Patent Publication Number: US-9900858-B2

Title: Apparatus, system and method of estimating a location of a mobile device

Description:
CROSS REFERENCE 
     This application is a National Phase Application of PCT International Application No. PCT/US2013/043213, International Filing Date May 30, 2013, the entire disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     Embodiments described herein generally relate to estimating a location of a mobile device. 
     BACKGROUND 
     Outdoor navigation is widely deployed thanks to the development of various global-navigation-satellite-systems (GNSS), e.g., Global Positioning System (GPS), GALILEO, and the like. 
     Recently, there has been a lot of focus on indoor navigation. This field differs from the outdoor navigation, since the indoor environment does not enable the reception of signals from GNSS satellites. As a result, a lot of effort is being directed towards solving the indoor navigation problem. This problem does not yet have a scalable solution with satisfactory precision. 
     One solution for indoor navigation includes a Time-of-Flight (ToF) measurement method. The ToF may be defined as the overall time a signal propagates from a first station, e.g., a user (“client”) mobile device, to a second station, e.g., an access point (AP), and back to the first station. A distance between the first and second stations may be calculated based on the ToF value. 
     An estimated location of the first station may be determined by calculating two or more distances between the first station and two or more other stations, e.g., other APs, by utilizing a suitable method, e.g., a trilateration method. 
     The location calculation method may not provide a location estimation with a desired accuracy, for example, if the one or more distances do not have a desired accuracy. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity of presentation. Furthermore, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. The figures are listed below. 
         FIG. 1  is a schematic block diagram illustration of a system, in accordance with some demonstrative embodiments. 
         FIG. 2  is a schematic sequence diagram illustration of operations between a mobile device and a wireless communication device, in accordance with some demonstrative embodiments. 
         FIG. 3  is a schematic sequence diagram illustration of operations and interactions between a mobile device and a wireless communication device during a discovery process, in accordance with some demonstrative embodiments. 
         FIG. 4  is a schematic block diagram illustration of a system, in accordance with some demonstrative embodiments. 
         FIG. 5  is a schematic illustration of a method of estimating a location of a mobile device, in accordance with some demonstrative embodiments. 
         FIG. 6  is a schematic illustration of a product of manufacture, in accordance with some demonstrative embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of some embodiments. However, it will be understood by persons of ordinary skill in the art that some embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, units and/or circuits have not been described in detail so as not to obscure the discussion. 
     Discussions herein utilizing terms such as, for example, “processing”, “computing”, “calculating”, “determining”, “establishing”, “analyzing”, “checking”, or the like, may refer to operation(s) and/or process(es) of a computer, a computing platform, a computing system, or other electronic computing device, that manipulate and/or transform data represented as physical (e.g., electronic) quantities within the computer&#39;s registers and/or memories into other data similarly represented as physical quantities within the computer&#39;s registers and/or memories or other information storage medium that may store instructions to perform operations and/or processes. 
     The terms “plurality” and “a plurality”, as used herein, include, for example, “multiple” or “two or more”. For example, “a plurality of items” includes two or more items. 
     References to “one embodiment”, “an embodiment”, “demonstrative embodiment”, “various embodiments” etc., indicate that the embodiment(s) so described may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Further, repeated use of the phrase “in one embodiment” does not necessarily refer to the same embodiment, although it may. 
     As used herein, unless otherwise specified the use of the ordinal adjectives “first”, “second”, “third” etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner. 
     Some embodiments may be used in conjunction with various devices and systems, for example, a Personal Computer (PC), a desktop computer, a mobile computer, a laptop computer, a notebook computer, a tablet computer, a server computer, a handheld computer, a handheld device, a Personal Digital Assistant (PDA) device, a handheld PDA device, an on-board device, an off-board device, a hybrid device, a vehicular device, a non-vehicular device, a mobile or portable device, a consumer device, a non-mobile or non-portable device, a wireless communication station, a wireless communication device, a wireless Access Point (AP), a wired or wireless router, a wired or wireless modem, a video device, an audio device, an audio-video (A/V) device, a wired or wireless network, a wireless area network, a Wireless Video Area Network (WVAN), a Local Area Network (LAN), a Wireless LAN (WLAN), a Personal Area Network (PAN), a Wireless PAN (WPAN), and the like. 
     Some embodiments may be used in conjunction with devices and/or networks operating in accordance with existing IEEE 802.11 standards ( IEEE  802.11-2012 , IEEE Standard for Information technology—Telecommunications and information exchange between systems Local and metropolitan area networks—Specific requirements Part  11 : Wireless LAN Medium Access Control  ( MAC )  and Physical Layer  ( PHY )  Specifications, Mar.  29, 2102; IEEE802.11 task group ac (TGac) (“ IEEE 802.11-09/0308 r 12— TGac Channel Model Addendum Document ”);  IEEE  802.11  task group ad  ( TGad ) ( IEEE P 802.11 ad Standard for Information Technology—Telecommunications and Information Exchange Between Systems—Local and Metropolitan Area Networks—Specific Requirements—Part  11 : Wireless LAN Medium Access Control  ( MAC )  and Physical Layer  ( PHY )  Specifications—Amendment  3:  Enhancements for Very High Throughput in the  60  GHz Band ); IEEE 802.11-REVmc ( IEEE P 802.11- REVmc/D 1.2 —Telecommunications and information exchange between systems, Local and metropolitan area networks—Specific requirements, Part  11 : Wireless LAN Medium Access Control  ( MAC )  and Physical Layer  ( PHY )  Specifications, April  2013)) and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing Wireless-Gigabit-Alliance (WGA) specifications ( Wireless Gigabit Alliance, Inc WiGig MAC and PHY Specification Version  1.1 , April  2011 , Final specification ) and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing Wireless Fidelity (WiFi) Alliance (WFA) Peer-to-Peer (P2P) specifications ( WiFi P 2 P technical specification, version  1.3, 2012) and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing cellular specifications and/or protocols, e.g., 3 rd  Generation Partnership Project (3GPP), 3GPP Long Term Evolution (LTE), and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing Open Mobile Alliance (OMA) standards, including the Secure User Plane Location (SUPL) protocol ( SUPL - OMA - AD - SUPL - V 2.0 5.3.1.8), the Mobile Location Protocol (MLP) ( OMA - TS - MLP v  3.3 , March  2009) and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing In Location Alliance protocols and/or standards and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing World-Wide-Web Consortium (W3C) standards, including the  W 3 C Hypertext Markup Language  ( HTML )  Version  5, October 2010 and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing WirelessHD™ specifications and/or future versions and/or derivatives thereof, units and/or devices which are part of the above networks, and the like. 
     Some embodiments may be used in conjunction with one way and/or two-way radio communication systems, cellular radio-telephone communication systems, a mobile phone, a cellular telephone, a wireless telephone, a Personal Communication Systems (PCS) device, a PDA device which incorporates a wireless communication device, a mobile or portable Global Positioning System (GPS) device, a device which incorporates a GPS receiver or transceiver or chip, a device which incorporates an RFID element or chip, a Multiple Input Multiple Output (MIMO) transceiver or device, a Single Input Multiple Output (SIMO) transceiver or device, a Multiple Input Single Output (MISO) transceiver or device, a device having one or more internal antennas and/or external antennas, Digital Video Broadcast (DVB) devices or systems, multi-standard radio devices or systems, a wired or wireless handheld device, e.g., a Smartphone, a Wireless Application Protocol (WAP) device, or the like. 
     Some embodiments may be used in conjunction with one or more types of wireless communication signals and/or systems, for example, Radio Frequency (RF), Infra Red (IR), Frequency-Division Multiplexing (FDM), Orthogonal FDM (OFDM), Time-Division Multiplexing (TDM), Time-Division Multiple Access (TDMA), Extended TDMA (E-TDMA), General Packet Radio Service (GPRS), extended GPRS, Code-Division Multiple Access (CDMA), Wideband CDMA (WCDMA), CDMA 2000, single-carrier CDMA, multi-carrier CDMA, Multi-Carrier Modulation (MDM), Discrete Multi-Tone (DMT), Bluetooth®, Global Positioning System (GPS), Wi-Fi, Wi-Max, ZigBee™, Ultra-Wideband (UWB), Global System for Mobile communication (GSM), 2G, 2.5G, 3G, 3.5G, 4G, Fifth Generation (5G) mobile networks, 3GPP, Long Term Evolution (LTE), LTE advanced, Enhanced Data rates for GSM Evolution (EDGE), or the like. Other embodiments may be used in various other devices, systems and/or networks. 
     The term “wireless device”, as used herein, includes, for example, a device capable of wireless communication, a communication device capable of wireless communication, a communication station capable of wireless communication, a portable or non-portable device capable of wireless communication, or the like. In some demonstrative embodiments, a wireless device may be or may include a peripheral that is integrated with a computer, or a peripheral that is attached to a computer. In some demonstrative embodiments, the term “wireless device” may optionally include a wireless service. 
     The phrase “docking station”, as used herein, may relate to an interface connected to one or more peripheral devices, e.g., a display, one or more speakers, a mouse, a keyboard and/or the like, configured to enable a device to connect to and communicate with the peripheral devices. For example, the docking station may be configured to enable a mobile device, e.g., a mobile computer, to connect to an external display and/or an external keyboard. 
     The term “communicating” as used herein with respect to a wireless communication signal includes transmitting the wireless communication signal and/or receiving the wireless communication signal. For example, a wireless communication unit, which is capable of communicating a wireless communication signal, may include a wireless transmitter to transmit the wireless communication signal to at least one other wireless communication unit, and/or a wireless communication receiver to receive the wireless communication signal from at least one other wireless communication unit. 
     Some demonstrative embodiments may be used in conjunction with a WLAN. Other embodiments may be used in conjunction with any other suitable wireless communication network, for example, a wireless area network, a “piconet”, a WPAN, a WVAN and the like. 
     Some demonstrative embodiments may be used in conjunction with a wireless communication network communicating over a frequency band of 60 GHz. However, other embodiments may be implemented utilizing any other suitable wireless communication frequency bands, for example, an Extremely High Frequency (EHF) band (the millimeter wave (mmWave) frequency band), e.g., a frequency band within the frequency band of between 20 Ghz and 300 GHZ, a WLAN frequency band, a WPAN frequency band, a frequency band according to the WGA specification, and the like. 
     The term “antenna”, as used herein, may include any suitable configuration, structure and/or arrangement of one or more antenna elements, components, units, assemblies and/or arrays. In some embodiments, the antenna may implement transmit and receive functionalities using separate transmit and receive antenna elements. In some embodiments, the antenna may implement transmit and receive functionalities using common and/or integrated transmit/receive elements. The antenna may include, for example, a phased array antenna, a single element antenna, a set of switched beam antennas, and/or the like. 
     The term “station” (STA), as used herein, may include any logical entity that is a singly addressable instance of a medium access control (MAC) and a physical layer (PHY) interface to a wireless medium (WM). 
     The phrase “access point” (AP), as used herein, may include an entity that contains one station (STA) and provides access to distribution services, via the WM for associated STAs. 
     The phrase “peer to peer (PTP or P2P) communication”, as used herein, may relate to device-to-device communication over a wireless link (“peer-to-peer link”) between a pair of devices. The P2P communication may include, for example, wireless communication over a direct link within a QoS basic service set (BSS), a tunneled direct-link setup (TDLS) link, a STA-to-STA communication in an independent basic service set (IBSS), or the like. 
     The phrases “directional multi-gigabit (DMG)” and “directional band” (DBand), as used herein, may relate to a frequency band wherein the Channel starting frequency is above 40 GHz. 
     The phrases “DMG STA” and “mmWave STA (mSTA)” may relate to a STA having a radio transmitter, which is operating on a channel that is within the DMG band. 
     The term “beamforming”, as used herein, may relate to a spatial filtering mechanism, which may be used at a transmitter and/or a receiver to improve the received signal power or signal-to-noise ratio (SNR) at an intended receiver. 
     Reference is now made to  FIG. 1 , which schematically illustrates a block diagram of a system  100 , in accordance with some demonstrative embodiments. 
     As shown in  FIG. 1 , in some demonstrative embodiments, system  100  may include one or more wireless communication devices capable of communicating content, data, information and/or signals via a wireless communication medium (WM)  103 . For example, system  100  may include a mobile device  110  and a wireless communication device  120 . Wireless communication medium  103  may include, for example, a radio channel, a cellular channel, an RF channel, a Wireless Fidelity (WiFi) channel, an IR channel, and the like. One or more elements of system  100  may optionally be capable of communicating over any suitable wired communication links. 
     In some demonstrative embodiments, system  100  may include one or more client STAs, and one or more APs. For example, device  110  may perform the functionality of a client STA, and device  120  may perform the functionality of an AP, e.g., a WiFi AP, a router, and the like. 
     In some demonstrative embodiments, device  110  and/or device  120  may perform the functionality of mmWave STAs, e.g., DMG stations (“DMG STA”). For example, device  110  and/or device  120  may be configured to communicate over the DMG band. 
     In some demonstrative embodiments, device  120  may include a mobile or a non-mobile device, e.g., a static device. 
     In some demonstrative embodiments, device  120  may perform the functionality of a wireless docking station, configured to enable mobile device  110  to connect to, e.g., in a wireless manner, one or more peripheral devices, e.g., a keyboard, a display, a mouse and/or the like. 
     In some demonstrative embodiments, mobile device  110  may include, for example, a User Equipment (UE), a mobile computer, a laptop computer, a notebook computer, a tablet computer, an Ultrabook™ computer, a mobile internet device, a handheld computer, a handheld device, a storage device, a PDA device, a handheld PDA device, an on-board device, an off-board device, a hybrid device (e.g., combining cellular phone functionalities with PDA device functionalities), a consumer device, a vehicular device, a non-vehicular device, a mobile phone, a cellular telephone, a PCS device, a PDA device which incorporates a wireless communication device, a mobile or portable GPS device, a relatively small computing device, a non-desktop computer, a “Carry Small Live Large” (CSLL) device, an Ultra Mobile Device (UMD), an Ultra Mobile PC (UMPC), a Mobile Internet Device (MID), an “Origami” device or computing device, a device that supports Dynamically Composable Computing (DCC), a video device, an audio device, an A/V device, a gaming device, a media player, a Smartphone, or the like. 
     In some demonstrative embodiments, wireless communication medium  103  may include a direct link, e.g., a P2P link, for example, to enable direct communication between device  110  and device  120 . 
     In some demonstrative embodiments, wireless communication medium  103  may include a wireless communication link over the mmWave band, e.g., the DMG band. 
     In some demonstrative embodiments, wireless communication medium  103  may include a wireless beamformed link. 
     In some demonstrative embodiments, wireless communication medium  103  may include a wireless gigabit (WiGig) link. For example, wireless communication medium  103  may include a wireless beamformed link over the 60 GHZ frequency band. 
     In other embodiments, wireless communication medium  103  may include any other suitable link and/or may utilize any other suitable wireless communication technology. 
     In some demonstrative embodiments, device  110  and/or device  120  may include wireless communication units, to perform wireless communication between device  110  and device  120  over wireless communication medium  103 . For example, device  110  may include a wireless communication unit  112 , and/or device  120  may include a wireless communication unit  122 . 
     In some demonstrative embodiments, wireless communication units  112  and/or  114  may include one or more radios, e.g., including one or more wireless transmitters, receivers and/or transceivers able to send and/or receive wireless communication signals, RF signals, frames, blocks, transmission streams, packets, messages, data items, and/or data. In one example, the radios may include modulation elements, demodulation elements, amplifiers, analog to digital and digital to analog converters, filters, and/or the like. For example, wireless communication units  112  and/or  114  may include or may be implemented as part of a wireless Network Interface Card (NIC), and the like. 
     In some demonstrative embodiments, the wireless communication units may include, or may be associated with, one or more antennas. For example, wireless communicate unit  112  may be associated with one or more antennas  108  and wireless communicate unit  122  may be associated with one or more antennas  128 . 
     Antennas  108  and/or  128  may include any type of antennas suitable for transmitting and/or receiving wireless communication signals, blocks, frames, transmission streams, packets, messages and/or data. For example, antennas  108  and/or  128  may include any suitable configuration, structure and/or arrangement of one or more antenna elements, components, units, assemblies and/or arrays. Antennas  108  and/or  128  may include, for example, antennas suitable for directional communication, e.g., using beamforming techniques. For example, antennas  108  and/or  128  may include a phased array antenna, a multiple element antenna, a set of switched beam antennas, and/or the like. In some embodiments, antennas  108  and/or  128  may implement transmit and receive functionalities using separate transmit and receive antenna elements. In some embodiments, antennas  108  and/or  128  may implement transmit and receive functionalities using common and/or integrated transmit/receive elements. 
     In some demonstrative embodiments, mobile device  110  and/or device  120  may also include, for example, one or more of a processor  191 , an input unit  192 , an output unit  193 , a memory unit  194 , and a storage unit  195 . Mobile device  110  and/or device  120  may optionally include other suitable hardware components and/or software components. In some demonstrative embodiments, some or all of the components of mobile device  110  and/or device  120  may be enclosed in a common housing or packaging, and may be interconnected or operably associated using one or more wired or wireless links. In other embodiments, components of mobile device  110  and/or device  120  may be distributed among multiple or separate devices. 
     Processor  191  includes, for example, a Central Processing Unit (CPU), a Digital Signal Processor (DSP), one or more processor cores, a single-core processor, a dual-core processor, a multiple-core processor, a microprocessor, a host processor, a controller, a plurality of processors or controllers, a chip, a microchip, one or more circuits, circuitry, a logic unit, an Integrated Circuit (IC), an Application-Specific IC (ASIC), or any other suitable multi-purpose or specific processor or controller. For example, processor  111  executes instructions, for example, of an Operating System (OS) of mobile device  110 , device  120  and/or of one or more suitable applications. 
     Memory unit  194  includes, for example, a Random Access Memory (RAM), a Read Only Memory (ROM), a Dynamic RAM (DRAM), a Synchronous DRAM (SD-RAM), a flash memory, a volatile memory, a non-volatile memory, a cache memory, a buffer, a short term memory unit, a long term memory unit, or other suitable memory units. Storage unit  195  include, for example, a hard disk drive, a floppy disk drive, a Compact Disk (CD) drive, a CD-ROM drive, a DVD drive, or other suitable removable or non-removable storage units. For example, memory unit  194  and/or storage unit  195 , for example, may store data processed by mobile device  110  and/or device  120 . 
     Input unit  192  includes, for example, a keyboard, a keypad, a mouse, a touch-screen, a touch-pad, a track-ball, a stylus, a microphone, or other suitable pointing device or input device. Output unit  193  includes, for example, a monitor, a screen, a touch-screen, a flat panel display, a Cathode Ray Tube (CRT) display unit, a Liquid Crystal Display (LCD) display unit, a plasma display unit, one or more audio speakers or earphones, or other suitable output devices. 
     In some demonstrative embodiments, mobile device  110  may estimate one or more parameters relating to a location of mobile device  110  based on a Time of Flight (ToF) measurement. 
     The ToF may be defined as the overall time (“round trip time”) a signal propagates from a first station, e.g., device  110 , to a second station, e.g., device  120 , and back to the first station. A distance between the first and second stations may be determined based on the ToF value, for example, by dividing the ToF value by two and multiplying the result by the speed of light. 
     In some demonstrative embodiments, device  110  may determine a distance of device  110  with respect to a wireless communication device, e.g., device  120 , based on the ToF measurement. 
     In some demonstrative embodiments, device  110  may determine an estimated location of device  110 , by calculating additional distances, e.g., two or more distances, between device  110  and two or more other stations, for example, by utilizing trilateration techniques. 
     In one example, device  110  may perform a ToF measurement with device  120  to determine a distance between device  110  and device  120 . 
     In some demonstrative embodiments, the ToF measurement performed between device  110  and device  120  may result in a non-accurate or an erroneous location, for example, if the ToF measurement is not accurate. 
     In some demonstrative embodiments, the overall time the signal propagates from the first station to the second station and back to the first station may include a delay period between receiving the signal from the first station at the second station and transmitting the signal from the second station to the first station. The delay period may be introduced by the second station, for example, due to hardware processing and/or any other processing of the signal at the second station. 
     Reference is made to  FIG. 2 , which is a schematic sequence diagram illustration  200  of operations between a first device  210  (Originator Baseband) and a second device  220  (Remote Baseband), in accordance with some demonstrative embodiments. For example, device  210  may perform the functionality of device  110  ( FIG. 1 ) and/or device  220  may perform the functionality of device  120  ( FIG. 1 ). 
     In some demonstrative embodiments, one or more operations of diagram  200  may be utilized, for example, for performing a ToF measurement between device  210  and device  220 , e.g., to determine a distance between device  210  and device  220 . 
     As shown in  FIG. 2 , device  210  may transmit to device  220  a message  211 , and device  220  may transmit a message  221  to device  210 , e.g., in response to message  211 . 
     In some demonstrative embodiments, message  211  and/or message  221  may include a ping message. For example, message  211  may include a ping request (Ping REQ) message, and message  221  may include a ping acknowledge (Ping Ack) message. In other embodiments, messages  211  and/or  221  may include any other suitable messages. 
     As shown in  FIG. 2 , a round trip time, denoted T RTT , from device  210  to device  220  and back to device  210 , may be based on a propagation time between device  210  and device  220 , denoted T PROP , and a delay period, denoted T DELAY . 
     As shown in  FIG. 2 , the delay period T DELAY  may include a time period between receiving message  211  at device  220  and transmitting message  221  by device  220 . 
     In some demonstrative embodiments, the round trip time T RTT  may be expressed as follows, e.g., assuming the signal travels from device  211  to device  220  and back to device  210  via the same path and at the same time:
 
 T   RTT =2 *T   PROP   +T   DELAY    (1)
 
     In some demonstrative embodiments, device  210  may determine the propagation time T PROP  based on the round trip time T RTT , e.g., according to Equation 1. 
     In some demonstrative embodiments, device  210  may determine a distance between device  210  and device  220  by multiplying the propagation time T PROP  by the speed of light. 
     In some demonstrative embodiments, device  210  may not be able to determine a relatively accurate distance if the delay period T DELAY  is not known to device  210 , and/or if the delay period T DELAY  is not known at a required accuracy level. 
     Referring back to  FIG. 1 , the ToF measurement performed between device  110  and device  120  may not be accurate, for example, if device  110  does not know the delay period T DELAY  introduced by device  120  between receiving the signal from device  110  and transmitting the signal from device  120  to device  110 . 
     For example, an estimated distance between device  110  and device  120  may be greater than the accurate distance between device  110  and device  120 , e.g., by at least one meter, for example, if the overall time of propagation between device  110  and device  120  and back to device  110  includes a relatively increased delay period T DELAY . 
     In some demonstrative embodiments, the delay period T DELAY  may be predefined, e.g., by any suitable Protocols or Specifications. 
     In some demonstrative embodiments, the delay period T DELAY  may be defined based on one or more attributes of device  120 , e.g., hardware attributes, processing attributes and/or the like. 
     In some demonstrative embodiments, the delay period T DELAY  may be defined to include a relatively decreased period of time, for example, to improve an accuracy of the estimation of the distance. For example, decreasing the delay period T DELAY  may decrease a drifting between clocks of device  110  and device  120 . 
     In some demonstrative embodiments, device  120  may transmit to device  110  information (“delay information”) relating to the delay period T DELAY  of device  120 . 
     In some demonstrative embodiments, device  110  may estimate the distance between device  110  and device  120  based on the delay information, e.g., as described below. 
     In some demonstrative embodiments, device  120  may transmit the delay information as part of a communication between device  120  and device  110  for establishing wireless communication link  103  between device  110  and device  120 , e.g., as described below. 
     In other embodiments, device  120  may transmit the delay information to device  110  as part of any other predefined procedure and/or any other dedicated messages. 
     In some demonstrative embodiments, the delay information may include a delay value representing the delay period T DELAY . 
     In some demonstrative embodiments, the delay value may include a value in time units, e.g., milliseconds, microseconds, nanoseconds and the like, and/or a value representing time, e.g., counts and/or increments of a counter and/or the like. 
     In some demonstrative embodiments, wireless communication units  112  and  122  may communicate a probe request and a probe response in response to the probe request. 
     In some demonstrative embodiments, the probe response may include the delay value representing the delay period T DELAY  between receiving the probe request and transmitting a frame in response to the probe request, e.g., as described below. 
     In some demonstrative embodiments, device  110  may establish a wireless communication link with device  120  over wireless communication medium  103 . In one example, device  110  may establish with device  120  a wireless beamformed link over the mmWave frequency band. In another example, device  110  may establish with device  120  any other suitable wireless link over wireless communication medium  103 . 
     In some demonstrative embodiments, wireless communication unit  112  may transmit the probe request to device  120  as part of the establishment of the wireless communication link over wireless communication medium  103 . 
     In some demonstrative embodiments, the probe request may include a unicast probe request. 
     In some demonstrative embodiments, the frame may include an acknowledge (Ack) frame configured to acknowledge receipt of the unicast probe request. 
     In some demonstrative embodiments, the frame may include any other frame transmitted in response to the probe request. 
     In some demonstrative embodiments, device  110  may include a controller  114  configured to control wireless communication unit  112  to transmit the probe request to device  120 , and to receive the frame and/or the probe response from device  120 . 
     In some demonstrative embodiments, device  120  may include a controller  124  configured to control wireless communication unit  122  to receive the probe request from device  110 , and to transmit the frame and/or the probe response to device  110  in response to the probe request. 
     In some demonstrative embodiments, controller  114  may estimate a distance between device  110  and mode  120  based on the frame, e.g., as described below. 
     In some demonstrative embodiments, controller  114  may estimate a distance between device  110  and mode  120  based on the probe response, e.g., as described below. 
     In some demonstrative embodiments, controller  114  may estimate the distance between device  110  and mode  120  based on the delay value included in the probe response, e.g., as described below. 
     In some demonstrative embodiments, controller  124  may control wireless communication unit  122  to transmit the frame to device  110  after the delay period T DELAY  from receiving the probe request from device  110 , e.g., as described below. 
     In some demonstrative embodiments, device  120  may include a counter  126  configured to be incremented at a symbol rate of device  120 . For example, a baseband sample rate of device  120  may be a rational multiplier of 2640 mega samples per second (Msps). Accordingly, counter  126  may be incremented at a rate of 2640 Mega (M) times per second, e.g., assuming counter  126  utilizes the sample rate of 2640 Msps. In another example, counter  126  may be incremented at a greater rate, e.g., if the baseband sample rate is greater, for example, a sample rate of 5280 Msps. 
     In some demonstrative embodiments, device  120  may include a register  127  configured to store a first value of counter  126 . 
     In some demonstrative embodiments, controller  124  may control register  127  to capture and store the first value of counter  126 , for example, when wireless communication unit  122  receives the probe request. 
     In some demonstrative embodiments, device  120  may include a register  128  configured to store a second value of counter  126 . 
     In some demonstrative embodiments, controller  124  may control wireless communication unit  122  to transmit the frame when a difference between the first value of register  127  and the second value of register  128  corresponds to the delay period T DELAY . 
     For example, the delay period T DELAY  may include a time period of one millisecond. Accordingly, controller  124  may control wireless communication unit  122  to transmit the frame when the difference between the second value and the first value is 2640 kilo-samples, e.g., assuming the sample rate of 2640 Msps. 
     In some demonstrative embodiments, the delay value may include the time period of the delay period T DELAY , and/or counts and/or increments of counter  126 , e.g., a difference between the first value of register  127  and the second value of register  128 . 
     In some demonstrative embodiments, wireless communication unit  112  may receive the probe response including the delay value transmitted from device  120 , and may determine a distance between device  120  and device  110  based on the probe response, e.g., as described below. 
     In some demonstrative embodiments, controller  114  may determine the distance between device  110  and device  120  based on the ToF between device  120  and device  110 , for example, based on the round trip time T RTT  and the delay value T DELAY , e.g., according to Equation 1. 
     In some demonstrative embodiments, controller  114  may be configured to determine a time of departure of the probe request and a time of arrival of the frame. 
     In some demonstrative embodiments, controller  114  may determine the round trip time T RTT  based on the difference between the time of arrival the frame at device  110  and the time of departure of the probe request from device  110 . 
     In some demonstrative embodiments, device  110  may include a counter  116  configured to be incremented at a symbol rate of device  110 . For example, a baseband sample rate of device  110  may be a rational multiplier of 2640 Msps. Accordingly, counter  110  may be incremented at a rate of 2640M times per second, e.g., assuming counter  116  utilizes the smallest sample rate. 
     In some demonstrative embodiments, device  110  may include a register  117  configured to store a first value of counter  116 . 
     In some demonstrative embodiments, controller  114  may control register  117  to capture and store the first value of counter  116 , for example, when wireless communication unit  112  transmits the probe request, e.g., to capture the time of departure of the probe request. 
     In some demonstrative embodiments, device  110  may include a register  118  to store a second value of counter  116 . 
     In some demonstrative embodiments, controller  114  may control register  118  to capture the second value of counter  116 , for example, when wireless communication unit  112  receives the frame from device  120 , e.g., to capture the time of arrival of the frame. 
     In some demonstrative embodiments, controller  114  may determine the round trip time T RTT  based on a difference between the second value stored in register  118  and the first value stored in register  117 . 
     For example, the round trip time T RTT  between device  110  and device  120  may be equal to 10 milliseconds, for example, if the difference between the second value of register  118  and the first value of register  117  is 26400 kilo samples, e.g., assuming a sample rate of 2640 Msps at device  110 . 
     In some demonstrative embodiments, controller  114  may be able to determine the distance between device  120  and device  110 , for example, based on the round trip time T RTT , and the delay value corresponding to device  120 . 
     In some demonstrative embodiments, controller  114  may determine the distance between device  120  and device  110  by determining the value of the propagation time T PROP  according to Equation 1, e.g., since the round trip time T RTT  and the delay period T DELAY  are known. 
     In some demonstrative embodiments, controller  114  may determine the distance between device  120  and device  110  by multiplying the value of the propagation time T PROP  by the speed of light. 
     In some demonstrative embodiments, controller  114  may determine the distance between device  120  and device  110  at an accuracy level, which is based on the sampling rate of device  110 . 
     For example, a distance, which a signal communicated between device  110  and  120  may travel during an increment counting unit of counter  116 , may be determined by dividing the speed of light, e.g., 300E6, by the sampling rate of device  110 , e.g., 2640E6. Accordingly, the signal may travel a distance of 0.113 meter or 11.3 centimeters (cm) every increment of counter  116 , e.g., if device  110  operates at a sample rate of 2640 Msps. 
     Accordingly, device  110  may have an accuracy level, which is not better than 11.3 cm. For example, device  110  may determine distances at a resolution equal to or higher than 11.3 cm. 
     In some demonstrative embodiments, controller  114  may determine the estimated distance between devices  110  and  120  by performing a plurality of measurements of the round trip time T RTT , determining a plurality of distances based on the plurality of measurements, and averaging the distances. 
     In some demonstrative embodiments, frequency offset of clocks of devices  110  and/or  120  may introduce a variation in the estimated distance between device  110  and device  120 . 
     In some demonstrative embodiments, the variation in the estimated distance may have a histogram having a Gaussian shape, and the average of the histogram may be the actual distance between device  110  and device  120 . 
     In some demonstrative embodiments, the sample mean variance of the histogram may be decreased by 1/N, wherein N denotes a number of measurements. For example, if the round trip time T RTT  has a mean of 10,000 samples and a variance of 1 sample, then the variance of averaging over ten measurements may give a variance of 1/10th of a sample. Accordingly, controller  114  may determine the distance between device  110  and device  120  by averaging over ten measurements, which may improve an accuracy of the estimated distance between device  110  and  120 . 
     In some demonstrative embodiments, controller  114  may estimate a location of device  110  based on a direction (RX directionality) from which the frame is received at device  110 . 
     In one example, a vector including the RX directionality and the distance between device  110  and  120  may enable estimating the location of device  110  at a relatively increased accuracy. 
     In some demonstrative embodiments, controller  114  may determine the direction based on a direction of steering of antennas  108 . For example, controller  114  may utilize angle of arrival information, e.g., when performing beamforming between antennas  108  and  128 . In other embodiments, controller  114  may determine the direction based on any other suitable method. 
     In some demonstrative embodiments, controller  114  may estimate a location of device  110  based on the azimuth of the direction and the location of device  120 , e.g., since device  120  is static, and the distance to device  120 , e.g., as determined by controller  114 , for example, using an azimuth range method. 
     In one example, controller  114  may determine that the frame is received via a direction having an azimuth of 70 degrees, and the distance to device  120  is one meter. Accordingly, controller  114  may estimate the location of device  110  to be one meter at an azimuth of 250 degrees from the location of device  120 . 
     In some demonstrative embodiments, device  110  may determine the delay period of device  120 , for example, without receiving delay information from device  120 , e.g., without receiving the delay value included in the probe request. 
     In some demonstrative embodiments, device  110  may utilize a plurality of messages, e.g., probe requests and acknowledge frames, to determine the delay period of device  120 , e.g., as described below. 
     In some demonstrative embodiments, controller  114  may be able to determine the distance between device  110  and device  120 , for example, after determining the delay period of device  120 , e.g., as described above. 
     In some demonstrative embodiments, controller  114  may control wireless communication unit  112  to communicate a plurality of message sequences with device  120 . 
     In some demonstrative embodiments, a message sequence of the plurality of message sequences may include a first message transmitted from wireless communication unit  112  to device  120  and a second message transmitted from wireless communication unit  122  to device  110 , in response to the first message. 
     In some demonstrative embodiments, controller  114  may determine delay time based on the plurality of message sequences. 
     In some demonstrative embodiments, the delay time may correspond to a delay period between receiving the first message by device  120  and transmitting the second message by device  120 . 
     In some demonstrative embodiments, the first message may include a probe request and the second message may include a frame to acknowledge receipt of the probe request. 
     In some demonstrative embodiments, the probe request may include a unicast probe request, and the frame may include an acknowledge (Ack) frame to acknowledge receipt of the unicast probe request. 
     In other embodiments, the frame may include any other frame, e.g., a probe response or the like. 
     In some demonstrative embodiments, controller  114  may be able to determine the delay time when device  110  is static. In other embodiments, controller  114  may be able to determine the delay time when device  110  is moving. 
     In some demonstrative embodiments, controller  114  may control wireless communication unit  112  to communicate a first message sequence and a second message sequence, e.g., when device  110  is static. 
     In some demonstrative embodiments, a first time period between receiving a first message of the first message sequence and transmitting a second message of the first message sequence by device  120  may be different than a second time period between receiving a first message of the second message sequence and transmitting a second message of the second sequence by device  120 . 
     In some demonstrative embodiments, the second time period may be a multiple of the first time period. For example, the second time period may be double the first time period. In one example, the first time period may include a time period of two milliseconds and the second time period may include a time period of four milliseconds. 
     In one example, controller  124  may control wireless communication unit  122  to transmit the second message of the first message sequence after the first time period from receiving the first message of the first message sequence, and to transmit the second message of the second message sequence after the second time period, e.g., double than the first time period, from receiving the first message of the second message sequence. For example, controller  124  may control wireless communication unit  122  to transmit the second message of the first and second sequences by controlling counter  126 , register  127  and register  128 , e.g., as described above. 
     In some demonstrative embodiments, wireless communication unit  112  may receive the second message of the first message sequence and the second message of the second message sequence. 
     In some demonstrative embodiments, controller  114  may determine the delay time of device  120  based on the first and second message sequences. 
     In some demonstrative embodiments, controller  114  may determine the distance between device  120  and device  110  based on the first and second message sequences. 
     In some demonstrative embodiments, controller  114  may determine a round trip time of the first message sequence, denoted T RTT1 , and a round trip time of the second message sequence, denoted T RTT2 , e.g., based on the values of registers  117  and  118 , as described above. 
     In some demonstrative embodiments, the round trip time T RTT1  may include the first time period, and the round trip time T RTT2  may include the second time period. 
     In some demonstrative embodiments, the round trip times T RTT1  and T RTT2  may be expressed, e.g., as follows:
 
 T   RTT1 =2 *T   PROP   +T   DELAY   (2)
 
 T   RTT2 =2 *T   PROP +2 *T   DELAY   (3)
 
     In some demonstrative embodiments, Equations 2 and 3 may form a nonsingular matrix, which may be solved to determine a value of the time delay T DELAY , and the propagation time T PROP , e.g., as follows:
 
 T   PROP   =T   RTT1 −½ *T   RTT2   (4)
 
 T   DELAY   =−T   RTT1   +T   RTT2   (5)
 
     In some demonstrative embodiments, controller  114  may estimate the distance between device  120  and device  110  by multiplying the value of T PROP  by the speed of light. 
     In some demonstrative embodiments, device  110  may be moving between a plurality of locations. 
     In some demonstrative embodiments, controller  114  may control wireless communication unit  112  to communicate three message sequences, e.g., when device  110  is moving. 
     In some demonstrative embodiments, controller  124  may control wireless communication unit  122  to transmit the second message of the first message sequence a first time period after receiving the first message of the first message sequence, to transmit the second message of the second message sequence a second time period after receiving the first message of the second message sequence, and to transmit the second message of the third message sequence a third time period after receiving the first message of the second message sequence. For example, controller  124  may control wireless communication unit  122  to transmit the second message of the first, second and third sequences by controlling counter  126 , register  127  and register  128 , e.g., as described above. 
     In some demonstrative embodiments, the first time period may be different from the second time period, and the second time period may be different from the third time period. 
     In some demonstrative embodiments, the third time period may be a multiple of the second time period, and the second time period may be a multiple of the first time period. For example, the third time period may be double the second time period, and the second time period may be double the first time period. In one example, the first time period may include a time period of two milliseconds, the second time period may include a time period of four milliseconds and the third time period may include a time period of eight milliseconds. 
     In some demonstrative embodiments, the first time period may include the delay time T DELAY  of device  120 . 
     In some demonstrative embodiments, wireless communication unit  112  may receive the second message of the first message sequence, the second message of the second message sequence and the second message of the third message sequence. 
     In some demonstrative embodiments, controller  114  may determine the delay time of device  120  based on the three message sequences. 
     In some demonstrative embodiments, controller  114  may determine the distance between device  120  and device  110  based on the three message sequences. 
     In some demonstrative embodiments, controller  114  may determine a round trip time of the first message sequence, denoted T RTT1 , a round trip time of the second message sequence, denoted T RTT2 , and a round trip time of the third message sequence, denoted T RTT3 , e.g., based on the values of registers  117  and  118 , as described above. 
     In some demonstrative embodiments, controller  114  may control wireless communication unit  112  to communicate the three message sequences at regular intervals, e.g., at a time interval, denoted Δt. For example, a first time interval, e.g., between transmitting the first message of the first message sequence and transmitting the first message of the second message sequence, and a second time interval, e.g., between transmitting the first message of the second message sequence and transmitting the first message of the third message sequence, may each be equal to the time interval Δt. 
     In some demonstrative embodiments, the round trip time T RTT1  may be expressed, e.g., as follows: 
                     T     RTT   ⁢           ⁢   1       =       2   *     (     d   c     )       +     T   DELAY               (   6   )               
wherein d denotes an initial distance in meters between device  110  and device  120  when transmitting the first message of the first message sequence, and c denotes the speed of light.
 
     In some demonstrative embodiments, the round trip time T RTT2  of the second message sequence may be expressed, e.g., as follows: 
                     T     RTT   ⁢           ⁢   2       =       2   *     (       d   +       v   ·   Δ     ⁢           ⁢   t       c     )       +     2   *     T   DELAY                 (   7   )               
wherein v denotes the relative velocity of device  110  with respect to device  120 .
 
     In some demonstrative embodiments, the relative velocity v may be positive, e.g., if device  110  is moving away from device  120 , or negative, e.g., if device  110  is moving towards to device  120 . 
     In some demonstrative embodiments, the round trip time T RTT3  may be expressed, e.g., as follows: 
     
       
         
           
             
               
                 
                   
                     T 
                     
                       RTT 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       3 
                     
                   
                   = 
                   
                     
                       2 
                       * 
                       
                         ( 
                         
                           
                             d 
                             + 
                             
                               
                                 2 
                                 · 
                                 v 
                                 · 
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                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               t 
                             
                           
                           c 
                         
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                       4 
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                         T 
                         DELAY 
                       
                     
                   
                 
               
               
                 
                   ( 
                   8 
                   ) 
                 
               
             
           
         
       
     
     In some demonstrative embodiments, the relative velocity v may be assumed to be constant during the three message sequences, for example, assuming the time interval Δt is relatively short. 
     In some demonstrative embodiments, Equations 6, 7 and 8 may form an invertible matrix, e.g., having three variables, which may be solved to determine a value of the time delay T DELAY , the value of the distance d between device  110  and device  120 , and the value of the relative speed v, e.g., as follows: 
     
       
         
           
             
               
                 
                   d 
                   = 
                   
                     c 
                     ⁡ 
                     
                       ( 
                       
                         
                           T 
                           
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                             ⁢ 
                             
                                 
                             
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                             1 
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                             T 
                             
                               RTT 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               3 
                             
                           
                         
                       
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                         ⁢ 
                         
                             
                         
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                     T 
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                         T 
                         
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                   ( 
                   11 
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     In some demonstrative embodiments, solving Equations 6, 7 and 8 may enable controller  114  to determine the distance d between device  110  and device  120 , for example, when device  110  is moving and the delay time of device  120  is not known to device  110 . 
     Reference is now made to  FIG. 3 , which schematically illustrates a sequence diagram  300  of operations and interactions between a mobile device  310  (“Originator Baseband”), and a wireless communication device  320  (“Remote Baseband”), in accordance with some demonstrative embodiments. For example, mobile device  310  may perform the functionality of mobile device  110  ( FIG. 1 ) and device  320  may perform the functionality of device  120  ( FIG. 1 ). 
     In some demonstrative embodiments, sequence diagram  300  may be utilized to determine a distance between device  310  and device  320 , for example, when establishing a link between device  320  and device  310 . 
     As shown in  FIG. 3 , device  310  may perform a search ( 321 ) over four predefined channels. For example, device  310  may perform the search over three social channels defined for the non-DBand, e.g., 2.4 GHz, and over a single social channel defined for the DBand, e.g., 60 GHZ. For example, the three social channels defined for the non-DBand may include channel 1 (ch 1), channel 6 (ch 6) and channel 11 (ch 11), and the single social channel defined for the DBand may include channel 2 (ch 2). 
     As shown in  FIG. 3 , device  320  may listen ( 341 ) over channel 2 to receive a beacon from device  310 . 
     As shown in  FIG. 3 , device  310  may transmit a probe request over each social channel of the three social channels of the 2.4 GHz band. For example, device  310  may transmit a probe request  324  over channel 1, a probe request  325  over channel 6, and a probe request  326  over channel 11. 
     As shown in  FIG. 3 , device  310  may transmit a plurality of beacons  327  in a plurality of directions over channel 2 of the DBand, for example, if device  310  did not receive any probe response, e.g., in response to probe requests  324 ,  325  and  326 . 
     As shown in  FIG. 3 , device  320  may transmit a response  343  to device  310  utilizing a transmit sector sweep (SSW), e.g., in response to beacons  327 . 
     As shown in  FIG. 3 , device  320  may transmit a feedback  328  to device  310 , e.g., upon receiving a beacon of beacons  327 . Device  310  may discover device  320  and may notify ( 329 ) an application  310  that device  320  is discovered. 
     As shown in  FIG. 3 , device  310  may transmit a probe request  330  to device  320 , e.g., after discovery of device  320 . 
     In some demonstrative embodiments, probe request  330  may include a unicast probe request. 
     In some demonstrative embodiments, device  320  may transmit an acknowledge (Ack) frame  344  to acknowledge receipt of the unicast probe request  330 . 
     As shown in  FIG. 3 , device  320  may transmit a probe response  345  to device  310 , e.g., in response to probe request  330 . 
     As shown in  FIG. 3 , probe response  345  may include the delay value T DELAY , representing the delay period between receiving probe request  330  from device  110  and transmitting Ack frame  344  by device  320 , e.g., as described above. 
     In some demonstrative embodiments, controller  114  ( FIG. 1 ) may estimate a distance between device  310  and device  320 , for example, based on the delay value T DELAY , e.g., as described above. 
     As shown in  FIG. 3 , device  310  may notify ( 332 ) application  310  that device  320  is discovered and may provide application  320  information with respect to the position of device  310 , e.g., the distance between device  310  and device  320 . 
     Reference is made to  FIG. 4 , which schematically illustrates a block diagram of a system  400 , in accordance with some demonstrative embodiments. 
     In some demonstrative embodiments, system  400  may include an originator device  410  and a remote device  420 . For example device  410  may perform the functionality of device  110  ( FIG. 1 ) and device  420  may perform the functionality of device  120  ( FIG. 1 ). 
     In some demonstrative embodiments, device  410  and device  420  may be configured to communicate over the WiGig frequency band. 
     In some demonstrative embodiments, device  410  and device  420  may communicate packets between device  410  and device  420 . 
     In some demonstrative embodiments, device  410  and device  420  may include baseband processors to process received and transmitted packets. For example, device  410  may include an originator baseband (OB) transmit (TX) baseband  431  and an OB receive (RX) baseband  432 , and device  420  may include a remote baseband (RB) TX baseband  441  and an RB RX baseband  442 . 
     In some demonstrative embodiments, device  410  and device  420  may include analog to digital (ADC) and digital to analog converters (DAC) configured to convert between an analog signal and a digital signal and vice versa. For example, device  410  may include an ADC  433  and a DAC  434 , and/or device  420  may include an ADC  443  and a DAC  444 . 
     In some demonstrative embodiments, device  410  may send a Ping request (REQ) packet  411  to device  420 . 
     In some demonstrative embodiments, device  410  may include an OB_tx_timer_gate block  412  including a counter  416  (OB_timestamp_cnt). For example, counter  416  may perform the functionality of counter  116  ( FIG. 1 ). 
     In some demonstrative embodiments, counter  416  may include a 32-bit counter to be incremented at the symbol rate of ADC  433  and DAC  434 , e.g., a symbol rate of 2640 Msps. 
     In some demonstrative embodiments, block  412  may capture a value of counter  416  in a register  417  (OB_tx_timestamp), e.g., the departure time of packet  411 . For example, register  417  may perform the functionality of register  117  ( FIG. 1 ). 
     In some demonstrative embodiments, device  420  may receive the Ping request packet  411  from device  410 . 
     In some demonstrative embodiments, device  420  may include an RB_acquisition block  424  including a counter  426  (RB_timestamp_cnt). For example, counter  416  may perform the functionality of counter  116  ( FIG. 1 ). 
     In some demonstrative embodiments, counter  426  may include a 32-bit counter to be incremented at the symbol rate of ADC  443  and DAC  444 , e.g., a symbol rate of 2640 Msps. 
     In some demonstrative embodiments, block  424  may capture a value of counter  426  in a register  427  (RB_acq_time), e.g., the arrival time of packet  411  at device  420 . For example, register  427  may perform the functionality of register  127  ( FIG. 1 ). 
     In some demonstrative embodiments, counters  416  and  426  may not be synchronized. For example, a value of counter  416  may be different from the value of counter  426 , for example, since a clock of RB  410  and a clock of OB  420  may not be synchronized. 
     In some demonstrative embodiments, device  420  may transmit a Ping acknowledge (ACK) packet  421  to device  410 , to acknowledge the receipt of ping request packet  411 , after the delay period T DELAY  from the reception time captured in register  427 . 
     In some demonstrative embodiments, device  420  may include an RB_tx_timer_gate block  422  including an RB_tx_timestamp register  428  to capture a value of counter  426 . For example, register  428  may perform the functionality of register  128  ( FIG. 1 ). 
     In some demonstrative embodiments, block  422  may enable transmission of ping packet  421  after the delay period T DELAY  from receiving packet  411 . For example, block  422  may transmit packet  421 , e.g., when a difference between registers  428  and  427  corresponds to the delay period T DELAY . 
     In some demonstrative embodiments, the delay period T DELAY  may be relatively short based on processing time in RB RX baseband  441  and RB TX baseband  442 . 
     In some demonstrative embodiments, device  410  may receive Ping ACK packet  421 . 
     In some demonstrative embodiments, device  410  may include an OB_acquisition block  419  including a register  418  (OB_acq_time). For example, register  418  may perform the functionality of register  118  ( FIG. 1 ). 
     In some demonstrative embodiments, block  419  may capture the value of counter  416  in register  418 , e.g., the time of arrival of packet  421  at device  410 . 
     In some demonstrative embodiments, device  410  may determine a round trip time between device  410  and device  420 , e.g., as the difference between the values of counters  418  and  417 , e.g., T RTT =OB_acq_time−OB_tx_timestamp. 
     In some demonstrative embodiments, the predefined delay period of device  420  may be a preset value known to device  410  and node  420 . In other embodiments, the predefined delay period of device  420  may be communicated at a later time, e.g., via a ping response (RES) packet transmitted from device  420  to device  410 , e.g., as described above. 
     Reference is made to  FIG. 5 , which schematically illustrates a method of estimating a location of a mobile device, in accordance with some demonstrative embodiments. In some demonstrative embodiments, one or more of the operations of the method of  FIG. 5  may be performed by any suitable wireless communication system, e.g., system  100  ( FIG. 1 ), a mobile device, e.g., device  110  ( FIG. 1 ), a wireless communication device, e.g., device  120  ( FIG. 1 ), a controller, e.g., controllers  114  and  124  ( FIG. 1 ), and/or a wireless communication unit, e.g., wireless communication units  112  and/or  122  ( FIG. 1 ). 
     As indicated at block  502 , the method may include communicating a probe request between a wireless communication device and a mobile device. For example, wireless communication units  112  and  122  ( FIG. 1 ) may communicate the probe request, e.g., as described above. 
     As indicated at block  504 , the method may include communicating a frame in response to the probe request between the wireless communication device and the mobile device. For example, wireless communication unit  112  and  122  ( FIG. 1 ) may communicate the frame in response to the probe request, e.g., as described above. 
     As indicated at block  506 , communicating the frame may include communicating an acknowledge (Ack) frame to acknowledge receipt of the probe request. For example, wireless communication unit  122  ( FIG. 1 ) may transmit to device  110  ( FIG. 1 ) the Ack frame to acknowledge receipt of the probe request, e.g., as described above. 
     As indicated at block  508 , communicating the frame may include communicating a probe response in response to the probe request. The probe response may include a delay value representing a delay period between receiving the probe request and transmitting the frame by the device. For example, wireless communication unit  122  ( FIG. 1 ) may transmit to device  110  ( FIG. 1 ) the probe response including the delay value, e.g., as described above. 
     As indicated at block  510 , the method may include estimating the distance between the wireless communication device and the mobile device. For example, controller  114  ( FIG. 1 ) may estimate the distance between device  110  ( FIG. 1 ) and device  120  ( FIG. 1 ), e.g., as described above. 
     As indicated at block  512 , estimating the distance between the wireless communication device and the mobile device may include estimating the distance based on the Ack frame. For example, controller  114  ( FIG. 1 ) may estimate the distance between device  110  ( FIG. 1 ) and device  120  ( FIG. 1 ) based on the Ack frame, e.g., as described above. 
     As indicated at block  514 , estimating the distance between the device and the mobile device may include estimating the distance based on the delay value. For example, controller  114  ( FIG. 1 ) may estimate the distance between device  120  ( FIG. 1 ) and device  120  ( FIG. 1 ) based on the delay value, e.g., as described above. 
     As indicated at block  516 , estimating the distance between the device and the mobile device may include estimating a location of the mobile device based on the direction from which the frame is received at the mobile device. For example, controller  114  ( FIG. 1 ) may estimate a location of device  110  ( FIG. 1 ) based on a direction from which the frame is received at mobile device  110  ( FIG. 1 ), e.g., as described above. 
     Reference is made to  FIG. 6 , which schematically illustrates a product of manufacture  600 , in accordance with some demonstrative embodiments. Product  600  may include a non-transitory machine-readable storage medium  602  to store logic  604 , which may be used, for example, to perform at least part of the functionality of device  110  ( FIG. 1 ), wireless communication unit  112  ( FIG. 1 ), wireless communication unit  122  ( FIG. 1 ), device  120  ( FIG. 1 ), controller  114  ( FIG. 1 ), controller  124  ( FIG. 1 ), and/or to perform one or more operations of the method of  FIG. 5 . The phrase “non-transitory machine-readable medium” is directed to include all computer-readable media, with the sole exception being a transitory propagating signal. 
     In some demonstrative embodiments, product  600  and/or machine-readable storage medium  602  may include one or more types of computer-readable storage media capable of storing data, including volatile memory, non-volatile memory, removable or non-removable memory, erasable or non-erasable memory, writeable or re-writeable memory, and the like. For example, machine-readable storage medium  602  may include, RAM, DRAM, Double-Data-Rate DRAM (DDR-DRAM), SDRAM, static RAM (SRAM), ROM, programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), Compact Disk ROM (CD-ROM), Compact Disk Recordable (CD-R), Compact Disk Rewriteable (CD-RW), flash memory (e.g., NOR or NAND flash memory), content addressable memory (CAM), polymer memory, phase-change memory, ferroelectric memory, silicon-oxide-nitride-oxide-silicon (SONOS) memory, a disk, a floppy disk, a hard drive, an optical disk, a magnetic disk, a card, a magnetic card, an optical card, a tape, a cassette, and the like. The computer-readable storage media may include any suitable media involved with downloading or transferring a computer program from a remote computer to a requesting computer carried by data signals embodied in a carrier wave or other propagation medium through a communication link, e.g., a modem, radio or network connection. 
     In some demonstrative embodiments, logic  604  may include instructions, data, and/or code, which, if executed by a machine, may cause the machine to perform a method, process and/or operations as described herein. The machine may include, for example, any suitable processing platform, computing platform, computing device, processing device, computing system, processing system, computer, processor, or the like, and may be implemented using any suitable combination of hardware, software, firmware, and the like. 
     In some demonstrative embodiments, logic  604  may include, or may be implemented as, software, a software module, an application, a program, a subroutine, instructions, an instruction set, computing code, words, values, symbols, and the like. The instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, and the like. The instructions may be implemented according to a predefined computer language, manner or syntax, for instructing a processor to perform a certain function. The instructions may be implemented using any suitable high-level, low-level, object-oriented, visual, compiled and/or interpreted programming language, such as C, C++, Java, BASIC, Matlab, Pascal, Visual BASIC, assembly language, machine code, and the like. 
     EXAMPLES 
     The following examples pertain to further embodiments. 
     Example 1 includes an apparatus of wireless communication, the apparatus comprising a controller to control a first wireless communication device to communicate a probe request with a second wireless communication device and to communicate a probe response with the second wireless communication device, wherein the probe response includes a delay value representing a delay period between a reception of the probe request and a transmission of a frame in response to the probe request. 
     Example 2 includes the subject matter of Example 1 and optionally, wherein the controller is to control the first wireless communication device to transmit the probe request to the second wireless communication device and to receive the probe response from the second wireless communication device. 
     Example 3 includes the subject matter of Example 2 and optionally, wherein the controller is to estimate a distance between the first and second wireless communication devices based on the frame. 
     Example 4 includes the subject matter of Example 2 or 3 and optionally, wherein the controller is to estimate a distance between the first and second wireless communication devices based on the delay value. 
     Example 5 includes the subject matter of any one of Examples 2-4 and optionally, wherein the controller is to determine a direction from which the probe response is received at the first wireless communication device, and wherein the controller is to estimate a location of the first wireless communication device based on the direction. 
     Example 6 includes the subject matter of any one of Examples 2-5 comprising a counter to be incremented at a symbol rate of the first wireless communication device; a first register to capture a first value of the counter at a transmission of the probe request; and a second register to capture a second value of the counter at a reception of the frame. 
     Example 7 includes the subject matter of Example 6 and optionally, wherein the controller is to estimate a distance between the first and second wireless communication devices based on a difference between the second value and the first value. 
     Example 8 includes the subject matter of any one of Examples 2-7 and optionally, wherein the first wireless communication device comprises a mobile device and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 9 includes the subject matter of Example 1 and optionally, wherein the controller is to control the first wireless communication device to receive the probe request from the second wireless communication device and to transmit the frame to the second wireless communication device after the delay period. 
     Example 10 includes the subject matter of Example 9 comprising a counter to be incremented at a symbol rate of the first wireless communication device; a first register is to capture a first value of the counter at the reception of the probe request; and a second register is to capture a second value of the counter; wherein the controller is to control the first wireless communication device to transmit the frame when a difference between the first value and the second value corresponds to the delay period. 
     Example 11 includes the subject matter of Example 9 or 10 and optionally, wherein the first wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station, and wherein the second wireless communication device comprises a mobile device. 
     Example 12 includes the subject matter of any one of Examples 1-11 and optionally, wherein the controller is to control the first wireless communication device to communicate the probe request and the probe response over the mmWave wireless frequency band. 
     Example 13 includes the subject matter of any one of Examples 1-12 and optionally, wherein the controller is to control the first wireless communication device to communicate the probe request and the probe response for establishing a wireless communication link between the first and second wireless communication devices. 
     Example 14 includes the subject matter of any one of Examples 1-13 and optionally, wherein the probe request comprises a unicast probe request, and wherein the frame comprises an acknowledge (Ack) frame, to acknowledge receipt of the probe request. 
     Example 15 includes the subject matter of any one of Examples 1-14 and optionally, wherein the probe response includes the frame. 
     Example 16 includes the subject matter of any one of Examples 1-15 and optionally, wherein the controller is to control the first wireless communication device to communicate the probe request and the probe response over a wireless Gigabit (WiGig) frequency band. 
     Example 17 includes an apparatus of wireless communication, the apparatus comprising a controller to control a first wireless communication device to communicate a probe request with a second wireless communication device and to communicate a frame in response to the probe request, the controller is to estimate a distance between the first and second wireless communication devices based on the frame. 
     Example 18 includes the subject matter of Example 17 and optionally, wherein the controller is to control the first wireless communication device to transmit the probe request to the second wireless communication device and to receive the frame from the second wireless communication device. 
     Example 19 includes the subject matter of Example 18 and optionally, wherein the controller is to control the first wireless communication device to communicate a probe response in response to the probe request, and wherein the probe response includes a delay value representing a delay period between a reception of the probe request by the second wireless communication device and a transmission of the frame by the second wireless communication device. 
     Example 20 includes the subject matter of Example 19 and optionally, wherein the controller is to estimate the distance based on the delay value. 
     Example 21 includes the subject matter of any one of Examples 18-20 and optionally, wherein the controller is to determine a direction from which the frame is received at the first wireless communication device, and wherein the controller is to estimate a location of the first wireless communication device based on the direction. 
     Example 22 includes the subject matter of any one of Examples 17-21 and optionally, wherein the controller is to control the first wireless communication device to transmit a plurality of probe requests and to receive a plurality of frames in response to the plurality of probe requests, and wherein the controller is to estimate a delay time between the reception of the probe request by the second wireless communication device and the transmission of the frame by the second wireless communication device based on the plurality of probe requests and frames. 
     Example 23 includes the subject matter of Example 22 and optionally, wherein the controller is to control the first wireless communication device to transmit the plurality of probe requests and to receive the plurality of frames when the first wireless communication device is moving. 
     Example 24 includes the subject matter of any one of Examples 17-23 comprising a counter to be incremented at a symbol rate of the apparatus; a first register to capture a first value of the counter at a transmission of the probe request; and a second register to capture a second value of the counter at a reception of the frame. 
     Example 25 includes the subject matter of Example 24 and optionally, wherein the controller is to estimate the distance based on a difference between the second value and the first value. 
     Example 26 includes the subject matter of any one of Examples 17-25 and optionally, wherein the controller is to control the first wireless communication device to communicate the probe request and the frame over the mmWave wireless frequency band. 
     Example 27 includes the subject matter of any one of Examples 17-26 and optionally, wherein the probe request comprises a unicast probe request, and wherein the frame comprises an acknowledge (Ack) frame to acknowledge receipt of the unicast probe request. 
     Example 28 includes the subject matter of any one of Examples 17-27 and optionally, wherein the controller is to control the first wireless communication device to communicate the probe request and the frame over a wireless Gigabit (WiGig) frequency band. 
     Example 29 includes the subject matter of any one of Examples 17-28 and optionally, wherein the first wireless communication device comprises a mobile device, and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 30 includes an apparatus of wireless communication, the apparatus comprising a controller to control a first wireless communication device to communicate a plurality of message sequences with a second wireless communication device, a message sequence of the plurality of message sequences including a first message transmitted from the first wireless communication device to the second wireless communication device and a second message transmitted from the second wireless communication device to the first wireless communication device in response to the first message, wherein the controller is to determine a delay time based on the plurality of message sequences, the delay time representing a delay period between a reception of the first message by the second wireless communication device and a transmission of the second message by the second wireless communication device. 
     Example 31 includes the subject matter of Example 30 and optionally, wherein the first message includes a probe request and the second message includes an acknowledge (Ack) frame or a probe response. 
     Example 32 includes the subject matter of Example 30 or 31 and optionally, wherein the controller is to estimate a distance between the first and second wireless communication devices based on the delay time. 
     Example 33 includes the subject matter of any one of Examples 30-32 and optionally, wherein the controller is to control the first wireless communication device to communicate a first message sequence and a second message sequence when the first wireless communication device is static. 
     Example 34 includes the subject matter of Example 33 and optionally, wherein a first time period between a reception of a first message of the first message sequence and a transmission of a second message of the first message sequence by the second wireless communication device is different from a second time period between a reception of a first message of the second message sequence and a transmission of a second message of the second sequence by the second wireless communication device. 
     Example 35 includes the subject matter of Example 34 and optionally, wherein the second time period is a multiple of the first time period, and wherein the controller is to estimate the time delay based on the first and second message sequences. 
     Example 36 includes the subject matter of any one of Examples 30-35 and optionally, wherein the controller is to control the first wireless communication device to communicate three message sequences when the first wireless communication device is moving. 
     Example 37 includes the subject matter of Example 36 and optionally, wherein the controller is to estimate the time delay based on the three message sequences. 
     Example 38 includes the subject matter of any one of Examples 30-37 and optionally, wherein the first wireless communication device comprises a mobile device and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 39 includes the subject matter of any one of Examples 30-38 and optionally, wherein the controller is to control the first wireless communication device to communicate the first and second messages over the mmWave wireless frequency band. 
     Example 40 includes the subject matter of any one of Examples 30-39 and optionally, wherein the controller is to control the first wireless communication device to communicate the first and second messages over a wireless Gigabit (WiGig) frequency band. 
     Example 41 includes a system of wireless communication, the system comprising a first wireless communication device comprising an antenna; and a controller to control the first wireless communication device to communicate a probe request with a second wireless communication device and to communicate a probe response with the second wireless communication device, wherein the probe response includes a delay value representing a delay period between a reception of the probe request and a transmission of a frame in response to the probe request. 
     Example 42 includes the subject matter of Example 41 and optionally, wherein the controller is to control the first wireless communication device to transmit the probe request to the second wireless communication device and to receive the probe response from the second wireless communication device. 
     Example 43 includes the subject matter of Example 42 and optionally, wherein the controller is to estimate a distance between the first and second wireless communication devices based on the frame. 
     Example 44 includes the subject matter of Example 42 or 43 and optionally, wherein the controller is to estimate a distance between the first and second wireless communication devices based on the delay value. 
     Example 45 includes the subject matter of any one of Examples 42-44 and optionally, wherein the controller is to determine a direction from which the probe response is received at the first wireless communication device, and wherein the controller is to estimate a location of the first wireless communication device based on the direction. 
     Example 46 includes the subject matter of any one of Examples 42-45 comprising a counter to be incremented at a symbol rate of the first wireless communication device; a first register to capture a first value of the counter at a transmission of the probe request; and a second register to capture a second value of the counter at a reception of the frame. 
     Example 47 includes the subject matter of Example 46 and optionally, wherein the controller is to estimate a distance between the first and second wireless communication devices based on a difference between the second value and the first value. 
     Example 48 includes the subject matter of any one of Examples 42-47 and optionally, wherein the first wireless communication device comprises a mobile device and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 49 includes the subject matter of Example 41 and optionally, wherein the controller is to control the first wireless communication device to receive the probe request from the second wireless communication device and to transmit the frame to the second wireless communication device after the delay period. 
     Example 50 includes the subject matter of Example 49 and optionally, wherein the first wireless communication device comprising a counter to be incremented at a symbol rate of the first wireless communication device; a first register is to capture a first value of the counter at the reception of the probe request; and a second register is to capture a second value of the counter; wherein the controller is to control the first wireless communication device to transmit the frame when a difference between the first value and the second value corresponds to the delay period. 
     Example 51 includes the subject matter of Example 49 or 50 and optionally, wherein the first wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station, and wherein the second wireless communication device comprises a mobile device. 
     Example 52 includes the subject matter of any one of Examples 41-51 and optionally, wherein the controller is to control the first wireless communication device to communicate the probe request and the probe response over the mmWave wireless frequency band. 
     Example 53 includes the subject matter of any one of Examples 41-52 and optionally, wherein the controller is to control the first wireless communication device to communicate the probe request and the probe response for establishing a wireless communication link between the first and second wireless communication devices. 
     Example 54 includes the subject matter of any one of Examples 41-53 and optionally, wherein the probe request comprises a unicast probe request, and wherein the frame comprises an acknowledge (Ack) frame, to acknowledge receipt of the probe request. 
     Example 55 includes the subject matter of any one of Examples 41-54 and optionally, wherein the probe response includes the frame. 
     Example 56 includes the subject matter of any one of Examples 41-55 and optionally, wherein the controller is to control the first wireless communication device to communicate the probe request and the probe response over a wireless Gigabit (WiGig) frequency band. 
     Example 57 includes a system of wireless communication, the system comprising a first wireless communication device comprising an antenna; and a controller to control the first wireless communication device to communicate a probe request with a second wireless communication device and to communicate a frame in response to the probe request, the controller is to estimate a distance between the first and second wireless communication devices based on the frame. 
     Example 58 includes the subject matter of Example 57 and optionally, wherein the controller is to control the first wireless communication device to transmit the probe request to the second wireless communication device and to receive the frame from the second wireless communication device. 
     Example 59 includes the subject matter of Example 58 and optionally, wherein the controller is to control the first wireless communication device to communicate a probe response in response to the probe request, and wherein the probe response includes a delay value representing a delay period between a reception of the probe request by the second wireless communication device and a transmission of the frame by the second wireless communication device. 
     Example 60 includes the subject matter of Example 59 and optionally, wherein the controller is to estimate the distance based on the delay value. 
     Example 61 includes the subject matter of any one of Examples 58-60 and optionally, wherein the controller is to determine a direction from which the frame is received at the first wireless communication device, and wherein the controller is to estimate a location of the first wireless communication device based on the direction. 
     Example 62 includes the subject matter of any one of Examples 57-61 and optionally, wherein the controller is to control the first wireless communication device to transmit a plurality of probe requests and to receive a plurality of frames in response to the plurality of probe requests, and wherein the controller is to estimate a delay time between a reception of the probe request by the second wireless communication device and a transmission of the frame by the second wireless communication device based on the plurality of probe requests and frames. 
     Example 63 includes the subject matter of Example 62 and optionally, wherein the controller is to control the first wireless communication device to transmit the plurality of probe requests and to receive the plurality of frames when the first wireless communication device is moving. 
     Example 64 includes the subject matter of any one of Examples 57-63 and optionally, wherein the first wireless communication device comprising a counter to be incremented at a symbol rate of the system; a first register to capture a first value of the counter at a transmission of the probe request; and a second register to capture a second value of the counter at a reception of the frame. 
     Example 65 includes the subject matter of Example 64 and optionally, wherein the controller is to estimate the distance based on a difference between the second value and the first value. 
     Example 66 includes the subject matter of any one of Examples 57-65 and optionally, wherein the controller is to control the first wireless communication device to communicate the probe request and the frame over the mmWave wireless frequency band. 
     Example 67 includes the subject matter of any one of Examples 57-66 and optionally, wherein the probe request comprises a unicast probe request, and wherein the frame comprises an acknowledge (Ack) frame to acknowledge receipt of the unicast probe request. 
     Example 68 includes the subject matter of any one of Examples 57-67 and optionally, wherein the controller is to control the first wireless communication device to communicate the probe request and the frame over a wireless Gigabit (WiGig) frequency band. 
     Example 69 includes the subject matter of any one of Examples 57-68 and optionally, wherein the first wireless communication device comprises a mobile device, and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 70 includes a system of wireless communication, the system comprising a first wireless communication device comprising an antenna; and a controller to control the first wireless communication device to communicate a plurality of message sequences with a second wireless communication device, a message sequence of the plurality of message sequences including a first message transmitted from the first wireless communication device to the second wireless communication device and a second message transmitted from the second wireless communication device to the first wireless communication device in response to the first message, wherein the controller is to determine a delay time based on the plurality of message sequences, the delay time representing a delay period between a reception of the first message by the second wireless communication device and a transmission of the second message by the second wireless communication device. 
     Example 71 includes the subject matter of Example 70 and optionally, wherein the first message includes a probe request and the second message includes an acknowledge (Ack) frame or a probe response. 
     Example 72 includes the subject matter of Example 70 or 71 and optionally, wherein the controller is to estimate a distance between the first and second wireless communication devices based on the delay time. 
     Example 73 includes the subject matter of any one of Examples 70-72 and optionally, wherein the controller is to control the first wireless communication device to communicate a first message sequence and a second message sequence when the first wireless communication device is static. 
     Example 74 includes the subject matter of Example 73 and optionally, wherein a first time period between a reception of a first message of the first message sequence and a transmission of a second message of the first message sequence by the second wireless communication device is different from a second time period between a reception of a first message of the second message sequence and a transmission of a second message of the second sequence by the second wireless communication device. 
     Example 75 includes the subject matter of Example 74 and optionally, wherein the second time period is a multiple of the first time period, and wherein the controller is to estimate the time delay based on the first and second message sequences. 
     Example 76 includes the subject matter of any one of Examples 70-75 and optionally, wherein the controller is to control the first wireless communication device to communicate three message sequences when the first wireless communication device is moving. 
     Example 77 includes the subject matter of Example 76 and optionally, wherein the controller is to estimate the time delay based on the three message sequences. 
     Example 78 includes the subject matter of any one of Examples 70-77 and optionally, wherein the first wireless communication device comprises a mobile device and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 79 includes the subject matter of any one of Examples 70-78 and optionally, wherein the controller is to control the first wireless communication device to communicate the first and second messages over the mmWave wireless frequency band. 
     Example 80 includes the subject matter of any one of Examples 70-79 and optionally, wherein the controller is to control the first wireless communication device to communicate the first and second messages over a wireless Gigabit (WiGig) frequency band. 
     Example 81 includes a method of wireless communication, the method comprising communicating a probe request between a first wireless communication device and a second wireless communication device; and communicating a probe response between the second wireless communication device and the first wireless communication device, the probe response includes a delay value representing a delay period between a reception of the probe request and a transmission of a frame in response to the probe request. 
     Example 82 includes the subject matter of Example 81 comprising transmitting the probe request to the second wireless communication device and receiving the probe response from the second wireless communication device. 
     Example 83 includes the subject matter of Example 82 comprising estimating a distance between the first and second wireless communication devices based on the frame. 
     Example 84 includes the subject matter of Example 82 or 83 comprising estimating a distance between the first and second wireless communication devices based on the delay value. 
     Example 85 includes the subject matter of any one of Examples 82-84 comprising determining a direction from which the probe response is received at the first wireless communication device; and estimating a location of the first wireless communication device based on the direction. 
     Example 86 includes the subject matter of any one of Examples 82-85 comprising incrementing a counter at a symbol rate of the first wireless communication device; capturing a first value of the counter at a transmission of the probe request; and capturing a second value of the counter at a reception of the frame. 
     Example 87 includes the subject matter of Example 86 comprising estimating a distance between the first and second wireless communication devices based on a difference between the second value and the first value. 
     Example 88 includes the subject matter of any one of Examples 82-87 and optionally, wherein the first wireless communication device comprises a mobile device and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 89 includes the subject matter of Example 81 comprising receiving the probe request from the second wireless communication device and transmitting the frame to the second wireless communication device after the delay period. 
     Example 90 includes the subject matter of Example 89 comprising incrementing a counter at a symbol rate of the first wireless communication device; capturing a first value of the counter at the reception of the probe request; capturing a second value of the counter; and transmitting the frame when a difference between the first value and the second value corresponds to the delay period. 
     Example 91 includes the subject matter of Example 89 or 90 and optionally, wherein the first wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station, and wherein the second wireless communication device comprises a mobile device. 
     Example 92 includes the subject matter of any one of Examples 81-91 comprising communicating the probe request and the probe response over the mmWave wireless frequency band. 
     Example 93 includes the subject matter of any one of Examples 81-92 comprising communicating the probe request and the probe response for establishing a wireless communication link between the first and second wireless communication devices. 
     Example 94 includes the subject matter of any one of Examples 81-93 and optionally, wherein the probe request comprises a unicast probe request, and wherein the frame comprises an acknowledge (Ack) frame, to acknowledge receipt of the probe request. 
     Example 95 includes the subject matter of any one of Examples 81-94 and optionally, wherein the probe response includes the frame. 
     Example 96 includes the subject matter of any one of Examples 81-95 comprising communicating the probe request and the probe response over a wireless Gigabit (WiGig) frequency band. 
     Example 97 includes a method of wireless communication, the method comprising communicating a probe request between a first wireless communication device and a second wireless communication device; communicating a frame in response to the probe request; and estimating a distance between the first and second wireless communication devices based on the frame. 
     Example 98 includes the subject matter of Example 97 comprising transmitting the probe request to the second wireless communication device and receiving the frame from the second wireless communication device. 
     Example 99 includes the subject matter of Example 98 comprising communicating a probe response in response to the probe request, and wherein the probe response includes a delay value representing a delay period between a reception of the probe request by the second wireless communication device and a transmission of the frame by the second wireless communication device. 
     Example 100 includes the subject matter of Example 99 comprising estimating the distance based on the delay value. 
     Example 101 includes the subject matter of any one of Examples 98-100 comprising determining a direction from which the frame is received at the first wireless communication device; and estimating a location of the first wireless communication device based on the direction. 
     Example 102 includes the subject matter of any one of Examples 97-111 comprising transmitting a plurality of probe requests and receiving a plurality of frames in response to the plurality of probe requests; and estimating a delay time between a reception of the probe request by the second wireless communication device and a transmission of the frame by the second wireless communication device based on the plurality of probe requests and frames. 
     Example 103 includes the subject matter of Example 102 comprising transmitting the plurality of probe requests and receiving the plurality of frames when the first wireless communication device is moving. 
     Example 104 includes the subject matter of any one of Examples 97-103 comprising incrementing a counter at a symbol rate of the first wireless communication device; capturing a first value of the counter at a transmission of the probe request; and capturing a second value of the counter at a reception of the frame. 
     Example 105 includes the subject matter of Example 104 comprising estimating the distance based on a difference between the second value and the first value. 
     Example 106 includes the subject matter of any one of Examples 97-105 comprising communicating the probe request and the frame over the mmWave wireless frequency band. 
     Example 107 includes the subject matter of any one of Examples 97-106 and optionally, wherein the probe request comprises a unicast probe request, and wherein the frame comprises an acknowledge (Ack) frame to acknowledge receipt of the unicast probe request. 
     Example 108 includes the subject matter of any one of Examples 97-107 comprising communicating the probe request and the frame over a wireless Gigabit (WiGig) frequency band. 
     Example 109 includes the subject matter of any one of Examples 97-108 and optionally, wherein the first wireless communication device comprises a mobile device, and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 110 includes a method of wireless communication, the method comprising communicating a plurality of message sequences between a first wireless communication device and a second wireless communication device, a message sequence of the plurality of message sequences including a first message transmitted from the first wireless communication device to the second wireless communication device and a second message transmitted from the second wireless communication device to the first wireless communication device in response to the first message; and determining a delay time based on the plurality of message sequences, the delay time representing a delay period between a reception of the first message by the second wireless communication device and a transmission of the second message by the second wireless communication device. 
     Example 111 includes the subject matter of Example 110 and optionally, wherein the first message includes a probe request and the second message includes an acknowledge (Ack) frame or a probe response. 
     Example 112 includes the subject matter of Example 110 or 111 comprising estimating a distance between the first and second wireless communication devices based on the delay time. 
     Example 113 includes the subject matter of any one of Examples 110-112 comprising communicating a first message sequence and a second message sequence when the first wireless communication device is static. 
     Example 114 includes the subject matter of Example 113 and optionally, wherein a first time period between a reception of a first message of the first message sequence and a transmission of a second message of the first message sequence by the second wireless communication device is different from a second time period between a reception of a first message of the second message sequence and a transmission of a second message of the second sequence by the second wireless communication device. 
     Example 115 includes the subject matter of Example 114 and optionally, wherein the second time period is a multiple of the first time period, and wherein the controller is to estimate the time delay based on the first and second message sequences. 
     Example 116 includes the subject matter of any one of Examples 110-115 comprising communicating three message sequences when the first wireless communication device is moving. 
     Example 117 includes the subject matter of Example 116 comprising estimating the time delay based on the three message sequences. 
     Example 118 includes the subject matter of any one of Examples 110-117 and optionally, wherein the first wireless communication device comprises a mobile device and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 119 includes the subject matter of any one of Examples 110-118 comprising communicating the first and second messages over the mmWave wireless frequency band. 
     Example 120 includes the subject matter of any one of Examples 110-119 comprising communicating the first and second messages over a wireless Gigabit (WiGig) frequency band. 
     Example 121 includes a product including a non-transitory storage medium having stored thereon instructions that, when executed by a machine, result in communicating a probe request between a first wireless communication device and a second wireless communication device; and communicating a probe response between the second wireless communication device and the first wireless communication device, the probe response includes a delay value representing a delay period between a reception of the probe request and a transmission of a frame in response to the probe request. 
     Example 122 includes the subject matter of Example 121 and optionally, wherein the instructions result in transmitting the probe request to the second wireless communication device and receiving the probe response from the second wireless communication device. 
     Example 123 includes the subject matter of Example 122 and optionally, wherein the instructions result in estimating a distance between the first and second wireless communication devices based on the frame. 
     Example 124 includes the subject matter of Example 122 or 123 and optionally, wherein the instructions result in estimating a distance between the first and second wireless communication devices based on the delay value. 
     Example 125 includes the subject matter of any one of Examples 122-124 and optionally, wherein the instructions result in determining a direction from which the probe response is received at the first wireless communication device; and estimating a location of the first wireless communication device based on the direction. 
     Example 126 includes the subject matter of any one of Examples 122-125 and optionally, wherein the instructions result in incrementing a counter at a symbol rate of the first wireless communication device; capturing a first value of the counter at a transmission of the probe request; and capturing a second value of the counter at a reception of the frame. 
     Example 127 includes the subject matter of Example 126 and optionally, wherein the instructions result in estimating a distance between the first and second wireless communication devices based on a difference between the second value and the first value. 
     Example 128 includes the subject matter of any one of Examples 122-127 and optionally, wherein the first wireless communication device comprises a mobile device and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 129 includes the subject matter of Example 121 and optionally, wherein the instructions result in receiving the probe request from the second wireless communication device and transmitting the frame to the second wireless communication device after the delay period. 
     Example 130 includes the subject matter of Example 129 and optionally, wherein the instructions result in incrementing a counter at a symbol rate of the first wireless communication device; capturing a first value of the counter at the reception of the probe request; capturing a second value of the counter; and transmitting the frame when a difference between the first value and the second value corresponds to the delay period. 
     Example 131 includes the subject matter of Example 129 or 130 and optionally, wherein the first wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station, and wherein the second wireless communication device comprises a mobile device. 
     Example 132 includes the subject matter of any one of Examples 121-131 and optionally, wherein the instructions result in communicating the probe request and the probe response over the mmWave wireless frequency band. 
     Example 133 includes the subject matter of any one of Examples 121-132 and optionally, wherein the instructions result in communicating the probe request and the probe response for establishing a wireless communication link between the first and second wireless communication devices. 
     Example 134 includes the subject matter of any one of Examples 121-133 and optionally, wherein the probe request comprises a unicast probe request, and wherein the frame comprises an acknowledge (Ack) frame, to acknowledge receipt of the probe request. 
     Example 135 includes the subject matter of any one of Examples 121-134 and optionally, wherein the probe response includes the frame. 
     Example 136 includes the subject matter of any one of Examples 121-135 and optionally, wherein the instructions result in communicating the probe request and the probe response over a wireless Gigabit (WiGig) frequency band. 
     Example 137 includes a product including a non-transitory storage medium having stored thereon instructions that, when executed by a machine, result in communicating a probe request between a first wireless communication device and a second wireless communication device; communicating a frame in response to the probe request; and estimating a distance between the first and second wireless communication devices based on the frame. 
     Example 138 includes the subject matter of Example 137 and optionally, wherein the instructions result in transmitting the probe request to the second wireless communication device and receiving the frame from the second wireless communication device. 
     Example 139 includes the subject matter of Example 138 and optionally, wherein the instructions result in communicating a probe response in response to the probe request, and wherein the probe response includes a delay value representing a delay period between a reception of the probe request by the second wireless communication device and a transmission of the frame by the second wireless communication device. 
     Example 140 includes the subject matter of Example 139 and optionally, wherein the instructions result in estimating the distance based on the delay value. 
     Example 141 includes the subject matter of any one of Examples 138-140 and optionally, wherein the instructions result in determining a direction from which the frame is received at the first wireless communication device; and estimating a location of the first wireless communication device based on the direction. 
     Example 142 includes the subject matter of any one of Examples 137-141 and optionally, wherein the instructions result in transmitting a plurality of probe requests and receiving a plurality of frames in response to the plurality of probe requests; and estimating a delay time between a reception of the probe request by the second wireless communication device and a transmission of the frame by the second wireless communication device based on the plurality of probe requests and frames. 
     Example 143 includes the subject matter of Example 142 and optionally, wherein the instructions result in transmitting the plurality of probe requests and receiving the plurality of frames when the first wireless communication device is moving. 
     Example 144 includes the subject matter of any one of Examples 137-143 and optionally, wherein the instructions result in incrementing a counter at a symbol rate of the first wireless communication device; capturing a first value of the counter at a transmission of the probe request; and capturing a second value of the counter at a reception of the frame. 
     Example 145 includes the subject matter of Example 144 and optionally, wherein the instructions result in estimating the distance based on a difference between the second value and the first value. 
     Example 146 includes the subject matter of any one of Examples 137-145 and optionally, wherein the instructions result in communicating the probe request and the frame over the mmWave wireless frequency band. 
     Example 147 includes the subject matter of any one of Examples 137-146 and optionally, wherein the probe request comprises a unicast probe request, and wherein the frame comprises an acknowledge (Ack) frame to acknowledge receipt of the unicast probe request. 
     Example 148 includes the subject matter of any one of Examples 137-147 and optionally, wherein the instructions result in communicating the probe request and the frame over a wireless Gigabit (WiGig) frequency band. 
     Example 149 includes the subject matter of any one of Examples 137-148 and optionally, wherein the first wireless communication device comprises a mobile device, and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 150 includes a product including a non-transitory storage medium having stored thereon instructions that, when executed by a machine, result in communicating a plurality of message sequences with a second wireless communication device, a message sequence of the plurality of message sequences including a first message transmitted from the first wireless communication device to the second wireless communication device and a second message transmitted from the second wireless communication device to the first wireless communication device in response to the first message; and determining a delay time based on the plurality of message sequences, the delay time representing a delay period between a reception of the first message by the second wireless communication device and a transmission of the second message by the second wireless communication device. 
     Example 151 includes the subject matter of Example 150 and optionally, wherein the first message includes a probe request and the second message includes an acknowledge (Ack) frame or a probe response. 
     Example 152 includes the subject matter of Example 150 or 151 and optionally, wherein the instructions result in estimating a distance between the first and second wireless communication devices based on the delay time. 
     Example 153 includes the subject matter of any one of Examples 150-152 and optionally, wherein the instructions result in communicating a first message sequence and a second message sequence when the first wireless communication device is static. 
     Example 154 includes the subject matter of Example 153 and optionally, wherein a first time period between a reception of a first message of the first message sequence and a transmission of a second message of the first message sequence by the second wireless communication device is different from a second time period between a reception of a first message of the second message sequence and a transmission of a second message of the second sequence by the second wireless communication device. 
     Example 155 includes the subject matter of Example 154 and optionally, wherein the second time period is a multiple of the first time period, and wherein the controller is to estimate the time delay based on the first and second message sequences. 
     Example 156 includes the subject matter of any one of Examples 150-155 and optionally, wherein the instructions result in communicating three message sequences when the first wireless communication device is moving. 
     Example 157 includes the subject matter of Example 156 and optionally, wherein the instructions result in estimating the time delay based on the three message sequences. 
     Example 158 includes the subject matter of any one of Examples 150-157 and optionally, wherein the first wireless communication device comprises a mobile device and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 159 includes the subject matter of any one of Examples 150-158 and optionally, wherein the instructions result in communicating the first and second messages over the mmWave wireless frequency band. 
     Example 160 includes the subject matter of any one of Examples 150-159 and optionally, wherein the instructions result in communicating the first and second messages over a wireless Gigabit (WiGig) frequency band. 
     Example 161 includes an apparatus of wireless communication, the apparatus comprising means for communicating a probe request between a first wireless communication device and a second wireless communication device; and means for communicating a probe response between the second wireless communication device and the first wireless communication device, the probe response includes a delay value representing a delay period between a reception of the probe request and a transmission of a frame in response to the probe request. 
     Example 162 includes the subject matter of Example 161 comprising means for transmitting the probe request to the second wireless communication device and receiving the probe response from the second wireless communication device. 
     Example 163 includes the subject matter of Example 162 comprising means for estimating a distance between the first and second wireless communication devices based on the frame. 
     Example 164 includes the subject matter of Example 162 or 163 comprising means for estimating a distance between the first and second wireless communication devices based on the delay value. 
     Example 165 includes the subject matter of any one of Examples 162-164 comprising means for determining a direction from which the probe response is received at the first wireless communication device; and means for estimating a location of the first wireless communication device based on the direction. 
     Example 166 includes the subject matter of any one of Examples 162-165 comprising means for incrementing a counter at a symbol rate of the first wireless communication device; means for capturing a first value of the counter at a transmission of the probe request; and means for capturing a second value of the counter at a reception of the frame. 
     Example 167 includes the subject matter of Example 166 comprising means for estimating a distance between the first and second wireless communication devices based on a difference between the second value and the first value. 
     Example 168 includes the subject matter of any one of Examples 162-167 and optionally, wherein the first wireless communication device comprises a mobile device and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 169 includes the subject matter of Example 161 comprising means for receiving the probe request from the second wireless communication device and transmitting the frame to the second wireless communication device after the delay period. 
     Example 170 includes the subject matter of Example 169 comprising means for incrementing a counter at a symbol rate of the first wireless communication device; means for capturing a first value of the counter at the reception of the probe request; means for capturing a second value of the counter; and means for transmitting the frame when a difference between the first value and the second value corresponds to the delay period. 
     Example 171 includes the subject matter of Example 169 or 170 and optionally, wherein the first wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station, and wherein the second wireless communication device comprises a mobile device. 
     Example 172 includes the subject matter of any one of Examples 161-171 comprising means for communicating the probe request and the probe response over the mmWave wireless frequency band. 
     Example 173 includes the subject matter of any one of Examples 161-172 comprising means for communicating the probe request and the probe response for establishing a wireless communication link between the first and second wireless communication devices. 
     Example 174 includes the subject matter of any one of Examples 161-173 and optionally, wherein the probe request comprises a unicast probe request, and wherein the frame comprises an acknowledge (Ack) frame, to acknowledge receipt of the probe request. 
     Example 175 includes the subject matter of any one of Examples 161-174 and optionally, wherein the probe response includes the frame. 
     Example 176 includes the subject matter of any one of Examples 161-175 comprising means for communicating the probe request and the probe response over a wireless Gigabit (WiGig) frequency band. 
     Example 177 includes an apparatus of wireless communication, the apparatus comprising means for communicating a probe request between a first wireless communication device and a second wireless communication device; means for communicating a frame in response to the probe request; and means for estimating a distance between the first and second wireless communication devices based on the frame. 
     Example 178 includes the subject matter of Example 177 comprising means for transmitting the probe request to the second wireless communication device and receiving the frame from the second wireless communication device. 
     Example 179 includes the subject matter of Example 178 comprising means for communicating a probe response in response to the probe request, and wherein the probe response includes a delay value representing a delay period between a reception of the probe request by the second wireless communication device and a transmission of the frame by the second wireless communication device. 
     Example 180 includes the subject matter of Example 179 comprising means for estimating the distance based on the delay value. 
     Example 181 includes the subject matter of any one of Examples 178-180 comprising means for determining a direction from which the frame is received at the first wireless communication device; and estimating a location of the first wireless communication device based on the direction. 
     Example 182 includes the subject matter of any one of Examples 177-181 comprising means for transmitting a plurality of probe requests and receiving a plurality of frames in response to the plurality of probe requests; and estimating a delay time between a reception of the probe request by the second wireless communication device and a transmission of the frame by the second wireless communication device based on the plurality of probe requests and frames. 
     Example 183 includes the subject matter of Example 182 comprising means for transmitting the plurality of probe requests and receiving the plurality of frames when the first wireless communication device is moving. 
     Example 184 includes the subject matter of any one of Examples 177-183 comprising means for incrementing a counter at a symbol rate of the first wireless communication device; means for capturing a first value of the counter at a transmission of the probe request; and means for capturing a second value of the counter at a reception of the frame. 
     Example 185 includes the subject matter of Example 184 comprising means for estimating the distance based on a difference between the second value and the first value. 
     Example 186 includes the subject matter of any one of Examples 177-185 comprising means for communicating the probe request and the frame over the mmWave wireless frequency band. 
     Example 187 includes the subject matter of any one of Examples 177-186 and optionally, wherein the probe request comprises a unicast probe request, and wherein the frame comprises an acknowledge (Ack) frame to acknowledge receipt of the unicast probe request. 
     Example 188 includes the subject matter of any one of Examples 177-187 comprising means for communicating the probe request and the frame over a wireless Gigabit (WiGig) frequency band. 
     Example 189 includes the subject matter of any one of Examples 177-188 and optionally, wherein the first wireless communication device comprises a mobile device, and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 190 includes an apparatus of wireless communication, the apparatus comprising means for communicating a plurality of message sequences with a second wireless communication device, a message sequence of the plurality of message sequences including a first message transmitted from the first wireless communication device to the second wireless communication device and a second message transmitted from the second wireless communication device to the first wireless communication device in response to the first message; and means for determining a delay time based on the plurality of message sequences, the delay time representing a delay period between a reception of the first message by the second wireless communication device and a transmission of the second message by the second wireless communication device. 
     Example 191 includes the subject matter of Example 190 and optionally, wherein the first message includes a probe request and the second message includes an acknowledge (Ack) frame or a probe response. 
     Example 192 includes the subject matter of Example 190 or 191 comprising means for estimating a distance between the first and second wireless communication devices based on the delay time. 
     Example 193 includes the subject matter of any one of Examples 190-192 comprising means for communicating a first message sequence and a second message sequence when the first wireless communication device is static. 
     Example 194 includes the subject matter of Example 193 and optionally, wherein a first time period between a reception of a first message of the first message sequence and a transmission of a second message of the first message sequence by the second wireless communication device is different from a second time period between a reception of a first message of the second message sequence and a transmission of a second message of the second sequence by the second wireless communication device. 
     Example 195 includes the subject matter of Example 194 and optionally, wherein the second time period is a multiple of the first time period, and wherein the controller is to estimate the time delay based on the first and second message sequences. 
     Example 196 includes the subject matter of any one of Examples 190-195 comprising means for communicating three message sequences when the first wireless communication device is moving. 
     Example 197 includes the subject matter of Example 196 comprising means for estimating the time delay based on the three message sequences. 
     Example 198 includes the subject matter of any one of Examples 190-197 and optionally, wherein the first wireless communication device comprises a mobile device and wherein the second wireless communication device comprises a device selected from the group consisting of an access point (AP) and a wireless docking station. 
     Example 199 includes the subject matter of any one of Examples 190-198 comprising means for communicating the first and second messages over the mmWave wireless frequency band. 
     Example 200 includes the subject matter of any one of Examples 190-199 comprising means for communicating the first and second messages over a wireless Gigabit (WiGig) frequency band. 
     Functions, operations, components and/or features described herein with reference to one or more embodiments, may be combined with, or may be utilized in combination with, one or more other functions, operations, components and/or features described herein with reference to one or more other embodiments, or vice versa. 
     While certain features have been illustrated and described herein, many modifications, substitutions, changes, and equivalents may occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.