TECHNICAL FIELD

The present teaching generally relates to wireless object tracking. More specifically, the present teaching relates to localizing and tracking multiple objects based on wireless channel information in a rich-scattering environment.

BACKGROUND

Over the past decade, indoor localization systems shift from an active device-based theme to a passive device-free manner, i.e. to localize and track a user without requiring her/him to carry or wear any device. Passive indoor localization can enable a wide range of applications that demand ubiquitous tracking of users' locations while not favoring/allowing a user to carry or wear a device. For example, it allows a smart television (TV) to localize users and intelligently rotate the viewing angle or turn on/off when users are coming/leaving. It would also enable an energy-efficient building to localize and count the occupants and adjust the heating and lighting accordingly. It can be used in a smart home to control the Internet of Things (IoT) devices in response to the users' locations. All of these applications would become more practical and attractive in natural indoor settings when multi-person localization is enabled.

Existing works focus on single target tracking and fail in the presence of multiple persons, mainly because the reflected signals from all targets as well as other objects in the environment are superimposed together. In addition, these works mainly focus on the tracking of a moving target and need cumbersome calibration to localize static objects. To achieve multi-person localization, many of past proposals resort to a dense deployment of many devices and/or prior training. Alternatively, a specialized hardware is built with many antennas in a quite large form factor. One existing system needs multiple receivers and assumes the knowledge of the number of persons. For all of these systems, the resolvability to disentangle the weak signals reflected off multiple targets is fundamentally limited by the antenna number and the system bandwidth.

SUMMARY

The present teaching generally relates to a wireless tracking system. In one embodiment, the present teaching relates to a multi-person localization and tracking system using a single 802.11ad device. A high spatial resolution is achieved by performing digital beamforming on the antenna array of the 60 GHz chipsets. A multi-object detection algorithm and a robust clustering technique are utilized to locate and count multiple users. The disclosed system also recovers the moving trajectories by a continuous tracking algorithm. According to one embodiment, experiments on commodity off-the-shelf (COTS) 802.11ad radios demonstrate that the disclosed system achieves a median location error of 9.9 cm and 19.7 cm for dynamic and static targets respectively, with a people counting error ≤1 for 97.8% of the time.

In one embodiment, a wireless tracking system is described. The wireless tracking system comprises: a transmitter, a receiver, and a processor. The transmitter is configured for transmitting a first wireless signal using a plurality of transmit antennas towards at least one object in a venue through a wireless multipath channel of the venue. The receiver is configured for: receiving a second wireless signal using a plurality of receive antennas through the wireless multipath channel between the transmitter and the receiver. The second wireless signal differs from the first wireless signal due to the wireless multipath channel and a modulation of the first wireless signal by the at least one object. The processor is configured for obtaining a set of channel information (CI) of the wireless multipath channel based on the second wireless signal received by the receiver, and tracking the at least one object simultaneously based on the set of CI. Each CI in the set is associated with a respective one of the plurality of transmit antennas and a respective one of the plurality of receive antennas. According to various embodiments, the processor is physically coupled to at least one of the transmitter and the receiver.

In another embodiment, a described apparatus for wireless tracking is in a venue where a transmitter and a receiver are located. The described apparatus comprises: a processor and at least one of the transmitter and the receiver. The transmitter is configured for transmitting a first wireless signal using a plurality of transmit antennas towards at least one object in the venue through a wireless multipath channel of the venue. The receiver is configured for receiving a second wireless signal using a plurality of receive antennas through the wireless multipath channel between the transmitter and the receiver. The second wireless signal differs from the first wireless signal due to the wireless multipath channel and a modulation of the first wireless signal by the at least one object. The processor is configured for: obtaining a set of channel information (CI) of the wireless multipath channel based on the second wireless signal, wherein each CI in the set is associated with a respective one of the plurality of transmit antennas and a respective one of the plurality of receive antennas; and tracking the at least one object simultaneously based on the set of CI.

In one embodiment, the apparatus includes the receiver but not the transmitter. The receiver receives the second wireless signal and extracts the CI, e.g. a channel state information (CSI), for performing the object tracking. In another embodiment, the apparatus includes the transmitter but not the receiver. The CSI is extracted by the receiver and obtained by the processor for object tracking. In still another embodiment, the apparatus includes the transmitter but not the receiver. The CSI is extracted at the receiver that sends the CSI to the transmitter. The object tracking is performed at the transmitter.

In a different embodiment, a method, implemented by a processor, a memory communicatively coupled with the processor, and a set of instructions stored in the memory to be executed by the processor, is described. The method comprises: obtaining a set of channel information (CI) of a wireless multipath channel of a venue, wherein: a transmitter transmits a first wireless signal using a plurality of transmit antennas towards at least one object in a venue through the wireless multipath channel of the venue, a receiver receives a second wireless signal using a plurality of receive antennas through the wireless multipath channel and computes the set of CI of the wireless multipath channel based on the second wireless signal, and the second wireless signal differs from the first wireless signal due to the wireless multipath channel and a modulation of the first wireless signal by the at least one object; and tracking the at least one object simultaneously based on the set of CI.

Other concepts relate to software for implementing the present teaching on wireless object tracking in a rich-scattering environment. Additional novel features will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and the accompanying drawings or may be learned by production or operation of the examples. The novel features of the present teachings may be realized and attained by practice or use of various aspects of the methodologies, instrumentalities and combinations set forth in the detailed examples discussed below.

