Classifications

• • 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
  • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
  • H04W52/02—Power saving arrangements
  • H04W52/0209—Power saving arrangements in terminal devices
  • H04W52/0212—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave
  • H04W52/0216—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave using a pre-established activity schedule, e.g. traffic indication frame
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
  • H04W52/02—Power saving arrangements
  • H04W52/0209—Power saving arrangements in terminal devices
  • H04W52/0212—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave
  • H04W52/0219—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave where the power saving management affects multiple terminals
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
  • H04W52/02—Power saving arrangements
  • H04W52/0209—Power saving arrangements in terminal devices
  • H04W52/0225—Power saving arrangements in terminal devices using monitoring of external events, e.g. the presence of a signal
  • H04W52/0241—Power saving arrangements in terminal devices using monitoring of external events, e.g. the presence of a signal where no transmission is received, e.g. out of range of the transmitter
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W76/00—Connection management
  • H04W76/10—Connection setup
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W84/00—Network topologies
  • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
  • H04W84/10—Small scale networks; Flat hierarchical networks
  • H04W84/12—WLAN [Wireless Local Area Networks]
• • 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

• TITLE A LOW-POWER WIRELESS BEACONING NETWORK
• the present invention relates generally to wireless communication systems
• low power wireless networks that include a plurality of wireless
• Wireless networks are well known in the art. Wireless networks are typically
• stations allow wireless devices to communicate with the infrastructure
• the base stations provide wireless communications within respective cells and
• wireless devices may
• stations and the infrastructure network facilitate communications between wireless
• wireless data terminal may communicate with other wireless devices connected to the
• the portable data terminal is battery
• the high power transmissions may significantly reduce battery life.
• Wireless communications are generally managed according to an operating
• Wireless devices typically provide their own
• timing mechanisms own timing mechanisms; however, it is common for the timing mechanisms to vary in their operations from device to device so that they fail to provide an accurate reference
• the personal LAN includes a plurality of wireless devices with each wireless
• the radio transceiver may take the form of an
• wireless devices establish a wireless network.
• the wireless network at least two of the
• plurality of wireless devices share beaconing responsibilities to coordinate operation of
• the beacons are provided on a periodic basis with at least
• beaconing responsibilities may be shared on a round robin basis or may be shared
• the plurality of wireless devices may include a primary beaconing wireless
• the other wireless devices may coordinate low power operations
• wireless devices may enter low power operations for multiple beacon cycles of beacons
• the other wireless devices may also be provided by the primary beaconing wireless device.
• the other wireless devices may also be provided by the primary beaconing wireless device.
• the other wireless devices may also be provided by the primary beaconing wireless device.
• the other wireless devices may also adjust timing
• the primary beaconing wireless device may also coordinate communications
• the other wireless devices may
• beaconing device Further, beaconing responsibilities may be coordinated to satisfy
• wireless device limitations For example, should one of the wireless devices face an
• responsibilities may be passed to other of the wireless devices.
• At least one of the wireless devices may also communicate with an infrastructure
• devices may separate from the wireless network to become a separated wireless device.
• At least one of the wireless devices attempts to reestablish communications
• the separated wireless device may also communicate with the separated wireless device.
• the separated wireless device may also communicate with the separated wireless device.
• the separated wireless device may
• wireless device may scan a plurality of predetermined control channels for a beacon
• beacon signal may rejoin the wireless network in response to receipt of the beacon signal.
• the separated wireless network may selectively join another wireless network.
• the separated wireless network may selectively join another wireless network.
• network device may establish wireless communication with an infrastructure network.
• devices may separate from the wireless network to form an alternate wireless network
• alternate network may rejoin the wireless network after the separation.
• the separation may be the
• At least two wireless devices may form the alternate network when they are physically
• alternate wireless network may transmit beacon signals intended for the at least two
• beacons signals may be
• plurality of wireless devices may establish a beaconing pattern to coordinate operation of
• the wireless network prior to separation of the at least two wireless devices.
• the at least two wireless devices of the alternate wireless network may then be
• the at least two wireless devices continue transmission of the beaconing pattern. Then, the at least two wireless devices
• the wireless network may recognize the wireless network based upon identification of the beaconing pattern.
• each wireless device includes a
• radio transceiver capable of transmitting at both a higher power level and at a lower
• the plurality of wireless devices establish a wireless
• the plurality of wireless devices communicate
• the plurality of wireless devices establish the wireless
• plurality of wireless devices separates from the wireless network when it moves outside
• At least one of the wireless devices may also be any wireless devices.
• infrastructure network occur at a power level greater than the higher power level.
• the present invention also includes a method of establishing a wireless network.
• the method includes selecting at least two wireless devices from a plurality of wireless
• Figure 1 is a perspective diagram showing a wireless personal local area network
• LAN LAN with a plurality of network devices, each of the plurality of network devices
• Figure 2 is a perspective diagram showing the devices of the personal wireless LAN
• Figure 3 is a perspective diagram showing two personal LANs, one of which is
• Figure 4A is a timing diagram showing two consecutive beacons transmitted by
• Figure 4B is a timing diagram showing a plurality of devices responsible for
• Figure 5 is a timing diagram showing a device sleeping through multiple beacons
• Figure 6 is a perspective diagram showing roaming devices on a low power personal
• Figure 7 is a timing diagram showing a missing beacon from one of the devices of
• Figure 8 illustrates a specific embodiment of a personal LAN according to the
• present invention operating to collect data and in coordination with an infrastructure
• FIG. 9 illustrates operation of a personal LAN 801 according to the present
• Figure 10 is a schematic block diagram illustrating the radio module and its
• Figure 1 is a perspective diagram showing an exemplary embodiment of a wireless
• personal LAN local area network
• each of the plurality of network devices 105, 107, 109 and 111 being capable of
• Each of the devices 105, 107, 109 and 111 contain radio modules,
• radio card 117 such as a radio card 117, operating pursuant to a common communication protocol.
• a hand held device 105 More specifically, a hand held device 105, a data collection device 107, a printer
• PDA personal digital assistant
• beacons that are transmitted by the devices 105, 107, 109, and 111 are primarily used for
• one network device transmits a
• the network devices 105 In the period between any two consecutive beacons, the network devices 105,
• 107, 109 and 111 selectively transmit and receive information from each other.
• the wireless personal LAN 100 might support a small number of devices, e.g., (up
• a user selects a set of devices to be part of the personal wireless LAN 100 and
• the user establishes the personal wireless
• the wireless LAN 100 via one of the devices such as the data collection device 107.
• collection device 107 through wireless interaction with the collected devices, delivers a list
• the personal wireless LAN 100 is formed.
• the devices are all placed in very close proximity before initiating
• the devices in the personal LAN 100 such as the data collection device 107, sends an
• This frame is always broadcast, and it includes a
• type field indicating the type of network being created, and a network identification to
• the attach request frame is broadcast using the network
• the data collection device 107 sends an "attach response
• the personal wireless LAN 100 operates in the vicinity of a high density of
• overlapping networks For example, in one embodiment 15 to 20 personal wireless LANs
• the personal LAN can simultaneously independently operate within a 300 foot area.
• the personal LAN can simultaneously independently operate within a 300 foot area.
• the personal LAN can simultaneously independently operate within a 300 foot area.
• device 107 is responsible for transmitting beacons, in other embodiments, more than one
• beaconing intervals are rather fixed (i.e., of a predetermined duration), such intervals may
• beacons in either a predetermined order or in a dynamically determined order.
• network devices 105, 107, 109 and 111 may choose not to participate in beaconing
• beacon signal protocol established allows each of the devices
• protocol also supports beacon hand-off and backup beacon functionality to support
• one of the beaconing devices is considered to be the network coordinator
• the printer 109 can be designated as the network coordinator and made
• the network coordinator may typically be the beaconing device, any non- beaconing device may take on such responsiblities as network coordinator
• the beacons are typically frames that include information about network time, dwell,
• a device may schedule its receiver to
• beacons may also include a count of the number of beacons that
• radio network device
• the personal wireless LAN 100 employs frequency hopping spread spectrum
• the available frequency band is divided into a number of channels and the
• control channels A few of the channels are designated as control channels, and are used for
• the beacons may also include hop
• the personal wireless LAN 100 is a low power network with a small range that
• the personal wireless LAN 100 initiates search and rescue missions.
• one embodiment of the search and rescue mechanism one of the beaconing devices in the
• the printer 109 for example, or any other device having the
• the beacons are sent at fixed intervals of time. Alternately they may be sent at
• beacons When the beacons are sent at variable intervals, they can be sent at
• a device that has not seen beacons in a given cycle will scan the designated control
• Devices join the personal wireless LAN 100 by requesting the network coordinator
• the network coordinator can accept or reject the device that wants to join the network.
• a network device that finds itself isolated due to roaming can choose to
• a single network device such as the hand held
• the device 105 transmits beacons at fixed beaconing intervals.
• the data collection device 107, the printer 109 and the PDA 111 use the
• the hand held device 105 is configured to control the hand held device 105 and to coordinate their communication with other devices.
• Communication is typically scheduled during the awake time window
• the device is anticipated, after the awake time window lapses, the device may choose to sleep
• the hand held device 105 as the network coordinator, periodically requests that all
• the other devices in the personal LAN 100 confirm their presence. It may also periodically
• the devices 107, 109 and 111 can choose to sleep for multiple beacon cycles and
• the network coordinator 105 is typically made aware of such
• sleeping device is coordinated by the network coordinator and scheduled for the beacon
• the PDA 111 re-acquires
• the personal LAN itself does not determine that the device is missing for the
• duration of the PDA's 111 resync time This period can be quite long.
• the device is the network coordinator (the station that normally transmits beacons), then after a
• the data collection device 107 for
• the hand held device 105 acting as a network coordinator
• the originating device sends the
• the network coordinator 105 subsequently transfers the received information to the
• Such information can be sent by the sending device to the network coordinator 105 during a designated slot in a beacon cycle or during a contention period
• the network coordinator 105 stores messages
• the network devices 105, 107, 109 and 111 are configured to communicate with the network devices 105, 107, 109 and 111.
• the hand-held device 105 first transmits its beacon, followed later
• beacons from the data collection device 107, the printer 109, and the PDA 111.
• one of the devices decides to halt beacon
• the other network devices 105, 109, and 111 continue transmitting their
• beaconing device or with each other.
• one of the devices such as the hand held
• device 105 acts as the network coordinator and broadcasts beacons that are used as the
• the primary beacon is used for clock synchronization by all the devices on the personal LAN 100.
• the secondary beacons are
• Devices that participate in beacon transmissions may suspend their own beacon
• device 107 may selectively decide to temporarily suspend transmission of its beacons.
• devices 105, 109 and 111 continue beaconing in round-robin order. Alternately, one of the
• Each of the network devices 105, 107, 109 and 111 includes a clock.
• a clock For example
• the hand held device 105 includes a clock 113 that it uses for several purposes including
• 109 and 111 also include a radio card, such as the radio card 117, for communicating with
• a radio card operates in coordination with a microprocessor
• radio operates independently of the microprocessor or host computer, and provides a
• both LANs may be unaltered. If the clocks in each device are not synchronized with each
• beacons are therefore
• beaconing devices used to synchronize the clocks.
• the beaconing devices one of the beaconing devices, called the
• network coordinator is considered to be the primary beaconer and its beacons are used by
• the other devices to calculate the difference between their clocks and the clock of the
• each device is able to wake
• beacons determines its clock's relative accuracy versus the network clock
• network clock enables the network devices on the personal LAN to sleep through
• each device can save power by minimizing the wakeup window required to
• Figure 2 is a perspective diagram showing the devices of the personal wireless LAN
• the hand held device in communication with a base station 227, that is part of an infrastructure network 200, employing a relatively higher power wireless communications 229.
• the data collection device 207 the printer 209 and the PDA 211 communicate with the
• base station 227 employing wireless links 229. Through the base station 227, the devices
• 205, 207, 209, and 211 communicate with a host computer 223 and with other personal
• the base station 227 employ communication links 221
• communication link 221 can be a wired communication link or a high powered wireless
• base station 227 may be high powered or low powered, depending on the distance between
• the personal LAN 203 may designate one or more of the devices 205, 207, 209 and 211
• the devices 205, 207, 209, and 211 within the personal LAN 203 to communicate when
• one or more devices that are part of the wireless personal LAN 203 acts
• the base station 227 As an access point to the infrastructure network 200.
• the base station 227 For example, the base station 227,
• LAN 203 It can communicate with another base station 225 and the host computer 223. It
• the hand held device 205 can also communicate with the hand held device 205, the data collection device 207, the
• the base station 227 also participates in
• the base stations 227 and 225 each may
• the base station 227 plays the
• the base station 227 or one of the devices To initiate the personal LAN 203, the base station 227 or one of the devices
• the initiate command would include the network id to use for the
• the data rate the type of network, the power level to be used, the information
• the type of the network could be specified as a personal LAN
• the data rate could be specified as 250 Kbps or 1000 kbps, and
• the power level could be specified as one of 3 for full power, 2 for
• the power be specified as 1000 kbps, the type of the network would be a personal LAN, and the power
• the initiate command includes solicitation of information on a device's ability to
• the device sending the initiate command, the base station 227 or the hand held
• attach request would include an address of the requesting device, the type of the remote
• an attach request also includes information on the device's
• the initiating device such as the hand held
• the join response includes the address of the remote
• join response also includes information on the device's role in distributed
• the start network command includes the dwell time of network in
• ticks where one tick is approximately 30.5 microseconds for an exemplary
• It also includes a device resync time, which is the number of beacon intervals
• the beacon interval in terms
• command is also used to reinitiate old networks.
• the devices receiving the start network command from the base station 227 or the
• hand held device 205 send a start network response that includes information on the success
• the start network For old networks being reinitiated, the start network
• the radio modules enter a low power or "sleep mode" to conserve battery power.
• Figure 3 is a perspective diagram showing two personal LANs 303 and 333, one of
• the personal LAN 333 includes a hand held device 325,
• a data collection device 327 a printer 329, and a PDA 331. These devices communicate
• the devices 305, 307, 309, and 311 not only communicate with each other
• a host computer 302 such as a personal computer 302
• a data collection device 317 such as a personal computer 302
• the wireless link 335 may be a low power wireless link or a
• the infrastructure network 300 may depend on a base station, such as the base
• the base station 313, being part of the infrastructure network 300, provides data
• the base station 313 acts as a
• wired bridge access point that attaches to the infrastructure network through a
• wireless personal LAN frames to wireless personal LAN frames. It also forwards wireless personal LAN frames to wireless personal LAN frames. It also forwards wireless personal LAN frames to wireless personal LAN frames.
• the base station 313 is shown wired to the
• infrastructure network 300 it may employ a high power wireless means to communicate
• the base station 313 may participate with the
• personal LAN 303 as an infrastructure device, or may be part of the personal LAN 303
• the data collection device 317, and the hand held device 319 are not part of any
• 317 may employ low power wireless communications or high power communications
• the data rate the data rate, the traffic, and the protocols.
• Figure 4A is a timing diagram 400 showing a window of two consecutive beacons
• the time line 405 shows two beacons 413 and 415, each transmitted for a
• the beaconing station may
• the sending device must participate in the beaconing
• beacons 413 and beacon 415 are likely to be transmitted by different
• beaconing devices If only one device, e.g., the network coordinator, is responsible for
• the beacons 413 and 415 originate from the network coordinator.
• beaconing information may be transmitted by a
• beaconing station on the personal LAN, and received by all the other devices on the
• a beacon gets to coordinate commumcation activity. It used to
• synchronize operation and may contain information such as pending message lists,
• the cycle sleep mode may sleep through multiple intervening beacons.
• the beacon transmission cycle 407 is the duration between two consecutive beacons.
• the wakeup window listening for the beacon stay awake for the beacon in a window called the wakeup window
• an awake time window may be optionally
• beaconing device listens to network traffic and communicates with the other devices.
• the beacon transmission cycle 407 may or may not be predetermined. It may also be predetermined. It may also be predetermined. It may also be predetermined. It may also be predetermined.
• the devices in the network vary with the data rate, the traffic and the protocol. If it is predetermined, the devices in the
• the beacon can be a
• ticks of 30.5 microseconds a next beacon time in terms of hops, a next beacon type, a
• beacon interval in units of hop dwells and a beacon count modulo 65536.
• the beacon frame also includes a request
• the next hop time indicates the time left in the current dwell from start of the
• the beacon frame includes the dwell time in network ticks, the hop
• the actual channel number is helpful to the receiving device because of the possibility of hearing adjacent channels.
• the type of beacon can be 0 for normal beacon from
• the type 2 also indicates that the beacons from the network coordinator have
• next beacon type information may be accompanied by information on the next
• beaconing device indicating the device that would beacon next. This would facilitate
• Figure 4B is a timing diagram 405 showing a plurality of devices responsible for
• Beacons 421, 423 and 425 are transmitted by the hand held device 105, the data
• the PDA 111 does
• One of the beacomng devices for example the hand held
• the network coordinator may be considered to be the primary or the master beacon, and
• the other two beacons 423 may be used by the other devices to synchronize their clocks.
• the other two beacons 423 may be used by the other devices to synchronize their clocks.
• Figure 5 is a timing diagram 505 showing a device sleeping through multiple
• beacons while still being able to wake up in time for a subsequent beacon.
• beacons 513, 515 and 517 are sent the
• the hand held device 105 the data collection device 107, and the printer 109, respectively.
• PDA 111 does not send beacons, and sleeps for multiple beacon cycles. Specifically, the
• PDA 111 wakes up for a wakeup window 511 to receive the beacon 513 from the hand held
• the PDA 111 does not send beacons, and sleeps for
• the hand held device 105 would be considered as the hand held device 105.
• the hand held device 105 would be considered as the hand held device 105.
• Figure 6 is a perspective diagram showing roaming devices on a low power personal
• personal LAN 600 includes a hand held device 605, a data collection device 607, a printer
• the devices 605, 607, 609, and 611 are exemplary embodiments.
• the devices 605, 607, 609, and 611 are exemplary embodiments.
• hand-held device 605 is the network coordinator and transmits primary beacons periodically
• the devices in the personal LAN 600 are typically worn using appropriate
• the personal LAN 600 is therefore dynamically
• the operation of the personal LAN 600 is continued and not disrupted despite the lack of
• the network coordinator 605 assesses all devices in the network by monitoring the
• coordinator 605 generates identify frames. The lack of an appropriate response to the
• network coordinator 605 then initiates a search and rescue mission for a numbers of
• beacons that was initially specified by the lost devices After the requested number of beacons has passed, the network coordinator 605 will wait for an indication of no activity
• the lost devices, the printer 609 and the PDA 611, are expected to wait on one of
• PDA 611 continue to transmit their beacons, and continue to receive each others beacons.
• the printer 609 and the PDA 611 communicate with
• the printer each other to identify a replacement for the network coordinator.
• the printer For example, the printer
• the PDA 611 may elect the printer 609 to become the network coordinator and
• the hand held device 605 abandons an unsuccessful search and
• the device wants to join, the number of beacons after missing which the device
• the lost devices then await a join network response from
• the lost devices then send network
• Figure 7 is a timing diagram showing a missing beacon from one of the devices of
• the data collection device 105 when the hand held device 105, the data collection device
• the time line 733 corresponds to the activity of the hand held device 105 while the
• time line 735 corresponds to the activity of the printer 109.
• the printer 109 wake up periodically for a wakeup window 709 to receive beacons. They
• beacons when it is their turn to transmit beacons.
• the hand held device 105, the data collection device 107, and the printer 109 are the hand held device 105, the data collection device 107, and the printer 109.
• beacons 711, 713 and 715 expected to transmit the beacons 711, 713 and 715 respectively, in that order.
• the other devices 105, 109, and 111 listening to the beacons identify the source of the missing beacon as the data
• the data collection device 107 is the network coordinator, both the
• beaconing devices 105 and 109 try to replace the missing beacon 719 with their own
• beacons 723 and 725 respectively.
• the hand held device 105 is the network coordinator, then the network
• coordinator 105 decides to replace the missing beacon from the data collection device 107
• the printer 109 refrains from transmitting its beacon in contention with
• the network coordinator 105 If the data collection device 107 decides later on to participate
• FIG. 8 illustrates a specific embodiment of a personal LAN 801 according to the
• present invention operating to collect data and in coordination with an infrastructure
• the personal LAN 801 includes a plurality of devices each having a radio
• module for enabling communication between itself, other devices within the personal
• Such a personal LAN 801 may be used by a personal LAN 801 and the infrastructure network.
• Such a personal LAN 801 may be used by a personal LAN 801
• person 810 in gathering data such as in a factory environment and may include, for
• a printer 814 for example, a printer 814, a data terminal 816 and a code reader 818, such devices perhaps attachable to the person via a harness 812.
• a harness 812. In operation, after initialization of the
• the radio modules When communication is not required by a particular device, the radio modules
• circuitry within the device may also be powered down.
• the personal LAN 801 may also establish communication with the infrastructure
• the infrastructure network may include a wired network having
• a wired backbone 826 connecting computer devices 828 to a wireless access point 824.
• the wireless access point 824 may participate with a multi-hop wireless network 822
• the multi-hop wireless network 822 may include, for example,
• printers 830 and other devices communicating wirelessly.
• the personal LAN 801 may designate one or more of the devices within the personal LAN
• Figure 9 illustrates operation of a personal LAN 901 according to the present
• the user 910 delivers packages
• the user 910 collects the packages
• the user 910 would then begin distribution of the packages 920.
• the user 910 establishes the personal LAN 901 by collecting desired devices and
• the terminal 916 through wireless interaction with the collected devices delivers a
• the personal LAN 901 is formed.
• the personal LAN 901 may then establish
• the access point 936 in the van 934 may participate with the personal LAN 901 as an
• the devices within personal LAN may be referred to as a host unit 1030 that contains a
• CPU central processing unit
• radio module 1034 various other circuitry
• the CPU 1032 operates in conjunction with the radio module 1034 to
• the CPU 1032 may place the radio module 1034 as well as
• An Infrastructure Network (such as those managing a majority of wireless
• communication flow a premises may depend on an access point for distributing
• the personal LAN provides a simple modem and an intelligent host interface option, e.g.,
• LAN also allows a user to select a set of devices and automatically configures itself
• Each device (or host) that may participate in personal LANs will contain a radio
• the radio and host protocol are implemented by a microprocessor in the radio module.
• the microprocessor will handle framing for both interfaces (simultaneously)
• NDIS device drivers and Windows 95 ⁇ virtual com ports This allows printers to have a
• radio devices via a stream of bytes.
• An NDIS interface would allow standard higher level
• a simple "C” language API may be used as a device driver.
• the physical interface to the host device is one of the following: a 3N
• CMOS serial interface and with an adapter, an RS-232 interface.
• Table 1 describes the 3V CMOS serial interface signals.
• a smart interface command can change the rate to one of
• the asynchronous framing will be 8 bit, no parity and 1 stop bit.
• a dumb interface is used by
• the radio protocol to support devices using the dumb interface.
• a smart interface is used when the host device is able to actively manage the
• the radio Upon reset, the radio assumes a dumb interface.
• the dumb interface passes just
• RTS must be asserted by the "dumb" host. In those cases where the connected host device does not use RTS/CTS signaling, this may be accomplished by
• the radio will power manage the radio
• the radio will send the data to one of the
• the smart interface can control operation of the radio such as establishing
• the host may then begin a sequence to enter the smart interface mode.
• the radio When the radio has a message to send to the host, it will assert RI. Whenever any
• the message/frame (either from or to the radio), the message/frame is considered aborted and
• the Ctl field is composed of two parts.
• the low 4 bits are the command and the
• Table 4 below defines the commands from the host device to the radio.
• Table 5 defines the commands and status messages from the radio to the host.
• Each frame transmitted across the interface has a sequence number.
• the Chk Field is a modulo 8 sum of all bytes in each command or response
• the Initiate Command is used by the host to Initiate a new Microlink network.
• the radio Upon receipt of this command, the radio will send Initiate commands on the radio control
• the Data Rate would be 1
• the Network Type would be 0
• the Status Request/Response pair is used to get status information from the radio.
• the format of the Status Request is as
• the Ack frame is sent by both the radio and host to acknowledge correct reception
• the radio will be sent to the host. This request indicates a remote device that has detected
• the host attempts to Initiate a network and has requested to join that network.
• the Join Response is used to indicate acceptability of a remote device in the
• the Start Network Command is used to start a PAN once the host has determined
• the Start Network Response is generated by the
• This may be as a response to the Start Network command or when the
• the Join Network Command is used to allow the host to join a network. It could be
• rejoin bit is set in the Type field, then the radio will attempt to rejoin the
• Scan Duty Cycle indicates how to scan
• the Join Network Response indicates to the host that one of the acceptable
• the Device Management Command provides various device management
• the Device Management Response is generated by the radio after an exchange
• the Diagnostics command is used to perform diagnostic and service functions on
• the Diagnostics Response is generated by the radio as the result of a Diagnostics
• the Set Parms Command is used to set the host interface parameters. It is
• the radio Upon receipt of this command, the radio will change its host interface parameters
• the Data Transmit Status command from the radio is used to indicate result of
• a Data Transmit Status will be generated by the radio
• the Version Request command is used to request version information from the
• radio module There is no data associated with this request.
• the Version response is generated by the radio upon receipt of a version request.
• the Network Management command is used by the host to manage network
• Command Responses have the high bit set. Each command or requires a response across the interface. Valid values
• Request device take over the network. This is used to transfer network control from this station to another device. If the destination devices accepts, it becomes the network coordinator. If the other device is "dumb" it will always accept this request. A smart device can reject the request.
• 8001 Device will begin beaconing on next hop.
• Device 4*number For Device List Response a list of address :type pairs of List of devices devices in network. ate a Smart Radio interface, the following steps are performed:
• the radio will respond with an Initiate response indicating the
• PAN PAN
• the network should be a PAN, power
• the frequency of the radio is in the 2.4GHz range, selectable on 1.5MHz
• radio is Synchronous HDLC using NRZI encoding.
• the radio supports relatively fast switching times between channels to allow FH
• the transmit power should be no more than Odbm,
• the BER should be no worse than 10 "5 .
• radio protocol The following elements of the radio protocol are common to personal LAN and to
• the framing is HDLC so starting and ending flags delimit the frame.
• the low 4 bits is the frame type which is defined below.
• the high 4 bits have the
• the DA and SA fields are each 16 bits. Station Addresses are randomly generated
• the Network Id field is passed to the radio from the network initiator. All ones is
• a broadcast id is not a valid id for a network but can be used to join any network
• This field is composed of two sub-fields.
• the high 4 bits are the fragment number
• FCS algorithm is CCITT CRC-16 as used by HDLC.
• the medium access rule used is CSMA/CA, that is carrier sense, multiple access
• CSMA CSMA alone would allow access to the medium as soon as it is sensed to be idle.
• Beacon frames sent by the network coordinator are that random time will the device send.

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• 1998
  • 1998-02-06 EP EP98906191A patent/EP0958665A4/de not_active Withdrawn
  • 1998-02-06 WO PCT/US1998/002317 patent/WO1998035453A1/en active Application Filing

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