TC Technology LLC v. Sprint Corporation et al

Filing 553

MEMORANDUM OPINION AND ORDER. Signed by Judge William C. Bryson on 4/26/2021. (nmg)

IN THE UNITED STATES DISTRICT COURT
FOR THE DISTRICT OF DELAWARE

TC TECHNOLOGY LLC,
Plaintiff,
v.
SPRINT CORPORATION and SPRINT
SPECTRUM, L.P.,
Defendants.

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Civil Action No. 16-153-WCB

MEMORANDUM OPINION AND ORDER
Before the court is a dispute between the parties over the meaning of the “mutually
exclusive” limitation in the two claims of U.S. Patent No. 5,815,488 (“the ’488 patent”), both of
which are asserted in this case. The parties, plaintiff TC Technology LLC (“TC Tech”) and
defendants Sprint Corporation and Sprint Spectrum, L.P., (collectively, “Sprint”) submitted a
series of briefs and letters concerning the dispute. After reviewing the parties’ briefs and letters, I
have concluded that the parties’ dispute actually relates to the interpretation of another claim
phrase, “set of orthogonal baseband frequencies.” This order provides a tentative construction for
that term and directs the parties to submit supplemental briefing directed to the construction of that
term.
BACKGROUND
The ’488 patent discloses a communication protocol that enables a plurality of remote
locations to transmit data simultaneously to a central location over a shared channel. ’488 patent,
col. 4, ll. 41–67. At each remote location, the data to be transmitted to the central location is
translated into a transform coefficient associated with a particular frequency. Id. at col. 3, ll. 49–

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57. That frequency is chosen from a subset of orthonormal baseband frequencies that is allocated
to the remote location. Id.
Claims 1 and 2 of the ’488 patent recite a method for conducting the “upstream”
transmissions, i.e., data that is transmitted from remote locations to a central location over a shared
communication channel. Claim 1 reads as follows in pertinent part:
1. A method for enabling a plurality of remote locations to transmit data to a central
location comprising the steps of:
at each remote location, coding data to be transmitted by translating each group of
one or more bits of said data into a transform coefficient associated with a particular
baseband frequency in a particular subset of orthogonal baseband frequencies
allocated to the remote location, the particular subset of orthogonal baseband
frequencies allocated to each remote location being chosen from a set of orthogonal
baseband frequencies, the subsets of baseband frequencies allocated to each remote
location being mutually exclusive; . . . .
’488 patent, col. 10, ll. 47–58; see also id. at col. 11, ll. 12–22 (independent claim 2 containing
identical language).
During a claim construction proceeding before Judge Andrews in 2017, the parties initially
disagreed about the construction of the phrase “the subsets of baseband frequencies allocated to
each remote location being mutually exclusive” in claims 1 and 2. Dkt. No. 71, at 5–21.
Subsequently, however, the parties agreed on a construction for that phrase. The agreed-upon
construction was: “for any given time slot, no individual baseband frequency is allocated to more
than one remote location.” Dkt. No. 93, at 4. In September of 2017, Judge Andrews issued a claim
construction order consistent with the parties’ proposed construction. Dkt. No. 95, at 1.
During summary judgment proceedings, Judge Andrews addressed the construction of the
“mutually exclusive” limitation. Sprint argued that its accused LTE technology did not infringe
the asserted claims of the ’488 patent, because certain frequencies in the upstream path of its LTE
network were not allocated in a “mutually exclusive” manner. Dkt. No. 272, at 2–3, 16 (redacted

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version of Dkt. No. 258). Sprint contended that TC Tech’s infringement theory was solely focused
on the transmission scheme conducted over Sprint’s “Physical Uplink Shared Channel (PUSCH)”
and improperly ignored the transmission scheme conducted over Sprint’s “Physical Uplink Control
Channel (PUCCH).” Id. at 14–16. According to Sprint, there could be no infringement because
the claims did not permit TC Tech to “artificially exclude from its infringement allegations the
[transmission scheme conducted over] PUCCH.” Id. at 14.
In a summary judgment order dated April 15, 2019, Judge Andrews rejected Sprint’s
noninfringement argument. He stated that the parties’ dispute over excluding PUCCH “appears
to be a factual dispute over whether certain elements of Sprint’s LTE network meet the ‘mutually
exclusive’ limitation.” Dkt. No. 354, at 10. Judge Andrews added: “Sprint’s noninfringement
theory assumes that the limitation must be met by both the PUSCH and PUCCH frequencies.
Because Sprint has failed to show that the limitation must be met by the PUCCH frequencies, it
has failed to meet its burden on summary judgment with respect to literal infringement.” Id.
On August 21, 2020, after this case was transferred to me, Sprint revived the dispute over
the “mutually exclusive” limitation by filing a memorandum requesting that I “preclude TC Tech
from arguing to the jury that the claims permit any frequencies to be allocated to more than one
remote location in a time slot.” Dkt. No. 524, at 15. Subsequent to that opening memo, the parties
submitted five more briefs and letters addressing the dispute. See Dkt. Nos. 530, 535, 539, 543,
544. In the first rounds of briefing, the parties raised several issues relating to the “mutually
exclusive” limitation. Those issues included whether Sprint’s request constitutes a duplicative
motion for summary judgment, see Dkt. No. 530, at 1, whether a literal interpretation of Judge
Andrews’ prior claim construction settles the issue at hand, see Dkt. Nos. 524, at 9, and 535, at 1–
3, whether TC Tech had forfeited its current position as a result of arguments it made in a prior

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inter partes review, see Dkt. No. 524, at 12–15, and whether there is a relevant distinction between
“user data” and “control data” for purposes of the parties’ dispute, see Dkt. Nos. 524, at 4–5, and
535, at 5–7.
In the subsequent rounds of briefing, the parties moved past those four issues and began
focusing on the actual dispute at hand—the construction of the phrase “a set of orthogonal
baseband frequencies.” As to that phrase, TC Tech’s position is that the “claims on their face
require only that a ‘set’ of frequencies be allocated to remote locations in a mutually exclusive
way.” Dkt. No. 530, at 11. According to TC Tech, the “claims do not require that all frequencies
in all frequency sets used by the network be allocated in a mutually exclusive way.” Id. More
explicitly, TC Tech asserts that “[t]he claims successively require (1) that ‘each remote location’
be allocated a ‘particular subset’ of frequencies from a ‘set’ of frequencies (the ‘Set’ limitation);
and that (2) the ‘subsets’ allocated to those different remote locations be ‘mutually exclusive’ from
one another (the ‘mutually exclusive’ limitation). . . . Thus, as Judge Andrews recognized when
he rejected Sprint’s arguments the first time, the claims require only that frequencies in the claimed
‘set’ (not ‘all’ frequencies in the system) be allocated in a mutually exclusive manner.” Dkt. No.
539, at 1.
Sprint counters by arguing that TC Tech is wrong in contending that “there may be multiple
‘subsets’ of frequencies allocated to a remote—some from the recited ‘set’ and some from outside
that ‘set’ (which TC Tech says are not claimed).” Dkt. No. 535, at 2. TC Tech’s position is wrong,
according to Sprint, because the patent unambiguously discloses that “the claimed ‘set’ of
frequencies from which the subsets allocated to each remote are chosen constitutes the set of all of
the available frequencies, not just some subset of available frequencies.” Id. at 3. Alternatively,
Sprint submits that even if TC Tech is correct that there could be subsets of frequencies allocated

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outside the claimed set, “[that] would not help TC Tech because those frequencies also must be
mutually exclusive.” Id. at 2. According to Sprint, the “mutually exclusive limitation at issue here
applies to ‘the subsets of baseband frequencies allocated to each remote location,’ without
exception and not limited to the ‘particular’ subsets allocated from the claimed ‘set.’” Id. at 2–3.
Thus, according to Sprint, “all frequencies allocated to remotes must be mutually exclusive, even
if a ‘particular subset’ were chosen from a set that constituted fewer than all available frequencies.”
Id. at 3.
In response, TC Tech asserts that the specification supports its position that the upstream
band of frequencies can have multiple sets of frequencies, some of which are allocated in a
mutually exclusive manner and some of which are not. Dkt. No. 539, at 2. TC Tech first points
to the ’488 patent’s statement at column 4, line 51, that the “upstream band” is, for example, 5–40
MHz. TC Tech then points to Figure 3 and column 5, lines 37–43, of the patent, which demonstrate
an allocated range of frequencies for upstream transmissions that is only 4 MHz wide. The contrast
between those two disclosures, TC Tech argues, demonstrates that there can be multiple allocated
sets of frequencies within the upstream channel, some of which may not be allocated in a mutually
exclusive manner. In that situation, according to TC Tech, the system infringes as long as all the
multiple frequencies within a particular set are allocated in a mutually exclusive manner. See Dkt.
No. 539, at 2. TC Tech provided a declaration of Dr. Zhi Ding in support of its assertions. See
Dkt. No. 540.
DISCUSSION
Before turning to the parties’ principal dispute, I briefly address the four peripheral issues
raised by the parties. First, TC Tech contends that Sprint’s request is a disguised motion for
summary judgment that should be denied as duplicative and untimely. Dkt. No. 530, at 1. I

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disagree. To be sure, granting the request in Sprint’s opening memo would have the same effect
as granting partial summary judgment by precluding TC Tech from litigating a particular issue at
trial. But that is frequently the consequence of a pretrial claim construction ruling. Sprint has
been careful to frame its position as relating to claim construction, and its briefing is best
interpreted as directed to the construction of a claim term. For example, in its reply memo, Sprint
concludes by stating that TC Tech should be precluded from asserting its “current claim
construction.” Dkt. No. 535, at 8. And in its letter in response to TC Tech’s surreply brief, Sprint
requests “oral argument on the claim construction issue.” Dkt. No. 543, at 2. Given those
statements, and in light of parallel statements in TC Tech’s briefing, see, e.g., Dkt. No. 544, at 2,
I conclude that the parties’ dispute is best viewed as raising a claim construction issue rather than
a duplicative motion for summary judgment, a motion to exclude certain expert testimony, or a
motion to strike certain infringement theories.
Second, Sprint argues that Judge Andrews’ prior construction of the claim term “subsets
of baseband frequencies allocated to each remote location being mutually exclusive” necessarily
requires that the “mutually exclusive” limitation applies to all frequencies that are allocated to the
remote locations and not just to a particular set of those frequencies. Dkt. No. 524, at 9; Dkt. No.
535, at 1–3. I disagree that Judge Andrews’ prior construction disposes of the present issue. Judge
Andrews’ prior construction, which provided that “no individual baseband frequency is allocated
to more than one remote location,” must be applied within the context of the surrounding claim
language. See Conoco, Inc. v. Energy & Env’t Int’l, L.C., 460 F.3d 1349, 1362 (Fed. Cir. 2006).
The claim language surrounding the term construed by Judge Andrews makes clear that the “subset
of orthogonal baseband frequencies” comes from a “set of orthogonal baseband frequencies.”
Because a “set” of frequencies could encompass only some of the frequencies used to transmit

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data from the remote locations to the central location, that suggests that infringement may be
possible even if there are other frequencies outside the “set of orthogonal baseband frequencies”
that are not allocated in a mutually exclusive manner. To resolve that possibility, I must construe
the phrase “set of orthogonal baseband frequencies.”
Third, Sprint asserts that TC Tech’s patent owner response in a prior inter partes review
constituted a disclaimer of claim scope with respect to the “mutually exclusive” limitation. See
Dkt. No. 524, at 12–15 (analyzing Dkt. No. 529-1, Exh. J, at 56–60). I disagree. In that patent
owner response, TC Tech distinguished the ’488 patent from a prior art patent by John M. Cioffi,
U.S. Patent No. 5,625,651. The heading of the relevant section of that response states that “Cioffi
does not teach allocating mutually exclusive subsets of baseband frequencies to a plurality of
remotes.” Dkt. No. 529-1, Exh. J, at 56. TC Tech argued that Cioffi “[was] not concerned with
the details of allocating the remaining tones to the remotes,” and that Sprint’s citation to a single
sentence in Cioffi was insufficient to support Sprint’s assertion that Cioffi disclosed the “mutually
exclusive” limitation. Id. TC Tech continued:
Further, nothing else in Cioffi states or implies that the [sic] each remote’s subset
of tones are or must be mutually exclusive. On the contrary, Cioffi teaches that all
of the remotes share at least the overhead subchannels. Specifically, Cioffi
provides a representative “DMT transmission band” having “a multiplicity of
subchannels” for communication and “dedicated overhead subchannels 33 and 34
to facilitate synchronization:”

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Cioffi FIG. 2 (annotated), 4:65-5:5; . . . . Subchannels 33 and 34 are not mutually
exclusive; they are shared by all of the remotes. Cioffi 5:3-9.
Dkt. No. 529-1, Exh. J, at 57.
The most reasonable reading of that passage is that TC Tech was responding to Sprint’s
reliance on Cioffi by explaining that Cioffi did not sufficiently disclose how its frequencies were
allocated and that Cioffi therefore did not disclose the “mutually exclusive” limitation. TC Tech
highlighted Cioffi’s shared overhead subchannel frequencies to demonstrate that, within the scant
discussion in Cioffi concerning allocation, the most explicit discussion actually taught the opposite
of what was required by the claims of the ’488 patent. Contrary to Sprint’s assertion, TC Tech
was not arguing to the Patent Office that if only one of the allocated frequencies is shared, then
the “mutually exclusive” limitation is not satisfied. Moreover, even if individual statements in TC
Tech’s patent owner response could be read to stand for such a proposition, TC Tech’s statements
do not rise to the level of a clear and unmistakable disclaimer of claim scope when examined in
the context of the entire response. See Aylus Networks, Inc. v. Apple Inc., 856 F.3d 1353, 1361–
64 (Fed. Cir. 2017) (noting that statements made in an inter partes review must be “both clear and
unmistakable” to constitute a prosecution disclaimer).
Fourth, the parties dispute whether there is a relevant distinction between “user data” and
“control data.” See Dkt. No. 524, at 4–5; Dkt. No. 530, at 5–7; Dkt. No. 535, at 4–5. Despite
having previously argued that the claim term “data” refers only to “user data,” see Dkt. No. 26216, Exh. P, ¶ 44, TC Tech now takes the position that “data” covers both “user data” and “control
data,” see Dkt. Nos. 530, at 7, and 527-1, Exh. I, at 1. Nonetheless, TC Tech argues that the
distinction between “user data” and “control data” is relevant to the patent’s disclosures concerning
the phrase “set of orthogonal baseband frequencies.” I concur with TC Tech’s conclusion but
disagree with its reasoning. The portion of the specification relied upon by TC Tech, ’488 patent,

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col. 8, ll. 42–53, does not teach that the way “control data” is transmitted from the remote locations
to the central location differs from the way “user data” is transmitted. In fact, that portion of the
specification does not teach the transmission of control data at all. Instead, it describes control
signals that are sent internally within the remote locations. It states, in relevant part, that the
“processing circuit 138 also includes control circuitry for sending control signals to the frequency
synthesizer 136 and timing adjuster generator 135.” Id. at col. 8, ll. 42–44 & Fig. 6.
While the specification does not describe the remote locations transmitting control data to
the central location, it describes the central location transmitting control data to the remote
locations. See id. at col. 9, ll. 15–26 (describing how the controller 204 of the central location
transmits “addressed commands” and “discrete frequency allocation information” to the remote
locations). The transmission of that control data is accomplished by modulating the control data
onto an RF carrier, but not by first translating the control data into a transform coefficient
associated with a particular frequency, as is done in the case of “data” in the claimed transmission
methods. Compare id. at col. 9, ll. 15–26, with id. at col. 10, ll. 47–67. The specification therefore
discloses sending control data over the downstream path without first distributing that data across
a frequency space, thereby eliminating the need to allocate frequencies for the control data in a
“mutually exclusive” manner. As explained in more detail below, the disclosure of that process
tends to support TC Tech’s interpretation of the phrase “set of orthogonal baseband frequencies”
with respect to the “mutually exclusively” limitation.
Turning to the matter that is the principal subject of the parties’ briefing, I understand the
essence of the parties’ dispute to be captured by the following question: Must the claimed “set of
orthogonal baseband frequencies” encompass all frequencies in the upstream band that are
allocated to the remote locations, or do the claims permit the allocation of frequencies other than

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those in the claimed “set”? If the former interpretation is correct, then a system with remote
locations sharing particular frequencies for upstream transmissions would fall outside the scope of
the claims. If the latter interpretation is correct, such a system would not necessarily fall outside
the scope of the claims. There is support in the specification for both interpretations.
Portions of the specification tend to support the conclusion that the referenced “set” must
encompass all frequencies in the upstream band that are allocated to the remote locations. The
specification states that the “present invention permits a plurality of remote locations (e.g., A, B,
C) to simultaneously share the upstream band for transmission to the headend with a high degree
of immunity to channel impairments.” ’488 patent, col. 4, ll. 57–60. From that passage, a person
of ordinary skill in the art could infer that the phrase “remote locations . . . simultaneously share
the upstream band” means that all frequencies available in the upstream path must be split up
among the remote locations according to the “present invention,” i.e., with a “mutually exclusive”
allocation of frequencies. That inference, if adopted, would indicate that the claims do not read
on a system in which additional frequencies outside a designated “set” are allocated to remote
locations for upstream communications in a non-mutually-exclusive manner.
The specification also states that “[i]n some embodiments of the invention, all of the n
values [of frequencies] may be allocated to a different remote location in each different time
slot. . . . This latter embodiment really amounts to a TDMA scheme of transformed data wherein
only one remote location can transmit to the headend in a time slot.” Id. at col. 6, ll. 3–12. A
person of ordinary skill could infer from the reference to “one remote location . . . transmit[ting]
to the headend in a time slot” that the general term “transmit” covers all data transmissions in the
upstream path, and that those transmissions are conducted according to the “invention.” That
inference would also eliminate the possibility that additional frequencies outside the claimed “set”

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could be allocated to remote locations for upstream communications in a non-mutually-exclusive
manner.
Further, the specification describes how the “central location keeps track of which
baseband frequencies are allocated to which remote location for subsequent translation of each
transform coefficient.” Id. at Abstract. The singular reference to a “remote location” suggests that
multiple “baseband frequencies” cannot be allocated to more than one remote location. If no
frequencies are shared, then all frequencies must be allocated in a mutually exclusive manner,
eliminating the possibility that additional frequencies outside the “set” could be allocated for
upstream communications in a non-mutually-exclusive manner. That conclusion, however, is
undercut by a nearly identical passage at column 4, lines 6 through 10, that uses the plural “remote
locations.” That passage reads: “The central location keeps track of which baseband frequencies
are allocated to which remote locations.”
Other portions of the specification tend to support the conclusion that the claims permit the
allocation of frequencies to remote locations other than those frequencies in the claimed “set.” As
mentioned above, a portion of the specification discusses how control data is transmitted over the
downstream path without first distributing that data across the frequency space and thus without
first allocating frequencies in a “mutually exclusive” manner. See id. at col. 9, ll. 15–26. A person
of ordinary skill could infer from that discussion that if it were necessary to transmit control data
over the upstream path, such a transmission could be carried out in a manner similar to the
transmission of control data over the downstream path, i.e., without distributing the control data
across a frequency space in a manner that is mutually exclusive to the remote locations. Such an
inference suggests that the claimed “set of orthogonal baseband frequencies” to which the

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“mutually exclusive” limitation applies does not necessarily encompass all frequencies used by
the remote locations to transmit data over the upstream path.
The specification also discusses the code division multiple access (“CDMA”) multiplexing
protocol. CDMA is another technique besides the invention’s frequency-division multiplexing
scheme that “allow[s] multiple receivers to use the same bandwidth resource simultaneously.” Id.
at col. 1, ll. 12–16; see also id. at col. 1, ll. 42–45 (describing CDMA as a proposed transmission
scheme for multiple user, multiple access upstream transmissions); id. at col. 1, ll. 32–35
(describing how CDMA works). The specification notes that “CDMA transmissions are rugged
to many of the above-mentioned impairments, but suffer from poor spectral efficiency, expressed
in bits of data per second, per Hertz of bandwidth.” Id. at col. 2, ll. 11–14. It is also well known
that CDMA schemes do not allocate frequencies in an exclusive manner. See High Point SARL v.
Sprint Nextel Corp., 817 F.3d 1325, 1327 (Fed. Cir. 2016) (“CDMA allows a large number of
cellphone users to share the same radio frequency by associating each user with a single code.”).
Thus, as demonstrated by the cited passages, the specification acknowledges the existence and at
least moderate usefulness of CDMA, a transmission scheme that does not allocate frequencies in
a mutually exclusive manner. It is not unreasonable to posit that the patent comprehends the
communication of certain data, such as control data, from the remote locations to the central
location over shared frequencies in a CDMA scheme, wherein those frequencies are outside the
claimed “set” of frequencies. See ’488 patent, col. 9, ll. 15–26 (describing how control signals are
transmitted over the downstream path without first distributing those signals across the frequency
space, but not identifying a specific transmission scheme).
Finally, and most notably, the ’488 patent contains an illustrated embodiment that tends to
support the conclusion that the claims permit the allocation of frequencies to remote locations

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other than those frequencies in the claimed “set.” As a preliminary step, the specification
characterizes the invention as a “communication method [that] enables a plurality of remote
locations to transmit data to a central location,” in which “[t]he remote locations simultaneously
share a channel.” Id. at Abstract; see also id. at col. 1, ll. 6–9; id. at col. 3, ll. 45–48; id. at col. 10,
ll. 33–35 (also stating that the invention concerns remote locations sharing a “channel”). When
describing Figure 1, the specification states that “[t]he channel 14 between the headend and the
remote locations” is generally “divided into a downstream band (e.g. 54–550 MHz) and an
upstream band (e.g. 5–40 MHz).” Id. at col. 4, ll. 41–51; see also id. at col. 1, ll. 39–42 (stating
that upstream signals “use the lower frequencies, such as [5–40] MHz”1). The specification uses
Figure 3 to “explain[] how the individual remote locations generate the time domain baseband
signals that are transmitted to the headend.” Id. at col. 5, ll. 28–30. Figure 3 illustrates that the
“frequency space” can be broken down into N discrete values and that, for example, a total
bandwidth of N = 512 frequency components results in a 4 MHz range. Id. at col. 5, ll. 36–43.
The specification then states that the allocation of the discrete frequencies within that range must
be done in a “mutually exclusive” manner. Id. at col. 5, ll. 44–54.
To summarize the embodiment illustrated in Figures 1 through 3, the specification
addresses the “mutually exclusive” limitation immediately after describing a “frequency space”
that is 4 MHz wide, stating that the “N frequency space values” can be broken down into
assignments of frequencies “n” to each remote location, and explaining that those assignments
must be mutually exclusive. See id. I understand those assignments to represent the “subset of
orthogonal baseband frequencies” described in the claims. See id. at col. 5, ll. 45–47 (“For

The text reads “540MHz,” but that appears to be a typographical error; from the context,
it is clear that the text was intended to read “5–40 MHz.”
1

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example, the values n=1, 3, 5 … N-1 are allocated to the remote location A. The values n=2, 6,
10, … are allocated to the remote location B.”). The “set,” therefore, appears to be the “frequency
space” that is 4 MHz wide. Given that the upstream channel is 35 MHz wide (5–40 MHz), a
person of ordinary skill could reasonably conclude that other frequencies in the 35 MHz-wide
channel besides those in the 4 MHz-wide “set” can be allocated to the remote locations.
After weighing the above disclosures, my tentative conclusion is that the patent favors an
interpretation of “set of orthogonal baseband frequencies” that permits the allocation of
frequencies to remote locations for upstream communications other than those frequencies
included in the claimed “set.” Put differently, the term “set” is not required to encompass all
frequencies used in the upstream channel. I find the patent’s discussion spanning column 5, lines
22–67, to be persuasive in this regard.
Sprint makes an alternative argument that even if there could be subsets of frequencies
allocated from outside the claimed set, that would be of no moment, because those frequencies
also must be allocated in a mutually exclusive manner according to the plain language of the claims
and Judge Andrews’ prior construction. See Dkt. No. 535, p. 2. In other words, Sprint argues that
the limitation “the subsets of baseband frequencies allocated to each remote location being
mutually exclusive” requires that any frequency allocated to the remote locations be allocated in a
mutually exclusive manner regardless of whether that frequency is within the claimed “set of
orthogonal baseband frequencies.” I disagree with that reading of the claims. Interpreting the
“mutually exclusive” limitation in such a way requires that the surrounding claim language be
disregarded. A person of ordinary skill reading the claims in the ’488 patent would most
reasonably conclude that the “mutually exclusive” limitation applies to the frequencies within the
“subsets of baseband frequencies allocated to each remote location,” and that those “subsets” come

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from the “set of orthogonal baseband frequencies.” Therefore, contrary to Sprint’s suggestion, the
claim language does not dictate that all frequencies allocated to the remote locations for upstream
communications must be allocated in a mutually exclusive manner.
Accordingly, I tentatively construe “set of orthogonal baseband frequencies” to mean “a
set of distinct orthogonal baseband frequencies that can be used to transmit data from the remote
locations to the central location, wherein the set is not required to span all orthogonal baseband
frequencies that could be used to transmit data from the remote locations to the central location.”
CONCLUSION AND DIRECTIVE
It is apparent from the parties’ briefs that the focus of the current dispute between the
parties has shifted over the course of the briefing. As indicated above, it now appears to me that
the true nature of the dispute between the parties is a disagreement about the proper construction
of the claim phrase “set of orthogonal baseband frequencies.” Because the parties’ briefs to date
have not focused squarely on that claim construction issue, I direct the parties to submit
supplemental briefing addressing whether my tentative construction should be adopted, rejected,
or modified, and why. I am interested in hearing the parties’ arguments regarding how my tentative
construction comports with the entirety of the claims, the patent specification, the prosecution
history, and any relevant extrinsic evidence. Expert testimony is not required but will be
considered if submitted.
In view of the fact that the parties’ previous briefs and letters already contain some
discussion of the phrase “set of orthogonal baseband frequencies,” and this order contains further
discussion of the construction of that phrase, the supplemental briefing will be conducted in only
two rounds. The parties are directed to file and serve simultaneous opening briefs of no more than
15 pages on that issue. Those briefs will be due by 5 pm ET on May 17, 2021. The parties shall

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file and serve simultaneous responsive briefs of no more than 10 pages. Those briefs will be due
by 5 pm ET on May 27, 2021. No reply briefs (or letters) will be entertained.2
IT IS SO ORDERED.
SIGNED this 26th day of April, 2021.

_________________________
WILLIAM C. BRYSON
UNITED STATES CIRCUIT JUDGE

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TC Tech has submitted a letter, Dkt. No. 544, objecting to a post-briefing letter filed by
Sprint, Dkt. No. 543. TC Tech’s letter refers to Sprint’s letter as a “sur-surreply” and notes that
no sur-surreply briefing was authorized by the court. Treating TC Tech’s letter as a motion to
strike Sprint’s letter, the motion is denied. Although Sprint’s letter was substantive in part, it
consisted principally of a request for a hearing or further briefing in light of what Sprint regarded
as a new argument in TC Tech’s surreply brief. Moreover, the substantive discussion in Sprint’s
letter was directed to the reason Sprint requested oral argument or additional briefing. In any
event, because I am directing further briefing, TC Tech has suffered no prejudice from Sprint’s
use of the letter to advance any further substantive argument.
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