Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L45/00—Routing or path finding of packets in data switching networks
  • H04L45/28—Routing or path finding of packets in data switching networks using route fault recovery
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W40/00—Communication routing or communication path finding
  • H04W40/005—Routing actions in the presence of nodes in sleep or doze mode
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W40/00—Communication routing or communication path finding
  • H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
  • H04W40/12—Communication route or path selection, e.g. power-based or shortest path routing based on transmission quality or channel quality
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W40/00—Communication routing or communication path finding
  • H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
  • H04W40/20—Communication route or path selection, e.g. power-based or shortest path routing based on geographic position or location
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W40/00—Communication routing or communication path finding
  • H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
  • H04W40/22—Communication route or path selection, e.g. power-based or shortest path routing using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W40/00—Communication routing or communication path finding
  • H04W40/24—Connectivity information management, e.g. connectivity discovery or connectivity update
  • H04W40/246—Connectivity information discovery
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W56/00—Synchronisation arrangements
  • H04W56/001—Synchronization between nodes
  • H04W56/0015—Synchronization between nodes one node acting as a reference for the others
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W84/00—Network topologies
  • H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W84/00—Network topologies
  • H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
  • H04W84/20—Leader-follower arrangements
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
  • Y02D30/00—Reducing energy consumption in communication networks
  • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

• communications networks are used to exchange messages among several interacting spatially-separated devices.
• Networks may be classified according to geographic scope, which could be, for example, a metropolitan area, a local area, or a personal area. Such networks would be designated respectively as a wide area network (WAN), metropolitan area network (MAN), local area network (LAN), wireless local area network (WLAN), or personal area network (PAN).
• WAN wide area network
• MAN metropolitan area network
• LAN local area network
• WLAN wireless local area network
• PAN personal area network
• Networks also differ according to the switching/routing technique used to interconnect the various network nodes and devices (e.g. circuit switching vs. packet switching), the type of physical media employed for transmission (e.g. wired vs. wireless), and the set of communication protocols used (e.g.
• Wireless networks are often preferred when the network elements are mobile and thus have dynamic connectivity needs, or if the network architecture is formed in an ad hoc, rather than fixed, topology.
• Wireless networks employ intangible physical media in an unguided propagation mode using electromagnetic waves in the radio, microwave, infra-red, optical, etc. frequency bands. Wireless networks advantageously facilitate user mobility and rapid field deployment when compared to fixed wired networks.
• a variety of processes and methods may be used for transmissions in the wireless communication system 100 between the AP 104 and the STAs and between an individual STA, such as the first STA 106a, and another individual STA, such as the second STA 106b.
• signals may be sent and received in accordance with OFDM/OFDMA techniques. If this is the case, the wireless communication system 100 may be referred to as an OFDM/OFDMA system.
• signals may be sent and received between the AP 104 and the STAs and between an individual STA, such as the first STA 106a, and another individual STA, such as the second STA 106b, in accordance with CDMA techniques. If this is the case, the wireless communication system 100 may be referred to as a CDMA system.
• a communication link may be established between STAs. Some possible communication links between STAs are illustrated in FIG. la. As an example, a communication link 1 12 may facilitate transmission from the first STA 106a to the second STA 106b. Another communication link 1 14 may facilitate transmission from the second STA 106b to the first STA 106a.
• the wireless communication system 100 may not have a central AP 104, but rather may function as an ad-hoc network between the STAs. Accordingly, the functions of the AP 104 described herein may alternatively be performed by one or more of the STAs.
• FIG. lb illustrates an example of a prior art wireless communication system 160 that may function as an ad-hoc network.
• the wireless communication system 160 shown in FIG. lb shows STAs 106a-i that may communicate with each other without the presence of an AP.
• the STAs, 106a-i may be configured to communicate in different ways to coordinate transmission and reception of messages to prevent interference and accomplish various tasks.
• the networks shown in FIG. lb may configured as a "near-me are network" (NAN).
• NAN near-me are network
• a NAN may refer to a network for communication between STAs that are located in close proximity to each other.
• the STAs operating within the NAN may belong to different network structures (e.g., STAs in different homes or buildings as part of independent LANs with different external network connections).
• a communication protocol used for communication between nodes on the ad-hoc communications network 160 may schedule periods of time during which communication between network nodes may occur. These periods of time when communication occurs between STAs a-i may be known as availability windows.
• An availability window may include a discovery interval or paging interval as discussed further below.
• the protocol may also define other periods of time when no communication between nodes of the network is to occur.
• nodes may enter one or more sleep states when the ad-hoc network 160 is not in an availability window.
• portions of the stations 106a-i may enter a sleep state when the ad-hoc network is not in an availability window.
• some stations may include networking hardware that enters a sleep state when the ad-hoc network is not in an availability window, while other hardware included in the STA, for example, a processor, an electronic display, or the like do not enter a sleep state when the ad-hoc network is not in an availability window.
• the ad-hoc communication network 160 may assign one node to be a root node.
• the assigned root node is shown as STA 106e.
• the root node is responsible for periodically transmitting synchronization signals to other nodes in the ad- hoc network.
• the synchronization signals transmitted by root node 160e may provide a timing reference for other nodes 106a-d and 106f-i to coordinate an availability window during which communication occurs between the nodes.
• a synchronization message 172a-d may be transmitted by root node 106e and received by nodes 106b-c and 106f-g.
• the synchronization message 172 may provide a timing source for the STAs 106b-c and 106f-g.
• the synchronization message 172 may also provide updates to a schedule for future availability windows.
• the synchronization messages 172 may also function to notify STAs 106b-c and 106f-g that they are still present in the ad-hoc network 160.
• One or more of the nodes in the ad-hoc communication network 160 may function as branch synchronization nodes.
• a branch synchronization node may retransmit both availability window schedule and master clock information received from a root node.
• synchronization messages transmitted by a root node may include availability window schedule and master clock information.
• the synchronization messages may be retransmitted by the branch synchronization nodes.
• STAs 106b-c and 106f-g are shown functioning as branch-synchronization nodes in the ad-hoc communication network 160.
• STAs 106b-c and 106f-g receive the synchronization message 172a-d from root node 106e and retransmit the synchronization message as retransmitted synchronization messages 174a-d.
• the branch synchronization nodes 106b-c and 106f-g may extend the range and improve the robustness of the ad-hoc network 160.
• the retransmitted synchronization messages 174a-d are received by nodes 106a, 106d, 106h, and 106L These nodes may be characterized as "leaf nodes, in that they do not retransmit the synchronization message they receive from either the root node 106e or the branch synchronization nodes 106b-c or 106f-g.
• selectively scanning for other ad-hoc networks further includes determining if a particular discovery packet or other message received outside the availability window includes information about one or more of a plurality of services that may be of interest to the device. Information that may be of interest to the device may match a criteria defined by configuration data.
• a leaf device for wireless communication in an ad- hoc communications network includes a receiver configured to receive a message identifying a number of times the message has been forwarded, and a processor configured to selectively scan for other ad-hoc networks based on the identified number.
• the processor is further configured to scan for other ad- hoc networks if the identified number is greater than or equal to a maximum number of hops. In some embodiments, the processor is further configured to increment the number of times the received message has been forwarded and forward the received message if the identified number is less than a maximum number of hops.
• the leaf device includes means for receiving a message identifying a number of times the message has been forwarded, and means for selectively scanning for other ad-hoc networks based on the identified number.
• the means for selectively scanning selectively scans for other ad-hoc networks if the identified number is greater than or equal to a maximum number of hops.
• the device also includes means for incrementing the number of times the received message has been forwarded and forwarding the received message if the identified number is less than a maximum number of hops.
• the device includes means for not forwarding the message if the identified number is greater than or equal to a maximum number of hops. In some embodiments, the device includes means for joining a second ad-hoc network based on the selective scanning. In some embodiments, the device is a leaf device of the ad-hoc network if the identified number of times is greater than or equal to a maximum number of hops. In some embodiments, the received message comprises a synchronization message transmitted by a root device. In some embodiments, the device includes means for configuring whether to selectively scan based on the identified number.
• the means for selectively scanning selectively scans for other ad-hoc networks by receiving messages outside an availability window for the ad-hoc communications network. In some embodiments, the means for selectively scanning determines if a particular discovery packet or other message received outside the availability window includes information about one or more of a plurality of services that may be of interest to the device. Information that may be of interest to the device may match a criteria defined by configuration data
• the method includes joining a second ad-hoc network based on the selective scanning.
• the device is a leaf device of the ad-hoc network if the identified number of times is greater than or equal to a maximum number of hops.
• the received message comprises a synchronization message sent from a root device.
• the method includes configuring whether to selectively scan based on the identified number.
• selectively scanning for other ad-hoc networks includes receiving messages outside an availability window for the ad-hoc communications network.
• selectively scanning for other ad-hoc networks further includes determining if a particular discovery packet or other message received outside the availability window includes information about one or more of a plurality of services that may be of interest to the device. Information that may be of interest to the device may match a criteria defined by configuration data.
• Another aspect disclosed is a method of wireless communication on an ad-hoc network.
• the method includes receiving, by a first device, a message identifying a location of a root device of a first ad-hoc network, determining, by the first device, a location of the first device, and selectively scanning, by the first device, for other ad-hoc networks based on the location of the first device and the location of the root device.
• the selective scanning is performed if the distance between the first device and the root device is greater than a threshold distance.
• the message from the root device can include a second threshold distance, which sets a maximum allowed device distance and should be no less than the first threshold distance for selective scanning.
• Devices with distance from the root device greater than the second threshold should not join the first ad-hoc network to limit the network within a certain area. If the second threshold distance is used, the difference between the two threshold distances should be less than typical device radio coverage radius, so that devices in the first ad- hoc network with distance from the root between the two thresholds are possible to reach those in other ad-hoc networks via selecting scanning.
• the method also includes joining a second ad-hoc network as a result of the selective scanning. In some aspects, the method also includes determining a window schedule for the second ad-hoc network, and transmitting a discovery message on the first ad-hoc network, the discovery message indicating the window schedule. In some aspects, the selective scanning is further based on a remaining battery life of the first device.
• the apparatus also includes a processor configured to determine a window schedule for the second ad-hoc network, and a transmitter configured to transmit a discovery message on the first ad-hoc network, the discovery message indicating the window schedule.
• the processor is further configured to selectively scan based on a remaining battery life of the apparatus.
• the apparatus includes means for receiving a message identifying a location of a root device of a first ad-hoc network, means for determining a location of the first device; and means for selectively scanning for other ad-hoc networks based on the location of the first device and the location of the root device.
• the selective scanning is performed if the distance between the first device and the root device is greater than a threshold distance.
• the apparatus also includes means for joining a second ad-hoc network as a result of the selective scanning.
• Another aspect disclosed is a non-transitory, computer readable medium comprising instructions that when executed cause a processor to perform a method of wireless communication on an ad-hoc network.
• the method includes receiving, by a first device, a message identifying a location of a root device of a first ad-hoc network, determining, by the first device, a location of the first device, and selectively scanning, by the first device, for other ad- hoc networks based on the location of the first device and the location of the root device.
• the selective scanning is performed if the distance between the first device and the root device is greater than a threshold distance.
• the method further includes joining a second ad-hoc network as a result of the selective scanning.
• the apparatus includes means for joining the ad-hoc network, means for determining a window schedule for a second ad-hoc network, and means for transmitting a discovery message on the first ad-hoc network, the discovery message indicating the window schedule.
• the apparatus also includes means for determining a second window schedule for a third ad-hoc network, wherein the means for transmitting is configured to transmit the discovery message further indicating the second window schedule.
• Another aspect disclosed is a non-transitory computer readable medium comprising instructions that when executed cause a processor to perform a method of wireless communication on an ad-hoc network.
• the method includes joining the ad-hoc network, determining a window schedule for a second ad-hoc network, and transmitting a discovery message on the first ad-hoc network, the discovery message indicating the window schedule.
• the method also includes determining a second window schedule for a third ad-hoc network, wherein the discovery message indicates the second window schedule.
• FIG. la illustrates an example of a prior art wireless communication system.
• FIG. 3 a illustrates an exemplary communication timeline in a wireless communication system in accordance with aspects of the present disclosure.
• FIG. 3b is a flowchart of an exemplary process of discovering devices in a wireless communication system in accordance with aspects of the present disclosure.
• FIG. 4A illustrates a message that may include a time value for synchronization.
• FIG. 4b illustrates an example of a wireless communication system.
• FIG. 4c illustrates another example of a wireless communication system.
• FIG. 5 is a flowchart of a method of synchronizing a wireless communications apparatus, in accordance with an embodiment.
• FIG. 6 is a functional block diagram of an exemplary wireless communication apparatus that may be employed with the wireless communication system of FIG. 4b, or FIG. 4c.
• FIG. 8 is a functional block diagram of an exemplary wireless communication apparatus that may be employed with the wireless communication system of FIG. 4b, or FIG. 4c.
• FIG. 9 is a flowchart of a method of synchronizing a wireless communications apparatus, in accordance with an embodiment.
• FIG. 10 is a functional block diagram of an exemplary wireless communication apparatus that may be employed with the wireless communication system of FIG. 4b, or FIG. 4c.
• FIG. 1 1 is a flowchart of a method of synchronizing a wireless communications apparatus, in accordance with an embodiment.
• FIG. 12 is a functional block diagram of an exemplary wireless communication apparatus that may be employed with the wireless communication system of FIG. 4b, or FIG. 4c.
• Wireless network technologies may include various types of wireless local area networks (WLANs).
• WLAN may be used to interconnect nearby devices together, employing widely used networking protocols.
• the various aspects described herein may apply to any communication standard, such as a wireless protocol.
• An access point may also comprise, be implemented as, or known as a NodeB, Radio Network Controller (“RNC”), eNodeB, Base Station Controller (“BSC”), Base Transceiver Station (“BTS”), Base Station (“BS”), Transceiver Function (“TF”), Radio Router, Radio Transceiver, or some other terminology.
• RNC Radio Network Controller
• BSC Base Station Controller
• BTS Base Transceiver Station
• BS Base Station
• Transceiver Function TF
• Radio Router Radio Transceiver
• a station “STA” may also comprise, be implemented as, or known as an access terminal ("AT”), a subscriber station, a subscriber unit, a mobile station, a remote station, a remote terminal, a user terminal, a user agent, a user device, user equipment, or some other terminology.
• an access terminal may comprise a cellular telephone, a cordless telephone, a Session Initiation Protocol ("SIP”) phone, a wireless local loop (“WLL”) station, a personal digital assistant (“PDA”), a handheld device having wireless connection capability, or some other suitable processing device or wireless device connected to a wireless modem.
• SIP Session Initiation Protocol
• WLL wireless local loop
• PDA personal digital assistant
• aspects of the present disclosure provide for methods, apparatus, and computer readable medium for nodes positioned near or at the edge of an ad-hoc network. These aspects provide for selective scanning for other ad-hoc networks based, at least in part, on an indicator of a number of times a message has been forwarded by a first ad-hoc network. If a device may determine that it is positioned at or near the edge of the first ad-hoc network, for example, based on a hop count included in a forwarded message from the first ad-hoc network, it may selectively scan for and join one or more other ad-hoc networks. By participating in or joining multiple ad-hoc networks, in an embodiment, a leaf or edge node may provide gateway functionality between the first and a second ad-hoc network.
• the selective scanning by an edge or leaf node and subsequent joining of one or more additional ad-hoc networks may provide for improved network connectivity for the leaf node. For example, a throughput or reliability from a second ad-hoc network available to a leaf node of a first ad-hoc network may be improved when compared to the network connectivity available to the leaf node via the existing first ad-hoc network connection.
• FIG. 2 illustrates various components that may be utilized in a wireless device 202 that may be employed within the wireless communication system 100 or 160.
• the wireless device 202 is an example of a device that may be configured to implement the various methods described herein.
• the wireless device 202 may comprise the AP 104 or one of the STAs.
• the wireless device 202 may include a processor 204 which controls operation of the wireless device 202.
• the processor 204 may also be referred to as a central processing unit (CPU).
• Memory 206 which may include both read-only memory (ROM) and random access memory (RAM), may provide instructions and data to the processor 204.
• a portion of the memory 206 may also include non-volatile random access memory (NVRAM).
• the processor 204 typically performs logical and arithmetic operations based on program instructions stored within the memory 206.
• the instructions in the memory 206 may be executable to implement the methods described herein.
• the processing system may also include machine-readable media for storing software.
• Software shall be construed broadly to mean any type of instructions, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Instructions may include code (e.g., in source code format, binary code format, executable code format, or any other suitable format of code). The instructions, when executed by the one or more processors, cause the processing system to perform the various functions described herein.
• the wireless device 202 may include a clock 224 configured to generate a clock signal that is used to coordinate and synchronize activities of the wireless device 202.
• the processor 204 may include the clock 224.
• the processor 204 may be configured to update the clock with a time value to allow for synchronization with other wireless devices.
• the wireless device 202 may also include a housing 208 that may include a transmitter 210 and/or a receiver 212 to allow transmission and reception of data between the wireless device 202 and a remote location.
• the transmitter 210 and receiver 212 may be combined into a transceiver 214.
• An antenna 216 may be attached to the housing 208 and electrically coupled to the transceiver 214.
• the wireless device 202 may also include (not shown) multiple transmitters, multiple receivers, multiple transceivers, and/or multiple antennas.
• the transmitter 210 may be configured to wirelessly transmit packets having different packet types or functions.
• the transmitter 210 may be configured to transmit packets of different types generated by the processor 204.
• the processor 204 may be configured to process packets of a plurality of different packet types.
• the processor 204 may be configured to determine the type of packet and to process the packet and/or fields of the packet accordingly.
• the processor 204 may also be configured to select and generate one of a plurality of packet types.
• the processor 204 may be configured to generate a discovery packet comprising a discovery message and to determine what type of packet information to use in a particular instance.
• the wireless device 202 may also include a signal detector 218 that may be used in an effort to detect and quantify the level of signals received by the transceiver 214.
• the signal detector 218 may detect such signals as total energy, energy per subcarrier per symbol, power spectral density and other signals.
• the wireless device 202 may also include a digital signal processor (DSP) 220 for use in processing signals.
• DSP 220 may be configured to generate a packet for transmission.
• the packet may comprise a physical layer data unit (PPDU).
• PPDU physical layer data unit
• the wireless device 202 may further comprise a user interface 222 in some aspects.
• the user interface 222 may comprise a keypad, a microphone, a speaker, and/or a display.
• the user interface 222 may include any element or component that conveys information to a user of the wireless device 202 and/or receives input from the user.
• the various components of the wireless device 202 may be coupled together by a bus system 226.
• the bus system 226 may include a data bus, for example, as well as a power bus, a control signal bus, and a status signal bus in addition to the data bus.
• the components of the wireless device 202 may be coupled together or accept or provide inputs to each other using some other mechanism.
• the AP 104 or STA 106 may have a plurality of operational modes.
• the STA 106 may have a first operational mode referred to as an active mode, normal operation mode, or full power mode. In the active mode, the STA 106 may always be in an "awake” state and actively transmit/receive data with another STA 106. Further, the STA 106 may have a second operational mode referred to as a power-save mode or sleep mode. In the power-save mode, the STA 106 may be in the "awake” state or may be in a "doze” or "sleep” state where the STA 106 does not actively transmit/receive data with another STA 106.
• FIG. 3a illustrates an exemplary communication timeline 300a in a wireless communication system where STAs may communicate via one channel.
• the communication according to the timeline shown in FIG. 3a may be used in an ad-hoc wireless network, such as the network shown in FIG. lb or FIG. lc.
• the exemplary communication timeline 300a may include a discovery interval (DI) 302a of a time duration ⁇ 306a, a paging interval (PI) 304a of a time duration ⁇ 308a, and an overall interval of a time duration AC 310a.
• DI discovery interval
• PI paging interval
• communications may occur via other channels as well. Time increases horizontally across the page over the time axis.
• APs or STAs may advertise services through broadcast messages such as discovery packets. APs or STAs may listen to broadcast messages transmitted by other APs or STAs.
• the duration of DIs may vary over time. In other aspects, the duration of the DI may remain fixed over a period of time.
• the end of the DI 302a may be separated from the beginning of the subsequent PI 304a by a first remainder period of time as illustrated in FIG. 3a.
• the end of the PI 304a may be separated from the beginning of a subsequent DI by a different remainder period of time as illustrated in FIG. 3a. However, different combinations of remainder time periods are contemplated.
• APs or STAs may indicate interest in one or more of a plurality of services advertised in a broadcast message by transmitting paging request messages such as paging request packets.
• APs or STAs may listen to paging request messages transmitted by other APs or STAs.
• the duration of the PI may vary over time. In other aspects, the duration of the PI may remain constant over a period of time. In some aspects, the duration of the PI may be less than the duration of the DI.
• the overall interval of duration AC 310a may measure the period of time from the beginning of one DI to the beginning of a subsequent DI as illustrated in FIG. 3a.
• the duration of the overall interval may vary over time. In other aspects, the duration of the overall interval may remain constant over a period of time. At the conclusion of the overall interval of duration AC 310a, another overall interval may begin, including a DI, a PI, and the remainder intervals. Consecutive overall intervals may follow indefinitely or continue for a fixed period of time.
• a STA may enter a sleep or power-save mode when the STA is not transmitting or listening or is not expecting to transmit or listen.
• the STA may sleep during periods other than the DI or PI.
• the STA in the sleep mode or power-save mode may awake or return to normal operation or full power mode at the beginning of the DI or PI to enable transmission or listening by the STA.
• the STA may awake or return to normal operation or full power mode at other times when the STA expects to communicate with another device, or as a result of receiving a notification packet instructing the STA to awake.
• the STA may awake early to ensure that the STA receives a transmission.
• APs or STAs may transmit discovery packets (DPs).
• DPs discovery packets
• PRs paging request packets
• a DP may be a packet configured to advertise a plurality of services provided by a STA or AP and to indicate when the paging interval is for the device that transmits the discovery packet.
• the DP may include a data frame, management frame, or management action frame.
• the DP may carry information generated by a higher layer discovery protocol or an application based discovery protocol.
• the PR may be a packet configured to indicate interest in at least one of the plurality of services provided by an AP or STA.
• the start and end of the DI and PI may be known via numerous methods to each STA desiring to transmit a discovery packet or a paging request packet.
• each STA may synchronize its clock with the other APs or STAs and set a shared DI and PI start time and DI duration and PI duration.
• a device may send a signal such as a special clear to send (S-CTS) signal to clear the medium of legacy communications, such as communications that may conflict or not be compliant with aspects of the present disclosure, and indicate the beginning and duration of the DI or PI period, as well as additional information about the DI and PI durations.
• S-CTS special clear to send
• a STA potentially interested in services advertised via discovery packets may awake or remain awake during the DI and process discovery packets to determine if a particular discovery packet includes information about one or more of a plurality of services that may be of interest to the receiving STA.
• STAs not planning to communicate information may enter a sleep or power-save mode for a break period until the next time the STAs plan to communicate.
• a STA may enter the sleep or power-save mode until the STA may communicate additional information with another device outside of the DI or PI.
• the STA may enter the sleep or power-save mode until the beginning of the next PI.
• the interested STA may awake to transmit a paging request packet to the provider of the service.
• the duration AC of the overall interval may equal approximately one to five seconds in some aspects. In other aspects, the overall interval may be less than one second or more than five seconds.
• the duration ⁇ of the DI may equal approximately 16 milliseconds in some aspects while more or less than 16 milliseconds in other aspects.
• the duration ⁇ of the PI may equal approximately the duration ⁇ in some aspects. In other aspects, the duration ⁇ may be more or less than the duration ⁇ .
• FIG. 3b is a flowchart of an exemplary process 300b of discovering devices in a wireless communication system.
• the process 300b may be used to introduce two devices, such as two STAs and 106b.
• a STA may advertise information about one or more of a plurality of services that may be of interest to various other STAs to which the information is directed.
• a service offered by a STA may include a service offered by an application (e.g., a gaming application, a shopping application, a social networking application, etc.) that a user has downloaded or that is native to the STA.
• an application e.g., a gaming application, a shopping application, a social networking application, etc.
• a user of the STA may want to invite other users of the application to interact with the user via the application.
• the STA may initiate transmission of announcements.
• Each announcement may include a discovery packet or message including the information relating to the one or more services.
• the STA may wake up from a power-save mode or sleep mode during a discovery interval to send announcements to one or more STAs.
• the STA may send one or more short announcements regarding a particular service, such as "Jack's Fruits," in order to facilitate discovery of the STA.
• the short announcements may include a discovery packet or message.
• the receiving STAs that are interested in the one or more services advertised by the STA may respond with a paging request (or query request) packet or message that indicates interest in the service provided by the STA.
• configuration data may store a list of services a device is "interested” in.
• the configuration data may be based on a user's preferences for services. These preferences may be received via a user interface or network connection. For example, the user's preferences may be initialized when a mobile device is provisioned.
• the user's preferences for services may be stored in configuration data.
• the configuration data may define one or more criteria that can be used to evaluate a service to determine whether the service is of interest to the device.
• the STA may receive queries (e.g., a paging or query request) for information on the particular service, such as "Jack's Fruits.”
• queries e.g., a paging or query request
• the STA may send a response to the queries.
• the STA and the various STAs may enter power-save mode or sleep mode in the intervals between the exchanges of messages between the STAs.
• the receiving may be performed by receiver 212 or the transceiver 214, for example, and the transmitting may be performed by the transmitter 210 or the transceiver 214, for example.
• a filter may be set up to allow the STA to wake up from a power-save mode or sleep mode only when a discovery packet or message is received for particular vendors or applications.
• the STA may wake up during a discovery interval to listen to announcements. Each announcement may include a discovery packet or message including information relating to one or more services offered by one or more other STAs.
• the STA may receive an announcement from a second STA, such as a "Jack's Fruits" announcement. The STA may determine whether it is interested in one or more sets of information related to the announcement and may respond with a paging request (or query request) packet or message that indicates its interest in the information.
• the STA may respond with a paging request (or query request) packet or message.
• the STA sends a query for more information relating to the announcement, such as more information on Jack's Fruits.
• the STA may receive a response to one or more queries that the STA sent to other STAs regarding services offered by the other STAs.
• STAs described above e.g., using a discovery protocol used in a social-WiFi network
• STAs may "sleep" a majority of a time period and wake up for short discovery intervals as described to decrease power consumption.
• STAs may make use of short time intervals to decrease power consumption while still effectively allowing discovery and advertisement of services within the network. For example, it is desirable that STAs that transmit during the short time intervals "know" that intended receivers are active to receive the transmitting messages. In addition, it is further desirable that STAs that are searching for different services advertised by another STA 106 activate their receivers at the appropriate time to receive messages advertising services from other STAs.
• certain embodiments described herein are directed to synchronization between different STAs to allow for performing device discovery as described above and for synchronization of other communications while allowing for reduced power consumption. For example certain embodiments are directed to synchronization so that STAs are activated for transmitting and receiving at the same time.
• Synchronization may provide a common reference time that may be used to determine timing of communication intervals such as the discovery interval 302a and the paging interval 304a.
• the clock signal may become out of sync. For example, if a STA 106 is in a "doze" state, the clock signal may drift and define a reference time value that is faster or slower as compared to other clocks signals of other STAs.
• the sync frame may include the schedule of the discovery interval and discovery period.
• the sync frame may also include information identifying a device to generate prospective synchronization messages. For example, an indication of a back-up root node may be included in the sync frame.
• a STA 106 Upon receipt of a sync frame, a STA 106 that may be new to the network may determine the time and the discovery interval/discovery period schedule in the network. STAs already communicating within the network may maintain synchronization while overcoming clock drift as described below. Based on the sync message, STAs may enter and exit a network (e.g., a NAN) without losing synchronization. Furthermore, the synchronization messages described herein may allow for avoiding excessive power drain and the STAs in the network may share the burden of messaging for synchronization. Furthermore, certain embodiments allow for a low messaging overhead (e.g., as only a few devices may send sync frames in every discovery period as will be described below). As described above with reference to FIG. 3A, discovery packets within a NAN are transmitted during a discovery interval 302a that occurs every discovery period. As such, sync messages may be sent during a discovery interval 302a for certain discovery periods.
• discovery packets within a NAN are transmitted during a discovery interval 30
• a STA 106 may not transmit a sync frame every discovery interval. Rather, a probability value (P sync), as is further described below, may be used to determine whether the STA 106 transmits and/or prepares a sync frame. As such, while at least some sync frames are sent for every discovery interval, not all the STAs participating in the NAN transmit a sync frame for every discovery interval. This may allow for reduced power consumption in transmitting sync frames while still enabling synchronization.
• P sync a probability value
• FIG. 4A illustrates a message 400 that may include a time value for synchronization.
• the message 400 may correspond to a discovery message as described above.
• the message 400 may include a discovery packet header 408.
• the message may further include 410 a time value for synchronization 410.
• the discovery packet header 408 may include the time value 410.
• the time value may correspond to a current time value of a clock signal of a STA 106 transmitting the message 400.
• the message 400 may further include a hop count 412. To extend the range of an ad-hoc network, nodes of the ad-hoc network may selectively forward synchronization messages.
• the hop count field 412 may identify the number of times the synchronization message 400 has been forwarded. When a node of the ad-hoc network forwards the message 400, it may increment the hop count field 412. If the hop count field reaches a maximum hop count, nodes receiving the message 400 may not forward the message. This prevents messages from being forwarded indefinitely.
• the message 400 may further include discovery packet data 414. While FIG. 4A shows discovery message serving as the sync message, it should be appreciated that according to other embodiments, the sync message may be sent apart from the discovery message.
• FIG. 4b illustrates an example of a wireless communication system 420 in which aspects of the present disclosure may be employed.
• FIG. 4b shows an ad-hoc network 420 including a root node 106j.
• the root node 106j transmits messages 430 and 428, which are received by nodes 106k and 106m respectively.
• messages 430 and 428 may be broadcast.
• messages 430 and 428 may be the same message, received by both nodes 106m and 106k.
• Messages 430 and 428 may include a hop count field 414 as illustrated in FIG. 4A. When root node 106j initially transmits a message, it may set the hop count field to an initial value, for example zero (0) or one (1).
• nodes 106k and 106m When the message(s) are received by nodes 106k and 106m, these nodes may compare the hop count field included in the message to a maximum value. If the hop count field is less than the maximum value, they may increment the hop count field and forward the message(s).
• messages 428 and 430 may be a synchronization message.
• FIG. 4b shows node 106k retransmitting or forwarding message 430 as message 432.
• Message 432 is received by node 1061.
• Node 106m retransmits or forwards message 428 as message 426 after incrementing the hop count field included in message 428.
• node 106n receives message 426, it may determine that the hop count included in the message has reached a maximum hop count. Therefore, node 106n does not forward message 426.
• node 1061 may also determine that the hop count field of message 432 has reached a maximum hop count value, and will not forward message 432 as a result.
• FIG. 4c illustrates an example of a wireless communication system 450 in which aspects of the present disclosure may be employed.
• FIG. 4c shows network 425 of FIG. 4b, with root node 106j and leaf node 1061. Other nodes from FIG. 4b have been omitted from FIG. 4c for clarity.
• FIG. 4c also shows other ad-hoc networks 440 and 445.
• Ad-hoc network 440 includes root node 106o and ad-hoc network 445 includes root node 106p.
• the circles 440 and 445 show the approximate edge of the ad-hoc networks of root nodes 106o and 106p respectively.
• leaf node 1061 is positioned at the edge of network 425. As such, when messages are received by lead node 1061 from root node 106j, the hop count may be set to a maximum hop value. Leaf node 1061 may not forward messages from root node 106j as a result.
• messages received from root node 106j by leaf node 1061 that include a hop count field greater than or equal to a maximum hop count may provide an indication to leaf node 1061 that it is positioned near an edge of network 425.
• node 1061 may selectively scan for other ad-hoc networks.
• FIG. 4c shows other ad-hoc networks 440 and 445.
• Node 1061 is positioned within range of these networks, and may be able to receive messages from root nodes 106o and/or 106p.
• node 1061 may join one or both of networks 440 and 445, in addition to participating in the first ad-hoc network 425.
• FIG. 5 is a flowchart of a method 500 of wireless communication.
• process 500 is performed by a device in an ad-hoc network.
• process 500 is performed by a leaf device in an ad-hoc network.
• the method 500 is described below with respect to the elements of the wireless device 202, those having ordinary skill in the art will appreciate that other components may be used to implement one or more of the blocks described herein.
• a message is received from a first ad-hoc network.
• the message is received from a root device of the first ad-hoc network.
• the message identifies a number of times the message has been forwarded.
• the message includes a "hop count” field.
• the "hop count” field is incremented whenever a node of a wireless network forwards the message. When the "hop count' reaches a maximum hop count, nodes receiving the message do not forward the message. This prevents messages from being forwarded indefinitely. Nodes receiving a message with a "hop count" field at a maximum value may be positioned at an edge of an ad-hoc network. In other words, these nodes may be leaf nodes.
• a leaf node may remain in communication with an ad- hoc network exhibiting superior network connectivity when compared to other ad-hoc networks it may be able to communicate with.
• whether to selectively scan for ad-hoc networks based on the identified number may be configurable. For example, in some aspects, a first set of leaf nodes may be configured to scan for other ad-hoc networks while a second set of leaf nodes are configured not to scan for other ad-hoc networks.
• selectively scanning for other ad-hoc networks includes determining if a particular discovery packet or other message received outside the availability window matches a criteria defined by configuration data.
• selectively scanning for other ad-hoc networks may include remaining awake and/or listening for network traffic during one or more DI or PI intervals to determine if a particular discovery packet or other message includes information about one or more of a plurality of services that may be of interest to the device.
• selectively scanning may comprise receiving and/or processing messages outside an availability window or discovery interval for an ad-hoc network a station is in communication with.
• the selective scanning may be based on the first device's remaining battery life. For example, in some aspects, if the remaining battery life is above a first energy threshold, the first scanning period and a first scanning duration may be utilized. A scanning period may be an elapsed time between scans. In some aspects, if the remaining battery life is below a second energy threshold, a second scanning period and a second scanning duration may be utilized. In some aspects, the second scanning period may be greater than the first scanning period. In some aspects, the second scanning duration may be lower than the first scanning duration.
• the selective scanning module 604 may include the processor unit(s) 204 of FIG. 2. In one aspect, the selective scanning module 604 may also include one or more of a processor, signal generator, transceiver, decoder, or a combination of hardware and/or software component(s), circuits, and/or module(s). In one aspect, means for selective scanning may include the selective scanning module 604. The selective scanning module 604 may be configured to perform one or more of the functions described above with respect to block 504 of FIG. 5.
• FIG. 7 is a flowchart of a method 700 of wireless communication.
• process 700 is performed by a device in an ad-hoc network.
• process 700 is performed by a leaf device in an ad-hoc network.
• the method 700 is described below with respect to the elements of the wireless device 202, those having ordinary skill in the art will appreciate that other components may be used to implement one or more of the blocks described herein.
• a message is received by a first device.
• the message identifies a location of a root device for a first ad-hoc network.
• the message may indicate global positioning coordinates of the root device.
• the location of the root device may be determined based on cellular signals.
• the location may be determined based on one or more distances from one or more corresponding keypoints.
• the keypoints may be access points, cellular transmitters, or stations.
• the received message is a synchronization message.
• the received message identifies a first ad-hoc network.
• the first device determines a location of the first device.
• the first device determines its location based on GPS signals.
• the first device may determine its location based on cellular signals. For example, the location may be determined based on measured round-trip delays to a plurality of cellular transmitters.
• the first device selectively scans for other ad-hoc networks based on the location of the first device and the location of the root device.
• the other ad-hoc networks are ad-hoc networks different than the first ad-hoc network.
• the first device may selectively scan for other ad-hoc networks if the distance between its location and the root device is greater than a first threshold distance.
• the selective scanning may be based on the first device's remaining battery life. For example, in some aspects, if the remaining battery life is above a first energy threshold, the first scanning period and a first scanning duration may be utilized. A scanning period may be an elapsed time between scans.
• a second scanning period and a second scanning duration may be utilized.
• the second scanning period may be greater than the first scanning period.
• the second scanning duration may be lower than the first scanning duration.
• a device may determine a distance between the root device and its present location. If this distance is greater than the second threshold distance, the device may not join the ad-hoc network identified by the message received in block 702. This provides a distance limit on devices participating in the ad-hoc network identified by the message received in block 702.
• FIG. 8 is a functional block diagram of an exemplary wireless communication device 800 that may be employed with the wireless communication system of FIG. 4b , or FIG. 4c.
• the wireless device 800 may include a receiving module 802.
• the receiving module 802 may comprise the receiver 212.
• the receiving module 802 may also include one or more of a processor, signal generator, transceiver, decoder, or a combination of hardware and/or software component(s), circuits, and/or module(s).
• means for receiving may include the receiving module 802.
• the receiving module 802 may be configured to perform one or more of the functions described above with respect to block 702 of FIG. 7.
• the wireless device 800 may further include a selective scanning module 804.
• the selective scanning module 804 may include the processor unit(s) 204 of FIG. 2. In one aspect, the selective scanning module 804 may also include one or more of a processor, signal generator, transceiver, decoder, or a combination of hardware and/or software component(s), circuits, and/or module(s). In one aspect, means for selective scanning may include the selective scanning module 804. The selective scanning module 804 may be configured to perform one or more of the functions described above with respect to block 706 of FIG. 7. The wireless device 800 may further include a determining module 806. The determining module 806 may include the processor unit(s) 204 of FIG. 2.
• FIG. 10 is a functional block diagram of an exemplary wireless communication device 1000 that may be employed with the wireless communication system of FIG. 4b , or FIG. 4c.
• the wireless device 1000 may include a determining module 1002.
• the determining module 1002 may comprise the processor 204.
• the determining module 1002 may also include one or more of a processor, signal generator, transceiver, decoder, or a combination of hardware and/or software component(s), circuits, and/or module(s).
• means for determining may include the determining module 1002.
• the determining module 1002 may be configured to perform one or more of the functions described above with respect to block 902 of FIG. 9.
• the wireless device 1000 may further include a generating module 1004.
• the transmitting module 1006 may also include one or more of a processor, signal generator, transceiver, decoder, or a combination of hardware and/or software component(s), circuits, and/or module(s).
• means for transmitting may include the transmitting module 1006.
• the transmitting module 1006 may be configured to perform one or more of the functions described above with respect to block 906 of FIG. 9.
• FIG. 12 is a functional block diagram of an exemplary wireless communication device 1200 that may be employed with the wireless communication system of FIG. 4b , or FIG. 4c.
• the wireless device 1200 may include a joining module 1202.
• the joining module 1202 may comprise the processor 204.
• the joining module 1202 may also include one or more of a processor, signal generator, transceiver, decoder, or a combination of hardware and/or software component(s), circuits, and/or module(s).
• means for joining may include the joining module 1202.
• the joining module 1202 may be configured to perform one or more of the functions described above with respect to block 1102 of FIG. 1 1.
• the wireless device 1200 may further include a determining module 1204.
• the determining module 1204 may include the processor unit(s) 204 of FIG. 2. In one aspect, the determining module 1204 may also include one or more of a processor, signal generator, transceiver, decoder, or a combination of hardware and/or software component(s), circuits, and/or module(s). In one aspect, means for determining may include the determining module 1204. The determining module 1204 may be configured to perform one or more of the functions described above with respect to block 1 104 of FIG. 11. The wireless device 1200 may further include a transmitting module 1206. The transmitting module 1206 may include the transmitter 210 of FIG. 2.
• the transmitting module 1206 may also include one or more of a processor, signal generator, transceiver, decoder, or a combination of hardware and/or software component(s), circuits, and/or module(s).
• means for transmitting may include the transmitting module 1206.
• the transmitting module 1206 may be configured to perform one or more of the functions described above with respect to block 1 106 of FIG. 11.
• any of the various illustrative logical blocks, modules, processors, means, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two, which may be designed using source coding or some other technique), various forms of program or design code incorporating instructions (which may be referred to herein, for convenience, as "software” or a "software module), or combinations of both.
• software or a “software module”
• the various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein and in connection with FIGS. 1-1 1 may be implemented within or performed by an integrated circuit (IC), an access terminal, or an access point.
• the IC may include a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, electrical components, optical components, mechanical components, or any combination thereof designed to perform the functions described herein, and may execute codes or instructions that reside within the IC, outside of the IC, or both.
• the logical blocks, modules, and circuits may include antennas and/or transceivers to communicate with various components within the network or within the device.
• a general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine.
• a processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
• the functionality of the modules may be implemented in some other manner as taught herein.
• the functionality described herein (e.g., with regard to one or more of the accompanying figures) may correspond in some aspects to similarly designated "means for" functionality in the appended claims.
• Computer-readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program from one place to another.
• a storage media may be any available media that may be accessed by a computer.
• such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store desired program code in the form of instructions or data structures and that may be accessed by a computer.
• Disk and disc includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and instructions on a machine readable medium and computer-readable medium, which may be incorporated into a computer program product.

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  • 2013-03-15 US US13/836,178 patent/US9307507B2/en not_active Expired - Fee Related
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