Obviousness

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

To determine the obviousness of US Patent 7310537, we must consider whether the claimed invention, as a whole, would have been obvious to a person having ordinary skill in the art (POSA) at the time of the invention (i.e., before the filing date of August 13, 2003), given the prior art. This involves identifying potential combinations of prior art references and explaining the motivation a POSA would have had to combine them, with a reasonable expectation of success.

The independent claims of US7310537 revolve around a method and system for multi-beam wireless communication where:

1. Beam identity information is included in signals transmitted on multiple beams from a first station.
2. A second station receives these signals and identifies the beams based on the identity information.
3. At least one beam is selected for transmission, specifically a set of "geometrically distinguished" beams.

Identified Prior Art References (from the patent document):

The patent US7310537 itself cites the following prior art documents:

• US5894598A: Radio communication system using portable mobile terminal
• US6377636B1: Method and wireless communications system using coordinated transmission and training for interference mitigation
• US6473467B1: Method and apparatus for measuring reporting channel state information in a high efficiency, high performance communications system
• US6745050B1: Multichannel multiuser detection
• US6754475B1: Transmission performance measurement and use thereof
• US6850741B2: Method for selecting switched orthogonal beams for downlink diversity transmission
• US6970682B2: Wireless packet switched communication systems and networks using adaptively steered antenna arrays
• US7020110B2: Resource allocation for MIMO-OFDM communication systems

Motivation to Combine Prior Art References

A person having ordinary skill in the art (POSA) in wireless communication systems, particularly those involving multi-antenna or multi-beam technologies, would be motivated to improve spectral efficiency, reduce interference, and enhance link capacity. The "Background of the Invention" section of US7310537 explicitly outlines these problems, stating that conventional fixed multiple beam arrangements suffer from issues like neighboring beam interference and difficulty in distinguishing between different signal propagation paths based solely on power measurements.

The motivation to combine elements from various prior art references would stem from the desire to overcome these known problems in multi-beam communication systems, particularly to achieve more intelligent and efficient beam selection.

Potential Obviousness Combinations:

Let's consider how a POSA might combine some of the cited prior art to arrive at the independent claims of US7310537.

Combination 1: US6970682B2 + US6377636B1 + General Knowledge of Beam Identification

• US6970682B2 (Vivato, Inc.): This patent describes "Wireless packet switched communication systems and networks using adaptively steered antenna arrays." This reference would teach the use of multiple beams (adaptively steered antenna arrays) for wireless communication between stations. It implicitly involves the transmission of signals on these multiple beams.
• US6377636B1 (Iospan Wirless, Inc.): This patent describes a "Method and wireless communications system using coordinated transmission and training for interference mitigation." This reference teaches methods for coordinating transmissions and using training sequences (e.g., pilot signals) to mitigate interference. A POSA would understand that training sequences or pilot signals can carry identifying information.
• Motivation to Combine: A POSA, observing the problems of interference and inefficient beam selection in multi-beam systems (as articulated in the background of US7310537), would be motivated to improve the process of identifying and selecting beams. By combining the adaptively steered beams of US6970682B2 with the training/coordination aspects of US6377636B1, a POSA would naturally consider embedding identifying information within the pilot signals or training sequences of each beam. This beam identity information would help distinguish individual beams, especially in systems with overlapping beams or complex propagation environments, addressing the "difficulty in determining whether the signals propagate as shown in FIG. 5 or as shown in FIG. 6" problem highlighted by US7310537. The selection of "geometrically distinguished beams" would follow logically from the desire to optimize performance and mitigate interference by selecting beams corresponding to distinct propagation paths, a known goal in multi-beam systems.

Combination 2: US6850741B2 + US6473467B1 + US6754475B1

• US6850741B2 (Agency For Science, Technology And Research): This patent details a "Method for selecting switched orthogonal beams for downlink diversity transmission." This directly teaches selecting beams for transmission, and the concept of "orthogonal beams" suggests a desire to distinguish between them for diversity.
• US6473467B1 (Qualcomm Incorporated): This patent describes a "Method and apparatus for measuring reporting channel state information in a high efficiency, high performance communications system." This reference teaches measuring and reporting channel state information (CSI), which often includes information about signal quality and characteristics that could be used for beam selection.
• US6754475B1 (Motorola, Inc.): This patent describes "Transmission performance measurement and use thereof." This reinforces the concept of measuring performance and using that information, which could be related to channel characteristics or beam quality.
• Motivation to Combine: A POSA seeking to optimize beam selection (as in US6850741B2) would recognize that more granular information about each beam's characteristics would be beneficial. By integrating the channel state information (US6473467B1) or transmission performance measurements (US6754475B1) with the beam selection process, a POSA would be motivated to associate unique identifiers with each beam to enable precise reporting and selection. The idea of "geometrically distinguished beams" would be an inherent consideration when dealing with diversity transmission and optimizing channel usage, as different geometries naturally lead to different channel characteristics that would be measured and reported. Encoding identity information into pilot signals (a common practice, also generally known in the art and mentioned in US7310537) would be a straightforward way to enable the receiving station to distinguish these beams and report back appropriate selection information.

General Considerations for Obviousness:

• Known Problem: The problems of interference from neighboring beams and the difficulty of distinguishing signal paths in multi-beam systems were known in the art prior to the filing date of US7310537. The patent itself articulates these problems, which provides a strong motivation for a POSA to seek solutions.
• Finite Number of Identifiers: The use of "beam identity information" is a straightforward solution to distinguish between multiple beams, especially in the context of pilot signals. This is analogous to using different spreading codes for different channels in CDMA or different time slots in TDMA, which were well-established techniques for differentiation in wireless communication systems.
• "Geometrically Distinguished Beams": The concept of geometrically distinguished paths is fundamental to understanding radio propagation and multi-path environments. Selecting beams based on their geometric distinction would be an intuitive step for a POSA aiming to maximize diversity gain, minimize interference, and improve overall system performance in a multi-beam system. This isn't necessarily a novel concept but rather an application of known principles to optimize beam selection.

Based on the above, a POSA, motivated by the recognized problems in multi-beam wireless communication, would have found it obvious to combine existing teachings of multi-beam transmission, training sequences/pilot signals, channel state information, and beam selection strategies with the straightforward idea of associating unique identifiers with individual beams to enable more intelligent and efficient selection of geometrically distinguished beams.