Obviousness

Obviousness Analysis of US Patent 10,103,845 under 35 U.S.C. § 103

This analysis identifies combinations of prior art references that would render the claims of US Patent 10,103,845 obvious to a person having ordinary skill in the art (PHOSITA) at the priority date of April 14, 2004.

A PHOSITA in this field would be an engineer or scientist skilled in the design and implementation of wireless communication systems, particularly those employing Orthogonal Frequency Division Multiplexing (OFDM) and Multiple-Input Multiple-Output (MIMO) technologies. They would be motivated to improve data rates, spectral efficiency, and system adaptability to varying channel conditions.

The primary prior art reference for this analysis is US20030235147A1 to Walton et al. ("Walton '147"), published on December 25, 2003, which predates the priority date of US10103845.

Combination: US20030235147A1 (Walton et al.) in view of general knowledge in the art

Motivation to Combine:
The background of US10103845 explicitly states the continuous demand for higher data rates in wireless communication systems. Walton '147 also addresses performance improvement and achieving higher spectral efficiency. A PHOSITA would be motivated to combine known techniques in spatial multiplexing and bandwidth utilization to meet these demands, particularly if such techniques could be integrated into a flexible, multi-mode communication system. The dual-mode architecture disclosed in US10103845 aims to reuse hardware for both spatial multiplexing and bandwidth expansion, a desirable efficiency.

Analysis of Independent Claims:

1. Claim 1 (Method of Transceiver Operation - Transmission):
Claim 1 describes a method of operation for a transceiver in a plurality of modes, including a first mode based on spatial multiplexing and a second mode based on spatial multiplexing and bandwidth expansion.

• First Mode (Spatial Multiplexing): Walton '147 teaches a "single-band transmission scheme for a MIMO OFDM system" where "multiple independent data streams may be transmitted... in a spatial multiplexing manner." This directly discloses the first mode of Claim 1, where separate first mode transmit symbols are generated and transmitted from first and second transmitters over a first and second set of antennas, respectively, across a spectrum of frequencies that is the same for each.
• Second Mode (Spatial Multiplexing and Bandwidth Expansion): Walton '147 further discloses a "multi-band transmission scheme" where "multiple independent data streams may be transmitted on two or more bands in a a spatial multiplexing manner" and "each portion may be transmitted on a different frequency band." This teaches the second mode of Claim 1, where separate second mode transmit symbols are generated and transmitted from first transmitters over a first set of antennas across a first spectrum of frequencies, and from second transmitters over a second set of antennas across a second spectrum of frequencies, wherein the first spectrum of frequencies does not overlap with the second spectrum of frequencies. The phrase "different frequency band" inherently implies non-overlapping frequencies.

2. Claim 7 (Method of Transceiver Operation - Reception):
Claim 7 describes a corresponding method for receiving signals in the two modes.

• The transmission methods taught by Walton '147 directly imply the capability for corresponding reception methods. A PHOSITA would understand that a communication system designed to transmit signals in "single-band" and "multi-band" spatial multiplexing modes would necessarily include receivers capable of receiving these signals in the described manner. Therefore, the reception aspects of Claim 7, mirroring the transmission aspects of Claim 1, would be obvious from Walton '147.

3. Claim 11 (Article of Manufacture - Transmission):
Claim 11 covers a non-transitory computer-readable medium having instructions that, when executed, cause a computing device to perform the transmission operations of Claim 1.

• Given that the method of Claim 1 is rendered obvious by Walton '147, implementing these communication methods in software or firmware stored on a non-transitory computer-readable medium is a conventional engineering practice for controlling transceivers in wireless communication systems. A PHOSITA would find it obvious to implement the disclosed methods using standard programming and hardware control techniques.

4. Claim 18 (Article of Manufacture - Reception at Mobile Station):
Claim 18 covers a non-transitory computer-readable medium having instructions that, when executed, cause a computing device to perform the reception operations of Claim 7, specifically at a mobile station.

• Similarly, if the reception method of Claim 7 is obvious from Walton '147, then embodying these instructions on a computer-readable medium for execution by a computing device, such as one found in a mobile station, would also be obvious to a PHOSITA.

Analysis of Dependent Claims:

• Switching Between Modes (Claims 2, 3, 15, 16): Walton '147's title, "Diversity transmission modes for MIMO OFDM communication systems," suggests the selection or switching between different modes. The disclosure describes how a single-band scheme "is modified to provide a multi-band transmission scheme," implying architectural flexibility for such transitions. A PHOSITA, motivated to optimize performance, would find it obvious to automatically switch between these modes based on operating conditions like signal-to-noise ratio and interference, as these factors directly influence the effectiveness of different transmission schemes and were well-known optimization parameters in wireless communication at the time.
• Same Period of Time for Transmission/Reception (Claims 4, 9, 13, 20): Spatial multiplexing, by definition, involves transmitting or receiving multiple independent data streams simultaneously (i.e., during the same period of time) over distinct spatial channels to increase data rates. This is a fundamental characteristic of spatial multiplexing as described in Walton '147.
• Non-Adjacent Frequencies (Claims 5, 10, 14, 21): While Walton '147 mentions "different frequency band" for the multi-band scheme, it does not explicitly state "non-adjacent." However, the use of non-adjacent frequency channels was a well-known technique in wireless communications prior to 2004 for mitigating interference and efficiently utilizing fragmented or available spectrum, as even acknowledged in the specification of US10103845 ("finding a free or available channel (since there is no requirement that the channels be adjacent)"). A PHOSITA, aiming to optimize channel selection and avoid interference, would find it obvious to utilize non-adjacent frequency bands when implementing the "different frequency bands" of Walton '147.
• Gap Filling (Claims 6, 17): Once multiple, potentially non-adjacent, frequency spectra are utilized (as in the second mode), the concept of "gap filling" with extra subcarriers in the intervening spectrum to increase the composite data rate (as described in US10103845 at) would be an obvious design optimization for a PHOSITA in OFDM systems. OFDM is inherently flexible in subcarrier allocation, and efficiently utilizing all available spectrum for data transmission is a fundamental goal in communication system design.

Conclusion:
All independent claims (1, 7, 11, and 18) of US10103845, along with their dependent claims, are rendered obvious by the teachings of US20030235147A1 (Walton et al.) in combination with the general knowledge of a person having ordinary skill in the art in wireless communication systems at the time of the invention. Walton '147 explicitly describes a MIMO OFDM system capable of both single-band (spatial multiplexing) and multi-band (spatial multiplexing with bandwidth expansion across different, non-overlapping frequency bands) operation, along with the motivation for switching between such modes to enhance spectral efficiency and performance. The remaining features of the dependent claims represent routine engineering choices for optimizing such a system.