Obviousness

Obviousness Analysis of U.S. Patent 7,193,986 under 35 U.S.C. § 103

This analysis evaluates whether the invention claimed in U.S. Patent 7,193,986 ('986 patent) would have been obvious to a person having ordinary skill in the art (POSITA) at the time the invention was made, circa 2002. A POSITA is considered to have a degree in electrical engineering or computer science and several years of experience designing wireless network protocols, specifically at the Medium Access Control (MAC) layer.

The central inventive concept of the '986 patent, as defined in independent claims 1 and 9, is a master-slave wireless network where the master device embeds a pointer into at least some of its regular data packets. This pointer indicates the relative time remaining until a "designated packet" (e.g., a broadcast beacon) is transmitted. This designated packet contains scheduling information that tells participating slave devices when they are cleared to transmit. The primary benefits articulated in the patent are improved power efficiency and faster re-synchronization for slave devices.

The prior art of record, particularly the references cited during prosecution, establishes a strong foundation for nearly all elements of the claims. The key question for an obviousness determination is whether the single distinguishing feature—the relative time pointer in a data packet—would have been an obvious addition to these existing systems to solve a known problem.

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Proposed Obviousness Combination: U.S. Patent 6,795,418 B2 (Philips) in view of General Engineering Principles and Known Problems in the Art

A strong case for obviousness can be made by combining the teachings of U.S. Patent 6,795,418 B2 (hereinafter "'418") with the knowledge and problem-solving toolkit of a POSITA at the time.

1. The Primary Reference: U.S. Patent 6,795,418 B2 ('418)

The '418 patent discloses a wireless MAC protocol that teaches the vast majority of the elements in claims 1 and 9 of the '986 patent:

• Master-Slave Structure: It describes a network with a central "coordinator" (the master device) and multiple "stations" (the slave devices).
• Designated Scheduling Packet: The coordinator transmits a "beacon" at the start of a recurring "superframe." This beacon is the "designated packet" recited in the '986 claims.
• Scheduling Information: The beacon in '418 contains detailed scheduling information, allocating time slots to specific stations for transmission. This directly teaches the claim elements of including "an indication of the slave network devices participating in said network and respective indications as to when participating slave network devices should transmit."
• Power Saving: The '418 patent explicitly describes a power-saving mode where stations can sleep and wake up just in time to receive the next beacon, based on knowledge of the superframe's fixed duration.

2. The Difference Between the Claims and the '418 Patent

The system in the '418 patent relies on a fixed, predetermined beacon interval. A slave device maintains synchronization by knowing this interval and waking at the next expected beacon time. The '418 patent does not disclose the key feature of the '986 patent: embedding a pointer indicating the relative time until the next beacon within an arbitrary data packet transmitted between beacons.

3. Motivation to Combine and Obviousness

The motivation to modify the system of '418 to include the pointer of the '986 patent stems from a well-understood problem in beacon-based networks: re-synchronization latency.

• The Known Problem: In a system like that of '418 or the contemporary Bluetooth standard (described in U.S. Patent 6,498,936), if a slave device loses synchronization—due to moving out of range, severe interference, or simply joining the network for the first time—it must enter a listening state and wait for the next scheduled beacon. Since superframes can last for a considerable time (the '986 patent suggests 80 ms as an example), this can introduce significant delay and waste power. A new device would have to listen continuously until it happens to catch a beacon to learn the network's timing.

• The Obvious Solution: A POSITA in 2002, tasked with improving the re-synchronization performance of the '418 system, would seek a way to provide timing information more frequently than the beacon interval without incurring the high overhead of sending a full beacon each time. The use of pointers, counters, and offsets to refer to future events in a data stream is a fundamental and ubiquitous technique in computer science and network protocol design.

  It would have been an obvious design choice to add a small field to the header or payload of regular, ongoing master-to-slave data packets. This field would simply contain a value representing the time remaining until the next master broadcast beacon. This modification would be a predictable solution to the known latency problem. A slave that is out of sync could then listen for any master packet, read the pointer, and immediately know when the next critical synchronization beacon will occur. It could then enter a low-power sleep mode until that precise moment.

This approach does not represent an inventive leap but rather the application of a known engineering technique (a timing pointer) to a known system (the beacon-based MAC of '418) to solve a known problem (re-synchronization latency). No undue experimentation would be required to implement this change.

Conclusion

The combination of the beacon-based, master-slave scheduling system taught by the '418 patent and the application of a basic, well-understood timing pointer to solve the known problem of re-synchronization latency would render the subject matter of independent claims 1 and 9 of the '986 patent obvious. The other prior art references of record, such as U.S. 6,088,337 and US 2002/0115458 A1, similarly teach the foundational beacon-based architecture and are susceptible to the same obviousness combination.

This conclusion is strongly supported by the fact that during an ex parte reexamination, the USPTO issued a notice of its intent to cancel claims 1-3, 5-6, and 8-9, indicating that the Patent Office itself found compelling arguments of unpatentability over prior art.