Obviousness

Obviousness Analysis of US Patent 9271243 under 35 U.S.C. § 103

This analysis identifies combinations of prior art references that would render the independent claims of US patent 9271243 obvious to a person having ordinary skill in the art (PHOSITA), along with the motivation for such combinations. The core innovation claimed by US9271243 lies in a centralized control device that manages wireless access point (AP) output strength to minimize interference, particularly for APs operating on the same channel, overcoming the inefficiencies of individual AP adjustment found in prior art.

The background of US9271243 explicitly references and identifies a problem with Korean Patent Publication 2006-0034461 (corresponding to KR100621592B1). The stated problem is that KR100621592B1 requires "the sub-AP itself needs to adjust the transmission power," making it "impossible and inefficient to minimize the interference within a short period of time" when multiple sub-APs use the same channel. This directly highlights the central control and coordinated adjustment as key differentiating features of US9271243.

Prior Art Combination 1: KR100621592B1 in view of US7715353B2 or US7653357B2

References:

• KR100621592B1: "Sub-access point, system and method for regulating power of transmission signal." This reference teaches a sub-AP that adjusts its transmission power based on received signal strength indicator (RSSI) readings and frame error rate (FER) from a main AP to eliminate shadow areas and minimize interference.
• US7715353B2: "Wireless LAN cell breathing." This patent describes a method for wireless access points to dynamically control their transmit power to provide desired coverage within a WLAN, where "a central entity controls cell sizes to avoid co-channel and adjacent-channel interference" by adjusting transmit power based on RSSI measurements and a desired coverage area.
• US7653357B2: "Access point interference control and selection methods." This patent describes a "centralized control of multiple APs in a WLAN environment is capable of distributing channels and transmission powers among the APs" for controlling transmission parameters based on interference.

Motivation for Combination:
A PHOSITA, aiming to improve the efficiency and coordination of interference management in a wireless network where multiple APs operate on the same channel, would be motivated to combine the local power adjustment techniques of KR100621592B1 with the centralized control mechanisms described in US7715353B2 or US7653357B2. The explicit problem stated in US9271243 regarding KR10061592B1 (inefficiency due to individual AP adjustment) directly points to the need for a coordinated, centralized approach. It would be obvious to integrate local AP capabilities into a broader system where a central entity manages multiple APs for optimal interference reduction.

Obviousness Analysis of Independent Claims:

Claim 1: Device for controlling a wireless access point

• Grouping unit configured to group wireless access points using a same channel based on channel use information received from the wireless access points: US7653357B2 teaches centralized control that is "capable of distributing channels and transmission powers among the APs." This inherently implies the central controller is aware of and groups APs by their channel use. A PHOSITA would find it obvious to group APs by their operating channel as a logical step for managing co-channel interference effectively.
• Map generator configured to compute a received signal strength indicator (RSSI) between the grouped wireless access points and an output strength value for each of the grouped wireless access points: KR10061592B1 teaches adjusting transmission power based on RSSI. US7715353B2 teaches a central entity adjusting transmit power "based on a received signal strength indicator (RSSI) measurement for each AP." Given that APs have output strength values (common in wireless communication) and measure RSSI (KR10061592B1, US7715353B2), it would be obvious for a central controller (US7715353B2, US7653357B2) to collect and organize this information, conceptually forming a "virtual map," to make informed decisions about power adjustments.
• Extractor configured to extract a wireless access point having a highest RSSI value among the grouped wireless access points, if interference occurs between the grouped wireless access points: The goal of interference minimization (KR10061592B1, US7715353B2) naturally leads to identifying the strongest source of interference to target remedial action. If interference is detected, identifying the AP with the highest RSSI value is a straightforward and obvious method for a central controller to pinpoint the primary interferer.
• Optimal output strength value-calculator configured to compute a corrected output strength value based on the highest RSSI value of the extracted wireless access point, a predetermined threshold value of the RSSI between the grouped wireless access points, and a currently used output strength value: KR10061592B1 teaches adjusting power based on RSSI. US7715353B2 states that transmit power is adjusted based on RSSI and a "desired coverage area," which implies a target signal strength or threshold. The calculation of a corrected output strength value based on a measured RSSI, a threshold, and current power is a well-known feedback control mechanism in power management algorithms.

Claim 6: Wireless access point

• A channel setter configured to set a channel for communication: This is a fundamental component of any wireless access point, including the sub-AP described in KR10061592B1.
• An information transmitter configured to search for neighboring wireless access points through the set channel and transmit information on the searched neighboring wireless access points and the wireless access point: The necessity for APs to discover neighbors and exchange information is inherent in any multi-AP wireless network and for systems like those described in KR10061592B1 (which interacts with a "main AP") and the centralized systems of US7715353B2 and US7653357B2. A PHOSITA would find this a standard AP function.
• A calculator configured to compute a number of ACK communication failures with a wireless terminal and a received signal strength indicator (RSSI) value, once the wireless terminal is connected: KR10061592B1 explicitly teaches power adjustment based on "received signal strength indicator (RSSI) readings and frame error rate (FER)." FER is directly related to ACK communication failures, making this element directly taught by KR10061592B1.
• An interference occurrence notifier configured to transmit a message indicating that interference has occurred, to the device for controlling the wireless access point if it is determined that the interference with the neighboring wireless access points has occurred, based on the computed number of ACK communication failures with the wireless terminal and the RSSI value: Given that KR10061592B1's AP can determine interference locally, and that US7715353B2 and US7653357B2 teach centralized control of APs for interference management, it would be obvious for an AP detecting interference to report this information to the central controlling device to enable coordinated action. This is a common implementation of a client (AP) reporting status to a controller.

Claim 11: Method for controlling an output strength value

• (a) setting a channel for communication, searching for neighboring wireless access points, and transmitting information on the wireless access point and the searched neighboring wireless access points to the device for controlling the wireless access point, wherein the setting, searching and transmitting is performed by the wireless access point: These steps represent standard AP functionalities necessary for an AP to operate and participate in a managed wireless network, as discussed for Claim 6.
• (b) grouping wireless access points using a same channel, based on the information on the wireless access point and the neighboring wireless access points received from the wireless access point, the grouping being performed by the device for controlling the wireless access point: As explained for Claim 1, US7653357B2 teaches a central controller managing APs and distributing channels. Grouping by channel is a logical and obvious step for a central device to efficiently manage interference.
• (c) determining whether interference has occurred between the grouped wireless access points and transmitting the determination to the device for controlling a wireless access point, the determining and the transmitting the determination being performed by the grouped wireless access points: KR10061592B1 teaches an AP determining interference. In a centralized system (US7715353B2, US7653357B2), it is obvious for APs to report their local interference status to the central controller to enable coordinated action.
• (d) computing a corrected output strength value for reducing the interference and transmitting the corrected output strength value to the grouped wireless access points, the computing and the transmitting the corrected output strength being performed by the device for controlling the wireless access point: US7715353B2 teaches a central entity adjusting transmit power based on RSSI to avoid interference. US7653357B2 teaches centralized control of transmission powers. The computation of a corrected value for reducing interference by a central controller is a fundamental aspect of centralized network management and optimization.
• (e) adjusting a current output strength value based on the corrected output strength value, the adjusting being performed by the grouped wireless access points: KR10061592B1 teaches an AP adjusting its transmission power. Receiving and implementing a power adjustment command from a central controller is a standard client-server interaction in network management and an obvious way for the APs to respond to the centralized control.

Therefore, a PHOSITA would find it obvious to combine the teachings of KR10061592B1 with either US7715353B2 or US7653357B2 to arrive at the inventions claimed in US9271243. The motivation would be to overcome the inefficiencies of individual AP power adjustment by implementing a more coordinated and effective centralized interference management system.