Cisco Technology, Inc.

Evgeny Yankevich

Matthew Aaron Silverman

Paul Jeffrey Stager

Fred Jay Anderson

John Matthew Swartz

Jack Chuang

Zhigang Gao

Tak Ming Pang

Huaiyi Wang

Ashish Pasha Sheikh

Matt Silverman

Michael B Delong

Arnab Sengupta

Techniques for identifying potentially interfering wireless incumbents are disclosed. These techniques include receiving, from an electronic repository, a list of one or more wireless devices operating in a wireless communication band used by a wireless communication network. The list is selected from a plurality of wireless devices operating in the wireless communication band, based on a geographical location relating to the wireless communication network. The techniques further include scanning a plurality of radio channels relating to the wireless communication band, and identifying an interfering device for the wireless communication network based on comparing spectral data from the scanning with data in the list of one or more wireless devices.

Interference classification of wireless incumbents using spectral analysis and AFC query

Methods and systems for distinguishing between radar signals and Wi-Fi signals are provided. When a set of electromagnetic signals are received, various tests are performed on the signals to determine if the signals are associated with radar pulses or if the signals are more likely to be associated with stray Wi-Fi signals or other non-radar interference. One such test relies on the relatively small variance of frequencies used by radar pulses when compared to the high variation of Wi-Fi signals. Another test relies on the relatively low peak to average power ratio of signals associated with radar pulses when compared to Wi-Fi signals. The tests described herein are an improvement on existing methods for distinguishing radar signals from Wi-Fi signals and result in less switching of Wi-Fi channels due to erroneously detected radar signals.

Systems and methods for reducing false radar detection

Dynamic automatic gain controller configuration in multiple input and multiple output receivers is provided by monitoring a given section of wireless spectrum for higher-priority signals using a first antenna set associated with a first Automatic Gain Controller (AGC) set while concurrently monitoring the given section of wireless spectrum for wireless packet-based traffic using a second antenna set associated with a second AGC set; in response to detecting a packet via the second antenna set: re-associating the first antenna set and the second antenna set to a third AGC set; receiving the packet via the first antenna set and the second antenna set using the third AGC set; and in response to the packet being received, re-associating the first antenna set to the first AGC set and the second antenna set to the second AGC set.

Dynamic automatic gain controller configuration in multiple input and multiple output receivers

A wireless node in a wireless communication network. The wireless node includes one or more interfaces configured to receive wireless transmissions, a memory comprising instructions, and a hardware processor. The wireless node samples a received wireless transmission into a plurality of time-based subdivisions for each subdivision of the wireless transmission the wireless node determines a cross-correlation between the subdivision and a local syncword. The local syncword is constructed to correlate to any primary synchronization signal, PSS, of a plurality of PSSs defined for synchronization in the wireless network. The wireless node, based on the cross-correlation, determines whether one PSS of the plurality of PSSs is present in the subdivision of the wireless transmission.

Detection and decoding of wireless synchronization signals

A pseudo low intermediate frequency (IF) configuration is provided for a receiver having a zero IF radio architecture dedicated for radar detection, in order to reduce false radar detection. Energy from local oscillator leakage is shifted away from DC. After filtering out of the desired sub-channel, the local oscillator leakage energy is suppressed, reducing false radar detection.

Pseudo low IF for zero IF receiver to reduce dynamic frequency selection (DFS) falsing

In a shared radio frequency (RF) band, regulations or standards can stipulate that a device using an RF channel must vacate the RF channel if another device having priority to the channel is detected. It takes time, however, to move channels and this added time reduces the effective speed of the communication. In some cases, a received signal from the other device may be received on the channel when the other device is not, in fact, operating on the channel. These received signals can lead the device to move channels, thereby slowing communications unnecessarily. Accordingly, disclosed herein are a system and method for checking the characteristics of a received signal's spectrum to determine if the source of the received signal is on-channel or off-channel. This determination may be used to minimize the device from taking unnecessary interference avoidance measures, such as dynamic frequency selection.

System and method for identifying an off-channel radio frequency source

In one embodiment, a method implemented on an access point of a wireless communication system includes: determining an estimate for a relative velocity between a mobile wireless client device and the access point, the mobile wireless client device communicating wirelessly with the access point over a channel; determining a channel coherence time for the channel using said estimated relative velocity; and determining a maximum aggregated frame size based on the determined channel coherence time.

Aggregation mechanism for moving vehicles

Dynamic frequency selection (DFS) is often a requirement for a wireless local area network (WLAN) apparatus to prevent the apparatus from interfering with other systems that have a priority to a radio frequency (RF) channel. When DFS is executed, the WLAN apparatus ceases WLAN operations on the channel and searches for an open channel to resume WLAN operations. Often a WLAN apparatus misinterprets signals from another system as operating on the channel when actually the received signals are signals leaked into the channel from a system transmitting on a different channel. Presented herein are methods and apparatuses for preventing unnecessary DFS operations resulting from misinterpreted signals through the use of a signal to noise ratio determined from a pulse spectral density of the received signal.

Dynamic frequency selection with discrimination

Access points and a wireless client device, such as a workgroup bridge, are configured to optimize a roaming algorithm of the client device for a high-speed vehicle scenario, such as a high-speed train. A static/dynamic neighbor list is generated and used to improve scanning efficiency. An improved parent access point selection procedure, metrics, and thresholds are provided to optimize client roaming along the vehicle's path, e.g., the train track.

Growing community of inventors

Beachwood, OH, United States of America

Evgeny Yankevich