Obviousness — US Patent 9717037

The following analysis addresses the obviousness of US patent 9717037 under 35 U.S.C. § 103, considering the provided patent text, including its "Related Art" section, and the cited prior art references. The analysis assumes a person having ordinary skill in the art (PHOSITA) in wireless LAN systems in June 2012 (the priority date of US9717037). A PHOSITA would be familiar with IEEE 802.11 standards, active scanning procedures, signal strength measurements, path loss calculations, and common wireless network optimization techniques.

General Motivation to Combine Prior Art:

The "Related Art" section of US9717037 explicitly identifies two key problems with conventional active scanning methods:

Waste of time by the station: Even after receiving a probe response from a superior access point (AP), the station waits for the maximum probe response time (Max_Probe_Response_Time) to elapse before requesting access, causing unnecessary delays.
Waste of wireless resources by the access point: APs unconditionally transmit probe response frames in response to every probe request, regardless of the wireless environment or the requesting station's uplink quality.

A PHOSITA would be strongly motivated to combine existing technologies to address these known inefficiencies. The goal would be to improve the speed of station connection, enhance the overall efficiency of the wireless LAN system, and conserve network resources.

Obviousness Analysis for Independent Claims:

1. Claim 1: An active scan method performed by a station
(Generating a probe request frame including signal strength information of the station; transmitting to access points; receiving a probe response frame from a certain access point; and accessing the certain access point based on the probe response frame and a maximum probe response time, implying access before the maximum probe response time elapses).

Prior Art Combination:
- US20120307685A1 (Eun Sun Kim), "Method and Apparatus of Active Scanning in Wireless Local Area Network": This patent, by its title, would teach fundamental active scanning methods, including a station generating and transmitting probe request frames, receiving probe response frames, and the conventional process of selecting an AP within a Max_Probe_Response_Time.
- US20110188486A1 / US8509173B2 (Eun Sun Kim / LG Electronics Inc.), "Method and apparatus of transmit power control in wireless local area network": These patents would disclose mechanisms for transmit power control in wireless networks, and would likely teach how a station's transmit power information can be generated and potentially communicated. It is well-established in wireless communications that devices manage and may report their transmission capabilities, including transmit power.
Motivation to Combine: A PHOSITA, aiming to mitigate the "waste of time" problem identified in US9717037's background, would be motivated to combine the known active scanning method (US20120307685A1) with the concept of incorporating a station's transmit power information (signal strength information) into its transmissions (US20110188486A1/US8509173B2). The motivation would be to enable a station to make a more informed decision regarding AP access. By including its own signal strength in the probe request, and then evaluating this in conjunction with the received probe response, the station could potentially assess the link quality more comprehensively. If a satisfactory link quality is determined (e.g., an AP's probe response indicates a good connection), the station would be motivated to initiate access immediately, without waiting for the entire Max_Probe_Response_Time to expire, thereby directly addressing the identified problem of unnecessary delay. This optimization for faster connection establishment is a common design goal in wireless network protocols.

2. Claim 10: An active scan method performed by a station
(Transmitting a probe request frame; receiving a probe response frame; acquiring information about downlink quality based on signal strength of the probe response frame; and accessing the certain access point based on whether the downlink quality satisfies a predetermined standard and further based on a maximum probe response time).

Prior Art Combination:
- US20120307685A1 (Eun Sun Kim), "Method and Apparatus of Active Scanning in Wireless Local Area Network": This patent would teach the basic active scanning process, including transmitting probe requests and receiving probe responses.
- US20110149766A1 (Electronics And Telecommunications Research Institute), "Association supporting apparatus and method in wireless communication system": This patent, focusing on association, would implicitly involve criteria for selecting an AP for association, which would naturally include evaluating signal quality (downlink quality) against a predetermined standard.
- Common General Knowledge: Measuring received signal strength (RSSI or dBm) from an AP's probe response to determine downlink quality and comparing this against a threshold for AP selection was a well-known and standard practice in WLAN systems.
Motivation to Combine: A PHOSITA, faced with the "waste of time" problem in station connections, would find it obvious to combine standard active scanning (US20120307685A1) with the well-established practice of assessing downlink quality against a standard (US20110149766A1 and general knowledge). The motivation is to allow the station to initiate the access (authentication and association) process to a suitable AP as soon as its downlink quality (derived from the signal strength of the probe response frame) satisfies a predefined standard, without waiting for the full Max_Probe_Response_Time. This direct optimization reduces connection latency and improves the user experience.

3. Claim 13: An active scan method performed by an access point
(Receiving a probe request frame including signal strength information of the station; acquiring information about uplink quality based on the signal strength information; transmitting a probe response frame to the station based on whether the uplink quality satisfies a predetermined standard; and granting access to the station based on the probe response frame and a maximum probe response time).

Prior Art Combination:
- US20120307685A1 (Eun Sun Kim), "Method and Apparatus of Active Scanning in Wireless Local Area Network": This patent would disclose an AP's role in active scanning, including receiving probe requests and transmitting probe responses.
- US20110188486A1 / US8509173B2 (Eun Sun Kim / LG Electronics Inc.), "Method and apparatus of transmit power control in wireless local area network": These patents would teach the communication of transmit power information in a wireless network. It would be obvious for a PHOSITA to include a station's transmit power information within a probe request frame.
- US20100284303A1 (Qualcomm Incorporated), "Method and apparatus for generating and exchanging information for coverage optimization in wireless networks": This patent, focused on coverage optimization, would likely describe using signal quality metrics (including uplink) to manage network resources and improve performance. This would include an AP assessing uplink quality based on received signals.
- Common General Knowledge: The concept of an AP receiving a signal from a station and determining uplink quality (e.g., path loss) from the received signal strength and the station's known transmit power was well-understood in wireless networking. The need to conserve wireless resources by avoiding unnecessary transmissions was also a known problem.
Motivation to Combine: A PHOSITA, seeking to prevent the "waste of wireless resources" by APs unconditionally responding to probe requests (as highlighted in US9717037's background), would be motivated to combine the active scanning process (US20120307685A1) with mechanisms for transmit power control (US20110188486A1/US8509173B2) and principles of coverage/resource optimization (US20100284303A1). It would be obvious to a PHOSITA to design the probe request frame to include the station's transmit power. Upon receiving this, it would be a straightforward engineering task for the AP to acquire uplink quality information (e.g., uplink path loss) by comparing the station's reported transmit power with the received signal strength of the probe request. To conserve resources and optimize coverage, it would then be obvious for the AP to transmit a probe response frame only if the calculated uplink quality satisfies a predetermined standard. This conditional response mechanism directly solves the problem of unconditional responses, thereby preventing wasted wireless resources. The subsequent "granting access" is a natural outcome if the AP chooses to respond, allowing the station to proceed with the connection.

In conclusion, the independent claims of US9717037 describe a method that, while offering practical improvements to WLAN active scanning efficiency, would have been obvious to a PHOSITA in light of the cited prior art and common general knowledge in wireless communication. The motivations to reduce wasted time and wireless resources were well-known problems that these combinations of existing techniques logically address.