摘要:
A wireless node location mechanism that dynamically adapts to changes to a surrounding physical environment that affect the propagation of radio signals. The wireless node location mechanism assesses radio signals from transmitters associated with a wireless node location infrastructure to adjust one or more parameters used to estimate location of a wireless node. In one implementation, path loss exponents are re-computed based on the signals transmitted between infrastructure radio transceivers. These path loss exponents are used, in one implementation, to compute the distance between a wireless node and a given infrastructure radio transceiver and, ultimately, to determine the location of the wireless node based on triangulation. In one implementation, path loss exponents are computed on demand based on the signals observed between infrastructure radios that detect the wireless node whose location is to be estimated.
摘要:
A wireless node location mechanism that defines a search region to optimize the computations associated with estimating the location of a given wireless node. According to one implementation, a coverage map associated with each radio receiver that records signal strength data is defined out to a threshold signal strength level. Before computing the estimated location of a given wireless nodes, a search region is defined based on the intersection of the coverage maps associated with each radio receiver that detects the wireless node. Some implementations use information provided by the fact that certain radio receivers did not detect the wireless node to further optimize the location estimate. By defining a search region, which is a generally small area relative to the space encompassed by an entire RF environment, the present invention provides several advantages, such as reducing the processing time and/or power to compute estimated locations for wireless nodes.
摘要:
Methods, apparatuses, and systems directed to a wireless node location mechanism that uses a signal strength weighting metric to improve the accuracy of estimating the location of a wireless node based on signals detected among a plurality of radio transceivers. In certain implementations, the wireless node location mechanism further incorporates a differential signal strength metric to reduce the errors caused by variations in wireless node transmit power, errors in signal strength detection, and/or direction-dependent path loss. As opposed to using the absolute signal strength or power of an RF signal transmitted by a wireless node, implementations of the present invention compare the differences between signal strength values detected at various pairs of radio receivers to corresponding differences characterized in a model of the RF environment. One implementation of the invention searches for the locations in the model between each pair of radio receivers where their signal strength is different by an observed amount.
摘要:
A wireless node location mechanism that employs a differential signal strength metric to reduce the errors caused by variations in wireless node transmit power, errors in signal strength detection, and/or direction-dependent path loss. As opposed to using the absolute signal strength or power of an RF signal transmitted by a wireless node, implementations of the location mechanism compare the differences between signal strength values detected at various pairs of radio receivers to corresponding differences characterized in a model of the RF environment. One implementation searches for the locations in the model between each pair of radio receivers where their signal strength is different by an observed amount.
摘要:
Methods, apparatuses and systems facilitating the configuration of transmit power and coverage areas corresponding to access points in a wireless network environment. The present invention in one embodiment facilitates the dynamic configuration of coverage boundaries across a plurality of access points, improving the performance of the wireless network environment.
摘要:
Rogue RFID readers are detected by listening to communication between rogue reader and a tag, capturing a time stamp and/or a channel associated with the communication, and checking the captured time stamp/channel to determine whether it is a result of a command from another legitimate reader. Audible or visible alerts may be issued, flags may be set, or messages transmitted to an administrator upon determining the operation of the rogue RFID reader. Based on the alert(s) affected tags or the rogue reader may be jammed or an effect of the illegal transmission by the rogue reader may be reversed or tags replaced.
摘要:
RFID reader systems, readers, components, software and methods can inventory RFID tags in one or more early attempts. Then they can facilitate the inventoried RFID tags to refrain from participating in one or more subsequent inventorying attempts. In some embodiments, an inventoried indicator in the tag becomes updated upon backscattering. The updated value is used by the tag to recognize a subsequent attempt, and thus refrain from participating in it. This permits the subsequent attempt to be used more intensively for inventorying the more elusive, harder-to-read tags, especially in more demanding scenarios.
摘要:
Systems, software, devices, and methods are described for an RFID reader system to communicate with RFID tags. RF energy detected in conjunction with using a selected channel is detected and used to adjust a waveform shaping parameter. The waveform shaping parameter can be additionally stored, and then reconstructed for later use in the same channel. Reconstruction can optionally be also from derived channel performance data. RF waves can be transmitted from the reader to the RFID tags and RF waves can be backscattered from the RFID tags. At least some of the RF waves transmitted to or backscattered from the RFID tags have a waveform with a shape according to the reconstructed waveform shaping parameter.
摘要:
The present invention provides for novel HCV replicon shuttle vectors useful for cloning in HCV polynucleotide sequences from samples of HCV-infected patients and testing the resulting replicons for drug susceptibility.