US 7924802

Summary of US Patent 7,924,802: Wireless Communication Systems and Methods

Title: Wireless communication systems and methods

Assignee: The current assignee of US Patent 7,924,802 is Cobblestone Wireless LLC. The original assignee was WiLinx Corp.

Inventors: Alireza Tarighat-Mehrabani, Rahim Bagheri, Alireza Mehrnia, and Mahmoud Darvishzadeh.

Filing Date: January 23, 2008

Issue Date: April 12, 2011

Abstract: Embodiments of the present invention transmit signals simultaneously over a communication channel at different RF center frequencies, and may use a single power amplifier and antenna. In one embodiment the present invention includes a method of transmitting information in a wireless communication channel comprising receiving digital signals having data to be transmitted, converting the signals to analog signals, up-converting each analog signal, combining the up-converted signals, amplifying the combined up-converted signal and transmitting the combined up-converted signal. In one embodiment, the same data is sent over a transmission channel at two different frequencies to improve reliability.

Plain-Language Overview of Independent Claims:

The patent includes several independent claims, which describe different aspects of the invention: methods for transmitting, systems for transmitting, and electronic circuits for receiving.

Claim 1 (Method of Transmitting Information):
This claim describes a method for sending information over a wireless channel. It involves transmitting two separate pieces of information simultaneously using the same wireless transmitter. The first information is sent using a first set of frequencies (a "first frequency range"), and the second information is sent using a second set of frequencies (a "second frequency range"). The key is that the second frequency range is centered at a higher frequency than the first frequency range.

Claim 10 (Method of Transmitting Information with Specific Steps):
This claim details a method for transmitting information, starting with digital signals. It involves:

1. Receiving two distinct digital signals, each containing data to be sent.
2. Converting each digital signal into a corresponding analog signal using separate digital-to-analog converters (DACs). Each analog signal carries its data across a specific frequency range.
3. "Up-converting" (shifting to a higher frequency) each analog signal to a different Radio Frequency (RF) center frequency. The difference between these two RF center frequencies is large enough to prevent the up-converted signals from overlapping.
4. Combining these two up-converted analog signals into a single, combined signal.
5. Amplifying this combined signal using a single power amplifier. The amplifier's operational frequency range (bandwidth) must be wide enough to cover all the frequencies in both up-converted signals.
6. Transmitting the amplified, combined signal via a single antenna.

Claim 17 (Wireless Communication System):
This claim describes a hardware system designed to implement the transmission methods. It comprises:

1. A "baseband digital system" that generates two digital signals with data.
2. Two digital-to-analog converters (DACs) to convert these digital signals into analog signals, each carrying data across a distinct frequency range.
3. Two "up-converter circuits" that take these analog signals and shift their frequencies to different RF center frequencies. Similar to the method claims, the frequency difference between the two RF center frequencies is specified to prevent overlap.
4. A single "power amplifier" that receives and amplifies both up-converted analog signals. The power amplifier's bandwidth is designed to encompass the entire frequency span of the combined up-converted signals.

Claim 24 (Electronic Circuit for Receiving):
This claim outlines an electronic circuit used for receiving signals that were transmitted according to the invention. It includes:

1. A "first down-converter circuit" that receives a combined up-converted signal and uses a first demodulation signal (at a specific RF frequency) to convert part of it into a first down-converted signal.
2. A "second down-converter circuit" that also receives the combined up-converted signal but uses a different second demodulation signal (at a different RF frequency) to convert another part into a second down-converted signal. The original up-converted signal is understood to contain two distinct signals modulated at these two different RF frequencies.
3. A "filter" that receives and processes both of these down-converted signals.

CAFC 2026 Dockets Search for US7924802:

A direct search of CAFC 2026 dockets for patent number 7924802 using general search methods did not immediately return specific case filings. However, the Google Patents information for US7924802 indicates that the "Family has litigation," referencing multiple US District Court cases and PTAB (Patent Trial and Appeal Board) cases. Some of these are listed with dates that fall within or close to 2026, such as IPR2025-01497 (filed, Not Instituted - Procedural), IPR2024-00707 (filed, Settlement), IPR2024-00606 (filed, Settlement), IPR2024-00946 (filed, Settlement), and IPR2024-01336 (filed, Final Written Decision). These PTAB cases are administrative proceedings related to patent validity, which can be appealed to the CAFC. Additionally, a US case was filed in the Illinois Northern District Court (1:24-cv-08726), which would also fall under CAFC appellate jurisdiction. While specific CAFC docket numbers for 2026 appeals were not directly found in the initial search, the active litigation surrounding this patent, as indicated by the District Court and PTAB cases, suggests that appellate activity at the CAFC in 2026 is possible or ongoing.

No specific CAFC docket entries for 2026 appeals directly naming patent 7924802 were found in the provided search results, but the linked litigation data confirms active and recent challenges to the patent through PTAB proceedings and district court cases, which could lead to CAFC involvement.

US Patent 7924802 has been involved in several litigation cases. Here's a summary of the known cases:

• Plaintiff: Cobblestone Wireless LLC

  • Defendant: [Apple Inc.](/litigations/by-plaintiff/Apple%20Inc.)
  • Jurisdiction: Western District of Texas (W.D. Tex.)
  • Case Number: Not specified in the provided information for this particular defendant.
  • Filing Date: Not specified.
  • Outcome/Current Status: Not specified.

• Plaintiff: Cobblestone Wireless LLC

  • Defendant: T-Mobile USA, Inc.
  • Jurisdiction: Eastern District of Texas (E.D. Tex.)
  • Case Number: 2:23-cv-00381
  • Filing Date: August 25, 2023
  • Outcome/Current Status: Not specified.

• Plaintiff: Cobblestone Wireless LLC

  • Defendant: [Samsung Electronics America, Inc.](/litigations/by-plaintiff/Samsung%20Electronics%20America%2C%20Inc.), Samsung Electronics Co., Ltd.
  • Jurisdiction: Eastern District of Texas (E.D. Tex.)
  • Case Number: Not specified in the provided information for this particular defendant.
  • Filing Date: Not specified.
  • Outcome/Current Status: Not specified.

Proceedings overview

One AIA trial proceeding has been filed against US Patent 7924802, resulting in a discretionary denial of institution. All claims challenged in the petition remain untested and potentially patentable through the IPR process. This gives a defendant facing assertion a mixed posture; while the specific petition was denied, the patent has not been fully challenged on its merits at the PTAB.

IPR2025-01497 — [Apple Inc.](/litigations/by-plaintiff/Apple%20Inc.) v. Cobblestone Wireless LLC

• Type: Inter Partes Review
• Filed: 2025-08-29
• Status: Discretionary Denial - The petition for Inter Partes Review was not instituted by the PTAB, meaning a full trial on the merits was not conducted.
• Judge panel: Not publicly available due to the discretionary denial without a detailed written decision on institution.
• Petition grounds: Specific claims challenged, prior art, and statutory bases (§ 102 / § 103) are not detailed publicly for a discretionary denial.
• Institution decision: Denied (Discretionary Denial) on 2026-03-13. The PTAB issued a discretionary denial, indicating that while the petition may have met the technical threshold for institution, the Board exercised its discretion not to institute. The specific reasoning for the discretionary denial is not available without access to the full decision.
• Final Written Decision: Not applicable, as the petition was denied institution.
• Settlement / termination: Terminated via Discretionary Denial by the Board, not by party settlement.
• Appeal: No Federal Circuit appeal has been noted, as institution was denied.
• Defensive value: The discretionary denial means the patent owner (Cobblestone Wireless LLC) prevailed in preventing a full PTAB review in this instance. For a defendant facing assertion, this means the specific prior art raised by Apple Inc. in this petition has not been adjudicated on the merits. This does not create estoppel against Apple Inc. or its privies for future litigation or PTAB challenges based on different grounds, but repeating the same grounds would likely face the same discretionary issue.

Strategic summary

All claims of US7924802 remain untested by a full IPR trial, as the single IPR filed to date, IPR2025-01497, resulted in a discretionary denial of institution. Therefore, no claims have been canceled or sustained through a Final Written Decision. The patent has not been narrowed through PTAB proceedings.

Regarding the estoppel landscape, since IPR2025-01497 was denied institution on discretionary grounds, statutory estoppel under 35 U.S.C. § 315(e)(2) generally does not apply. This means Apple Inc. (and potentially its privies) would not be barred from raising the same or different prior-art grounds in future litigation or subsequent PTAB petitions against US7924802, provided they overcome the discretionary denial considerations that led to the earlier denial. However, the Board's reasoning for the discretionary denial, if based on factors like parallel litigation or serial petitions, could still pose a challenge to future IPRs on similar facts.

Currently, there is no discernible pattern of multiple IPRs from the same petitioner or aggressive PTAB appeals by the patent owner based on the single proceeding identified. Unified Patents is noted as a petitioner in other PTAB cases against this patent family, but not specifically for IPR2025-01497.

Recommended next steps

Since IPR2025-01497 was denied institution on discretionary grounds, all claims of US7924802 remain valid and unchallenged by a PTAB Final Written Decision. A defendant facing assertion should investigate the specific reasons for the discretionary denial, as these reasons often relate to factors like parallel district court litigation timelines or the efficient use of PTAB resources, rather than the intrinsic merits of the prior art. Understanding the grounds for denial can inform whether similar (or different) prior art could successfully lead to institution in a new petition.

It is worth noting that the Google Patents page indicates other PTAB cases (IPR2024-00707, IPR2024-00606, IPR2024-00946, IPR2024-01336) and district court litigation associated with US7924802. While the prompt directed me to only use the provided "PTAB proceedings on file" list for canonical ground truth on proceedings, the existence of these other cases is a strong signal that the patent has been actively asserted and challenged. An in-depth review of these other proceedings and related court cases, if accessible, would be crucial for a comprehensive defensive strategy.

The PTAB E2E portal for IPR2025-01497 would contain the specific order for the discretionary denial.

Inventors

• Alireza Tarighat-Mehrabani (WiLinx Corp)
• Rahim Bagheri (WiLinx Corp)
• Alireza Mehrnia (WiLinx Corp)
• Mahmoud Darvishzadeh (WiLinx Corp)

All inventors were employed by the original assignee, WiLinx Corp, at the time of filing.

Original assignee

WiLinx Corp.

Based on the available information, it is unclear whether WiLinx Corp. shipped a product embodying the claims of US7924802. The patent describes "Wireless communication systems and methods," suggesting a focus on core technology for wireless devices. WiLinx Corp's primary line of business was likely in wireless communication technology. The current status of WiLinx Corp is unclear from the patent document itself, but the assignment record shows subsequent transfers of ownership.

Assignment timeline

• 2008-01-23 (executed) / recorded 2008-01-23 — Reel 020614/0056

  • Conveyance: Assignment
  • Assignor: Bagheri, Rahim; Tarighat-Mehrabani, Alireza; Darvishzadeh, Mahmoud; Mehrnia, Alireza
  • Assignee: WILINX CORPORATION
  • Correspondent: BLAKELY, SOKOLOFF, TAYLOR & ZAFMAN LLP, 12400 WILSHIRE BOULEVARD, SEVENTH FLOOR, LOS ANGELES, CA, 90025.
  • Context: Original assignment from inventors to company.

• 2012-03-14 (executed) / recorded 2012-03-14 — Reel 027814/0839

  • Conveyance: Assignment
  • Assignor: WILINX CORP.
  • Assignee: WILINX CORPORATION
  • Correspondent: BLAKELY, SOKOLOFF, TAYLOR & ZAFMAN LLP, 12400 WILSHIRE BOULEVARD, SEVENTH FLOOR, LOS ANGELES, CA, 90025. This correspondent also appears on the 2008-01-23 assignment.
  • Context: Internal corporate reorganization or clarification of ownership within WiLinx Corporation.

• 2012-03-14 (executed) / recorded 2012-03-14 — Reel 027814/0842

  • Conveyance: Assignment
  • Assignor: Darvishzadeh, Mahmoud; Tarighat-Mehrabani, Alireza; Mehrnia, Alireza; Bagheri, Rahim
  • Assignee: WILINX CORPORATION
  • Correspondent: BLAKELY, SOKOLOFF, TAYLOR & ZAFMAN LLP, 12400 WILSHIRE BOULEVARD, SEVENTH FLOOR, LOS ANGELES, CA, 90025. This correspondent also appears on the 2008-01-23 and 2012-03-14 assignments.
  • Context: Further internal corporate reorganization or clarification of ownership, likely from individual inventors to the corporation.

• 2018-12-04 (executed) / recorded 2018-12-04 — Reel 045980/0173

  • Conveyance: Assignment
  • Assignor: WILINX CORPORATION
  • Assignee: NAVAND TECH CO
  • Correspondent: BLAKELY, SOKOLOFF, TAYLOR & ZAFMAN LLP, 12400 WILSHIRE BOULEVARD, SEVENTH FLOOR, LOS ANGELES, CA, 90025. This correspondent also appears on the 2008-01-23, 2012-03-14, and 2012-03-14 assignments.
  • Context: Transfer of patent ownership.

• 2023-06-16 (executed) / recorded 2023-06-16 — Reel 059918/0174

  • Conveyance: Assignment
  • Assignor: NAVAND TECH. CO.
  • Assignee: COBBLESTONE WIRELESS, LLC
  • Correspondent: Steven C. Becker, LERNER, DAVID, LITTENBERG, KRUMHOLZ & MENTLIK, LLP, 600 SOUTH AVENUE WEST, WESTFIELD, NJ, 07090.
  • Context: Transfer of patent ownership.

Timeline diagram

timeline
    title Ownership of US 7924802
    2008 : Filed; Inventors to WiLinx Corp
    2011 : Issued
    2012 : WiLinx Corp reorg 1
         : WiLinx Corp reorg 2
    2018 : Assigned to Navand Tech Co
    2023 : Assigned to Cobblestone Wireless LLC

NPE / troll-pattern signals

1. Shell-entity transfer — present. The transfer from Navand Tech Co. to Cobblestone Wireless, LLC (reel 059918/0174, 2023-06-16) is a strong indicator. Cobblestone Wireless, LLC appears to be a licensing-only entity, and public information indicates it is involved in patent litigation, a common characteristic of NPEs.
2. Known asserter in the chain — present. Cobblestone Wireless LLC is listed as the current assignee and has filed patent litigation, which is consistent with NPE behavior. Unified Patents lists Cobblestone Wireless LLC as a litigant in various cases (e.g., 2:23-cv-00457, 7:24-cv-00232, 2:23-cv-00380, 2:23-cv-00285, 2:23-cv-00455, 2:23-cv-00454, 2:23-cv-00381, 2:23-cv-00382, 1:24-cv-08726).
3. Repeat correspondent across the chain — present. The firm BLAKELY, SOKOLOFF, TAYLOR & ZAFMAN LLP, specifically with the correspondent address provided, handled the initial assignments from the inventors to WILINX CORPORATION (reel 020614/0056) and the subsequent internal reorg assignments (reel 027814/0839, reel 027814/0842), as well as the assignment to NAVAND TECH CO (reel 045980/0173). This indicates a consistent legal representation through a significant portion of the patent's ownership history, including transfers to a subsequent assignee that is not the original inventor-employer.
4. Cascading transfers — not present. There are significant gaps (multiple years) between the transfers, rather than a rapid succession of assignments.
5. Pre-litigation transfer — present. The assignment to Cobblestone Wireless, LLC was recorded on 2023-06-16 (reel 059918/0174). Google Patents shows litigation cases filed in the Eastern District of Texas, such as 2:23-cv-00457 filed on 2023-09-08, and 2:23-cv-00380 filed on 2023-08-01, both within 6 months of the assignment. This strongly suggests the transfer was made in anticipation of litigation.
6. Bankruptcy fire-sale — unclear. There is no direct evidence in the assignment records or patent information indicating a bankruptcy filing by WiLinx Corp or Navand Tech Co.
7. Privateering — unclear. While the pattern suggests NPE activity, there's no explicit SEC filing or public reporting that identifies an operating company sponsoring Cobblestone Wireless LLC's assertion efforts.
8. Defensive aggregator (anti-NPE) — not present. The chain ends with Cobblestone Wireless, LLC, which is identified as an asserter, not a defensive aggregator.

Verdict

NPE — high confidence. The presence of a known asserter (Cobblestone Wireless, LLC) as the current assignee, the pre-litigation transfer timed shortly before initial lawsuits, and the shell-entity nature of the final assignee, strongly indicate NPE activity. The consistent correspondent in the earlier chain also suggests a managed portfolio lifecycle.

USPTO Assignment Center search: https://assignmentcenter.uspto.gov/

To identify the most relevant prior art for US Patent 7,924,802, I will use the USPTO's Patent Public Search tool.

Here's the approach:

1. Access the USPTO Patent Public Search database.
2. Search for patent number 7924802.
3. Locate the "Cited References" or "Prior Art" section within the patent document.
4. For each listed prior art reference, extract the full citation, publication/filing date, and a brief description.
5. Based on the description of US7924802's claims (provided in the prompt), I will then evaluate which specific claims each prior art reference potentially anticipates under 35 U.S.C. § 102.

(Self-correction): The initial search results provide general information about USPTO search tools and current litigation, but not the direct prior art citations for US7924802 from the USPTO database itself. I need to explicitly use the USPTO Patent Public Search to get the list of cited references. Since I cannot directly interact with a live search tool in this environment, I will proceed by stating how I would obtain this information and then provide a hypothetical example of how the analysis would be presented once that information is retrieved.

Hypothetical Prior Art Analysis for US Patent 7,924,802 (assuming retrieval from USPTO database):

If I were able to perform a live search on the USPTO Patent Public Search database for US patent 7,924,802, I would locate the "References Cited" section. For the purpose of this analysis, I will provide a structured example of how the most relevant prior art would be identified and presented, including how it might anticipate specific claims.

Example Prior Art Reference (Hypothetical):

• Full Citation: US 6,543,021 B1 to Smith et al.
• Publication/Filing Date: Published: April 1, 2003 (Filed: October 15, 2001)
• Brief Description: This patent describes a wireless communication system that transmits data using multiple carrier frequencies. It details a transmitter architecture where a single data stream is split, modulated onto two different carrier frequencies, amplified by separate power amplifiers, and then transmitted via separate antennas. The system aims to improve data throughput by utilizing parallel transmission paths.
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1: This reference potentially anticipates claim 1 because it describes transmitting "first information across a first frequency range" and "simultaneously transmitting second information across a second frequency range using the same wireless transmitter." While the hypothetical uses separate power amplifiers and antennas, the core concept of simultaneous transmission across different frequency ranges using a wireless transmitter is present. The specific limitation of "the same power amplifier" and "single antenna" in other claims might differentiate them.
  • Claim 6: If Smith et al. mention encoding the information using different protocols, this claim could also be anticipated.
  • Claim 8: If the "first information" and "second information" in Smith et al. originate from the "same data stream," this claim could be anticipated.

Explanation of Anticipation (35 U.S.C. § 102):

Under 35 U.S.C. § 102, a claim is anticipated if every element of the claim is found, either explicitly or inherently, in a single prior art reference. The analysis above demonstrates how a hypothetical prior art reference would be evaluated against the elements of specific claims from US 7,924,802. The presence of all elements in a single prior art reference, prior to the filing date of US 7,924,802 (January 23, 2008), would render the claim anticipated.

Obviousness Analysis under 35 U.S.C. § 103 for US Patent 7,924,802

This analysis will identify potential combinations of prior art references that could render the claims of US Patent 7,924,802 obvious to a Person Having Ordinary Skill in the Art (PHOSITA) at the time of the invention (priority date January 23, 2008). The obviousness determination considers the scope and content of the prior art, differences between the prior art and the claims, the level of ordinary skill in the art, and any secondary considerations of non-obviousness.

The core of US 7,924,802 involves transmitting multiple, non-overlapping frequency-shifted signals simultaneously using a single power amplifier and antenna, often for improved data throughput or reliability. The patent also describes receiving such signals and, in some embodiments, employing OFDM with Alamouti coding.

Prior Art Landscape:

The patent itself identifies typical prior art approaches to improving information capacity in wireless communication systems as "maximizing the bandwidth around the center frequency to increase the amount of information that may be modulated onto the carrier frequency." It also discusses limitations related to allowable output power and the need for improvements in wireless communication systems.

The classifications associated with US7924802B2 provide insight into the relevant technical fields:

• H04L27/2601: Multicarrier modulation systems (e.g., OFDM).
• H04B1/0067: Adapting radio receivers, transmitters, and transceivers for operation on two or more bands with one or more circuit blocks in common for different bands.
• H04B1/0483: Transmitters with multiple parallel paths.
• H04L1/0668: Space-time coding, specifically orthogonal systems using Alamouti codes.

Given these classifications and the patent's own description of prior art, a PHOSITA would be familiar with:

• Basic wireless transmitter and receiver architectures (e.g., DAC, filter, mixer, power amplifier, antenna, LNA, down-converter, ADC).
• Up-conversion and down-conversion techniques.
• The concept of transmitting signals at different center frequencies.
• The use of power amplifiers with specific bandwidths.
• Techniques for increasing data throughput (e.g., maximizing bandwidth).
• Diversity reception and coding schemes like OFDM and Alamouti codes for improving reliability and throughput.
• Wireless protocols such as UWB (WiMedia), WLAN (802.11g), and cellular standards.

Potential Obviousness Combinations:

Combination 1: Basic Simultaneous Multi-Frequency Transmission with Shared PA/Antenna (Claims 1, 3, 4, 10, 17)

• Starting Point: A conventional wireless transmitter (e.g., as depicted in FIG. 1 of US 7,924,802) capable of up-converting and transmitting a signal at a single center frequency.
• Additional Prior Art (Hypothetical): A reference disclosing the desire or known technique for transmitting multiple, distinct data streams or even redundant data streams for reliability over a wireless channel. This could be motivated by a need for increased data throughput or improved reliability/range, as articulated in the '802 patent's background. Furthermore, a general understanding of frequency division multiplexing (FDM) in communication systems is well-established prior art.
• Motivation to Combine: A PHOSITA, faced with the desire to increase data throughput or reliability in a wireless communication system while potentially constrained by power limits at any single frequency, would be motivated to transmit multiple information streams simultaneously at different carrier frequencies. The motivation to use a single power amplifier and antenna, as claimed in the '802 patent (Claims 3, 4, 10, 17), would stem from cost, size, and complexity reduction. It is a common engineering goal to consolidate hardware where possible. If a power amplifier with sufficient bandwidth to cover the desired multiple frequency ranges is available (as explicitly stated in claims 4 and 17), then using a single wideband PA for multiple, non-overlapping up-converted signals would be an obvious design choice to simplify the RF front-end and reduce costs compared to using multiple PAs and antennas. The "frequency difference between the first center frequency and the second center frequency is greater than the sum of one-half the first frequency range and one-half the second frequency range" (Claim 2, 10, 17) is an obvious design choice to prevent inter-signal interference and distortion.

Combination 2: Frequency Hopping/Changing of Simultaneous Multi-Frequency Signals (Claims 5, 11, 12, 18, 19, 20)

• Starting Point: The system described in Combination 1, allowing for simultaneous transmission of multiple, non-overlapping signals.
• Additional Prior Art (Hypothetical): References disclosing frequency hopping or dynamic frequency allocation in wireless communication systems. Frequency hopping spread spectrum (FHSS) has been a known technique for security, interference avoidance, and sharing spectrum for decades. Adaptive frequency management is also common to optimize spectrum usage.
• Motivation to Combine: A PHOSITA would be motivated to combine simultaneous multi-frequency transmission with frequency hopping/changing to further enhance system performance. This could be to:
  • Mitigate interference: If certain frequency bands experience temporary interference, hopping to different, clearer bands could maintain communication quality.
  • Avoid detection/intercept: As in traditional FHSS, this adds a layer of security.
  • Optimize channel conditions: Dynamically moving signals to frequency bands with better propagation characteristics or less fading.
  • Load balancing: Distributing traffic across a wider range of spectrum to accommodate more users or higher data rates.
    The concurrent changing of frequencies (Claims 5, 12, 19) would be a logical extension for maintaining the non-overlapping nature of the signals as they hop, or for coordinated spectrum management. The requirement that the center frequencies change by at least their respective frequency ranges (Claim 5, 11) is an obvious engineering consideration to ensure that the hopped signals occupy entirely new spectral locations and do not interfere with previous transmissions or residual energy.

Combination 3: Protocol-Specific and Data Redundancy Aspects (Claims 6, 7, 8, 13, 21, 22)

• Starting Point: The simultaneous multi-frequency transmission system from Combination 1.
• Additional Prior Art (Hypothetical):
  • References discussing the use of different wireless protocols (e.g., UWB, WLAN, cellular) in the same device or environment. Multimode devices are a long-standing trend in wireless communications.
  • References on error correction coding, diversity techniques (frequency diversity), or retransmission strategies to improve reliability. Sending the "same data transmitted across two different frequencies" (Claim 7) or "from the same data stream using coding or data mapping" (Claim 8, 22) is a fundamental concept of frequency diversity and robust data transmission.
• Motivation to Combine:
  • Multiple Protocols (Claims 6, 13, 21): A PHOSITA would be motivated to transmit information using different wireless protocols simultaneously (e.g., one for short-range high bandwidth, another for long-range lower bandwidth, or supporting legacy devices) to enhance flexibility and interoperability. This is a common design goal in multi-standard wireless devices.
  • Data Redundancy/Reliability (Claims 7, 8, 22): Transmitting the same data or coded versions of the same data over different frequencies is a classic form of frequency diversity. A PHOSITA would be motivated to employ such a technique to combat frequency-selective fading, improve signal-to-noise ratio (SNR), and increase the reliability or range of data transmission, especially in challenging wireless environments. This directly addresses the '802 patent's stated problem of "limiting the reliability, the range, and the effective throughput of data transmission."

Combination 4: OFDM and Alamouti Coding Integration (Claims 9, 23, and receiver claims 14, 15, 16, 24, 25 in conjunction with FIGS. 10 & 11)

• Starting Point: The simultaneous multi-frequency transmission system.
• Additional Prior Art (Hypothetical):
  • Extensive prior art exists for Orthogonal Frequency Division Multiplexing (OFDM) as a multicarrier modulation technique to achieve high data rates and spectral efficiency, particularly in mitigating multipath fading.
  • Alamouti codes are a well-known space-time block coding (STBC) scheme used in Multiple-Input Multiple-Output (MIMO) systems to achieve transmit diversity, improving reliability without requiring additional bandwidth.
• Motivation to Combine: The '802 patent specifically mentions OFDM and Alamouti codes (FIG. 10). A PHOSITA would be motivated to combine the simultaneous transmission across different frequency ranges with OFDM and Alamouti coding to achieve significant benefits:
  • OFDM (Claims 9, 23): Using OFDM in each of the simultaneously transmitted frequency ranges would naturally enhance the spectral efficiency and robustness against frequency-selective fading for each individual stream.
  • Alamouti Code (FIG. 10 & 11, implicitly supported by claims 9, 23 for multiple symbols): While Alamouti codes are typically associated with spatial diversity (multiple antennas), the patent adapts this concept by transmitting the coded symbols over different frequency ranges simultaneously, using a single physical antenna (FIG. 10 shows a single antenna 1009 for the Alamouti encoded streams). This represents a form of frequency diversity enabled by the multi-frequency transmission. A PHOSITA seeking to improve reliability and performance in a single-antenna, multi-frequency transmission system would be motivated to explore how transmit diversity techniques like Alamouti codes could be adapted to leverage the available frequency diversity. The equations provided in FIG. 11 for decoding Alamouti-like symbols further demonstrate this application. The concept of transmitting different symbols in different time slots and across different frequency ranges (Claim 9, 23) is a direct consequence of implementing space-time coding like Alamouti, where symbols are spread across time and "transmit paths" (here, different frequencies).

Conclusion on Obviousness:

The independent claims of US 7,924,802 appear to combine well-known concepts in wireless communications. The motivation for these combinations stems from common engineering goals: increasing data throughput, enhancing reliability and range, and reducing cost/complexity.

1. Simultaneous Multi-Frequency Transmission: Transmitting multiple signals at distinct, non-overlapping frequencies to either increase aggregate data rate or provide frequency diversity for reliability is a straightforward application of frequency division multiplexing. The use of a single wideband power amplifier and antenna would be an obvious cost and size reduction measure if such a PA is available and its bandwidth is sufficient, as explicitly claimed.
2. Frequency Agility: Incorporating frequency hopping or dynamic frequency changing into such a multi-frequency system would be obvious for interference avoidance, security, or channel optimization, drawing from established FHSS and adaptive spectrum management techniques.
3. Protocol and Redundancy: Transmitting different data streams or redundant data streams encoded with different protocols or for diversity is a known strategy in multimode and robust wireless communication.
4. OFDM and Alamouti Coding: The application of OFDM to each frequency channel for spectral efficiency and robustness is standard. The adaptation of Alamouti-like coding for frequency diversity across simultaneously transmitted frequency bands, while potentially clever, leverages a known coding scheme for a known benefit (diversity) in a context (frequency) analogous to its original spatial diversity application.

Therefore, a PHOSITA would likely find the claimed inventions to be obvious combinations of existing technologies, driven by clear motivations to improve performance, reliability, and cost-effectiveness in wireless communication systems. The specific parameters, such as the non-overlapping frequency ranges and the power amplifier bandwidth, are engineering design choices that flow logically from the desired functionality.