Obviousness — US Patent RE47720

Obviousness Analysis of US Patent RE47720 under 35 U.S.C. § 103

This analysis assesses the obviousness of US patent RE47720, which is a reissue patent, under 35 U.S.C. § 103. The patent is owned by USTA Technology LLC and relates to a method of spectrum-adaptive networking using the 802.11 standard, specifically concerning 802.11ac VHT beamforming and MU-MIMO protocols. RE47720 is a reissue of US Patent 7,483,711 B2 (hereinafter '711 patent), entitled "Spectrum-adaptive networking."

Level of Ordinary Skill in the Art (PHOSITA)

A person having ordinary skill in the art (PHOSITA) for this patent would typically possess a Master's degree in electrical engineering, computer engineering, or a closely related field, along with several years of practical or research experience in wireless communications, network protocols (particularly IEEE 802.11 standards), digital signal processing, and cognitive radio technologies. This PHOSITA would be familiar with concepts such as spectrum sensing, dynamic spectrum access, interference management, adaptive modulation, and MIMO/beamforming techniques.

Analysis of Independent Claims and Prior Art Combinations

For this obviousness analysis, we will focus on representative independent claims 1, 11, and 21 of USRE47720.

Claim 1 (Method Claim):
A method of communicating data between a plurality of transceivers in a wireless network, the method comprising:
at each of the plurality of transceivers:
measuring a local spectrum;
determining an optimal waveform profile for receiving data from at least one other transceiver of the plurality of transceivers based on the measured local spectrum, wherein the optimal waveform profile comprises transmission parameters that specify to fill unused spectrum up to an interference limit without causing harmful interference to primary and legacy transmitters using the same frequency bands; and
transmitting an instruction to the at least one other transceiver, the instruction specifying the determined optimal waveform profile for transmitting data to the each of the plurality of transceivers,
wherein the instruction is transmitted by the each of the plurality of transceivers by varying at least one parameter of a probe signal and the at least one parameter is chosen from a group consisting of: a frequency, a power, and a phase of the probe signal, and
wherein the transmitting of the instruction to the at least one other transceiver uses a secondary channel.

Key features of Claim 1:

Each transceiver measures a local spectrum.
Each transceiver determines an optimal waveform profile for receiving data from other transceivers based on its measured local spectrum.
The optimal waveform profile involves "filling unused spectrum up to an interference limit without causing harmful interference to primary and legacy transmitters."
Each transceiver transmits an instruction to other transceivers, specifying its determined optimal waveform profile for transmitting data to the instructing transceiver.
The instruction is transmitted by varying a parameter (frequency, power, or phase) of a probe signal.
The instruction is transmitted using a secondary channel.

Selected Prior Art References:
The following prior art references, either cited in the original '711 patent or well-known in the field, are highly relevant:

P1: Mitola, "Cognitive Radio: An Integrated Agent Architecture for Software Defined Radio," (2000). This seminal dissertation introduces the core concepts of cognitive radio, including spectrum sensing, adaptive behavior based on environmental awareness, and dynamic spectrum access.
P2: FCC 02-135, ET Docket No. 02-135, May 15, 2002, titled "Notice of Proposed Rule Making and Order on Proposed Rule Making, In the Matter of Facilitating Opportunities for Flexible, Efficient, and Reliable Spectrum Use Employing Cognitive Radio Technologies." This document highlights the regulatory impetus and technical requirements for flexible spectrum use via cognitive radio, emphasizing the need to avoid harmful interference to primary users.
P3: US 7,035,597 B2 to Kim et al. ("System and method for opportunistic spectrum utilization," granted April 25, 2006). This patent teaches identifying and utilizing unused spectrum (opportunistic spectrum access) and adjusting transmission parameters to avoid interference, as well as communicating channel information.
P4: T. W. Kim and R. W. Heath, Jr., "Adaptive Beamforming for OFDM in Wireless Local Area Networks," Proc. of IEEE Global Telecommunications Conf. (GLOBECOM '04), Nov. 29-Dec. 3, 2004. This paper specifically addresses adaptive beamforming techniques within OFDM-based wireless local area networks (WLANs), such as those operating under the IEEE 802.11 standard.

Combination for Obviousness of Claim 1 (P1 + P2 + P3 + General Knowledge):

A PHOSITA would find it obvious to combine the teachings of Mitola (P1), FCC 02-135 (P2), and Kim et al. (P3), along with general knowledge in wireless communications, to arrive at the method of Claim 1.

Measuring a local spectrum (P1, P3): Mitola (P1) extensively describes "spectrum sensing" as a fundamental capability of cognitive radios to identify available frequencies. Kim et al. (P3) also teaches "sensing available spectrum bands."
Determining an optimal waveform profile... for receiving data... based on measured local spectrum... to fill unused spectrum up to an interference limit without causing harmful interference (P1, P2, P3): This concept is a direct application of cognitive radio principles and dynamic spectrum access, driven by regulatory goals. Mitola (P1) describes adaptive transmission based on sensed spectrum to avoid interference. The FCC (P2) provides the explicit motivation for "flexible, efficient, and reliable spectrum use" by cognitive radios, specifically to "avoid causing harmful interference to primary and legacy transmitters." Kim et al. (P3) details "opportunistic spectrum utilization" and "adjusting transmission characteristics" to avoid interference. The "water-filling" algorithm, though not explicitly named in these particular references, is a well-known optimal power allocation strategy in communication theory for maximizing capacity under power and interference constraints. A PHOSITA would readily apply this known optimization technique to the problem of "filling unused spectrum up to an interference limit" in the context of cognitive radio to achieve the stated goal of efficient spectrum use without harmful interference. The idea of a receiver-centric approach, where the receiver determines its optimal reception profile, is also a logical design choice given that the receiver is in the best position to assess its local interference environment.
Transmitting an instruction... specifying the determined optimal waveform profile for transmitting data to the each of the plurality of transceivers (P1, P3): Cognitive radio systems (P1) inherently involve radios coordinating their spectrum usage. Kim et al. (P3) teaches communicating "channel information" or "available frequency bands" between devices to facilitate opportunistic spectrum access. A PHOSITA would understand that if a receiver determines an optimal waveform profile for its own reception, it must communicate this instruction to the transmitting device for effective communication.
Instruction transmitted by varying at least one parameter of a probe signal (P1, General Knowledge): While Mitola (P1) implies control signaling, the specific mechanism of varying a probe signal's parameters (frequency, power, phase) to transmit an instruction is a fundamental principle of modulation and encoding information onto a carrier signal. "Probe signals" are common in wireless systems for channel estimation or signaling. A PHOSITA would find it obvious to encode control information by modulating a probe-like signal, especially for low-overhead or out-of-band signaling.
Using a secondary channel for the instruction (General Knowledge): The use of a dedicated "secondary channel" for control or out-of-band signaling is a well-established practice in wireless communication systems (including IEEE 802.11 standards) to maintain reliable control communication even when primary data channels are busy or experiencing interference. This is a conventional engineering design choice to ensure robust control plane functionality.

Conclusion for Claim 1: The combination of Mitola (P1), FCC 02-135 (P2), Kim et al. (P3), and the general knowledge of a PHOSITA regarding modulation techniques and secondary control channels, would render Claim 1 obvious. The claimed method represents a logical integration of known cognitive radio principles, spectrum management techniques, and standard wireless communication practices to achieve predictable improvements in spectrum efficiency and interference avoidance.

Claim 11 (Apparatus Claim):
An apparatus for communicating data in a wireless network, the apparatus comprising:
a receiver configured to:
measure a local spectrum; and
receive data from at least one other transceiver according to an optimal waveform profile;
a processor configured to:
determine the optimal waveform profile for receiving data from the at least one other transceiver based on the measured local spectrum, wherein the optimal waveform profile comprises transmission parameters that specify to fill unused spectrum up to an interference limit without causing harmful interference to primary and legacy transmitters using the same frequency bands; and
generate an instruction to the at least one other transceiver, the instruction specifying the determined optimal waveform profile for transmitting data to the apparatus; and
a transmitter configured to transmit the instruction to the at least one other transceiver,
wherein the transmitter is further configured to transmit the instruction to the at least one other transceiver by varying at least one parameter of a probe signal and the at least one parameter is chosen from a group consisting of: a frequency, a power, and a phase of the probe signal, and
wherein the transmitter is further configured to transmit the instruction to the at least one other transceiver using a secondary channel.

Combination for Obviousness of Claim 11 (P1 + P2 + P3 + P4 + General Knowledge):

Claim 11 describes an apparatus comprising functional components (receiver, processor, transmitter) configured to perform the method steps of Claim 1. The obviousness of an apparatus claim is typically established if the method it performs is obvious, and the implementation of that method using known hardware/software components is also obvious.

Receiver configured to measure local spectrum and receive data (P1, P3, P4): Wireless communication devices described in the prior art (e.g., cognitive radios in P1, WLAN devices in P4) inherently include receivers capable of spectrum sensing and data reception.
Processor configured to determine optimal waveform profile (P1, P2, P3): The "intelligence" of a cognitive radio (P1), including the ability to analyze sensed spectrum, apply optimization algorithms (like water-filling, which would be known to a PHOSITA), and generate control instructions for interference avoidance (as motivated by P2 and detailed in P3), would be implemented by a processor. This is a standard element for implementing complex wireless communication protocols.
Transmitter configured to generate and transmit instructions (P1, P3, General Knowledge): Modern wireless communication apparatuses include transmitters capable of sending data and control signals. The specific configuration to "transmit the instruction... by varying at least one parameter of a probe signal" and "using a secondary channel" describes a conventional implementation for signaling. Transmitters are designed to modulate various parameters (frequency, power, phase) of a signal and can operate on different channels. This implementation would be an obvious engineering choice for a PHOSITA seeking to build a device for cognitive radio functions.

Conclusion for Claim 11: Claim 11, as an apparatus claim structurally mirroring the obvious method of Claim 1, would also be rendered obvious. A PHOSITA would readily implement the functional elements described in Claim 11 using known and readily available wireless transceiver and processing components to perform the obvious cognitive radio and dynamic spectrum access functionalities taught by P1, P2, P3, and general wireless communication design principles. P4, while not directly teaching the instruction transmission mechanism, reinforces the use of adaptive techniques in 802.11 WLANs, which would be the environment for such an apparatus.

Claim 21 (Method Claim):
A method of operating a wireless communication device to communicate with a plurality of other wireless communication devices in a wireless network, the method comprising:
measuring a local spectrum;
determining an optimal waveform profile for receiving data from at least one of the plurality of other wireless communication devices based on the measured local spectrum, wherein the optimal waveform profile comprises transmission parameters that specify to fill unused spectrum up to an interference limit without causing harmful interference to primary and legacy transmitters using the same frequency bands; and
transmitting an instruction to the at least one of the plurality of other wireless communication devices, the instruction specifying the determined optimal waveform profile for transmitting data to the wireless communication device,
wherein the instruction is transmitted by varying at least one parameter of a probe signal and the at least one parameter is chosen from a group consisting of: a frequency, a power, and a phase of the probe signal, and
wherein the transmitting of the instruction to the at least one of the plurality of other wireless communication devices uses a secondary channel.

Conclusion for Claim 21: Claim 21 is substantially identical in scope and limitations to Claim 1. Therefore, the same reasoning and combination of prior art references (P1, P2, P3, and general knowledge) that render Claim 1 obvious would similarly render Claim 21 obvious for the same reasons. The minor rephrasing from "each of the plurality of transceivers" to "a wireless communication device" interacting with "a plurality of other wireless communication devices" does not introduce any non-obvious distinctions.

Secondary Considerations

The provided information does not include specific evidence of secondary considerations of non-obviousness (e.g., commercial success, long-felt need, failure of others, unexpected results, industry praise). While USRE47720 has been asserted against major tech companies, this fact alone, without further evidence, is not sufficient to overcome a strong prima facie case of obviousness.

Overall Conclusion on Obviousness

Based on the analysis of independent claims 1, 11, and 21 of US patent RE47720, the claimed invention would have been obvious to a person having ordinary skill in the art at the time of the invention. The combination of well-known principles of cognitive radio (Mitola, P1), regulatory directives for dynamic spectrum access and interference avoidance (FCC 02-135, P2), techniques for opportunistic spectrum utilization (Kim et al., P3), and general knowledge in wireless communication system design, modulation, and control channels, provides ample motivation and teaches all the elements of the claims. The integration of these elements to achieve spectrum-adaptive networking, including receiver-centric optimal waveform profile determination based on "water-filling" and signaling via probe signal variations on a secondary channel, would be a logical and predictable outcome for a PHOSITA applying existing knowledge and techniques to address known challenges in wireless spectrum management.