Obviousness

Obviousness Analysis of US Patent 6,961,310 under 35 U.S.C. § 103

This analysis identifies combinations of prior art references that would render the independent claims of US Patent 6,961,310 obvious to a person having ordinary skill in the art (POSITA) at the time of the invention (priority date August 8, 2002). The motivation for combining these references stems from the well-known challenges and desired improvements in mobile ad hoc network (MANET) routing, explicitly articulated in the background section of US6961310 itself.

The patent US6961310 aims to improve upon conventional reactive routing protocols like Dynamic Source Routing (DSR) and Ad Hoc On-Demand Distance Vector (AODV). The background notes that conventional DSR "finds multiple paths, but it only uses a single path for the transmission of message data/mission traffic," and that "Conventionally, AODV finds a single path." It further highlights that "Failure of the primary path often results in significant delay" and that "Quality-of-service (QoS) routing in mobile ad hoc networks is gaining interest," requiring protocols to "not only to find a route but also to secure the resources along the route." These statements provide clear motivation for a POSITA to seek solutions that enable multi-path routing, utilize advanced link metrics for route selection, and incorporate QoS considerations into reactive ad hoc network protocols.

Combination of Prior Art References

A strong case for obviousness can be made by combining:

1. US5754543A to Alcatel Data Networks, Inc. (Alcatel): Entitled "Connectivity matrix-based multi-cost routing," this patent teaches evaluating and routing based on multiple "costs" or metrics, rather than a single metric like hop count.
2. US5832197A to NEC Corporation (NEC): Entitled "Alternate routing by increasing initially low QOS value of a selected alternate path during failure to user-specified value," this patent teaches QoS routing, the use of alternate paths, and dynamic adjustments during failure, all with a focus on QoS values.
3. General knowledge of reactive ad hoc routing protocols (e.g., DSR and AODV): As described in the background of US6961310, DSR is known to discover multiple routes, and both DSR and AODV use route request/reply mechanisms and have error notification (RERR) processes.

Obviousness Argument for Independent Claim 1 (Method with Route Confirmations)

Claim 1 describes a method including route discovery, intermediate node resource assessment/reservation, destination replies, ranking routes by link metric, selecting a plurality of routes, sending route confirmations, and distributing data along these routes.

A POSITA, motivated by the shortcomings of conventional DSR/AODV and the growing interest in QoS routing in MANETs (as stated in US6961310's background), would find the steps of Claim 1 obvious through the following combination:

• Transmitting a route request to discover routing: This is a fundamental step in reactive routing protocols like DSR and AODV, which are explicitly mentioned in US6961310's background. US5987011A (Toh) also describes routing methods for ad-hoc networks involving route discovery.
• Intermediate node determining support, forwarding, and temporarily reserving node resources: NEC (US5832197A) teaches using "QOS value" for path selection and using "alternate paths" in a QoS context. A POSITA familiar with QoS routing (which US6961310 acknowledges as "gaining interest," citing Zhu and Mirhakkak et al. for QoS approaches involving resource reservation) would understand that intermediate nodes in a QoS-aware ad hoc network would need to assess and temporarily reserve resources for requested routes.
• Destination generating a reply for each discovered route: The background of US6961310 states that "Conventional DSR finds multiple paths." This inherently suggests that a destination could receive route requests via multiple paths and generate replies corresponding to each.
• Ranking discovered routes according to at least one link metric: Alcatel (US5754543A) explicitly teaches "multi-cost routing," which directly maps to ranking routes based on multiple link metrics. The specific metrics (link delay, capacity, available capacity, and reliability), as claimed in US6961310, are standard parameters considered in QoS routing (as understood by a POSITA, especially given NEC US5832197A's focus on QoS value).
• Selecting a plurality of routes based upon the ranking: Given that DSR already discovers multiple paths (US6961310 background) and Alcatel teaches ranking these paths by multiple costs (US5754543A), a POSITA aiming to improve network reliability and load balancing would find it obvious to select not just one, but a plurality of the best-ranked routes. This directly addresses the stated problem in US6961310 that DSR "only uses a single path."
• Transmitting route confirmations to intermediate nodes on the plurality of selected routes: This step logically follows the intermediate node's temporary resource reservation and the selection of QoS-enabled routes. Confirming resource usage is a standard practice in QoS signaling, as evident from the QoS approaches cited in US6961310's background (Zhu, Mirhakkak et al.) and NEC's QoS teaching (US5832197A).
• Distributing the message data to the destination node along the plurality of discovered routes: With multiple ranked routes selected for improved performance (as motivated by US6961310's background), distributing data across these routes for load balancing, reliability, or timeliness (e.g., distributing duplicate data or different portions, as mentioned in the patent) is a well-known engineering solution in networking.

Obviousness Argument for Independent Claim 13 (Method for Simultaneously Distributing Message Data)

Claim 13 describes discovering routes, ranking them by link metric, and simultaneously distributing message data along a plurality of these routes based on ranking. This claim builds directly on the concepts made obvious for Claim 1, with an emphasis on simultaneous distribution.

• Discovering routing to the destination node: As discussed for Claim 1.
• Ranking discovered routes according to at least one link metric: As discussed for Claim 1, taught by Alcatel (US5754543A) for "multi-cost routing."
• Simultaneously distributing the message data to the destination node along a plurality of the discovered routes based upon the ranking: Given the prior art's teaching of multi-cost routing (Alcatel US5754543A) and the recognized desire to utilize multiple paths for load balancing and reliability (explicitly stated in US6961310's background as an improvement over DSR/AODV), it would be an obvious design choice for a POSITA to simultaneously distribute data across these multiple, ranked paths. Techniques for splitting and distributing data across multiple paths for throughput or redundancy were known in the art of networking.

Obviousness Argument for Independent Claim 25 (Mobile Ad Hoc Network System)

Claim 25 defines a mobile ad hoc network system with specific units (route discovery, route ranking, message data distribution) that implement the methods of Claims 1 and 13.

The system described in Claim 25 would be an obvious implementation of the methods made obvious by the combination of prior art. A POSITA would readily understand how to implement a "route discovery unit," a "route ranking unit" that uses multiple link metrics (based on Alcatel US5754543A), and a "message data distribution unit" that simultaneously distributes data across multiple ranked routes, using standard hardware and software components available at the time of invention. The functions of these units directly correspond to the method steps deemed obvious above.

Conclusion

The independent claims of US Patent 6,961,310 would have been obvious to a person having ordinary skill in the art in light of a combination of US5754543A (Alcatel), US5832197A (NEC), and general knowledge of reactive ad hoc routing protocols like DSR and AODV (as explicitly detailed in US6961310's own background). The motivation to combine these references arises from the recognized need to improve the reliability, timeliness, and load balancing of MANET routing, particularly by overcoming the limitations of single-path or underutilized multi-path reactive protocols and incorporating QoS considerations, which were identified problems and goals in the field at the time.