Patent Description:
Given the advent of new applications and services directed to marketing opportunities and social networking, it has become increasingly important to accurately determine the location or position of wireless devices.

Various attempts have been made to develop indoor navigation systems that provide a digital electronic map to a wireless device upon entering a particular indoor area, e.g., a room, a shopping mall, etc. Typically, such indoor positioning systems have been based on Wi-Fi networks, using either received signal strength indicators (RSSls) or timing- based techniques. However, these indoor positioning systems are not without accuracy and reliability issues, as they sometimes rely on certain assumptions that do not reflect real-world conditions or operational characteristics.

<CIT> describes an apparatus, system and method for determining the physical location of a mobile client device operating on a wireless local area network (WLAN).

<CIT> describes a method and system for position location of clients in wireless local area networks (WLANS), wherein the position location technique utilizes time-of-flight (TOF) measurements of signals transmitted from a client to an number of wireless access points (APs) or vice versa to determine distances.

<CIT> describes methods and apparatus to locate a wireless device, wherein the method includes receiving a response location message at a first wireless station from a second wireless station that identifies the location of a third wireless station.

<CIT> describes a method, apparatus and system for transmitting and receiving a channel availability query and response in a wireless communication system.

The scope of the present invention is defined by appended independent claims. Optional features are specified by the sub-claims.

In the description that follows, like components have been given the same reference numerals, regardless of whether they are shown in different embodiments. To illustrate an embodiment(s) of the present disclosure in a clear and concise manner, the drawings may not necessarily be to scale and certain features may be shown in somewhat schematic form.

In accordance with various embodiments of this disclosure, what is proposed is a wireless communication system and methods thereof for information exchange between a location point (LP) and a wireless device. Supplemental location-related information of a LP includes distance data from another LP and may include a geographic location source, geographic location accuracy, geographic location update time, LP type, timing offset calibration accuracy, may be wirelessly transmitted from a LP to a wireless device.

A system is presented that includes at least one wireless device and a location point (LP) configured to wirelessly transmit data to the at least one wireless device. The transmitted data includes location specific information of the LP, which includes distance data from another LP and may include one or more of the following: geographic location source, geographic location accuracy, geographic location update time, LP type, timing offset calibration accuracy.

In another embodiment, a system is presented that includes a wireless device configured to receive data from one or more location points (LPs). The data received by the wireless device at least includes location specific information of each LP of the one or more LPs.

A method is presented that includes sending data from a location point (LP) to a wireless device. The data sent from the LP to the wireless device at least includes location specific information of the LP, which includes distance data from another LP.

These and other features and characteristics, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of claims. As used in the specification and in the claims, the singular form of "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

By way of review, the inventors have observed that conventional wireless indoor navigation and location identification systems rely on certain assumptions that do not always hold true, thereby compromising reliability and accuracy. For example, some Wi-Fi-based techniques, especially those predicated on crowdsourcing/surveys, assume that network access points (APs) remain at a fix position. However, APs may be mounted on a vehicle (e.g., bus, train, etc.) or in a mobile apparatus, thereby severely impacting the efficacy of the associated location algorithm.

As another example, sometimes additional pseudo-AP devices are deployed to address certain coverage issues. These pseudo-AP devices are configured to act like a network AP for location purposes but intentionally lack full communication capabilities. However, without having any information as to whether a proximate pseudo-AP device is a fully functioning network AP or a pseudo device, wireless devices may attempt to associate and transfer/negotiate communication commands with the pseudo-AP device, thereby wasting power and bandwidth.

In yet another example, for wireless indoor location identification systems employing RSSI techniques, the associated location algorithm assumes that the network AP transmits its radio-frequency (RF) beacon at constant power. As a practical and/or implementation-specific matter, beacons do not always operate at constant energy.

With this said, the disclosed embodiments are directed to a wireless location identification system and method that is capable of exchanging certain supplemental location-related information that addresses many of the deficiencies noted above. In particular, <FIG> depicts a non-limiting example of a wireless location identification system <NUM>, in accordance with various aspects and principles of the present disclosure. System <NUM> includes a network location point (AP) <NUM> in communication with a number of wireless devices, including wireless telephones <NUM> and <NUM>, notebook computer <NUM>, and personal digital assistant <NUM>. LP <NUM> is configured to provide the wireless devices <NUM>, <NUM>, <NUM>, <NUM> access to network <NUM>. As will be appreciated, network <NUM> is communicatively coupled, either wirelessly or wired, to server <NUM> that may comprise one or more computing platforms.

As used herein, the term "wireless device(s)" refers to any device that may communicate with other devices via wireless signals. Such devices may comprise, for example, a laptop, mobile device, cellular/smartphone, gaming device, tablet computer, a wireless-enabled patient monitoring device, personal communication system (PCS) device, personal digital assistant (PDA), personal audio device (PAD), portable navigational device, and/or any other electronic wireless-enabled device configured to receive a wireless signal. It may also include relatively stationary devices such as desktop computers with wireless capabilities. Such wireless devices may communicate via any number of wireless communication protocols, examples of which are noted below.

As used herein, the term "location point" or "LP" refers to a device with location determining capabilities. Such devices include a network access point (AP) and may include a dedicated location entity.

As used herein, the term "access point" or "network access point" refers to any device with the ability to receive wireless signals from one or more devices and provides access to a network, such as a local area network (LAN) or the Internet, for example. It should be appreciated that such devices also include location determining operations. In embodiments, a network AP may be installed at a fixed terrestrial location or may be installed on a vehicle or mobile apparatus. In one aspect, a network AP may include a femtocell utilized to extend cellular telephone service into a business or home. In such an implementation, one or more wireless devices may communicate with the femtocell via a code division multiple access (CDMA) cellular communication protocol, for example, and the femtocell would provide the wireless devices access to a larger cellular telecommunication network by way of another broadband network such as the Internet. Of course, these are example implementations utilizing one or more wireless devices and a network AP, and the scope of claimed subject matter is not limited in this respect.

As used herein, a dedicated location entity may be a degraded AP, as compared with a network AP, with only location determining capabilities and lacking network access and/or connectivity. As used herein, a dedicated location entity or a degraded AP may include a Pseudo AP, and/or a dedicated ToF tag AP.

As used herein, the term "network" refers to a wireless communication network that may be utilized in example implementations as discussed below. The network may be configured to operate under a variety of wireless communication protocols and standards, such as, for example, Wi-Fi, WiMax, WWAN, WLAN, WPAN, Bluetooth, GSM, CDMA, GPRS, <NUM> or <NUM>, LTE, Wireless USB, IEEE <NUM>. 11x standard, IEEE std. <NUM>-<NUM> published June <NUM>, <NUM>, or IEEE std. <NUM>-<NUM> published March <NUM>, <NUM>, or any other implementation of a suitable wireless standard. It will be appreciated that the wireless communication is not limited to any specific standard and the examples discussed may be implemented separately or in combination with each other.

Referring to <FIG>, wireless location identification system <NUM> is configured to facilitate transmit of supplemental location-related information between LP <NUM> and wireless devices <NUM>, <NUM>, <NUM>, <NUM>, in accordance with various aspects and principles of the present disclosure. This supplemental information enables the accurate location/position determination of wireless devices <NUM>, <NUM>, <NUM>, <NUM> and may be conveyed during the initial, unassociated communication stages (e.g., acknowledgement, hand-shaking, negotiation phases, etc.) between wireless devices <NUM>, <NUM>, <NUM>, <NUM> and LP <NUM> - without having to establish full network connectivity.

That is, wireless standards/protocols define the contents and field formats of certain packet frames that contain basic information regarding the communicating entities, such as, LP <NUM> and wireless devices <NUM>, <NUM>, <NUM>, <NUM>. For example, IEEE <NUM>-<NUM> and/or IEEE <NUM>-<NUM> define the packet frame formats for WiFi communications. Such framing formats may be exploited to introduce supplemental location-related information that can be transmitted between the entities in order to optimize the determination of entity location/position.

Consistent with various embodiments, the supplemental location-related information may be configured to include, for example, geographic location source data indicative of which type of source the LP obtains its geographic location; geographic location accuracy data indicative of how accurate the obtained geographic location is; and geographic location update timing data indicative of the last time the geographic location was updated.

Supplemental location-related information includes distance data indicative how far the LP is from other APs. In addition, the supplemental location-related information may include LP type data, such as, for example, data indicating whether the LP is stationary or mobile, whether the LP is a pseudo AP or not, whether the LP is a dedicated time-of-flight (ToF) tag AP or not, and/or whether the LP is a WiFi AP or WiFi non-AP (e.g., a client); timing offset calibration accuracy data, which is set to zero when the LP is not calibrated, or combinations thereof.

In various embodiments, the geographic location source can be manually configured, automatically deduced from other APs within a certain precision, provided by a network server, etc. In certain embodiments, the pseudo-AP may be configured to provide lower radiated RF power, smaller coverage, and deployed for only location determination purposes.

Returning to <FIG>, the supplemental location-related information may be broadcasted simultaneously to numerous wireless devices <NUM>, <NUM>, <NUM>, <NUM> by employing the RF beacon of LP <NUM>, in accordance with various aspects and principles of the present disclosure. That is, in certain wireless implementations, such as, for example, a WiFi network, LP <NUM> alerts wireless devices <NUM>, <NUM>, <NUM>, <NUM> that are within range as to its existence, by broadcasting an RF beacon signal containing a beacon frame. As such, the RF beacon signal identifies and announces LP <NUM> along with supplying AP-related information, as contained in the beacon frame. LP <NUM> (or pseudo-APs) may transmit the beacon signal on the order of milliseconds. Such broadcasting occurs in an unassociated WiFi state in which wireless devices <NUM>, <NUM>, <NUM>, <NUM> have not established network connectivity through LP <NUM>. Given the capability to transmit AP-related information <NUM> in an unassociated state, supplemental location-related information may be introduced in the beacon frame.

To this end, <FIG> depicts flow diagram of process <NUM> that supplies supplemental location-related information via broadcasting beacon frames, in accordance with various aspects and principles of the present disclosure. It is, once again noted, that although the disclosed embodiments are herein described relative to WiFi implementation and compatible with one or more IEEE <NUM>. 11x standards for the sake of clarity and tractability, the scope of claimed subject matter is not limited in this regard.

In process <NUM>, location specific information <NUM> of LP <NUM> may be defined in location specific information element (LIE) <NUM>.

As noted above, standard information, such as, for example, geographic location of LP <NUM>, may be included in LIE <NUM>. However, LIE <NUM> may be defined to include supplemental location-related information, such as location specific information <NUM>. In various embodiments, LIE <NUM> may use one of the reserved WiFi format frame element IDs (e.g., IDs <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>-<NUM>) as shown in Table <NUM>-<NUM> at IEEE <NUM>-<NUM> or the reserved element IDs as listed in Table <NUM>-<NUM> at IEEE <NUM>-<NUM>. For example, the location specific IE <NUM> may be defined as element <NUM> in Table <NUM>-<NUM> at IEEE <NUM>-<NUM>.

By way of illustration, LIE <NUM> may be configured to include supplemental location-related data as shown in following Table <NUM>.

As depicted in Table <NUM>, LIE <NUM> may include location specific information <NUM> indicative of AP-type information, such as, whether LP <NUM> is stationary or mobile, or whether it is a pseudo AP or not; geographic location source, geographic location accuracy, geographic location update time, distance from another AP; and/or timing offset calibration accuracy. The location specific information <NUM> may occupy a number of octets as may be suitable for implementation purposes. For complete description of LIE <NUM>, Table <NUM> also includes standard information such as geographic location information having octet framing similar to the measurement report field format for the location configuration information report, as provided by IEEE <NUM>-<NUM>, section <NUM>. <NUM> or IEEE <NUM>-<NUM>, section <NUM>.

Referring back to process <NUM>, at block <NUM>, LIE <NUM> defined at block <NUM> may be introduced into a beacon frame format <NUM>. Generally, beacon frame includes a MAC header, a beacon frame body, and a frame check sequence (FCS), as known to one of ordinary skill in the art. For example, the beacon frame body of Table <NUM>-<NUM> at IEEE <NUM>-<NUM> includes mesh channel switch parameter information and vendor specific information. In the example shown in Table <NUM>, beacon frame body <NUM> includes information of LIE <NUM>.

At block <NUM> of process <NUM>, the beacon frame is broadcasted from LP <NUM> to wireless devices <NUM>, <NUM>, <NUM>, <NUM>. The beacon frame body includes LIE <NUM> which contains supplemental location specific information <NUM> indicative of AP-type information, such as, whether LP <NUM> is stationary or mobile, or whether it is a pseudo AP or not; geographic location source, geographic location accuracy, geographic location update time, distance from another AP; and/or timing offset calibration accuracy. In this manner, supplemental location-related information may be broadcasted to numerous wireless devices <NUM>, <NUM>, <NUM>, <NUM> by virtue of broadcast RF beacon of LP <NUM> without requiring an association or connection to a network.

In certain embodiments, the supplemental location-related information may be provided to wireless devices <NUM>, <NUM>, <NUM>, <NUM> by employing the Location Configuration Information (LCI) Report as defined by IEEE <NUM>. 11x standard. In particular, wireless devices <NUM>, <NUM>, <NUM>, <NUM> in the vicinity of the LP <NUM> may initiate an inquiry to LP <NUM> requesting its current position. In response, LP <NUM> transmits an LCI Report, which typically includes standard current position information, such as, for example, latitude data, longitude data, altitude data, and optionally azimuthal data.

Given this preliminary reporting scheme, supplemental location-related information may be adapted and introduced into the LCI report format to transmit or convey the supplemental location-related information to inquiring devices <NUM>, <NUM>, <NUM>, <NUM> in an unassociated state manner.

<FIG> depicts flow diagram of process <NUM> that supplies supplemental location-related information via the LCI report, useful to understand the invention but not falling within the literal wording of the claims. At block <NUM> of process <NUM>, location specific information element (LIE) 205including at least the location specific information <NUM> as defined above can be introduced into the LCI Report in a manner consistent with IEEE <NUM>-<NUM> or IEEE <NUM>-<NUM> standards.

At block <NUM> of process <NUM>, the LCI report including location specific information element (LIE) <NUM> may be transmitted to inquiring wireless device(s) <NUM>, <NUM>, <NUM>, <NUM>, in accordance with IEEE <NUM>-<NUM> or IEEE <NUM>-<NUM> standards.

In certain embodiments, the supplemental location-related information may be provided to wireless devices <NUM>, <NUM>, <NUM>, <NUM> by exploiting the time-of-flight (ToF) measurement protocol. That is, the supplemental location-related information may be provided in response to ToF measurement requests.

As such, <FIG> depicts sequence flow diagram <NUM> illustrating a ToF technique for supplying supplemental location-related information and <FIG> depicts a functional block diagram of a corresponding wireless location system <NUM> configured to perform ToF measurements, in accordance with various aspects and principles of the present disclosure.

As shown in <FIG>, system <NUM> comprises multiple network APs, e.g., AP1, AP2, AP3, AP4, etc., and wireless device <NUM> at an unknown position. APs <NUM>-<NUM> may be devices that allow for wireless devices to communicate with each other by acting as both a transmitter and receiver of WLAN radio signals. APs <NUM>-<NUM> may take the form of LP <NUM> discussed above, including dedicated hardware devices that include a built-in network adapter, antenna, radio transmitter, etc. while wireless device <NUM> may take the form of any one of wireless devices <NUM>, <NUM>, <NUM>, <NUM>. In one embodiment, system <NUM> incorporates at least three APs (although <FIG> depicts AP1 through AP4 for illustration purpose), that receive wireless signals from an unknown location.

Referring to <FIG>, at interval <NUM>, wireless device <NUM> may initially transmit an action frame M1 (e.g., request message) to LP and record timestamp T1 indicating the time instant that the message is transmitted (e.g., time of departure (ToD) of M1).

At interval <NUM>, the LP may receive action frame M1, record the time instant it receives message M1 as T2 (i.e., time of arrival (ToA) of M1) and, at a later time, transmits an acknowledgement message M1-ACK back to wireless device <NUM> and records M1-ACK's ToD as T3.

At interval <NUM>, wireless device <NUM> may receive the acknowledgement message M1-ACK and record the time instant it receives the message M1-ACK as T4 (i.e., ToA of M1-ACK).

At interval <NUM>, the LP may send frame M2, in response to the action frame M1, to wireless device <NUM>. The frame M2 may contain the time T2, which is the time instant the LP received message M1, i.e., ToA of M1, the time T3 that represents the time instant the LP sends the acknowledgement message M1-ACK, i.e., ToD of M1-ACK, and may accommodate other information. That is, information can be piggybacked onto or otherwise coupled to the ToF response frame (or message) M2. The piggybacked information can then be transmitd between the LP and wireless device <NUM>. In certain embodiments, supplemental location-related information may be introduced via response frame M2. For example, location specific information element (LIE) <NUM> may be piggybacked onto response frame M2.

With this in mind, at interval <NUM>, wireless device <NUM> may receive response frame M2, which may at least include location specific information element (LIE) <NUM>. Wireless device <NUM> may then possesses T1 and T4 information, which have been recorded at intervals <NUM> and <NUM>, respectively, T2, T3 information, as well as piggybacked location specific information element (LIE) <NUM>, which has been retrieved from response frame M2 at interval <NUM>.

The time-of-flight (ToF) between wireless device <NUM> and the LP can then be calculated using the following equation:
<MAT>.

The distance between wireless device <NUM> and the LP can then be calculated according to rk=ToF*C, wherein C is the speed of light, wherein k= <NUM>, <NUM>,. k, and K is greater than <NUM> for trilateration (e.g., k=<NUM> in the example of <FIG>).

Meanwhile, wireless device <NUM> may retrieve the piggybacked location specific information element (LIE) <NUM> from response frame M2, which is a response to the action frame M1. In addition, at a later time, wireless device <NUM> may send acknowledge frame M2-ACK to LP according to the ToF measurement protocol. In so doing, supplemental location-related information may be supplied by piggybacking location specific information element (LIE) <NUM> on the ToF protocol in an unassociated state manner.

Having thus described the basic concepts, it will be rather apparent to those skilled in the art after reading this detailed disclosure that the foregoing detailed disclosure is intended to be presented by way of example only and is not limiting. Various alterations, improvements, and modifications will occur and are intended to those skilled in the art, though not expressly stated herein. These alterations, improvements, and modifications are intended to be suggested by this disclosure.

Claim 1:
A wireless apparatus comprising:
means for requesting location measurement from an Access Point, AP (<NUM>); and
means for retrieving location related information from a time of flight, ToF, message received from said AP (<NUM>) according to a ToF measurement protocol;
characterised in that
the ToF message comprises supplemental location-related information including distance data indicative of how far the AP (<NUM>) is from an other Access Point, AP.