rabinovich defines cnt(s, xs) as the access 

count for a particular file by the client, not the host, and it 

defines cnt(E, xs) as the number of appearances of an 

entity (E) (which may be a host) along a request’s path 

from the client to a requested file. J.A. 577. Dr. David 

Ratner confirmed this understanding of cnt(E, xs) in his 

testimony, where he further explained that cnt(E, xs) 

simply measures “possible future demand for a replica of 

[file] x.” J.A. 432. The Board specifically credited this 

unchallenged testimony. See Final Written Decision, 

at 34–35. 

AC nonetheless argues that the Board should have 

accepted its understanding of Rabinovich, and it further 

argues that without explicit disclosure affirming that 

Rabinovich does not depend on an access of the host,

Rabinovich cannot disclose independent access. AC’s 

contentions lack merit. The first misunderstands our role 

on appeal. We evaluate whether substantial evidence 

supports the Board, but “[w]e may not re-
14 AC TECHS. v. AMAZON.COM

weigh . . . evidence.” In re Warsaw Orthopedic, Inc., 

832 F.3d 1327, 1333 (Fed. Cir. 2016). The second misapprehends the law. Contrary to AC’s suggestion, a reference need not state a feature’s absence in order to disclose 

a negative limitation. See, e.g., Sud-Chemie, Inc. v. Multisorb Techs., Inc., 554 F.3d 1001, 1004–05 (Fed. Cir. 

2009) (affirming finding that reference disclosed “uncoated” film where it did not describe the film as coated and 

did not suggest necessity of coatings). 

B 

We review the Board’s ultimate determination that 

claims 2, 4, and 6 would have been obvious de novo, and 

we review its underlying factual findings for substantial 

evidence. See Harmonic Inc. v. Avid Tech., Inc., 815 F.3d 

1356, 1363 (Fed. Cir. 2016). 

AC asserts that per the Board’s constructions and 

Amazon’s petition, Rabinovich’s data storage units and its 

computer unit must both serve as hosts. Continuing from 

that premise, it contends that only “ad hoc” networks 

permit hosts to directly connect to one another and that 

Rabinovich could not operate with an ad hoc network. As 

a result, AC claims, the Board erred in finding that it 

would have been obvious to connect Rabinovich’s system 

over a wireless network. 

AC assumes that the phrase “connected over a wireless network” requires a direct wireless connection. But 

the Board specifically found the claims “broad enough to 

encompass a connection through a wireless hub.” Rehearing Decision, at 8. AC fails to explain how or why the 

Board erred in doing so, and we see no error in the 

Board’s construction.2 Consequently, we affirm. 

 

2 Though AC does not directly challenge the Board’s 

construction, we note that it finds support in the claims, 
AC TECHS. v. AMAZON.COM 15

CONCLUSION

We have reviewed the parties’ remaining arguments 

and find them unpersuasive. Accordingly, we affirm the 

Board.

AFFIRMED

COSTS

Costs to Appellees. 

 

which do not recite “direct” or “ad hoc” network connections, the specification, which describes the claimed 

wireless connections in only the broadest terms, see 

’680 patent col. 3 ll. 41–49, and in the prosecution history, 

in which the examiner specifically recognized that “wireless networks were notoriously well known in the art and 

commonly used at the time of the invention,” see Rehearing Decision, at 6.