Methods and apparatus for triggering cooperative positioning or learning in a wireless network

FIELD

0001Various embodiments relate to mobile device location determination related operations, and more particularly, to location determination related methods and apparatus involving mobile device cooperation.

BACKGROUND

0002It can be useful and desirable to perform mobile wireless device position determination in a wireless communications system. Accurate mobile wireless device position determination can be a difficult task particularly in an indoor environment. There may be an insufficient number of permanent fixed location anchor points from which to transmit reference signals or measured detected signals. It may be inconvenient or impractical, e.g., from a physical construction viewpoint or financial cost benefit analysis viewpoint, to install and operate a complete set of permanent fixed location anchor points in the building to provide full coverage. Some mobile device location determination approaches are based on the use a signal reference map with measured signals being matched to expected values. However, the initial signal reference map may have been based on a limited or incomplete survey and/or estimation. The survey which generated the map may have used a very limited number of actual measurements and relied on a large amount of estimation and/or interpolation. As another example, accurate signal loss parameters associated with different wall construction materials and/or different wall thicknesses used throughout a building may not be known. In addition environmental conditions may change over time, e.g., a door may be opened or closed at different times of a day, partitions may be added in an office due to remodeling, furniture may be added, removed or rearranged, different electrical equipment may be installed in the building over time, different electrical equipment may be operating at different times of the day, etc.

0003Based on the above discussion it should be appreciated that there is a need for improved methods and apparatus related to mobile device position determination to provide move complete and/or accurate location determination of mobile devices. At times one mobile device may be in a situation where it could provide assistance in determining the location of other mobile devices. Cooperation is particularly challenging in wireless networks where many physical resources such as power or network capacity are limited. In a cooperative positioning framework, it is beneficial if distributive approaches used for different types of joint position estimation and/or joint environment estimation are resource efficient, e.g., in terms of air link resource utilization.

0004In view of the above discussion, it should be appreciated that there is a need for methods and apparatus for facilitating cooperation with regard to position determination operations. It would be beneficial if such methods and/or apparatus allowed cooperation when needed without excessive overhead and/or unnecessary signaling.

SUMMARY

0005Various embodiments relate to cooperative methods for environment learning and/or position determining in a wireless communications system, e.g., in a peer-to-peer network. In accordance with various embodiments one or more bits are used, e.g., in a predetermined dedicated manner, in peer discovery signals to signal a devices ability and/or willingness to participate in a cooperative manner with regard to one or more location determination related operations. The bit or bits conveying cooperative location determination operation capabilities, in some embodiments, are located in a predetermined location within a header portion of a peer discovery signal. The peer discovery signal, in some embodiments, is transmitted, e.g., broadcast, periodically or on some predetermined basis by a mobile wireless communications device. In this manner, a device listening to the peer discovery signals of other devices can determine which other devices in its vicinity are willing and/or able to perform particular location discovery related operations with very little signaling overhead. The number of bits used in some embodiments to convey cooperation determination abilities may be small, e.g., less than 10 bits in some embodiments. In various exemplary embodiments the number of bits used to indicate location determination abilities and/or willingness to help in a location determination related operation may be less than four bits, e.g., 3, 2 or 1 bit depending on the particular embodiment. Thus, very little overhead is associated with the communication of cooperation determination ability information, e.g., as part of a broadcast discovery signal. Since an advertising device's capability and/or willingness to assist in a location discovery operation is known, signaling to inquire about a device's ability to assist or participate in a location discovery related operation is minimized or avoided altogether.

0006Various exemplary location determination related operations, in some embodiments, include one or more or all of: providing a past location of the communications device, providing a current location of the communications device, determining a map related parameter used in mobile device location determination, providing location information regarding another mobile device, confirming a location of another mobile device, transmitting a signal used in a round trip timing estimation, serving as a temporary location anchor point and transmitting a reference signal, and serving as a temporary location anchor point and measuring received signals from other mobile devices.

0007An exemplary method of operating a first mobile communications device to communicate device information, in accordance with some embodiments, comprises: transmitting a peer discovery signal including a predetermined bit designated for use in signaling a willingness to perform a first device location determination related operation, said predetermined bit being set to a first value when said first mobile communications device is willing to perform said first device location determination related operation and being set to a second value when said first mobile communications device is not willing to perform said first device location determination related operation; and monitoring for a signal from a second mobile communications device corresponding to said first device location determination related operation. A exemplary first mobile communications device, in accordance with some embodiments, comprises at least one processor configured to: transmit a peer discovery signal including a predetermined bit designated for use in signaling a willingness to perform a first device location determination related operation, said predetermined bit being set to a first value when said first mobile communications device is willing to perform said first device location determination related operation and being set to a second value when said first mobile communications device is not willing to perform said first device location determination related operation; and monitor for a signal from a second mobile communications device corresponding to said first device location determination related operation. The exemplary first communications device further comprises memory coupled to said at least one processor.

0008An exemplary method of operating a communications device, in accordance with some embodiments, comprises: transmitting a signal including a first value at a predetermined location in said signal, said first value indicating that the communications device is operating as a location anchor point. The exemplary method further comprises performing at least one of: i) transmitting information indicating the known location of the communications device; or ii) measuring signals received from other devices and reporting the signal measurement information and information indicating the devices from which the measured signals were received to a location determination server. An exemplary communications device, in accordance with some embodiments, comprises: at least one processor configured to: transmit a signal including a first value at a predetermined location in said signal, said first value indicating that the communications device is operating as a location anchor point; and perform at least one of: i) transmitting information indicating the known location of the communications device; or ii) measuring signals received from other devices and reporting the signal measurement information and information indicating the devices from which the measured signals were received to a location determination server. The exemplary communications device further comprises memory coupled to said at least one processor.

0009While various embodiments have been discussed in the summary above, it should be appreciated that not necessarily all embodiments include the same features and some of the features described above are not necessary but can be desirable in some embodiments. Numerous additional features, embodiments and benefits of various embodiments are discussed in the detailed description which follows.

BRIEF DESCRIPTION OF THE FIGURES

0010<figref idref="DRAWINGS">FIG. 1</figref> is a drawing of an exemplary communications system supporting mobile device location determination in accordance with various exemplary embodiments.

0011<figref idref="DRAWINGS">FIG. 2</figref> is a drawing of a flowchart of an exemplary method of operating a first mobile communications device in accordance with various embodiments.

0012<figref idref="DRAWINGS">FIG. 3</figref> is a drawing of an exemplary first mobile communications device in accordance with an exemplary embodiment.

0013<figref idref="DRAWINGS">FIG. 4</figref> is an assembly of modules which can, and in some embodiments is, used in the exemplary first mobile communications device illustrated in <figref idref="DRAWINGS">FIG. 3</figref>.

0014<figref idref="DRAWINGS">FIG. 5</figref> is a drawing of an exemplary communication system in which mobile devices can, and sometimes do, serve as temporary location anchor points in accordance with an exemplary embodiment.

0015<figref idref="DRAWINGS">FIG. 6</figref> is a flowchart of an exemplary method of operating a communications device, e.g., a mobile communications device, in accordance with various embodiments.

0016<figref idref="DRAWINGS">FIG. 7</figref> is a drawing of an exemplary first mobile communications device in accordance with an exemplary embodiment.

0017<figref idref="DRAWINGS">FIG. 8</figref> is an assembly of modules which can, and in some embodiments is, used in the exemplary first mobile communications device illustrated in <figref idref="DRAWINGS">FIG. 7</figref>.

0018<figref idref="DRAWINGS">FIG. 9</figref> is a drawing illustrating an example in which a mobile wireless communications device transmits a signal indicating its willingness to perform a location determination related operation and then performs a location determination related operation in accordance with an exemplary embodiment.

0019<figref idref="DRAWINGS">FIG. 10</figref> is a drawing illustrating another example in which a mobile wireless communications device transmits a signal indicating its willingness to perform a location determination related operation and then performs a location determination related operation in accordance with an exemplary embodiment.

0020<figref idref="DRAWINGS">FIG. 11</figref> is a drawing illustrating yet another example in which a mobile wireless communications device transmits a signal indicating its willingness to perform a location determination related operation and then performs a location determination related operation in accordance with an exemplary embodiment.

0021<figref idref="DRAWINGS">FIG. 12</figref> is a drawing illustrating still another example in which a mobile wireless communications device transmits a signal indicating its willingness to perform a location determination related operation and then performs a location determination related operation in accordance with an exemplary embodiment.

0022<figref idref="DRAWINGS">FIG. 13</figref> is a drawing illustrating an example, in which a mobile wireless communications device transmits a signal including a first value at a predetermined location which indicates that the communications device is temporarily operating as a location anchor point in accordance with an exemplary embodiment.

0023<figref idref="DRAWINGS">FIG. 14</figref> illustrating the first part of an example, in which a mobile wireless communications device transmits a signal including a first value at a predetermined location which indicates that the communications device is temporarily operating as a location anchor point in accordance with an exemplary embodiment.

0024<figref idref="DRAWINGS">FIG. 15</figref> illustrating the second part of an example, in which a mobile wireless communications device transmits a signal including a first value at a predetermined location which indicates that the communications device is temporarily operating as a location anchor point in accordance with an exemplary embodiment.

0025<figref idref="DRAWINGS">FIG. 16</figref> illustrates an exemplary peer discovery signal, which includes predetermined header bits used to signal a willingness to perform specific cooperative location determination operations, in accordance with various embodiments.

DETAILED DESCRIPTION

0026<figref idref="DRAWINGS">FIG. 1</figref> is a drawing of an exemplary communications system <b>100</b> including mobile device location determination capability in accordance with various exemplary embodiments. Exemplary system <b>100</b> includes a core network node <b>102</b>, e.g., a centralized control node and/or location determination server node, and a plurality of fixed location access points (access point <b>1</b><b>104</b>, access point <b>2</b><b>106</b>, . . . , access point N <b>108</b>) coupled together via a backhaul network <b>120</b>. The fixed location access points (<b>104</b>, <b>106</b>, . . . , <b>108</b>) serve as location anchor points in the system. The backhaul network <b>120</b> couples the nodes (<b>102</b>, <b>104</b>, <b>106</b>, . . . , <b>108</b>) to one another, to other network nodes and/or to the Internet. There is a mapped coverage area <b>103</b> for which mobile device position determinations are performed based on signal prediction maps.

0027In some embodiments, core network node <b>102</b> is located within the coverage area <b>103</b>. In other embodiments, core network node <b>102</b> is located outside the coverage area <b>103</b>. In still other embodiments, core network node <b>102</b> is located on a boundary of the coverage area <b>103</b>. In yet still other embodiments, the core network node is not included. In some embodiments, at least some of the fixed location access points are not connected via a backhaul network.

0028Within the coverage area <b>103</b>, there are a plurality of obstructions (obstruction <b>1</b><b>116</b>, . . . , obstruction N <b>118</b>). An exemplary obstruction is a wall, which potentially affects signaling between a fixed location access point and a mobile device, e.g., causing attenuation as a signal passes through one or more walls and/or causing attenuation due to diffraction as a signal bends around a corner. Some of the obstruction may be present during some times and not present during other times, e.g., a door may be closed at times creating an obstruction to signaling, but may be open at other times reducing or eliminating the obstruction. In addition, obstructions may be added or deleted over time, e.g., cubicle partitions may be added and/or deleted in a floor plan space of an office building over time.

0029System <b>100</b> also includes a plurality of mobile wireless devices (mobile device <b>1</b><b>110</b>, mobile device <b>2</b><b>112</b>, . . . , mobile device N <b>114</b>), which may move throughout the system. A mobile device's current position is determined based on signal prediction maps. In some embodiments, a mobile device determines its position based on signal prediction map information and signal measurement information. In some embodiments, another node, e.g. a location determination server node, determines a mobile device's position based on signal prediction map information and signal measurement information.

0030In various embodiments, a peer to peer signaling protocol is used for the wireless signaling. The mobile communications devices (<b>110</b>, <b>112</b>, . . . , <b>114</b>) can, and sometimes does, participate in cooperative location discovery operations. A mobile communications device, e.g., mobile node <b>110</b>, advertises its willingness to participate in one or more cooperative location discovery operations using one or more predetermined bits in a peer discovery signal. For example, a header of a peer discovery signal, in some embodiments, includes a plurality of predetermined bits corresponding to different location determination related operations. In some such embodiments, the mobile communications device controls setting of the predetermined bits corresponding to different location determination operations to indicate its willingness or lack thereof to perform the various possible location determination related operations which are supported.

0031Various exemplary location determination related operations include: (i) transmitting, e.g., broadcasting, information indicating a current or past location of the mobile communications device, (ii) performing a map parameter determination operation, e.g., based on measurements of received signals, (iii) providing location information in response to a received signal from another mobile device, and (iv) transmitting a signal used to make a round trip timing determination.

0032<figref idref="DRAWINGS">FIG. 2</figref> is a drawing of a flowchart <b>200</b> of an exemplary method of operating a first mobile communications device, e.g., a battery powered handheld wireless mobile node supporting peer to peer signaling, in accordance with various embodiments. Operation of the exemplary method starts in step <b>202</b>, where the first mobile communications device is powered on and initialized. Operation proceeds from start step <b>202</b> to step <b>204</b>.

0033In step <b>204</b> the first mobile communications device transmits a peer discovery signal including a predetermined bit designated for use in signaling a willingness to perform a first device location determination related operation, said predetermined bit being set to a first value when said first mobile communications device is willing to perform said first device location determination related operation and being set to a second value when said first device is not willing to perform said first device location determination related operation. Operation proceeds from step <b>204</b> to step <b>206</b>.

0034In step <b>206</b>, the first mobile communications device controls operation as a function of said predetermined bit in said the transmitted peer discovery signal. If the predetermined bit in the transmitted peer discovery signal indicated a willingness to perform a first device location determination related operation, then operation proceeds from step <b>206</b> to step <b>208</b>; otherwise operation proceeds from step <b>206</b> to the input of step <b>204</b>, via connecting node A <b>224</b>.

0035Returning to step <b>208</b>, in step <b>208</b> the first mobile communications device monitors for a signal from a second mobile communications device corresponding to said first device location determination related operation. Operation proceeds from step <b>208</b> to step <b>210</b>. In step <b>210</b> the first mobile communications device checks if the monitoring of step <b>208</b> detected receipt of a signal from the second mobile communications device corresponding to said first device location determination related operation. If the monitoring of step <b>208</b> detected receipt of a signal from the second mobile communications device corresponding to said first device location determination related operation, then operation proceeds from step <b>210</b> to one or more or all of steps <b>212</b>, <b>214</b>, <b>220</b> and <b>222</b>; otherwise operation proceeds from step <b>210</b> to step <b>218</b> for additional monitoring.

0036In some embodiments, the first device location determination related operation may be, and sometimes is, supplying a position fix of the current or past location of the first communications device. Returning to step <b>212</b>, in step <b>212</b> the first mobile communications device transmits information indicating a current or past position. Operation proceeds from step <b>212</b> via connecting node A <b>224</b> to step <b>204</b>.

0037In some embodiments, the first device location determination related operation may be, and sometimes is, a map parameter determination operation. Returning to step <b>214</b>, in step <b>214</b> the first mobile communications device performs a signal measurement on the received signal. In some embodiments, the received signal from the second mobile communications device is a signal transmitted by the second mobile communications device in response to receipt of said transmitted peer discovery signal. Then in step <b>216</b>, the first mobile communications device used said signal measurement in determining a map parameter. In some embodiments, the map parameter indicates the presence or absence of a physical obstruction, e.g., a door or a movable partition, at a location on said map. Other exemplary map parameters include, e.g., a specific wall material, the presence of a crowd, a state to describe whether a door is open or closed. Operation proceeds from step <b>216</b> to step <b>218</b> in which the first mobile communications device transmits said determined parameter, e.g., to a second mobile communications device or to another device such as a location determination server. Operation proceeds from step <b>218</b> via connecting node A <b>224</b> to step <b>204</b>.

0038In some embodiments, the first device location determination related operation may be, and sometimes is, a first type of position ambiguity resolution operation. Returning to step <b>220</b>, in step <b>220</b> the first mobile communications device provides location information in response to said received signal from the second mobile communications device, said location information indicating one of a location of the first mobile communications device or a location of the second mobile communications device. Operation proceeds from step <b>220</b>, via connecting node A <b>224</b>, to step <b>204</b>.

0039In some embodiments, the first device location determination related operation may be, and sometimes is, a second type of position ambiguity resolution operation. Returning to step <b>222</b>, in step <b>222</b> the first mobile communications device transmits a signal used in making a round trip timing determination. Operation proceeds from step <b>222</b>, via connecting node A <b>224</b>, to step <b>204</b>.

0040In various embodiments, the first mobile communications device advertises in a peer discovery signal its willingness to participate in a cooperative location discovery operation using one or more predetermined bits, e.g., in the header of a peer discovery signal, with the predetermined bits corresponding to different discovery operations. For example, a first predetermined bit, in some embodiments, corresponds to the operation of step <b>212</b>, a second predetermined bit, in some embodiments, corresponds to the operations of steps <b>214</b>, <b>216</b> and <b>218</b>, a third predetermined bit corresponds to the operation of step <b>220</b> and a fourth predetermined bit corresponds to the operation of step <b>222</b>. At different times different bits may be set and the first mobile communications may perform different location determination related operations for other mobile devices, e.g. in accordance with its current bit settings.

0041In some embodiments, the transmitted peer discovery signal from the first communications device is a broadcast advertisement for cooperative location determination related operations, e.g., an advertisement intended to initiate a sequence of events to provide a cooperative location determination related operation or operations. In some such embodiments, the monitored signal from the second communications device is a peer to peer paging signal from the second communications device directed to the first communications device in response to the peer discovery signal. In some such embodiments, a location determination related operation, e.g., proving mobile location information, providing a location map parameter, providing a device position confirmation, or providing a signal used for a round trip timing measurement, is communicated during a peer to peer traffic interval. In some such embodiments, the first and second mobile communications devices implement a peer to peer signaling protocol including a recurring peer to peer timing structure including: a peer discovery interval, a peer to peer paging interval and a peer to peer traffic interval.

0042<figref idref="DRAWINGS">FIG. 3</figref> is a drawing of an exemplary first mobile communications device <b>300</b> in accordance with an exemplary embodiment. Exemplary first mobile wireless device <b>300</b> is, e.g., one of the mobile devices of system <b>100</b> of <figref idref="DRAWINGS">FIG. 1</figref>. Exemplary first mobile communications device <b>300</b> may, and sometimes does, implement a method in accordance with flowchart <b>200</b> of <figref idref="DRAWINGS">FIG. 2</figref>.

0043First mobile communications device <b>300</b> includes a processor <b>302</b> and memory <b>304</b> coupled together via a bus <b>309</b> over which the various elements (<b>302</b>, <b>304</b>) may interchange data and information. First mobile communications device <b>300</b> further includes an input module <b>306</b> and an output module <b>308</b> which may be coupled to processor <b>302</b> as shown. However, in some embodiments, the input module <b>306</b> and output module <b>308</b> are located internal to the processor <b>302</b>. Input module <b>306</b> can receive input signals. Input module <b>306</b> can, and in some embodiments does, include a wireless receiver and/or a wired or optical input interface for receiving input. Output module <b>308</b> may include, and in some embodiments does include, a wireless transmitter and/or a wired or optical output interface for transmitting output. In some embodiments, memory <b>304</b> includes routines <b>311</b> and data/information <b>313</b>.

0044In various embodiments, processor <b>302</b> is configured to transmit a peer discovery signal including a first predetermined bit designated for use in signaling a willingness to perform a first device location determination related operation, said at least one predetermined bit being set to a first value when said mobile communications device is willing to perform said first device location determination related operation and being set to a second value when said mobile communications device is not willing to perform said first device location determination related operation; and monitor for a signal from a second mobile communications device corresponding to said first device location determination related operation. In some such embodiments, processor <b>302</b> is further configured to: transmit information indicating a current or past position, e.g., a current or past position of first mobile communications device <b>300</b>.

0045In some embodiments, said first device location determination related operation is a map parameter determination operation. In some such embodiments, processor <b>302</b> is further configured to: perform a signal measurement on the received signal; and use said signal measurement in determining said map parameter; when said monitoring for a signal from a second mobile communications device detects receipt of a signal from the second mobile communications device corresponding to said first device location determination related operation. In various embodiments, said signal from the second mobile communications device is a signal transmitted by said second mobile communications device in response to receipt of said transmitted peer discovery signal. In some such embodiments, said parameter indicates the presence or absence of a physical obstruction, e.g., door or movable partition, at a location on a map. In some embodiments, processor <b>302</b> is further configured to transmit said determined parameter, e.g., e.g. to the second mobile communications device or some other device such as a location determination server.

0046In some embodiments, the first device location determination related operation is a position ambiguity resolution operation. In some such embodiments, processor <b>302</b> is further configured to: provide location information in response to a signal from said second device, said location information indicating one of the location of the first device or the location of the second device.

0047In some embodiments, the first device location determination related operation is a position ambiguity resolution operation. In some such embodiments, processor <b>302</b> is further configured to: transmit a signal used in making a round trip timing determination, when said monitoring for a signal from a second mobile communications device detects receipt of a signal from the second mobile communications device corresponding to said first device location determination related operation.

0048<figref idref="DRAWINGS">FIG. 4</figref> is an assembly of modules <b>400</b> which can, and in some embodiments is, used in the exemplary first mobile communications device <b>300</b> illustrated in <figref idref="DRAWINGS">FIG. 3</figref>. The modules in the assembly <b>400</b> can be implemented in hardware within the processor <b>302</b> of <figref idref="DRAWINGS">FIG. 3</figref>, e.g., as individual circuits. Alternatively, the modules may be implemented in software and stored in the memory <b>304</b> of first mobile communications device <b>300</b> shown in <figref idref="DRAWINGS">FIG. 3</figref>. In some such embodiments, the assembly of modules <b>400</b> is included in routines <b>311</b> of memory <b>304</b> of device <b>300</b> of <figref idref="DRAWINGS">FIG. 3</figref>. While shown in the <figref idref="DRAWINGS">FIG. 3</figref> embodiment as a single processor, e.g., computer, it should be appreciated that the processor <b>302</b> may be implemented as one or more processors, e.g., computers. When implemented in software the modules include code, which when executed by the processor, configure the processor, e.g., computer, <b>302</b> to implement the function corresponding to the module. In some embodiments, processor <b>302</b> is configured to implement each of the modules of the assembly of modules <b>400</b>. In embodiments where the assembly of modules <b>400</b> is stored in the memory <b>304</b>, the memory <b>304</b> is a computer program product comprising a computer readable medium, e.g., a non-transitory computer readable medium, comprising code, e.g., individual code for each module, for causing at least one computer, e.g., processor <b>302</b>, to implement the functions to which the modules correspond.

0049Completely hardware based or completely software based modules may be used. However, it should be appreciated that any combination of software and hardware (e.g., circuit implemented) modules may be used to implement the functions. As should be appreciated, the modules illustrated in <figref idref="DRAWINGS">FIG. 4</figref> control and/or configure the first mobile communications device <b>300</b> or elements therein such as the processor <b>302</b>, to perform the functions of the corresponding steps illustrated and/or described in the method of flowchart <b>200</b> of <figref idref="DRAWINGS">FIG. 2</figref>.

0050Assembly of modules <b>400</b> includes a module <b>403</b> for generating a peer discovery signal including a predetermined bit designated for use in signaling a willingness to perform a first device location determination related operation, said first predetermined bit being set to a first value when said first mobile communications device is willing to perform said first device location determination related operation and being set to a second value when said first mobile communications device is not willing to perform said first device location determination related operation, and a module <b>404</b> for transmitting a peer discovery signal including a predetermined bit designated for use in signaling a willingness to perform a first device location determination related operation, said first predetermined bit being set to a first value when said first mobile communications device is willing to perform said first device location determination related operation and being set to a second value when said first mobile communications device is not willing to perform said first device location determination related operation. Assembly of modules <b>400</b> further includes a module <b>406</b> for controlling operation as a function of whether the predetermined bit in the transmitted peer discovery signal indicates a willingness to perform a first device location determination related operation, a module <b>408</b> for monitoring for a signal from a second mobile communications device corresponding to said first device location determination related operation, a module <b>409</b> for receiving a signal from the second mobile communications device corresponding to said first device location determination related operation, and a module <b>410</b> for controlling operation as a function of whether the monitoring detected receipt of signal from the second mobile communications device corresponding to said first device location determination related operation.

0051Assembly of modules <b>400</b> further includes a module <b>412</b> for transmitting information indicating a current or past position, a module <b>414</b> for performing a signal measurement on the received signal, a module <b>416</b> for using said signal measurement in determining a map parameter, a module <b>418</b> for transmitting said determined parameter, a module <b>420</b> for providing location information in response to said received signal from the second mobile communications device, said location information indicating one of the location of the first mobile communications device or a location of the second mobile communications device and a module <b>422</b> for transmitting a signal used in making a round trip timing determination.

0052<figref idref="DRAWINGS">FIG. 5</figref> is a drawing of an exemplary communication system <b>500</b>, e.g. a wireless communications system, in accordance with an exemplary embodiment. Exemplary communications system <b>500</b> includes a plurality of access points (access point <b>1</b><b>502</b>, . . . , access point N <b>504</b>) which do not serve as location anchor points, a plurality of access points (access point <b>1</b>′ <b>506</b>, . . . , access point N′ <b>508</b>) which serve as fixed location anchor points and a location determination server, which are coupled together via a backhaul network <b>512</b>. The backhaul network is also coupled to other network elements and/or the Internet.

0053Exemplary communications system <b>500</b> also includes a plurality of mobile devices, e.g., mobile wireless terminals, which do not include the capability to serve as a temporary location anchor point (mobile device <b>1</b><b>514</b>, mobile device <b>2</b><b>516</b>, . . . , mobile device M <b>518</b>. Exemplary communications system <b>500</b> also includes a plurality of mobile devices, e.g., mobile wireless terminals, which can and sometimes do, serve a temporary location anchor points (mobile device <b>1</b>′ <b>520</b>, mobile device <b>2</b>′ <b>522</b>, . . . mobile device M′ <b>524</b>).

0054In some embodiments, the wireless communications devices (<b>502</b>, . . . , <b>504</b>, <b>506</b>, . . . , <b>508</b>, <b>514</b>, <b>516</b>, . . . , <b>518</b>, <b>520</b>, <b>522</b>, . . . , <b>524</b>) support a peer to peer signaling protocol and can communicate with one another directly. In some such embodiments, two mobile communications devices may, and sometimes do, communicate directly with one another without the signaling traversing an access point. In some embodiments, the location determination server is not included. In some embodiments, an access point serves as a location determination server node. In some embodiments, each of the access points are fixed location anchor points. In various embodiments, each of the mobile devices includes temporary location anchor point capability. In some embodiments at least some of the access points are not interconnected via a backhaul network. In some embodiments, there is no backhaul network.

0055In various embodiments, a mobile device with the capability to serve as a temporary location anchor point, e.g., mobile device <b>1</b>′ <b>520</b> advertises information indicating that the mobile device is operating temporarily as a location anchor point. In some embodiments, when a mobile device is operating as a temporary location anchor point it transmits a signal including at first value at a predetermined location indicating that the communications device is operating as a location anchor point. In some embodiments, the transmitted signal is a peer discovery signal. In some such embodiments, the peer discovery signal includes a header, and one bit in the header field is used to indicate that the communications device is operating as a location anchor point. In some embodiments, operating as a temporary location anchor point includes transmitting information indicating the known location of the communications device, e.g., intended to be received and used by other mobile device to determine their position. In some embodiments, operating as a temporary location anchor point includes measuring signals received from other devices, e.g., other mobile nodes, and reporting the signal measurement information and information indicating the devices from which the signals were received to a location determination server.

0056<figref idref="DRAWINGS">FIG. 6</figref> is a flowchart <b>600</b> of an exemplary method of operating a communications device, e.g., a mobile communications device, in accordance with various embodiments. The exemplary mobile device is, e.g., one of the mobile devices (<b>520</b>, <b>522</b>, . . . , <b>524</b>) with temporary location anchor point capability of system <b>500</b> of <figref idref="DRAWINGS">FIG. 5</figref>. Operation of the exemplary method starts in step <b>602</b>, where the communications device is powered on and initialized. Operation proceeds from start step <b>602</b> to step <b>604</b>. In step <b>604</b>, the communications device transmits a signal including a first value at a predetermined location in said signal, said first value indicating that said communications device is operating as a location anchor point. Operation proceeds from step <b>604</b> to step <b>606</b>. In step <b>606</b> the communications device performs at least one of: i) transmitting information indicating the known location of the communications device; or ii) measuring signals received from other devices and reporting the signal measurement information and information indicating the devices from which the measured signal were received to a location determination server. Step <b>606</b> includes steps <b>608</b>, <b>610</b>, <b>612</b>, <b>614</b>, <b>616</b>, <b>618</b>, <b>620</b><b>622</b> and <b>624</b>. In one embodiment, step <b>608</b> is performed. In another embodiment, steps <b>610</b>, <b>612</b>, <b>614</b>, <b>616</b>, <b>618</b>, <b>620</b>, <b>622</b> and <b>624</b> are performed. In still another embodiment, steps <b>608</b>, <b>610</b>, <b>612</b>, <b>614</b>, <b>616</b>, <b>618</b>, <b>620</b><b>622</b> and <b>624</b> are performed. In yet another embodiment, step <b>608</b> is performed during one iteration of the flow including step <b>604</b> and step <b>608</b>; and steps <b>610</b>, <b>612</b>, <b>614</b>, <b>616</b>, <b>618</b>, <b>620</b>, <b>622</b> and <b>624</b> are performed during another iteration of the flow including step <b>604</b> and step <b>606</b>.

0057In step <b>608</b> the communications device transmits information indicating the known location of the communications device. In some embodiments, the said information indicating the known location of the communications device includes a second value identifying one of a plurality of predetermined locations, said one of the plurality of predetermined locations being the location of the communications device. In some embodiments, the known location is a predetermined anchor point location from a set of possible anchor point locations, e.g., anchor point location <b>2</b> where location <b>2</b> corresponds to a predetermined map or floor plan location.

0058In step <b>610</b> the communications device measures signals received from other devices. Step <b>610</b> includes steps <b>612</b> and <b>614</b>, which may be performed serially or in parallel. In step <b>612</b> the communications device measures the received power of a first peer discovery signal communicating a first device identifier. Operation proceeds from step <b>612</b> to step <b>616</b>. Returning to step <b>614</b>, in step <b>614</b>, the communications device measures the received power of a second peer discovery signal communicating a second device identifier. Operation proceeds from step <b>614</b> to step <b>618</b>.

0059Returning to step <b>616</b>, in step <b>616</b> the communications device determines from the first peer discovery signal the first device identifier. Returning to step <b>618</b>, in step <b>618</b> the communications device determines from the second peer discovery signal the second device identifier. Operation proceeds from steps <b>616</b> and <b>618</b> to step <b>620</b>.

0060In step <b>620</b> the communications device reports the signal measurement information and information indicating the devices from which the measured signals were received to a location determination server. Step <b>620</b> includes steps <b>622</b> and <b>624</b>, which may be performed serially or in parallel. In step <b>622</b> the communications device communicates the measured power of the first peer discovery signal and the first communicated device identifier to said location determination server. In step <b>624</b>, the communications device communicates the measured power of the second peer discovery signal and the second communicated device identifier to said location determination server.

0061In some embodiments the first and second peer discovery signals are received during the same peer discovery interval, and the reporting of the measured signal power information and corresponding device identifiers to said location determination server occur after the discrete peer discovery time interval in which peer discovery signals are received. In some embodiments, a peer to peer timing structure is implemented including a peer discovery time interval and a corresponding time interval for reporting signal power measurement and corresponding device identifiers to said location determination server. In some such embodiments, for each peer discovery interval, there is a corresponding reporting interval. In some embodiments, there are a predetermined number of peer discovery time intervals corresponding to each reporting interval, wherein said predetermined number is greater than 1.

0062Operation proceeds from step <b>606</b> to step <b>626</b>. In step <b>626</b> the communications device decides if it is to continue operating as location anchor point. If the communications device determines that it is to continue operating as a location anchor point, then operation proceeds from step <b>626</b> to step <b>604</b>. However, if the communications device determines that it is not to continue operating as a location anchor point then operation proceeds from step <b>626</b> to step <b>628</b>. In various embodiments, the communications device makes the decision of step <b>626</b> whether or not to continue operating as a location anchor point as a function of one or more of: time remaining in a time interval in which the communications device has agreed to operate as a location anchor point, a number of detected peer devices in its vicinity, a level of peer to peer communications in its vicinity, an amount of remaining battery power, a number of other devices which can be detected which also are currently acting as location anchor points, a request to continue operating as a location anchor point, a command to continue operating as a location anchor point, motion of the communications device, and a change in its current location, e.g., to outside a specified location anchor point designated region.

0063In step <b>628</b> the communications device decides if it should restart operating as a location anchor point. If the communications device determines that it should restart operating as a location anchor point, then operation proceeds from step <b>628</b> to step <b>604</b>; otherwise operation proceeds from the output of step <b>628</b> to the input of step <b>628</b> for another check if it should restart operating as a location anchor point. In various embodiments, the communications device makes the decision of step <b>628</b> whether or not to restart operating as a location anchor point as a function as a function of one or more of: a received request to operate as a location anchor point, a received command to start operating as a location anchor point, a number of detected peer devices in its vicinity, a level of peer to peer communications in its vicinity, an amount of remaining battery power, a number of other devices which can be detected which also are currently acting as location anchor points, a request to restart operating as a location anchor point, a change in its status from motion to stationary, a change in its current location, e.g., to within a specified location anchor point designated region, current time matching a predetermined time for which the communications device is commanded or requested to start operating as a location anchor point.

0064<figref idref="DRAWINGS">FIG. 7</figref> is a drawing of an exemplary communications device <b>700</b>, e.g., a mobile communications device supporting peer to peer signaling, in accordance with an exemplary embodiment. Exemplary communications device <b>700</b> is, e.g., one of the mobile devices (<b>520</b>, <b>522</b>, . . . , <b>524</b>) with temporary location anchor point capability of system <b>500</b> of <figref idref="DRAWINGS">FIG. 5</figref>. Exemplary communications device <b>700</b> may, and sometimes does, implement a method in accordance with flowchart <b>600</b> of <figref idref="DRAWINGS">FIG. 6</figref>.

0065Communications device <b>700</b> includes a processor <b>702</b> and memory <b>704</b> coupled together via a bus <b>709</b> over which the various elements (<b>702</b>, <b>704</b>) may interchange data and information. Communications device <b>700</b> further includes an input module <b>706</b> and an output module <b>708</b> which may be coupled to processor <b>702</b> as shown. However, in some embodiments, the input module <b>706</b> and output module <b>708</b> are located internal to the processor <b>702</b>. Input module <b>706</b> can receive input signals. Input module <b>706</b> can, and in some embodiments does, include a wireless receiver and/or a wired or optical input interface for receiving input. Output module <b>708</b> may include, and in some embodiments does include, a wireless transmitter and/or a wired or optical output interface for transmitting output. In some embodiments, memory <b>704</b> includes routines <b>711</b> and data/information <b>713</b>.

0066In various embodiments, processor <b>702</b> is configured to: transmit a signal including a first value at a predetermined location in said signal, said first value indicating that the communications device is operating as a location anchor point; and perform at least one of: i) transmitting information indicating the known location of the communications device; or ii) measuring signals received from other devices and reporting the signal measurement information and information indicating the devices from which the measured signals were received to a location determination server. In some embodiments, processor <b>702</b> is configured to transmit information indicating the known location of the communications device; and said information includes a second value identifying one of a plurality of predetermined locations, said one of the plurality of predetermined locations being the location of said communications device. In various embodiments, the known location is a predetermined anchor point location from a set of possible anchor point locations, e.g. anchor point location <b>2</b> where location <b>2</b> corresponds to a predetermined map/floor location.

0067In some embodiments, the communications device <b>700</b> is a mobile communications device. For example, communications device <b>700</b> is a handheld battery powered mobile node supporting peer to peer communications which may, and sometimes does, serve as a temporary location anchor point.

0068Processor <b>702</b>, in some embodiments, is configured to measure signals received from other devices and report the signal measurement information and information indicating the devices from which the measured signals were received, and processor <b>702</b> is configured to measure the received power of a first peer discovery signal communicating a first device identifier, as part of being configured to measure signals. In some such embodiments, processor <b>702</b> is further configured to: determine from the first peer discovery signal the first communicated device identifier.

0069Processor <b>702</b>, in various embodiments, is configured to communicate the measured received power of the first peer discovery signal and said first communicated device identifier to said location determination server, as part of being configured to report the signal measurement information and information indicating the devices from which the measured signals were received. In some such embodiments, processor <b>702</b> is further configured to: measure the received power of a second peer discovery signal communicating a second device identifier, and processor <b>702</b> is configured to communicate the measured received power of the second peer discovery signal and said second communicated device identifier to said location determination server, as part of being configured to report the signal measurement information and information indicating the devices from which the measured signals were received.

0070In various embodiments, the first and second peer discovery signals are received during the same peer discovery interval, and processor <b>702</b> is configured to report the measured received signal power information and corresponding device identifiers to said location determination server after the discrete discovery time interval in which peer to peer discovery signals are received. In some embodiments, corresponding to each peer discovery interval there is a corresponding interval for reporting measured signal power measurement information and corresponding device identifiers to said location determination server.

0071<figref idref="DRAWINGS">FIG. 8</figref> is an assembly of modules <b>800</b> which can, and in some embodiments is, used in the exemplary communications device <b>700</b> illustrated in <figref idref="DRAWINGS">FIG. 7</figref>. The modules in the assembly <b>800</b> can be implemented in hardware within the processor <b>702</b> of <figref idref="DRAWINGS">FIG. 7</figref>, e.g., as individual circuits. Alternatively, the modules may be implemented in software and stored in the memory <b>704</b> of communications device <b>700</b> shown in <figref idref="DRAWINGS">FIG. 7</figref>. In some such embodiments, the assembly of modules <b>800</b> is included in routines <b>711</b> of memory <b>704</b> of device <b>700</b> of <figref idref="DRAWINGS">FIG. 7</figref>. While shown in the <figref idref="DRAWINGS">FIG. 7</figref> embodiment as a single processor, e.g., computer, it should be appreciated that the processor <b>702</b> may be implemented as one or more processors, e.g., computers. When implemented in software the modules include code, which when executed by the processor, configure the processor, e.g., computer, <b>702</b> to implement the function corresponding to the module. In some embodiments, processor <b>702</b> is configured to implement each of the modules of the assembly of modules <b>800</b>. In embodiments where the assembly of modules <b>800</b> is stored in the memory <b>704</b>, the memory <b>704</b> is a computer program product comprising a computer readable medium, e.g., a non-transitory computer readable medium, comprising code, e.g., individual code for each module, for causing at least one computer, e.g., processor <b>702</b>, to implement the functions to which the modules correspond.

0072Completely hardware based or completely software based modules may be used. However, it should be appreciated that any combination of software and hardware (e.g., circuit implemented) modules may be used to implement the functions. As should be appreciated, the modules illustrated in <figref idref="DRAWINGS">FIG. 4</figref> control and/or configure the communications device <b>700</b> or elements therein such as the processor <b>702</b>, to perform the functions of the corresponding steps illustrated and/or described in the method of flowchart <b>600</b> of <figref idref="DRAWINGS">FIG. 6</figref>.

0073Assembly of modules <b>800</b> includes a module <b>801</b> for determining if the current location of the communications device matches one of a plurality of predetermined anchor point locations, a module <b>803</b> for generating a signal including a first value at a predetermined location in said signal, said first value indicating that the communications device is operating as a location anchor point, a module <b>804</b> for transmitting a signal including a first value at a predetermined location in said signal, said first value indicating that the communication device is operating as a location anchor point, a module <b>806</b> for performing at least one of: i) transmitting information indicating the known location of the communications device; or ii) measuring signals received from other devices and reporting the signal measurement information and information indicating the devices from which the measured signals were received to a location determination server, a module <b>826</b> for determining if the communications device is to continue operating as a location anchor point, a module <b>827</b> for controlling operations as a function of the determination as to whether or not the communications device is to continue operating as a location anchor point, a module <b>828</b> for determining if said communications device is to restart operating as a location anchor point and a module <b>829</b> for controlling operations as a function of the determination as to whether or not the communications device is to restart operating as a location anchor point.

0074Module <b>806</b> includes a module <b>808</b> for transmitting information indicating the known location of the communications device, and a module <b>810</b> for measuring signals received from other devices. Module <b>810</b> includes a module <b>812</b> for measuring the received power of a first peer discovery signal communicating a first device identifier and a module <b>814</b> for measuring the received power of a second peer discovery signal communicating a second device identifier. Module <b>806</b> further includes a module <b>816</b> for determining from the first peer discovery signal the first device identifier, a module <b>818</b> for determining form the second peer discovery signal the second device identifier, and a module <b>820</b> for reporting the signal measurement information and information indicating the devices from which the measured signals were received to a location determination server. Module <b>820</b> includes a module <b>822</b> for communicating the measured power of the first peer discovery signal and the first communicated device identifier to said location determination server and a module <b>824</b> for communicating the measured power of the second peer discovery signal and second communicated device identifier to said location determination server.

0075In the assembly of modules <b>800</b>, some of the modules are shown as being included internal to other modules. In some embodiments, one or more or all of the modules shown as being included within other modules may be standalone modules.

0076<figref idref="DRAWINGS">FIG. 9</figref> is a drawing <b>900</b> illustrating an example in which a mobile wireless communications device transmits a signal indicating its willingness to perform a location determination related operation and then performs a location determination related operation in accordance with an exemplary embodiment. Mobile device <b>1</b><b>902</b> generates and transmits peer discovery signal <b>906</b>. Peer discovery signal <b>906</b> includes information <b>908</b> including a header field in which Bit <b>1</b>_LRD0has been set equal to 1 indicating that mobile device <b>1</b> is willing to perform a first type of location determination related operation.

0077The transmitted peer discovery signal <b>906</b> is received and recovered by mobile device <b>2</b><b>904</b>. Mobile device <b>2</b><b>904</b> generates signal <b>910</b> including a request for the current and/or past location of mobile device <b>1</b><b>912</b>. Mobile device <b>1</b><b>902</b> monitors for receipt of signals from other mobile devices corresponding to its offer to perform the first type of location determination related determination operation. Mobile device <b>1</b><b>902</b> receives and recovers signal <b>910</b>. Mobile device <b>1</b><b>902</b> generates and transmits signal <b>914</b> communicating information <b>916</b> indicating the current and/or past position of mobile device <b>1</b>. Mobile device <b>2</b><b>904</b> receives signal <b>914</b> and recovers the information <b>916</b>. Mobile device <b>2</b><b>904</b> uses the recovered information to estimate its own past and/or current position.

0078<figref idref="DRAWINGS">FIG. 10</figref> is a drawing <b>1000</b> illustrating another example in which a mobile wireless communications device transmits a signal indicating its willingness to perform a location determination related operation and then performs a location determination related operation in accordance with an exemplary embodiment. In this example, there is an obstruction <b>1002</b>, which is a door which may be open or closed at different times, and the door is at a known location on a gridmap which is stored in the mobile devices. Mobile device <b>1</b><b>902</b> generates and transmits peer discovery signal <b>1004</b>. Peer discovery signal <b>1004</b> includes information <b>1006</b> including a header field in which Bit <b>2</b>_LRD0has been set equal to 1 indicating that mobile device <b>1</b><b>902</b> is willing to perform a second type of location determination related operation.

0079The transmitted peer discovery signal <b>1004</b> is received and recovered by mobile device <b>2</b><b>904</b>. Mobile device <b>2</b><b>904</b> generates signal <b>1008</b> including a request for a map parameter which identifies if the door <b>1002</b> is open or closed at the current time <b>1010</b>. Mobile device <b>1</b><b>902</b> monitors for receipt of signals from other mobile devices corresponding to its offer to perform the second type of location determination related determination operation. Mobile device <b>2</b><b>904</b> receives and recovers signal <b>1008</b>. Mobile device <b>1</b><b>902</b> performs a signal measurement on the received signal, e.g., a power measurement, and uses the signal measurement in determining the requested map parameter. In this example, consider that mobile device <b>1</b><b>902</b> determines that the door <b>1002</b> is open. Mobile device <b>1</b><b>902</b> generates and transmits signal <b>1012</b> communicating information indicating that the door is open. Mobile device <b>2</b><b>904</b> receives signal <b>1012</b> and recovers the information <b>1014</b>. Mobile device <b>2</b><b>904</b> updates the communicated parameter indicating the status of the door. Mobile device <b>2</b><b>904</b> subsequently uses the updated parameter in performing a position determination of its location.

0080<figref idref="DRAWINGS">FIG. 11</figref> is a drawing <b>1100</b> illustrating yet another example in which a mobile wireless communications device transmits a signal indicating its willingness to perform a location determination related operation and then performs a location determination related operation in accordance with an exemplary embodiment. Mobile device <b>1</b><b>902</b> generates and transmits peer discovery signal <b>1102</b>. Peer discovery signal <b>1102</b> includes information <b>1104</b> including a header field in which Bit <b>3</b>_LRD0has been set equal to 1 indicating that mobile device <b>1</b> is willing to perform a third type of location determination related operation.

0081The transmitted peer discovery signal <b>1102</b> is received and recovered by mobile device <b>2</b><b>904</b>. Mobile device <b>2</b><b>904</b> generates signal <b>1106</b> including a request for the mobile node <b>1</b>'s estimation of the current position of mobile device <b>2</b><b>1108</b>. Mobile device <b>1</b><b>902</b> monitors for receipt of signals from other mobile devices corresponding to its offer to perform the third type of location determination related determination operation. Mobile device <b>1</b><b>902</b> receives and recovers signal <b>1108</b>. Mobile device <b>1</b><b>902</b> generates and transmits signal <b>1110</b> communicating information <b>1112</b> indicating mobile device <b>1</b>'s estimation of the current position of mobile device <b>2</b>. Mobile device <b>2</b><b>902</b> receives signal <b>1110</b> and recovers the information <b>1112</b>. Mobile device <b>2</b><b>904</b> uses the recovered information to validate and/or update its estimation of its current position.

0082<figref idref="DRAWINGS">FIG. 12</figref> is a drawing <b>1200</b> illustrating still another example in which a mobile wireless communications device transmits a signal indicating its willingness to perform a location determination related operation and then performs a location determination related operation in accordance with an exemplary embodiment. Mobile device <b>1</b><b>902</b> generates and transmits peer discovery signal <b>1202</b>. Peer discovery signal <b>1202</b> includes information <b>1204</b> including a header field in which Bit <b>4</b>_LRD0has been set equal to 1 indicating that mobile device <b>1</b> is willing to perform a fourth type of location determination related operation.

0083The transmitted peer discovery signal <b>1202</b> is received and recovered by mobile device <b>2</b><b>904</b>. Mobile device <b>2</b><b>904</b> generates signal <b>1206</b> including a request for a timing signal used in making a round trip timing determination. Mobile device <b>1</b><b>902</b> monitors for receipt of signals from other mobile devices corresponding to its offer to perform the fourth type of location determination related determination operation. Mobile device <b>1</b><b>902</b> receives and recovers signal <b>1208</b>. Mobile device <b>1</b><b>902</b> generates and transmits signal <b>1210</b> communicating information used in making a round trip timing determination. Mobile device <b>2</b><b>902</b> receives signal <b>1210</b> and recovers the information <b>1212</b>. Mobile device <b>2</b><b>904</b> makes a round trip timing determination based on signal <b>1210</b> and/or information <b>1212</b>. Mobile device <b>2</b><b>904</b> uses the round trip timing determination to estimate its current position.

0084Exemplary mobile devices (mobile device <b>1</b><b>902</b> and mobile device <b>2</b><b>904</b>) of <figref idref="DRAWINGS">FIGS. 9-12</figref> are, e.g., any of the mobile devices (<b>119</b>, <b>112</b>, . . . , <b>114</b>) of system <b>100</b> of <figref idref="DRAWINGS">FIG. 1</figref>. Mobile device <b>1</b><b>902</b>, is, e.g., first mobile communications device <b>300</b> of <figref idref="DRAWINGS">FIG. 3</figref> which implement a method in accordance with flowchart <b>200</b> of <figref idref="DRAWINGS">FIG. 2</figref>.

0085<figref idref="DRAWINGS">FIG. 13</figref> is a drawing <b>1300</b> illustrating an example, in which a mobile wireless communications device transmits a signal including a first value at a predetermined location which indicates that the communications device is temporarily operating as a location anchor point in accordance with an exemplary embodiment. Mobile device <b>1</b>′ <b>1302</b> is temporarily operating as a location anchor point as indicated by box <b>1310</b>. Mobile device <b>1</b>′ <b>1310</b> generates and transmits peer discovery signal <b>1312</b>. Peer discovery signal <b>1312</b> includes information <b>1314</b> which includes a header field in which header field bit <b>5</b> has been set equal to 1 indicating that mobile device <b>1</b>′ is currently operating as a location anchor point. Peer discovery signal <b>1312</b> also includes information <b>1316</b> which indicates the mobile device <b>1</b>′ is at position <b>2</b> in a set of predetermined possible alternative temporary location anchor point locations. Transmitted peer discovery signal <b>1312</b> is received and recovered by mobile device <b>2</b><b>1304</b> and mobile device <b>2</b>′ <b>1306</b>.

0086Fixed location access point <b>1</b><b>1308</b> which serves as a permanent location anchor point, generates and transmits peer discovery signal <b>1318</b>. Mobile device <b>2</b> receives and recovers peer discovery signal <b>1318</b>. Mobile device <b>2</b><b>1304</b> determines its position as a function of signals received from mobile device <b>1</b>′, which is serving as a temporary location anchor point and signals received from fixed location access point <b>1</b> which is a permanent location anchor point, as indicated by block <b>1320</b>. Mobile device <b>2</b>′ <b>1306</b> determines its position as a function of signals received from mobile device <b>1</b>′, which is serving as a temporary location anchor point.

0087Mobile device <b>1</b>′ <b>1302</b> and mobile device <b>2</b>′ <b>1306</b> are, e.g., any of the mobile devices with temporary location anchor point capability (<b>520</b>, <b>522</b>, . . . , <b>524</b>) of system <b>500</b> of <figref idref="DRAWINGS">FIG. 5</figref>. Mobile device <b>2</b><b>1304</b> is, e.g., any of the mobile devices (<b>514</b>, <b>516</b>, . . . , <b>518</b>) of system <b>500</b> of <figref idref="DRAWINGS">FIG. 5</figref>. In some embodiments, each of the mobile communications devices includes temporary location anchor point capability. Mobile device <b>1</b>′ <b>1302</b> is, e.g., communications device <b>700</b> of <figref idref="DRAWINGS">FIG. 7</figref> which implements a method in accordance with flowchart <b>600</b> of <figref idref="DRAWINGS">FIG. 6</figref>.

0088<figref idref="DRAWINGS">FIG. 14</figref> and <figref idref="DRAWINGS">FIG. 15</figref> illustrating another example, in which a mobile wireless communications device transmits a signal including a first value at a predetermined location which indicates that the communications device is temporarily operating as a location anchor point in accordance with an exemplary embodiment.

0089Drawing <b>1400</b> of <figref idref="DRAWINGS">FIG. 14</figref> illustrates mobile device <b>1</b>′ <b>1402</b>, mobile device <b>2</b><b>1404</b>, mobile device <b>2</b>′ <b>1406</b>, access point <b>1</b><b>1408</b> and location determination server <b>1420</b>. Access point <b>1</b><b>1408</b> is coupled to location determination server <b>1420</b> via backhaul network <b>1422</b>. Mobile device <b>1</b>′ <b>1402</b> is temporarily operating as a location anchor point as indicated by box <b>1424</b>. Mobile device <b>1</b>′ <b>1402</b> generates and transmits peer discovery signal <b>1426</b>. Peer discovery signal <b>1426</b> includes information <b>1428</b> which includes a header field in which header field bit <b>6</b> has been set equal to 1 indicating that mobile device <b>1</b>′ is currently operating as a location anchor point.

0090Transmitted peer discovery signal <b>1426</b> is received and recovered by mobile device <b>2</b><b>1404</b> and mobile device <b>2</b>′ <b>1406</b>. Mobile device <b>2</b><b>1404</b> generates and transmits peer discovery signal <b>1430</b> including device identifier <b>2</b><b>1432</b>. Mobile device <b>2</b>′ <b>1406</b> generates and transmits peer discovery signal <b>1434</b> including device identifier <b>2</b>′ <b>1436</b>.

0091Mobile device <b>1</b>′ <b>1402</b> receives peer discovery signals (<b>1430</b>, <b>1434</b>), measures the received power of the received signals obtaining information (<b>1440</b>, <b>1444</b>). Mobile device <b>1</b>′ <b>1402</b> also determines the communicated identifiers obtaining information (<b>1428</b>, <b>1442</b>).

0092In drawing <b>1500</b> of <figref idref="DRAWINGS">FIG. 15</figref>, mobile device <b>1</b>′ <b>1402</b>, which is acting as a location anchor point, generates a signal <b>1502</b> to report the signal measurement information and information identifying the devices from which the measured signals were received to a location determination server. Wireless signal <b>1502</b> communicates information ((<b>1438</b>, <b>1440</b>), (<b>1442</b>, <b>1444</b>)) to access point <b>1</b><b>1408</b>. Access point <b>1</b><b>1408</b> generates and transmits signal <b>1504</b>, which communicates information ((<b>1438</b>, <b>1440</b>), (<b>1442</b>, <b>1444</b>)) over backhaul network <b>1422</b> to location determination server <b>1420</b>.

0093Location determination server <b>1420</b> uses the received signal measurement information and corresponding identifier information to determine the location of mobile device <b>2</b><b>1506</b> and the location of mobile device <b>2</b>′ <b>1508</b>. The received measurement information obtained from mobile device <b>1</b>′ <b>1402</b> may be, and sometimes is, used in combination with received measurement information communicated to the location determination server from other location anchor points which may permanent and/or temporary location anchor point.

0094Mobile device <b>1</b>′ <b>1402</b> and mobile device <b>2</b>′ <b>1406</b> are, e.g., any of the mobile devices with temporary location anchor point capability (<b>520</b>, <b>522</b>, . . . , <b>524</b>) of system <b>500</b> of <figref idref="DRAWINGS">FIG. 5</figref>. Mobile device <b>2</b><b>1404</b> is, e.g., any of the mobile devices (<b>514</b>, <b>516</b>, . . . , <b>518</b>) of system <b>500</b> of <figref idref="DRAWINGS">FIG. 5</figref>. In some embodiments, each of the mobile communications devices includes temporary location anchor point capability. Mobile device <b>1</b>′ <b>1402</b> is, e.g., communications device <b>700</b> of <figref idref="DRAWINGS">FIG. 7</figref> which implements a method in accordance with flowchart <b>600</b> of <figref idref="DRAWINGS">FIG. 6</figref>. Access point <b>1</b><b>1408</b> is, e.g., any of the access points (<b>502</b>, . . . , <b>504</b>, <b>506</b>, . . . , <b>508</b>) of system <b>500</b> of <figref idref="DRAWINGS">FIG. 4</figref>. Location determination serve <b>1420</b> is, e.g., location determination server <b>510</b> of system <b>500</b> of <figref idref="DRAWINGS">FIG. 5</figref>.

0095Various aspects and features of some embodiments will be described below. <figref idref="DRAWINGS">FIG. 16</figref> illustrates an exemplary peer discovery signal <b>1600</b> in accordance with various embodiments. The exemplary peer discovery signal <b>1600</b> conveys peer discovery information bits. The exemplary peer discovery signal includes a header portion <b>1602</b> and a payload portion <b>1604</b>. The header potion <b>1602</b> includes a plurality of header bits (<b>1606</b>, <b>1608</b>, <b>1610</b>, <b>1612</b>). The header bits include a subset of bits (<b>1610</b>, <b>1612</b>) which are predetermined header bits used to signal a willingness to perform specific cooperative location determination operations. Bit <b>1610</b> is used to indicate the device's willingness to perform a first specific cooperative location determination operation, while bit <b>1612</b> is used to indicate the device's willingness to perform a second specific cooperative location determination operation. A cooperative location determination operation is sometimes referred to as a location determination related operation.

0096In some embodiments, a typical characteristic of a wireless network, e.g., a peer to peer wireless network, is that, at regular time intervals, e.g., in accordance with a predetermined peer to peer timing schedule, a subset of devices broadcast a subset of identifiers. This feature, which takes place during the peer discovery phase in some embodiments, is a core feature for many dynamic peer-to-peer networks. In some embodiments, a part of the peer discovery identifier signal is used to encode the participation of a peer to a particular positioning/estimation function. Hence, an active signal is formed that may enable a sequence of events.

0097More precisely, consider, e.g., an exemplary peer to peer network where the willingness of a peer to participate into a positioning function is carried by, e.g., predetermined bits of a peer discovery signal, and the peers broadcasting their peer discovery signals in a synchronized manner so the peer discovery signals are easy to receive. In some embodiments, a positioning function refers to functions associated with, for example RF fingerprint prediction map learning, joint position determination operations, and/or or any alternative hybrid position determination scheme.

0098For example, in some embodiments, a mobile device may, and sometimes does, signal, through the setting of a predetermined bit in a peer discovery signal that it is acting temporarily as a location anchor point, e.g., that it is temporarily broadcasting its position to other devices and/or communicating signal measurement information relating to other devices to a position determination server which uses the signal measurements and corresponding information identifying a transmitting device to determine the location of the transmitting device.

0099Several examples will be discussed below. A first example addresses cases where a device notifies its readiness to participate in estimating a local map parameter. Such parameters include, e.g., a specific wall material, the presence of a crowd, or a state to describe whether a door is open. For example, consider that exemplary peer mobile wireless device A happens to know its own position with some satisfying accuracy and further consider that this position is adjacent to an obstruction of undefined constituent material, e.g., a wall whose undefined constituent material makes the generation of the fingerprint prediction map unreliable. Further consider that another device, peer mobile wireless device B, shares characteristics similar to peer A. Then, either peer A or peer B may initiate paging and the two devices may exchange information regarding their respective positions. The two devices may, and sometimes do, further decide to jointly estimate the critical wall parameter. For example, they may exchange information and/or run a certain protocol, e.g., based on received power or multipath characteristics, to finely estimate the wall characteristics. In summary, a sequence of events, e.g., paging, traffic, estimation protocol, follows again from the detection of particular format bits.

0100A second example addresses cases where a device wants to and/or is willing to perform a position ambiguity resolution function. As in the previous example, the device's willingness can be carried by the format bits in the header of the peer discovery signal. Here, willingness may be of two types: (i) the format bits may indicate that that the emitting device's position is ambiguous and that the device wants to resolve this ambiguity or (ii) the format bits may indicate that the emitting device is ready to support a certain protocol to help other devices to resolve their location ambiguity. In the two cases, the device that detects the format bits may decide to participate in the positioning function: in this case, it will page the emitting device, and eventually may start an estimation protocol such as an RTT-based or a power-based distance estimation to solve the position ambiguity. For instance, once such a device is discovered, a sequence of events, e.g., paging, traffic, and estimation protocol, may follow. Exemplary estimation protocols include positioning protocols such as, e.g., distance estimation with pulse-based detection.

0101A third class of examples addresses cases when exemplary peer mobile wireless device A acts temporarily as a location anchor point in the peer to peer communications network. For example, in some embodiments, the peer to peer network includes fixed location permanent location anchor points and also includes at least some mobile wireless devices which may, and sometimes do, serve as temporary location anchor points. In some embodiments, the anchor points may be referred to as nitelites.

0102A first exemplary case of this third class of examples occurs if peer A is obtaining GPS or any other accurate positioning information, if peer A is at a fixed location which is well defined or known, if peer A has a sufficient level of power resources available, or if peer A is characterized by a mixture of such characteristics. If peer B comes in the vicinity of peer A, then peer B may discover and interpret the signal emitted by peer A. Consider that peer B needs to refine its position. Then, peer B will page peer A and further exchange information regarding the position of peer A and/or the associated fingerprint prediction map.

0103A second exemplary case of this third class of examples will now be discussed. Consider that exemplary mobile device A: (i) has obtained enough information to determine its position and (ii) has determined its position, estimated up to some satisfying reliability. For example, device A has determined its current location and has determined an estimated accuracy of the current location determination that exceeds a predetermined accuracy threshold value used by the positioning system. In this case, peer A will participate to the positioning function, and broadcast corresponding format bits. If peer B receives peer A's signal, then a sequence of events, e.g., paging, traffic, etc., similar to the previous case may occur.

0104In the previous examples, the detection of some specific signal encapsulated in the format/header bits of a peer discovery signal triggers a sequence of events. For example, first, a peer, e.g. in the distributed case, or a server, e.g., in the centralized case, pages the device; second, it exchanges relevant information; third and potentially, it engages a specific protocol. The specific protocol may be used to perform effective measurements. Depending on the format bits, the system behavior may change accordingly. Format bits allow for active broadcasting: the discovery by another device of a particular message carried by those format bits may enable specific processing and/or operations, and subsequent steps may again engage active broadcasting, processing and/or operations. In some embodiments, the initial broadcast of some format bits, e.g., as part of a header in a peer discovery signal, may trigger multi-level processing and/or operation, i.e., sequences of inter-dependent subroutines. The inter-dependent subroutines are, e.g., for implementing protocols, performing communications, or performing estimation. In some exemplary peer to peer protocols, format bits, e.g., peer discovery header bits, are used to trigger dependent processes in a broadcast manner. In some embodiments the format bits are also used to keep track of the state of the multi-level processing and/or operations.

0105In various embodiments a device, e.g., first mobile communications device <b>300</b> of <figref idref="DRAWINGS">FIG. 3</figref> or communications device <b>700</b> of <figref idref="DRAWINGS">FIG. 7</figref>, includes a module corresponding to each of the individual steps and/or operations described with regard to any of the Figures in the present application and/or described in the detailed description of the present application. The modules may, and sometimes are implemented in hardware. In other embodiments, the modules may, and sometimes are, implemented as software modules including processor executable instructions which when executed by the processor of the communications device cause the device to implement the corresponding step or operation. In still other embodiments, some or all of the modules are implemented as a combination of hardware and software.

0106The techniques of various embodiments may be implemented using software, hardware and/or a combination of software and hardware. Various embodiments are directed to apparatus, e.g., network nodes such as location determination server nodes, mobile nodes such as mobile terminals, access points such as base stations serving as location anchor points, and/or communications systems. Various embodiments are also directed to methods, e.g., method of controlling and/or operating network nodes, mobile nodes, access points such as base stations and/or communications systems, e.g., hosts. Various embodiments are also directed to machine, e.g., computer, readable medium, e.g., ROM, RAM, CDs, hard discs, etc., which include machine readable instructions for controlling a machine to implement one or more steps of a method. The computer readable medium is, e.g., non-transitory computer readable medium.

0107It is understood that the specific order or hierarchy of steps in the processes disclosed is an example of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged while remaining within the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

0108In various embodiments nodes described herein are implemented using one or more modules to perform the steps corresponding to one or more methods, for example, signal processing, signal generation and/or transmission steps. Thus, in some embodiments various features are implemented using modules. Such modules may be implemented using software, hardware or a combination of software and hardware. Many of the above described methods or method steps can be implemented using machine executable instructions, such as software, included in a machine readable medium such as a memory device, e.g., RAM, floppy disk, etc. to control a machine, e.g., general purpose computer with or without additional hardware, to implement all or portions of the above described methods, e.g., in one or more nodes. Accordingly, among other things, various embodiments are directed to a machine-readable medium, e.g., a non-transitory computer readable medium, including machine executable instructions for causing a machine, e.g., processor and associated hardware, to perform one or more of the steps of the above-described method(s). Some embodiments are directed to a device, e.g., communications node, including a processor configured to implement one, multiple or all of the steps of one or more methods of the invention.

0109In some embodiments, the processor or processors, e.g., CPUs, of one or more devices, e.g., communications nodes such as network nodes, access nodes and/or wireless terminals, are configured to perform the steps of the methods described as being performed by the communications nodes. The configuration of the processor may be achieved by using one or more modules, e.g., software modules, to control processor configuration and/or by including hardware in the processor, e.g., hardware modules, to perform the recited steps and/or control processor configuration. Accordingly, some but not all embodiments are directed to a device, e.g., communications node, with a processor which includes a module corresponding to each of the steps of the various described methods performed by the device in which the processor is included. In some but not all embodiments a device, e.g., communications node, includes a module corresponding to each of the steps of the various described methods performed by the device in which the processor is included. The modules may be implemented using software and/or hardware.

0110Some embodiments are directed to a computer program product comprising a computer-readable medium, e.g., a non-transitory computer-readable medium, comprising code for causing a computer, or multiple computers, to implement various functions, steps, acts and/or operations, e.g. one or more steps described above. Depending on the embodiment, the computer program product can, and sometimes does, include different code for each step to be performed. Thus, the computer program product may, and sometimes does, include code for each individual step of a method, e.g., a method of controlling a communications device or node. The code may be in the form of machine, e.g., computer, executable instructions stored on a computer-readable medium, e.g., a non-transitory computer-readable medium, such as a RAM (Random Access Memory), ROM (Read Only Memory) or other type of storage device. In addition to being directed to a computer program product, some embodiments are directed to a processor configured to implement one or more of the various functions, steps, acts and/or operations of one or more methods described above. Accordingly, some embodiments are directed to a processor, e.g., CPU, configured to implement some or all of the steps of the methods described herein. The processor may be for use in, e.g., a communications device or other device described in the present application.

0111Various embodiments are well suited to communications systems using a peer to peer to peer signaling protocol. Various embodiments are well suited to location determination in indoor environments.

0112While described in the context of an OFDM system, at least some of the methods and apparatus of various embodiments are applicable to a wide range of communications systems including many non-OFDM and/or non-cellular systems.

0113Numerous additional variations on the methods and apparatus of the various embodiments described above will be apparent to those skilled in the art in view of the above description. Such variations are to be considered within the scope. The methods and apparatus may be, and in various embodiments are, used with CDMA, orthogonal frequency division multiplexing (OFDM), and/or various other types of communications techniques which may be used to provide wireless communications links between communications devices. In some embodiments one or more communications devices are implemented as access points which establish communications links with mobile nodes using OFDM and/or CDMA and/or may provide connectivity to the internet or another network via a wired or wireless communications link. In various embodiments the mobile nodes are implemented as notebook computers, personal data assistants (PDAs), or other portable devices including receiver/transmitter circuits and logic and/or routines, for implementing the methods.