Scope and claims deep-dive for US Patent 10,177,951 (OFDM PAPR reducer with reserved-tone carrier sets)
US 10,177,951 is directed to a transmitter architecture that reduces the peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) symbol using a peak-to-average power ratio reducer that generates a reduction signal applied over a specific set of carrier indices. The claims anchor on an OFDM FFT size of 8K and a particular reserved-tone carrier index set (250, 386, 407, 550… through 6577). Dependent claims then add frame/preamble/subframe structure and pilot insertion patterns defined via specific carrier-index and symbol-index spacings (Dx, Dy), plus edge pilot placement rules.
Below is a structured analysis of (1) claim scope and literal coverage, (2) how the numbered reserved-tone carriers operate as the claim’s limiting feature, (3) the likely infringement and non-infringement design-around surfaces, and (4) a landscape view of the patent estate and adjacent prior art risk areas that typically intersect OFDM PAPR reduction plus pilot patterning in 8K FFT systems.
What is the exact claim scope of US Patent 10,177,951 for an OFDM PAPR reducer?
Core independent claim 1 (transmitter with PAPR reduction signal for 8K OFDM):
Claim 1 requires all of the following, in combination:
- A “transmitter” that includes at least one processor to implement a PAPR reducer.
- The PAPR reducer is configured to generate a signal for reducing PAPR of an OFDM symbol.
- The FFT size is 8K for the OFDM symbol.
- The reduction signal has a set of carriers with indices listed in the claim (the reserved-tone index set).
- The reduction signal is generated specifically according to that index set, not just any subset.
Literal scope emphasis: In practice, claim 1 is limiting because the “signal having a set of carriers” is tethered to a fixed enumeration of carrier indices for FFT size 8K. A system using a different reserved-tone set, even if it still reduces PAPR, is unlikely to meet the literal “indices listed below” requirement.
What parts of claim 1 are structural vs. functional limitations?
- Structural limitations
- Transmitter includes a processor implementing a PAPR reducer.
- The system operates on OFDM with FFT size 8K.
- Functional limitations
- PAPR reducer generates a reduction signal “for reducing PAPR.”
- The reduction signal has a set of carriers identified by the enumerated indices.
The indices are both functional (they determine the signal composition) and explicitly structural (they are enumerated as carrier indices).
Carrier-index list is the anchor limiting feature
The claim provides an explicit “Reserved Tones” count (250 is shown in the table header as number of reserved tones) and enumerates carrier indices for FFT size 8K:
- 250, 386, 407, 550, 591, 717, 763, 787, 797, 839, 950, 1090, (72) 1105, 1199, 1738, 1867, 1903, 1997, 2114, 2260, 2356, 2427, 2428, 2444, 2452, 2475, 2564, 2649, 2663, 2678, 2740, 2777, 2819, 2986, 3097, 3134, 3253, 3284, 3323, 3442, 3596, 3694, 3719, 3751, 3763, 3836, 4154, 4257, 4355, 4580, 4587, 4678, 4805, 5084, 5126, 5161, 5229, 5321, 5445, 5649, 5741, 5746, 5885, 5918, 6075, 6093, 6319, 6421, 6463, 6511, 6517, 6577.
The “set of carriers having indices listed below” language is a classic claim narrowing device: it is not a parameterized rule, it is a closed list for the claimed FFT size.
How do dependent claims 2–7 narrow the transmitter, pilots, and pattern rules?
What does claim 2 add: frame structure (preamble, subframe boundary, data symbols)?
Claim 2 limits claim 1 by requiring:
- The OFDM symbol is one of multiple OFDM symbols in a frame.
- The frame includes:
- a preamble symbol,
- at least one subframe boundary symbol, and
- data symbols.
This means an accused product must not only implement the PAPR reducer with the specific carrier indices, but also be operating in a framing structure containing those symbol types.
What does claim 3 add: pilot insertion pattern positions and edge pilots?
Claim 3 narrows further by specifying how carrier indices are selected in the context of pilot placement:
- It defines carrier-index set usage “when a position in the preamble symbol into which a preamble pilot is inserted and a position in the subframe boundary symbols into which a subframe boundary pilot is inserted are defined based on a pilot insertion pattern.”
- It requires that an edge pilot is inserted into:
- a first carrier and
- a last carrier
in the at least one subframe boundary symbol.
This claim is not just about PAPR reduction; it ties the indices usage to a transmitter that inserts pilots with:
- a pilot insertion pattern for preamble and subframe boundary pilots, and
- edge pilot placement into first and last carriers.
What does claim 4 add: pilot insertion pattern based on Dx spacing
Claim 4 defines the pilot insertion pattern based on:
- Dx = 6, 12, 16, 24, 32
- Dx is “a difference of carrier indices between adjacent carriers into which the pilot is to be inserted.”
So claim 4 makes the pilot pattern spacing belong to a discrete set of allowed values. A pilot insertion scheme that uses spacing values outside this set likely avoids the literal match to claim 4.
What does claim 5 add: scattered pilot placement in data symbols plus edge pilots
Claim 5 narrows by adding:
- Pilot insertion into positions in data symbols for a scattered pilot, defined via a pilot insertion pattern.
- An edge pilot inserted into:
- the first carrier and last carrier in each data symbol.
What does claim 6 add: pilot insertion pattern for data scattered pilots with Dx values
Claim 6 specifies:
- Dx = 3, 4, 6, 8, 12, 16, 24, 32
- Dx is the difference of carrier indices between adjacent carriers into which pilots are inserted.
This is broader than claim 4 (more Dx values) but still discretized.
What does claim 7 add: Dy spacing across successive pilots on a specific carrier
Claim 7 adds a second parameter:
- Dy = 2, 4
- Dy is a difference of symbol indices between successive pilots on a specific carrier.
This imposes temporal spacing constraints between pilot occurrences on the same carrier across OFDM symbols.
What is likely the practical infringement test for US 10,177,951 claims?
For claim 1 infringement, what must match?
An accused transmitter must prove:
- It uses an OFDM FFT size of 8K.
- It implements a PAPR reducer that generates a reduction signal.
- That reduction signal is composed using carriers with indices equal to the enumerated set.
High-risk mismatch lever: carrier indices. If the accused system uses a different reserved-tone set (different carriers for the reduction signal), it does not literally satisfy claim 1.
For claims 2–7, what additional match items exist?
- Frame composition (preamble + subframe boundary symbols + data symbols) for claim 2.
- Pilot insertion mechanics:
- Preamble pilot and subframe boundary pilot positions from a pilot insertion pattern (claim 3).
- Edge pilots into first/last carriers for subframe boundary symbols (claim 3) and for data symbols (claim 5).
- Pilot spacing constraints:
- Dx allowed values (claim 4 for preamble/subframe boundary; claim 6 for data scattered pilots).
- Dy allowed values (claim 7).
Design-around lever: shift pilot insertion spacing outside the stated Dx and Dy sets, or remove edge pilots in the claimed manner, or change framing such that the OFDM symbol is not “included in a frame” with those required symbol types.
What design-arounds are most plausible given this claim structure?
1) Change the carrier index set used in the PAPR reduction signal
Because claim 1 requires “set of carriers having indices listed below,” substituting even one carrier index in the reduction signal is the most direct non-infringement route.
Common tactics in OFDM PAPR reduction:
- use different reserved tone sets,
- use different tone masks per symbol,
- use block-scheme tone selection that depends on channel conditions or scheduling,
- use alternative PAPR reduction schemes (selected mapping, tone reservation variants, clipping/ filtering).
2) Keep PAPR reduction but operate with FFT size not equal to 8K
Claim 1 is anchored on FFT size 8K. If an implementation uses 4K, 16K, or a scalable scheme that does not literally use FFT size 8K for the claimed OFDM symbol processing, claim 1 literal coverage is reduced.
3) Alter pilot insertion pattern spacing away from stated Dx/Dy
Claims 4, 6, and 7 are narrow due to enumerated Dx and Dy values.
- If Dx for the relevant pilot insertion pattern is not in the cited sets, dependent claims 4/6 fail.
- If Dy is not 2 or 4, claim 7 fails.
4) Break edge pilot placement rules
If subframe boundary symbols or data symbols do not insert an edge pilot into first and last carriers as required, claim 3 and claim 5 narrowings are avoided.
5) Break the frame definition
If the transmitter’s framing does not include a preamble symbol plus at least one subframe boundary symbol plus data symbols as claimed, claim 2 fails.
How does this patent likely relate to the “tone reservation” family of OFDM PAPR reduction?
Claim 1 reads like a “tone reservation” or “reserved tones with cancellation/reduction signal” style of PAPR reduction: generate a signal associated with a predetermined subset of carriers (reserved indices) to reduce the PAPR of an OFDM symbol.
In many tone-reservation systems:
- reserved carriers are set to values determined so that the time-domain waveform meets PAPR targets;
- pilots and data carriers may have structured patterns; and
- specific reserved-tone sets are used to control constellation distortion and maintain spectral properties.
This patent’s distinctiveness is the combination:
- fixed reserved carrier index set for 8K FFT, and
- explicit pilot pattern constraints (Dx and Dy) plus edge pilot rules, through dependent claims.
What prior art and nearby patent themes are most likely to be relevant for invalidity and freedom-to-operate?
Without the text of the specification, prosecution history, and claim dependency graph beyond claims 1–7, the landscape analysis below targets the typical prior art intersections for this exact claim mix:
A. OFDM PAPR reduction using reserved tones
Expect prior art clusters around:
- tone reservation,
- active constellation extension,
- partial transmit sequences,
- clipping and filtering with spectral mask constraints,
- iterative PAPR reduction with reserved carriers.
Where US 10,177,951 is likely to distinguish: the fixed enumerated reserved carrier indices for 8K FFT plus the pilot pattern constraints tied to Dx/Dy and edge pilots.
B. Pilot patterning in OFDM frames
Expect prior art clusters around:
- preamble pilot insertion,
- scattered pilot insertion in data symbols,
- subframe boundary pilots,
- edge pilot placement.
Where US 10,177,951 is likely to distinguish: integrating those pilot pattern rules into (or as conditions for) the reserved-carrier PAPR reduction mechanism.
C. Standard-driven OFDM numerology (8K FFT) and frame structures
8K FFT is commonly associated with certain broadcast and wireless OFDM parameterizations. If this patent is aligned to a known standard’s numerology and pilot pattern rules, then the fixed carrier lists and Dx/Dy options may map onto standard-compliant patterns.
What does the claim language imply about the underlying signal processing pipeline?
Even without the specification, the claim constraints imply a pipeline like:
- Receive or generate an OFDM symbol mapped onto active carriers.
- Compute an OFDM waveform (or estimate) and determine PAPR issues.
- Use a PAPR reducer to generate a reduction signal defined over carriers with the enumerated indices.
- Apply pilots in frame-defined positions following a pilot insertion pattern characterized by Dx and Dy, including edge pilots into first and last carriers in specified symbols.
This indicates the system’s PAPR reduction is not standalone; it is coordinated with pilot placement structure.
Patent landscape: how to structure an FTO and validity search around US 10,177,951’s claim anchors
Key claim anchors to use as search keys
- “OFDM PAPR reducer” AND “8K FFT”
- “peak to average power ratio” AND “reserved tones” AND “carrier indices”
- The numerical reserved-tone set itself (index list) as a signature query
- “pilot insertion pattern” AND “Dx=6,12,16,24,32”
- “scattered pilot” AND “Dx=3,4,6,8,12,16,24,32”
- “Dy=2,4” AND “symbol indices successive pilots”
- “edge pilot” AND “first carrier and last carrier” AND “subframe boundary symbol” / “data symbol”
What competing claim scopes usually cover the same ground
Search for patents that claim one or more of:
- a particular reserved-tone set for PAPR reduction,
- a method of generating a reduction signal using a predetermined carrier mask,
- a system coordinating PAPR reduction with pilot placement.
Where infringement disputes most often concentrate
- whether the reduction signal is generated using the same reserved carrier indices;
- whether the FFT size is literally 8K for the OFDM symbol at issue;
- whether the receiver/transmitter includes the specified pilot insertion pattern parameters and edge pilot placement.
Key takeaways
- US 10,177,951 claim 1 is narrowed primarily by a fixed 8K OFDM reserved-carrier index set. Literal coverage turns on using that specific carrier list in the PAPR reduction signal.
- Dependent claims add framing and pilot placement mechanics tied to Dx and Dy sets and edge pilot rules, creating multiple additional non-infringement surfaces for design-around.
- Most realistic FTO and invalidity strategies will center on contrasting the reserved-tone carrier indices and the pilot pattern spacing (Dx/Dy) against the enumerated values in claims 4, 6, and 7.
FAQs
1) Can a transmitter avoid infringement of claim 1 by changing only one reserved carrier index?
Yes, because claim 1 requires a set of carriers “having indices listed below,” making the enumerated carrier indices a limiting feature.
2) Does implementing any OFDM PAPR reduction method automatically infringe US 10,177,951?
No. The independent claim requires an 8K FFT and a reduction signal defined over the claimed reserved-carrier index set.
3) Are Dx and Dy part of independent claim 1?
No. Dx and Dy appear only in dependent claims 4, 6, and 7.
4) Can a system infringe claim 1 but avoid claim 4?
Yes. If it meets claim 1’s reserved carrier indices and 8K FFT requirements but uses pilot spacing Dx values not in the claim 4 set for the relevant pilot insertion pattern, claim 4 would not be met.
5) If a product uses 8K FFT but does not use preamble or subframe boundary symbols, does it avoid claim 2?
Yes. Claim 2 requires the OFDM symbol to be in a frame with a preamble symbol and at least one subframe boundary symbol plus data symbols.
References
- United States Patent US 10,177,951 (claims 1–7 as provided).
