Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
  • H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/72—Mobile telephones; Cordless telephones, i.e. devices for establishing wireless links to base stations without route selection
  • H04M1/725—Cordless telephones

Definitions

• the present invention relates to wireless communication, and more
• modems couple a
• wireless modems have been designed to enable users to
• FIG. 1 shows a block diagram of an exemplary embodiment of the present
• FIG. 2 shows a flowchart of the power-up initialization for the devices shown
• FIG. 3 shows a flowchart for a continuously running loop, RL, that executes
• FIG. 4 shows a flowchart for data transmission by the devices shown in FIG. I.
• FIG. 5 shows a flowchart for U ART/ modem interrupt handling by the devices
• FIG. 6 shows a flowchart for data reception by the devices shown in FIG. 1.
• FIG. 7 shows a flowchart for no packet received channel tracking timer
• FIG. 8 shows a schematic diagram of a main processor used in the devices
• FIG. 1 shown in FIG. 1 and includes an SST (Spread Spectrum Technology) processor and a SST (Spread Spectrum Technology) processor and a SST (Spread Spectrum Technology) processor and a SST (Spread Spectrum Technology) processor and a SST (Spread Spectrum Technology) processor.
• SST Read Spectrum Technology
• FIG. 9 shows a schematic diagram of the UART, the led indicator and an RS-
• FIG. 10 shows a schematic diagram of the RF transceiver used in the devices
• FIG. 11 shows a schematic diagram of a power supply used in the devices
• FIGS. 12 and 13 show a circuit diagram of the devices shown in FIG. 1.
• Wireless modem (WM) devices used for the Wireless modem system
• WJ wireless modem jack
• RF link RF link
• the wireless local area network will operate, for example, in the 900 MHz ISM band (902 - 928 MHz).
• modem system comprises one base unit 1000 and one wireless remote modem unit
• modem e.g., 18'
• telephony processing e.g.,
• the design of the system is based preferably on the Direct Sequence Spread
• DSSS Spectrum Spectrum
• the maximum data transmission rate for the WMJ will be up to
• the WMJ can be used for Internet
• All transmission is in the SST digital encryption format.
• the present invention allows RF link supports of up to 115 kbps data
• the system provides automatic RF signal detection and locks into the
• Base unit 1000 consists of a serial port, the system can be used not only
• the system may also support Hyper Terminal data transmission.
• a consumer can, for example, access the Internet, or
• the data (signal) will be in the Digital format with signal encryption.
• Radio Frequency (RF) signal will be in the 900 MHz range; from 902 - 928 MHz.
• any 900 MHz device that transmits the signal in a regular Analog modulation format.
• Part 15 of FCC regulations allows any device with Digital Modulation format to have
• FIG. 1 For a base unit RF link.
• a remote unit has additionally a modem function 18' built in and additional
• circuit 20' for interfacing to an RJ-11 jack to a telephone network. Therefore, to avoid
• a DCE port 2 is coupled to the PC computer, not shown and conveys the
• a UART 6 translates the serial data into parallel data and a
• processor 14 constructs a data packet having an alignment bit, a lead byte, message
• the packet is then stored in a Tx buffer in a SRAM 8.
• SST 10 looks for unused channels in an RF module 12, reads the data from the Tx
• the SST When the RF link of FIG. 1 is to receive data from an exterior RF links, the SST
• decision block 26 it is determined whether something is present
• the modem 18 is ignored and the BU must be set as
• a master slave as indicated at 28.
• the master bit of DIPSW 1 shown in FIG. 8 is tested.
• EU master unit
• Base Unit (BU) is set as slave unit (the one that is always in listening mode). For
• two BUs may be used. In such case,
• serial port selected may also be set as master while another BU (with serial port
• extension unit EU is set as a slave.
• RSSI Receiveive Signal Strength Indicator
• master unit monitors if there is any transmission activity on the
• a timer of MCU 14 is used
• the no packet received timer is actuated as
• the unit enters a runtime loop RL shown in FIG. 3. Referring to decision block 30, if the unit is not set as a master and is therefore
• This function is only carried out in a slave unit and consists of scanning the RF
• each channel is scanned for 20
• modem 18 is installed. If it is, the unit is set as a slave and enable modem Rx
• the radio links enter a
• the unit forwards data
• DTR is active (e.g. PC connecting to the port is not ready), and the link is in 'up'
• the modem function is relevant to only the BU. Writing/ reading to/ from
• UART 6 or the modem corresponds to writing/ reading to/ from UART 6 or the
• SRAM 8 is restored at 60, but if not, the data is read from the Tx data buffer at 62.
• Tx buffer pointer is saved at 64, and the data packet is constructed in the UART 6 as
• Data is copied from transmit buffer of the SRAM 8 to the data portion
• the number of bytes in a data packet is 0 (nil)
• the envelope comprises packet header byte, link
• the routine calculates and appends 16-bit fletcher checksum at the end
• a transmitted packet is preceded by 15 preamble bytes (0x00) and 2 alignment bytes (0x80). Five trailing bytes (Oxff) are appended at the end of
• FIG. 5 shows a flowchart depicting the steps for UART/ Modem Interrupt
• the unit reads remaining bytes from SST and stores in packet
• the link is declared up at block 84 by
• the master/ slave switch is set at the slave position. If so, the user may set the baud rate at 88 with a combination of switches or via software. Usually the baud rate is set at a
• the no packet received timer is started at 90, see FIG. 7, and at 92 a link
• setup packet is set up in MCU 14 to ask for more data from the buffer. If decision
• block 86 indicates it is a master, data is sent at a block 87 and the runtime loop of FIG.
• decision blocks 76, 80 and 94 causes the procedure to go back to the runtime loop
• FIG. 7 illustrates for both masters and slaves the No Packet Received/ Channel
• decision block 110 i.e., if there has been a handshake between them, a time out
• a time out counter starts counting if there is an interruption of
• a time-out counter is maintained and used by both the master and slave units
• the value of the counter is different for the master and slave units, i.e., 10 and 1 for the master and slave, respectively. Furthermore, the value of
• the NPR (No-packet received) timer is different for the master and slave units, i.e.,
• the master unit re-transmits the data packet.
• the unit re-enters the channel scan process.
• the counter is re-loaded each time a valid
• the value of the NPR should be sufficient to cope with the
• the data packet length varies from 6 to 78 bytes, excluding the
• preamble alignment and trailing bits.
• the slave unit Since the slave unit is always in listening mode, i.e., never initiates data packet
• the value of the NPR is chosen to cover the total time the master unit attempts to
• the master unit has declared link down and re-initiated link set-up. Note that the
• decision block 116 whether this is a master or slave. If it is a master, the SST 10 scans channels at 117
• decision block 116 indicates that the RF link is not a
• a block 122 finds available
• a data packet is sent at a block 126 and a no packet received
• timer is started at a block 128.
• microchips designated are only exemplary of what can be used. They
• FIG. 8 is a schematic diagram of the main processor in which the MCU 140 is
• An oscillator 138 provides RF to the SST chip 141 to the GFSK transceiver 142 of FIG. 10 via a lead 144, and it provides ten RF channels to an antenna 145 of FIG. 10.
• FIG. 9 is a schematic diagram showing the UART 6 as U_o and the RS-232
• the DCE com port 2 is indicated by 148 and the LEDs
• FIG. 11 is a schematic diagram showing a power supply 152 for use with a
• FIGS. 12 and 13 are schematic diagrams for the modem 18 that permits an
• extension unit to communicate with the Internet. It is comprised of U 8 and Uis, and
• jack 154 for coupling to a phone line.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Communication Control (AREA)

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• 2000
  • 2000-10-30 WO PCT/US2000/029930 patent/WO2001033824A1/en not_active Ceased
  • 2000-10-30 EP EP00974036A patent/EP1230786A1/de not_active Withdrawn
  • 2000-10-30 CN CNB008150583A patent/CN1241432C/zh not_active Expired - Fee Related
  • 2000-10-30 JP JP2001534851A patent/JP2003535489A/ja not_active Withdrawn
  • 2000-10-30 AU AU12469/01A patent/AU1246901A/en not_active Abandoned
  • 2000-10-30 KR KR1020027005281A patent/KR20020044575A/ko not_active Ceased

Non-Patent Citations (1)

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