Obviousness

Analysis of Obviousness for U.S. Patent 10,468,047

Introduction to Obviousness under 35 U.S.C. § 103

Under United States patent law, an invention is not patentable if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art (PHOSITA). This analysis prevents the patenting of inventions that are merely trivial modifications or logical combinations of existing technologies. The core of an obviousness rejection lies in identifying a motivation to combine prior art references with a reasonable expectation of success.

Analysis of Independent Claims of U.S. Patent 10,468,047

The independent claims of U.S. Patent 10,468,047 are directed towards a portable spread spectrum audio receiver and a corresponding transmitter. A breakdown of the key elements of independent claim 1 reveals the following components for the receiver:

• Portability and Spread Spectrum Reception: A portable receiver capable of receiving spread spectrum wireless transmissions from a transmitter connected to a music source.
• Unique User Code: The receiver is configured to receive and store a unique user code for communication with a specific transmitter using Code Division Multiple Access (CDMA).
• Intersymbol Interference (ISI) Reduction: The receiver includes a direct conversion module to receive transmissions that have been processed to reduce ISI, and the receiver itself performs further processing to reduce ISI.
• Digital-to-Analog Conversion: A Digital-to-Analog Converter (DAC) to produce an analog audio output.
• Audio Output: A speaker to generate an audio signal, excluding content from other transmitters.
• Multiple Demodulation Schemes: The receiver can perform both Differential Phase Shift Keying (DPSK) and a non-DPSK demodulation.
• Separate ISI Processing and Demodulation: The ISI reduction processing is distinct from the demodulation process.

Independent claim 17 outlines the corresponding transmitter, which includes:

• Encoding for ISI Reduction: An encoder to process the audio signal to reduce ISI in the transmitted signal.
• Multiple Modulation Schemes: The ability to perform both DPSK and a non-DPSK modulation.
• CDMA Communication: Use of a unique user code and CDMA for wireless transmission.

Potential Obviousness Combinations

Based on the prior art cited in the patent, a compelling case for obviousness can be constructed by combining the teachings of several references.

Primary Combination: Altstatt (U.S. Patent 5,771,441) and Khayrallah (U.S. Patent Application Publication 2001/0033621)

• Altstatt (U.S. Patent 5,771,441): This patent discloses a small, battery-operated RF transmitter that connects to a portable audio device and transmits to headphones with an RF receiver. This reference establishes the foundational concept of a portable, wireless audio system for personal use. A PHOSITA would readily understand the core functionality of wirelessly transmitting audio from a portable player to headphones.

• Khayrallah (U.S. Patent Application Publication 2001/0033621): This reference teaches a method of differential coding and modulation, specifically addressing techniques like DPSK. The motivation for a PHOSITA to combine Khayrallah with Altstatt is clear. Altstatt provides the system, but lacks specifics on advanced digital modulation techniques that enhance signal integrity and noise immunity. A person skilled in wireless communication would naturally look to improve the reliability of the wireless link in Altstatt's system. Khayrallah provides a direct solution by introducing DPSK, a known and effective modulation scheme for wireless communication. The combination would result in a portable wireless audio system with a more robust digital transmission, which would be a predictable improvement.

Adding L.S. Research, Inc. (U.S. Patent 5,946,343) for CDMA and Digital Processing

• L.S. Research, Inc. (U.S. Patent 5,946,343): This patent describes a digital wireless speaker system. Crucially, it introduces the concept of using spread spectrum techniques and unique codes to allow multiple wireless systems to operate in the same area without interfering with each other. This is a direct teaching of the principles of CDMA.

A PHOSITA, starting with the combined system of Altstatt and Khayrallah, would recognize a significant limitation: the potential for interference if multiple users are in close proximity. The L.S. Research patent provides an elegant and well-established solution to this problem. The motivation to integrate the teachings of L.S. Research is to enable the private and interference-free listening experience that is a key feature of the '047 patent. Combining the unique user codes and spread spectrum techniques of L.S. Research with the portable wireless audio system of Altstatt, already enhanced with the digital modulation of Khayrallah, would lead a PHOSITA directly to a system with private, multi-user capability.

Further Refinement with Ericsson (U.S. Patent 6,563,892) for ISI Reduction

• Ericsson (U.S. Patent 6,563,892): This patent discloses a method and system for the detection of binary information in the presence of disturbances, which is directly related to mitigating Intersymbol Interference.

A PHOSITA, having developed the system described above, would continue to seek improvements in signal quality. ISI is a known problem in digital communication systems that can lead to errors in the received data. The Ericsson patent teaches methods for detecting and correcting such errors. A person skilled in the art would be motivated to incorporate the teachings of Ericsson to further enhance the reliability and audio fidelity of the wireless system. This would involve adding processing steps in both the transmitter (encoding to reduce ISI) and the receiver (processing to detect and correct for ISI), as claimed in the '047 patent. The expectation would be that applying these known signal processing techniques would lead to a predictable improvement in performance.

Conclusion

The independent claims of U.S. Patent 10,468,047 appear to be obvious over a combination of the prior art. The combination of Altstatt, Khayrallah, L.S. Research, Inc., and Ericsson would have provided a PHOSITA with all the necessary elements to arrive at the claimed invention. The motivation to combine these references stems from a logical and predictable progression of improving a basic wireless audio system. Starting with the fundamental concept from Altstatt, a PHOSITA would be motivated to enhance the modulation for robustness (Khayrallah), add multi-user, interference-free capability (L.S. Research, Inc.), and further refine the signal quality by addressing ISI (Ericsson). Each of these steps represents a well-understood improvement in the field of wireless digital communications, and their combination would have been a matter of routine engineering for a person of ordinary skill in the art at the time of the invention.