Microsoft Technology Licensing, LLC

Guobin (Jacky) Shen

Yongqiang Xiong

Thomas Moscibroda

Feng Zhao

Yongguang Zhang

Chunshui Zhao

Some implementations include identifying a location for a device perceived landmark. The location is identified by monitoring received signal strength of a signal of a wireless access point, detecting the location at which the trend in the received signal strength changes direction, and qualifying the location based on measurements taken form one or more inertial measurement unit sensors.

Crowd sourced pathway maps

Techniques for indoor location-finding are described herein. Inside buildings, anomalies in the Earth's magnetic field may be caused by the buildings' structures. These anomalies tend to be location specific and temporally stable. Accordingly, a database or map may be constructed of field strength measurements, and made available to clients, either online (e.g., through cloud services) or offline. As a user carrying a portable device walks within a building, magnetic field measurements may be made. The measurements may be configured in as vectors and compared to the database. A specific location may be indicated by anomaly information seen in both the vector(s) and database. Optionally, techniques may be combined with a particle filter that may be operated step-by-step as the user moves within the building. In another option, fusion with Wi-Fi signals may be performed, such as with a two-pass bidirectional particle filtering.

Indoor location-finding using magnetic field anomalies

Hybrid tree/mesh overlays for data delivery involve using a tree overlay network and a mesh overlay network to delivery a data stream via a push mechanism and a pull mechanism, respectively. In an example embodiment, a network node enters a mesh overlay network and attaches to a tree overlay network. In operation, the network node receives data blocks of a data stream over the tree overlay network via a push mechanism. The network node ascertains if a data block is not received over the tree overlay network. If a data block is missing, the network node retrieves the missing data block over the mesh overlay network via a pull mechanism. In another example embodiment, the tree overlay network includes a subset of nodes forming a tree-based backbone. Network nodes that are identified as being stable may join the backbone and provide the data stream to other nodes.

Growing community of inventors

Beijing, China

Guobin (Jacky) Shen