Obviousness

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

A patent claim is unpatentable if the differences between the claimed invention and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art (PHOSITA). A PHOSITA is a hypothetical person who possesses the ordinary skills and knowledge in a particular technical field and is also a person of ordinary creativity. The analysis involves identifying the scope and content of the prior art, ascertaining the differences between the prior art and the claims, and determining whether a PHOSITA would have found the claimed invention obvious.

The priority date for US 10051556 is June 28, 2012. Therefore, the relevant prior art would be anything publicly available before this date.

Person Having Ordinary Skill in the Art (PHOSITA):
In the context of US 10051556, a PHOSITA would be an engineer or technician with practical experience in wireless local area network (WLAN) systems, familiar with IEEE 802.11 standards, active scanning procedures, and the mechanisms for communication between stations and access points. They would understand concepts like probe request/response frames, SSIDs, transmission power, received signal strength, and path loss.

Prior Art References:

1. US20120307685A1 (Kim): "Method and Apparatus of Active Scanning in Wireless Local Area Network" (Publication Date: December 6, 2012; Priority Date: January 20, 2010). Although published after the priority date of US '556, its priority date is earlier, making it relevant prior art. Kim describes active scanning in a WLAN, addressing the issue of stations waiting for a maximum probe response time.
2. US20110188486A1 (Kim et al.): "Method and apparatus of transmit power control in wireless local area network" (Publication Date: August 4, 2011; Priority Date: February 2, 2010). This reference teaches transmit power control in WLANs and the inclusion of transmission power information in frames.
3. US20130294354A1 (Interdigital Patent Holdings, Inc.): "Enhanced active scanning in wireless local area networks" (Publication Date: November 7, 2013; Priority Date: May 3, 2012). This patent application describes enhanced active scanning techniques. Although published after the priority date of US '556, its priority date is earlier, making it relevant prior art.
4. US20050227623A1 (Micro-Star Int'l. Co., Ltd.): "Wireless network service provider and associated channel-searching method" (Publication Date: October 13, 2005; Priority Date: March 19, 2004). This reference broadly discusses wireless network scanning and access point selection.
5. CA2620318A1: "Passively scanning according to WLAN regulatory domain" (Publication Date: July 23, 2008). This document describes both passive and active scanning methods in WLANs, noting that in active scanning, a device transmits an active probe request and may receive probe responses.
6. IEEE 802.11-2012 Standard: This standard provides the fundamental framework for WLANs, including active scanning procedures and the structure of probe request/response frames.

Obviousness Combinations and Rationales:

Combination 1: US20110188486A1 (Kim et al.) in view of general knowledge of IEEE 802.11 active scanning (e.g., from CA2620318A1 and IEEE 802.11-2012)

• Claim 1 Analysis: Claim 1 of US 10051556 describes a method for active scanning by a station, comprising: transmitting a probe request frame including signal strength information; receiving a probe response frame; the probe response being transmitted based on the signal strength information; and the station accessing the AP based on the probe response and a maximum probe response time.

  • US20110188486A1 (Kim et al.) teaches including transmission power information (a type of signal strength information) in frames for transmit power control in WLANs.
  • CA2620318A1 describes active scanning where a device transmits a probe request and receives probe responses.
  • The IEEE 802.11-2012 standard details the structure of probe request and response frames and the active scanning process.
  • A PHOSITA would be motivated to combine these references to optimize the active scanning process. Knowing that signal strength (like transmission power) is crucial for connection quality, it would be obvious to a PHOSITA to include this information in a probe request frame, as taught by US20110188486A1, to enable the access point to make a more informed decision about responding. The motivation would be to improve the efficiency and quality of initial access and resource allocation. Having the AP transmit a probe response based on this information (e.g., if the uplink quality, derived from the station's signal strength, is sufficient) and allowing the station to access the AP before a maximum probe response time elapses, as generally aimed for in active scanning, would be a logical refinement. The concept of a maximum probe response time is inherent to active scanning as described in the background of US 10051556 and in general IEEE 802.11 practices, where a station waits for responses for a certain duration. Therefore, basing the station's access decision on both the probe response and this existing time constraint would be obvious.

• Claim 9 Analysis: Claim 9 focuses on the access point's perspective, involving receiving the probe request with signal strength, transmitting a response based on that signal strength, and the station's access being based on the response and maximum probe response time.

  • As established above, including signal strength in a probe request (from US20110188486A1) and active scanning with probe requests/responses (from CA2620318A1 and IEEE 802.11-2012) are known. A PHOSITA would recognize that if a station sends signal strength information, an access point could use this information to decide whether or not to respond, for instance, to conserve wireless resources or to only respond to stations with a potentially good uplink quality, as identified in the background of US 10051556 as a problem with the related art. This would be a routine design choice to improve network efficiency. The final step regarding the station's access being based on the response and maximum probe response time is the natural outcome of the active scanning process.

• Claims 10 and 11 Analysis: These claims describe a station and an access point configured to perform the methods of Claims 1 and 9, respectively.

  • The configuration of devices (transceivers and processors) to implement known communication protocols and methods, including those described in Claims 1 and 9, would be obvious to a PHOSITA. The inclusion of hardware and software to send/receive specific frame types and to process information contained within them, such as signal strength information, is a matter of routine engineering design for anyone skilled in the art of WLAN device development.

Combination 2: US20130294354A1 (Interdigital) in view of US20110188486A1 (Kim et al.)

• Claim 1 Analysis (and dependent claims): US20130294354A1 teaches enhanced active scanning in wireless local area networks, and US20110188486A1 teaches including transmission power information in frames. A PHOSITA would be motivated to enhance the active scanning methods described in US20130294354A1 by incorporating the transmission power information from US20110188486A1 into probe request frames. This combination would allow for more intelligent decision-making by both the station and the access point regarding connection establishment, leading to improved efficiency, which is a common goal in WLAN optimization. For example, if an enhanced scanning method aims to find the "best" AP, providing the AP with the station's transmission power would allow the AP to better assess uplink quality.

• Claim 6 (Dependent on Claim 1): Claim 6 adds acquiring downlink path loss and accessing the AP if it satisfies a predetermined standard.

  • The concept of calculating path loss (difference between transmission power and received signal strength) is fundamental in wireless communication. US20110188486A1 explicitly mentions transmit power control. A PHOSITA would know how to use the received signal strength of a probe response frame and the AP's transmission power (which could be known or included in the probe response) to calculate downlink path loss. Determining whether this path loss satisfies a predetermined standard for access is a common practice for evaluating link quality.

• Claim 7 (Dependent on Claim 6): Claim 7 states that the probe response frame includes target path loss information as the predetermined standard.

  • It would be an obvious design choice for an access point, when responding to a probe request, to include its desired or "target" path loss information in the probe response frame. This allows the station to directly compare its calculated downlink path loss against the AP's preferred standard, streamlining the access decision. This practice of APs providing network parameters to guide station behavior is well-known in WLANs.

Conclusion on Obviousness:

The independent claims of US 10051556 appear to be obvious in light of the prior art and the knowledge of a person having ordinary skill in the art at the time of the invention (before June 28, 2012). The core inventive concepts—including signal strength in probe request frames for more efficient active scanning, and APs responding based on this information, leading to quicker station access—are logical extensions and combinations of existing WLAN technologies and problem-solving approaches. A PHOSITA would have been motivated to combine the references to improve the efficiency of active scanning and resource utilization in WLAN systems, addressing the known problems of wasted time and wireless resources during the scanning process, as highlighted in the background section of US 10051556.