Obviousness

The prior art analysis for U.S. Patent 7,593,428 indicates that none of the cited references individually anticipate the independent claims. However, an analysis under 35 U.S.C. § 103 requires evaluating whether combinations of these references, driven by a motivation that would have been obvious to a person having ordinary skill in the art (PHOSITA), would render the claimed invention obvious.

The core inventive concept of US7593428 is the creation and processing of a single data packet containing multiple, distinct, and dynamically selectable portions, each protected by its own checksum, with the selection criteria being responsive to communication channel conditions and/or data content type. This extends the functionality of protocols like UDP-Lite, which traditionally only offer a binary choice of protecting an entire payload or none of it.

Obviousness Analysis under 35 U.S.C. § 103

A PHOSITA in the field of packet communication systems, particularly those involved with real-time data transmission over variable communication channels (such as radio environments), would have been motivated to enhance the flexibility and robustness of error detection beyond the limitations of standard UDP or UDP-Lite. The patent's background itself identifies the problem that "Conventional UDP checksum protection provides protection for an entire payload portion of a UDP-formatted data packet or for none of the payload portion of the data packet" and that "errors contained in the unprotected part of the data packet do not cause the data packet to be discarded," which can be problematic for applications. The patent explicitly states the need for improved communications if "a second checksum were provided for the data packet" for an "additional portion of the UDP-Lite data packet." This forms a clear motivation for a PHOSITA to seek solutions for more granular and adaptive error protection.

Combination of Prior Art References:
The claims of US7593428 would likely have been obvious to a PHOSITA by combining the teachings of:

1. U.S. Patent Application 2002/0184598 A1 (Bace): Providing a header checksum for packet data communications.
2. U.S. Patent 7,269,186 B2 (Qualcomm): Protocol for framing a payload.
3. General knowledge in the art regarding dynamic adaptation of communication parameters in response to channel conditions.

Motivation for Combination:

1. Motivation to provide multiple checksums for different portions of data:

   • Bace (US20020184598A1) teaches the concept of applying separate checksums to logically distinct sections of a data packet, specifically a header checksum and a payload checksum. A PHOSITA, seeking to overcome the inflexibility of UDP-Lite's single protected/unprotected payload scheme, would be motivated to extend this concept. Instead of merely a header and a single payload checksum, it would be an obvious step to apply the same principle to multiple sub-portions within the payload itself, thereby allowing finer-grained error detection for different data priorities or sensitivities. This directly addresses the stated problem in US7593428 that a single checksum is insufficient.

2. Motivation to define and delineate these multiple portions within a data packet:

   • Qualcomm (US7269186B2) discloses a framing protocol that segments a payload into one or more frames, with each frame including a header that contains information like its length. A PHOSITA would readily recognize that such a well-known payload segmentation technique could be adapted to define the "multiple portions" within a UDP-Lite payload that are intended to be separately checksum-protected. The "length sub-fields" (104) described in US7593428 and referenced in claims 5 and 9 directly correspond to the length indication found in framing protocols like Qualcomm's.

3. Motivation for dynamic selection based on communication conditions or content type:

   • The background of US7593428 notes the relevance of UDP-Lite for "communications in a radio environment." In such environments, communication channel conditions (e.g., signal-to-noise ratio, interference levels) are inherently dynamic and often unpredictable. It is a fundamental and well-established engineering practice in wireless communication systems to dynamically adapt transmission parameters (such as coding rates, modulation schemes, power control, or retransmission strategies) in response to real-time measurements of channel conditions. A PHOSITA, having conceived of applying granular checksum protection to different parts of a packet (through the combination of Bace and Qualcomm), would be strongly motivated to dynamically adjust which parts are protected, and potentially how they are protected (e.g., selecting different checksum types or covering more extensive portions), based on the prevailing communication conditions or the inherent criticality of the data (content type). This dynamic adaptation would optimize resource utilization by providing appropriate levels of error protection only where and when needed, a standard objective in communication system design. The patent itself highlights this, stating, "Dynamic reselection of the characteristics of the data packet is made, for instance, responsive to measurements of communication conditions upon a communication channel... And, such dynamic reselection of the characteristics of the data is also, or alternately, made responsive to the type of data."

Conclusion:
A PHOSITA, motivated by the recognized limitations of existing UDP-Lite checksumming and the desire for more flexible and robust error handling in dynamic communication environments, would have found it obvious to combine the concept of multiple checksums for distinct logical data units (Bace), with a method for defining and delineating these units within a payload (Qualcomm), and to further integrate the well-known practice of dynamically adapting communication parameters based on channel conditions or data type. This combination would lead directly to the apparatus and methods claimed in US7593428 for forming and operating upon a data packet with multiple, dynamically-selected, checksum-protected parts.