WO2000016508A1 - Wireless spread-spectrum data network and interface between fixed positions - Google Patents
Wireless spread-spectrum data network and interface between fixed positions Download PDFInfo
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- WO2000016508A1 WO2000016508A1 PCT/US1999/016748 US9916748W WO0016508A1 WO 2000016508 A1 WO2000016508 A1 WO 2000016508A1 US 9916748 W US9916748 W US 9916748W WO 0016508 A1 WO0016508 A1 WO 0016508A1
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
- H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
- H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
- H01Q1/246—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for base stations
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
Definitions
- This invention relates to the field of data networks, and more particularly to devices and methods for replacing high-capacity cables with wireless spread- spectrum radio links between fixed positions.
- radio communication links are known.
- a CDMA/TDMA spread spectrum radio communication link is described in U.S. Patent No. 5,410,568 to Schilling.
- a base station time multiplexes a synchronization code signal and a first plurality of data signals, to generate a time-multiplexed signal, and then spreads the time multiplexed signal to generate a spread-spectrum time multiplexed signal.
- the remote units receive this signal and demultiplex data in the data stream to recover the signal being sent to it.
- the remote units each send signals to the base station during specified times.
- the remote unit does not transmit and receive at the same time.
- the Schilling system is directed to a voice communication system, however, so there is no provision to adjust the bandwidth of the data being communicated to and from remote units. Moreover, no implementation of a computer interface card is provided, and the input and output of the system at the remote station is an analog signal rather than digital network data or IP data packets. Because the system disclosed in Schilling is directed to a mobile cellular communication system, there are no adaptations for its implementation in a wide area wireless computer network.
- U.S. Patent No. 5,488,631 describes a wireless spread spectrum time-division multiple access (TDMA) communication system providing digital communications between pairs of remote units among a plurality of remote units organized into a communication network by a master unit that authorizes, schedules, and controls all network transmissions.
- This system provides a transceiver device adapted for a personal computer, and the master unit and remote unit have identical circuitry.
- a segmented antenna at a head end station to serve fixed units in different regions of space, and a master unit controls communication between remote unit initiators and remote unit receivers. Once the master unit has designated a particular remote unit to become a remote unit initiator and another to become a remote unit receiver, all other network remote units continue to listen to transaction headers even though they will not be participants during a transaction cycle.
- the system it is possible for the system to be used in client- server applications, where the clients send messages to the master unit.
- the system is used in a client-server application or for control direct remote unit to remote unit communication
- there is no polling of remote units so two remote units could send a request for transmission time simultaneously, resulting in data collisions.
- once a remote link is established it is maintained and may be kept open for as long as the remote unit needs it. The bandwidth available to the remote units therefore may not be directly controlled by the master unit.
- U.S. Patent No. 5,592,490 describes a spectrally efficient high capacity wireless communication system.
- the system uses antenna arrays and signal processing to separate combinations of received uplink signals, and transmits spatially multiplexed downlink signals. Capacity is increased by allowing multiple users to share the same conventional communication channel within a spatial cell without interfering with one another.
- the system can use frequency division or time division multiplex access.
- the system behaves much like a standard wireless communication system base station, except that it supports more simultaneous communications channels than it has conventional communication channels by allowing multiple spatial channels on each of the conventional channels.
- the system as described does not support varying the bandwidth allocated by a base station in response to polling of remote stations or the timing of such transmissions within successive TDMA/TDD frames. Instead, conventional two-way communication channels are allocated by the base station. Although there is an embodiment briefly described for applications involving data transfer of short bursts or packets of data, this embodiment is described as not requiring an uplink control channel, and the system may service requests for communication and other control functions during control time intervals that are interspersed with communications intervals. Thus, there is no orderly polling of the remote stations to determine whether there is traffic from each remote station. Instead, the remote stations must, as with the conventional two-way communications channel, compete with one another during a control time slot to send initiation requests that may possibly collide.
- Ahl et al. U.S. Patent No. 5,313,461 describes a scheme in which a time period, or frame, is divided into a number of shorter periods, or time slices. Each time slice is of uniform length. Channels communicating through the communications system occupy some portion of one or more time slices or slots. A control package sent from a central station to one or more peripheral stations conveys to the peripheral stations the time slot during which each channel has been allocated. When traffic on one or more channels is sparse, information associated with another channel can be transferred during the sparse channels time slot. However, it is apparently necessary for the time slices to consist of constant burst lengths.
- Ahl et al. does not describe the structure of a suitable PC-based network interface card for use at the base station or remote stations of the network.
- Fig. 24 of Ahl et al. shows that a separate signal channel may be required to request a connection, and other embodiments described in Ahl et al . seem to require analysis of the transmitted data packets on the fly to determine their bandwidth requirements.
- Ahl et al. does not describe a system in which orderly polling of remote units to determine their traffic needs occurs. In addition, the connection of remote continues until a number of consecutive samples indicates that information no longer has to be transferred.
- the wireless data communication system described herein can be viewed, in standard network terms, as a "wireless IP router.” From a user point of view, the system is accessed as an IP (Internet Protocol) gateway to the wireless network. Once a connection is established, packets are routed to their final destination as with any wire-based system.
- IP Internet Protocol
- a plurality of users' LANs within an approximately 20 mile radius of a central antenna system are connected to each other and/or a network such as the Internet at rates of up to 4 MBPS at a fraction of the cost of conventional "wired" technology.
- the system may be used, with additional head end locations in multiple cities, to connect user networks on an intercity and interstate basis in a high- speed private network.
- Spread spectrum and frequency agile technology is used to transmit data wirelessly and securely.
- the system is ideal for multi-location businesses within a metropolitan area to inexpensively create a high-speed wireless wide area network (WAN) .
- WAN wide area network
- Speeds almost 3 times higher than standard Tl lines are possible in the preferred embodiment at a fraction of the cost of microwave, laser, ATM, or Tl lines, and a full- time, permanent virtual connection may be provided. Even higher speeds could be achieved in frequency bands in which different modulation formats, such as QAM (quadrature amplitude modulation) , are permitted.
- Standard network protocols and operating systems can easily be supported, and security is provided through digital spread spectrum modulation techniques.
- the system is bi-synchronous (unlike VSAT, cable, and ADSL services), and independent of existing infrastructure.
- Part of the hardware for the wireless communication system can be assembled using hardware as simple and common as ordinary personal computers (PCs) .
- the LINUX® operating system is to control the PC, which is configured with a typical ethernet NIC (network interface card) , which is configured as a port of the user's wired network.
- the PC has one or more inventive interface cards that act as a secondary NIC to the wireless network.
- the LINUX® operating system performs the gateway/routing service to properly route packets.
- the inventive interface cards each interface to an RF transceiver that is mounted at an antenna.
- a digital wireless communication system for interconnecting a plurality of spatially separated, remote end computers to a head end computer, said system comprising a fixed head end computer and a plurality of fixed remote end computers, each of said computers having a transceiver for communicating digital data in spread spectrum format, said head end computer being connected to a spatially arrayed antenna through which its transceiver communicates said digital data to and from said remote end computers.
- the head end computer may be configured for assigning a communication bandwidth to each of the remote end computers and for controlling the transmission of data to and from the head end computer with each of the remote end computers.
- the spatially arrayed antenna may be segmented into a plurality of directional sectors, wherein each of the remote end computers may be located in one of the directional sectors, and the head end computer may assign a frequency, a time for commencing transmission"Of data, and an allotted time for data to be transmitted.
- the head end computer may also be configured to synchronize data being communicated between the head end computer and each of the remote end computers.
- a wireless interface for IP routing of data packets to and from a host computer through a wireless link
- the wireless interface comprising: a wireless transceiver; a buffer memory coupled to the host computer and the wireless transceiver for receiving data packets received from the wireless transceiver and data packets from the host computer to be transmitted through the wireless transceiver; and a controller operatively coupled to the wireless transceiver and the buffer memory for timing transmission of data packets to be transmitted and the reception of data packets from the wireless transceiver in accordance with control data received from a head end computer communicating with the host computer through the wireless transceiver.
- the buffer memory and controller may be on an indoor unit configured for mounting in the host computer, while at least a portion of the wireless transceiver may be configured to be separable from the interface card in an outdoor unit.
- Both the indoor unit and the outdoor unit may comprise frequency converters; and the indoor unit and the outdoor unit may communicate the received data packets and data packets to be transmitted to and from one another over an intermediate frequency.
- the intermediate frequency link may be duplexed to provide a DC power path from the indoor unit to the outdoor unit.
- the intermediate frequency link may be a time-division duplex link so that transmission of data from the indoor unit to the outdoor unit and transmission of data from the outdoor unit to the indoor unit occur at different times.
- the device may also comprise a digital spread spectrum processor operatively coupled to the wireless transceiver, the buffer memory, and the controller for spreading and despreading data packets communicated through the wireless transceiver.
- a device for communication of data via a wireless link comprising a host computer and a communication interface, in which the communication interface comprises a communication processor; shared memory operatively coupled between the communication processor and the host computer so that the communication processor and the host computer can separately and asynchronously access data packets in the shared memory; and a wireless transceiver coupled to the communication processor for transmission of data packets stored in the shared memory and reception of data packets over a wireless link for storing in the shared memory and subsequent transfer to the host computer.
- the wireless transceiver may be a spread spectrum wireless transceiver, and may be a TDMA/TDD transceiver.
- the wireless transceiver may also comprise an outdoor unit coupled to the baseband digital signal processor for transmitting a signal from the baseband digital signal processor to a remote station.
- a method of communicating digital data between computers comprising the steps of subdividing space around a head end computer into a plurality of independent sectors served by separate directional antennas of the head end computer; communicating data, via TDMA/FDMA channels, with remote end computers over wireless links served by the separate directional antennas; routing data received by the head end computer to a computer network; and routing data received from the computer network to the remote end computers in accordance with a specified address.
- the communicating step may comprise spreading communicated data with a spread spectrum modulation sequence.
- poll responses may be transmitted from each of the remote end computers to the head end computer, and schedules for transmitting data from each of the remote end computers to the head end computer may be transmitted from the head end computer to each of the remote end computers in response to the poll responses .
- Fig. 8 is a flow chart of the head end driver system timing software
- Fig. 13 is a flow chart of the remote end driver system timing software
- Fig. 14 is a flow chart of the portion of the remote end driver system software that interprets and implements various IOCTL commands from the operating system
- Fig. 16 is a flow chart of the portion of the remote end driver system software that processes hardware interrupts
- Fig. 1 illustrates a typical installation of a wireless data communications system in accordance with the invention.
- two remote stations are shown at buildings Bl and B2. It should be understood, however, that two remote stations are shown only for purposes of explanation, and that one or more remote stations (up to a limit to be described later) , which may not necessarily all be located at different buildings, may be accommodated by a base station.
- Directional antennas AN1, AN2 of the remote stations are mounted at a point on buildings Bl, B2 in such a way that there is provided a reliable radio path, to a central station having an antenna AN3 mounted on a building B3.
- Antennas AN1 and AN2 are directional antennas, and AN3 preferably comprises a plurality of separately directed antennas, as is explained later.
- Antenna ANT comprises a plurality of individual antennas 104 that are described in more detail below. These antennas are spaced in an array that provides 30° sectors (i.e., roughly pie-shaped sectors around the antenna) to have essentially independent communications paths. The antennas are selected to allow transmission at a frequency and in a bandwidth consistent with FCC and/or other regulatory requirements, with reuse of the same frequency being possible at least within adjacent sectors by employing orthogonally polarized antenna elements in adjacent sectors.
- Fig. 3 is a representation of data timing across one of the communication channels, i.e., one channel out of the multiplicity of channels at different frequencies (and/or different polarizations) , which is located in one geographic sector out of the multiplicity of geographic sectors served by the head end.
- the times are given in microseconds. Starting at the left of the figure, the head end starts transmitting the header two microseconds from time 0. This delay allows for the set-up times necessary to allow system hardware, more specifically, an FPGA (a Field Programmable Gate Array, to be described later) , to convert data streams between serial and parallel formats.
- FPGA Field Programmable Gate Array
- 96 microseconds is used to transmit a header from the head end station to the remote end stations for synchronization and error checking purposes.
- the head end station then transmits control data for the next 64 microseconds.
- a 44 MHz clock provides a 22 MBPS chip rate spreading sequence, which modulates QPSK data transmitted at a 2 MBPS symbol rate.
- the resulting bit rate is 4 MBPS, which corresponds to a data transmission rate of one byte every two microseconds .
- the control data is followed by a transmission gap (or guard band) of 96 microseconds that ends 258 microseconds from the start of the head end transmit period.
- This gap is followed by another header of 96 microseconds, followed by data transmitted by the head end to the remote ends.
- This data is of unspecified length, but is not longer than 3544 microseconds in this embodiment, or more generally, not longer than to the end of the head end transmit period, because a different head end transmit period length may be selected for different embodiments.
- the actual data length depends upon the amount of user data that is ready for transmission.
- the receive window starts with a gap of 256 microseconds to account for minimum transmission delays from the head end to the subscriber, and to allow the head end receiver time to turn on following the head end transmission.
- a 40 microsecond gap occurs before the end of the head end receive period, and the beginning of the next head end transmit period.
- the data and poll responses in any particular frame need not necessarily be from the same remote user, and no such constraint is imposed by the system. It should be noted that, while the lengths of the headers may be dictated by the requirements of the hardware and synchronization systems used in the system, it is possible to vary the data periods over rather wide ranges to accommodate various system requirements for any particular installation. For example, either or both of the head end transmit periods and the head end receive period could be shortened or lengthened, depending upon the expected system traffic and acceptable time delays.
- the gap lengths could be adjusted, provided that there is sufficient guard band space to accommodate the range of distances and propagation delays to and from the various remote end stations.
- an important feature of the system is that it is a TDD/TDMA system (time division duplex/time division multiple access system) dividing an arbitrary length of time into outbound and inbound time windows that do not vary from cycle to cycle.
- the windows can be optimized for the number and sizes of packets to be communicated, the distances of the stations from one another, etc.
- the return path to the head end i.e., the inbound time window
- the return path to the head end is a TDMA return path that is or can be shared by a number of different stations.
- each head end receive period may be divided so that more than one remote end station transmits headers followed by data to the head end station.
- Data packet lengths may be variable within the selected system limits, while control packet sizes will vary depending upon the number of users. However, every packet will require at least about 42 bytes of data to accommodate system overhead if the preferred hardware is used, except for "dummy" data packets, which in the preferred embodiment are only 12 bytes, with no overhead required.
- the remote end has a fixed delay programmed into its radio interface card that depends upon the distance of its antenna from the head end transmitter antenna.
- the fixed delay is programmable on a user-by-user basis, and is, in a preferred embodiment, programmable via the wireless links.
- the remote end unit As the remote end unit is placed further away from the head end transmitter, more of this delay would be used in the propagation path, so the remote end unit would be programmed with a corresponding fixed delay that was 256 microseconds minus the round-trip propagation delay. This system could accommodate remote units up to almost 24 miles distant from the head end. Propagation delays are handled by determining the distance between the head end and each remote end station, and accounting for the transmission delays by building in fixed delay values that vary from remote station to remote station. These delay values, together with the guard bands that are provided, provide an orderly flow of data over the radio channels.
- a head end station may be controlled by an application program running on a computer, such as a typical personal computer.
- a computer such as a typical personal computer.
- flow charts are provided here to explain the functions of this program.
- a hardware platform that is more than sufficient for the head end driver software is a 75 MHz PENTIUM® processor-based PC-compatible computer having at least 4 MB of RAM and sufficient hard disk memory to hold the operating system, the driver program, and optionally, either or both of an error log or an accounting log.
- PENTIUM® is a registered trademark of Intel Corporation, Santa Clara, CA.
- error log and/or accounting log entries may be sent through a network or via modem or other connection to another computer, or to a local or remote printer or display. All or a portion of the head end driver and operating system may also be placed in ROM, thereby reducing or eliminating the need for hard disk memory.
- Outdoor unit 100 includes a directional, polarized antenna 104, which, in a preferred embodiment, may be a CONIFER® QD5430 Microscepter Antenna available from Conifer Corporation, Burlington, IA.
- This antenna is a linearly polarized, planar array providing 16 dB gain, a 3 dB beamwidth of 30°, and 30 dB crosspolarization isolation at (approximately) 2.455 GHz, which is a suitable center frequency for this system. Because the antenna provides narrow beamwidth and high crosspolarization isolation, it is possible and practical to reuse the same frequency at different polarizations in adjacent 30° sectors. It is more difficult, but not impossible, to reuse the same frequency even in the same sector, through the use of orthogonal polarizations. However, the interfering signals will then be in the main beam of the affected antennas, and distances between the stations and power levels will have to be more carefully coordinated to avoid interference and measurable increases in bit error rate.
- Antenna 104 is connected to an LNA/PA (low noise amplifier/power amplifier) 108 though a band pass filter 106.
- Band pass filter 106 is, in a preferred embodiment, a 100 MHz, 3-pole filter having a 2.455 GHz center frequency. This bandwidth is sufficiently wide to pass the entire 86 MHz bandwidth of interest without significant distortion.
- LNA/PA 108 is preferably a CAS2403AN 2.4 to 2.5 GHz Power Amplifier-T/R Switch available from Celeritek, Inc., Santa Clara, CA.
- This device includes a low noise receiver preamplifier 110, a transmitter power amplifier 112, and a transmit/receive switch 114 for connecting the antenna to an appropriate one of preamplifier 110 and power amplifier 112.
- the output of low noise amplifier 110 is filtered by band pass filter 114, which in a preferred embodiment has the same characteristics as band pass filter 106 to thereby provide further selectivity without degrading the receiver noise figure or bit error rate.
- the input to power amplifier 112, i.e., signals to be amplified and transmitted over the radio link, is also filtered through a separate filter 116 that also preferably has the same characteristics as band pass filter 106.
- the LNA/PA provides a switched function allowing the weak signal received by the antenna to be amplified to a suitable level. When transmission is desired, LNA 110 is switched off and the PA 112 is turned on to amplify the signal to a level of 4 watts EIRP, including an antenna gain of about 17 dB.
- a mixer 120 converts the received signal down to a suitable intermediate frequency, which, in a preferred embodiment, is approximately 280 MHz.
- the frequency of the local oscillator 126 is thus approximately 2.2 GHz in this embodiment, but this varies depending upon which of the channels within the total system bandwidth is selected for communication.
- the frequency of this oscillator can be controlled using a PLL controller (i.e., frequency synthesizer) 136, such as a MOTOROLA® MC12210 2.5 GHz bipolar monolithic serial input phase locked loop (PLL) synthesizer, available from Motorola, Inc., Schaumburg, IL.
- PLL controller i.e., frequency synthesizer
- MOTOROLA® MC12210 2.5 GHz bipolar monolithic serial input phase locked loop (PLL) synthesizer available from Motorola, Inc., Schaumburg, IL.
- PLL phase locked loop
- the output of the mixer is filtered in a preferred embodiment through a 280 MHz center frequency band pass filter 128 having a 3 dB band width of 20 MHz (i.e., the passband is 280 MHz ⁇ 10 MHz.)
- a transmit/receive switch (T/R switch) 132 sends the output of filter 128 back to indoor unit 102 during receive time intervals. It is a coaxial cable with suitable connectors may be used as a transmission line 134 for this purpose. The same transmission line 134 is used to transfer signals from indoor unit 102 to outdoor unit 100 during transmission times, using T/R switch 132.
- T/R switch 132 causes the signal sent from indoor unit 102 to outdoor unit 100 to be sent through band pass filter 130 and up-converted by mixer 124 using local oscillator 126.
- Band pass filter 130 preferably has the same characteristics as band pass filter 128.
- the output of mixer 124 is fed into a driver amplifier 122, and the output of the driver amplifier is fed into band pass filter 116 to remove unwanted mixing components.
- the remaining circuit path to the antenna includes power amplifier 112, T/R switch 114, band pass filter 106, and antenna 104, all of which have been described above.
- Mixers 120 and 124, along with driver amp 122, may be provided as a single up/down converter component, the CCV2501AN 2.4 to 2.5 GHz Integrated Converter, available from Celeritek, Inc., Santa Clara, CA.
- the up/down converter translates the 280 MHz signal to the desired final output frequency in the 2.4 GHz ISM band. This is a single conversion operation and is half-duplex in nature due to the TDD format. It thus will be seen that the outdoor unit provides at least part of the functions of a wireless transceiver.
- the functional features of indoor unit 102 will now be described. A functional block diagram of indoor unit 102 is shown in Fig. 5.
- Unit 102 functionally comprises a PC ISA interface that maps the proper signals from the ISA card to the PC's ISA bus 194.
- the indoor unit card 102 occupies 32 locations of I/O address space and 8 K bytes of memory space.
- An example of I/O mapping is 300H - 31FH for I/O and 0D000H to 0D7FFH for memory space.
- the PC ISA interface is part of a Field Programmable Gate Array (FPGA, also known as an Electrically Programmable Logic Device or EPLD) 154.
- FPGA Field Programmable Gate Array
- EPLD Electrically Programmable Logic Device
- a shared RAM controller 212 is also shown, and this is also preferably part of FPGA 154.
- Shared RAM controller 212 formats serial data received from a spread spectrum signal processor 156 into a shared RAM 152 in byte format.
- registers in the spread spectrum processor 156 as well as the I/O and memory mapping locations are programmed by an on-board processor or controller 150.
- Indoor unit 102 also includes IF amplifiers and filters, shown in an integrated unit 158.
- the 280 MHz signal received from outdoor unit 100 is filtered and amplified on the indoor unit 102 ISA card. Since the signal transmits for a period of time and receives for a period of time (i.e., it is time-division duplexed, or TDD) , the IF amplifiers include transmit and receive paths that either drives or is driven by a switch 160, which is controlled by line SWC from DSP 156.
- An IF to baseband converter within integrated unit 158 takes the 280 MHz signal and down-converts the signal to baseband using identical active mixers and switched capacitor filters.
- the LO 164 is divided and split to provide a quadrature source for the downconversion.
- Indoor unit 102 also provides a data formatter/timing generator as part of EPLD 154. A time reference is established, and the driver program preloads the time values, length and memory locations for the data packets so that all real time functions are removed from the driver program.
- Data formatter 222 acts as a combined DMA controller with a parallel to serial and serial to parallel data converter. Formatter 222 also receives a block address, which, relative to the base address, provides an absolute address to which to send or from which to access data in shared RAM 194. The data is sent to and received from DSP interface 206.
- Timing generator 204 is used to provide timing for the DSP 154. However, when the EPLD is used in a remote end station, timing must also be coordinated with the received data. This is provided by a connection DL (shown in dashed lines) to DSP interface 206, which is present only in the remote end units. This is the only difference between the head end unit and remote end unit interface card.
- a reset function is also provided by providing connectivity between the microprocessor bus interface 210 and timing generator 204 through internal address decoder 214. (This reset function is described below in conjunction with Fig. 18.)
- the indoor unit includes a controller for the wireless transceiver (as well as portions of the transceiver function in the described embodiment) and the shared RAM.
- the head end driver operation is described in the flow charts of Fig. 7 to Fig. 11, inclusive. Referring first to Fig. 7, the loading of the driver software (indicated by block 1000) will now be described.
- the driver software When the driver software is loaded either manually or automatically as part of a boot-up procedure, it attempts to register with the operating system as a network interface. This step is indicated at block 1002.
- a check is performed by the software to determine whether the registration was successful.
- the ISA cards are probed to identify the radio interface cards, and at block 1012, each such card detected is added to the database and its resources are registered with the operating system. (Registration details vary in accordance with the operating system used, as would be known by those skilled in the art.)
- a watchdog timer is highly desirable feature to ensure that the driver code operates properly. Therefore, a watchdog timer is initialized and activated at block 1014 before the loading process terminates successfully at block 1016. It is to be understood that a head end computer will most likely be equipped with multiple indoor units, each communicating with a corresponding outdoor unit, the antenna for which comprises a sector of a sectored antenna. Thus, multiple cards would most likely be added to the head end database.
- the IOCTL command is a request to add a new user
- data for the new user contained in the IOCTL function arguments is added to the database at 1204.
- the IOCTL command is a request to update an existing user
- the data in the table corresponding to the existing user is modified at 1210.
- the IOCTL command is a request to delete a user
- the specified user is deleted from the database at 1214.
- An IOCTL command is also provided to change frequencies. Such a request may be necessary to provide load sharing, in the event one frequency is carrying excess traffic, or if there is radio interference or a hardware failure.
- the head end driver If it is not a poll response, the head end driver requests a system buffer and passes the packet to the operating system in the requested system buffer at block 1422. Then, execution proceeds to block 1416, repeating the searching, parsing, and passing of packets to the operating system until either an invalid header is found at block 1418 or a poll response is found at block 1420.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU52263/99A AU5226399A (en) | 1998-09-11 | 1999-07-23 | Wireless spread-spectrum data network and interface between fixed positions |
EP99937424A EP1112631A1 (en) | 1998-09-11 | 1999-07-23 | Wireless spread-spectrum data network and interface between fixed positions |
BR9913603-1A BR9913603A (en) | 1998-09-11 | 1999-07-23 | Digital wireless communication system to interconnect a plurality of remote terminal computers, spatially separated, to a main terminal computer, wireless interface for ip routing of data packets to and from a host computer over a wireless connection, device for data communication over a wireless connection, computer / router, and, process for communicating digital data between computers |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US15152798A | 1998-09-11 | 1998-09-11 | |
US09/151,527 | 1998-09-11 |
Publications (1)
Publication Number | Publication Date |
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WO2000016508A1 true WO2000016508A1 (en) | 2000-03-23 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/US1999/016748 WO2000016508A1 (en) | 1998-09-11 | 1999-07-23 | Wireless spread-spectrum data network and interface between fixed positions |
Country Status (5)
Country | Link |
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EP (1) | EP1112631A1 (en) |
AU (1) | AU5226399A (en) |
BR (1) | BR9913603A (en) |
TW (1) | TW420909B (en) |
WO (1) | WO2000016508A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1744467A1 (en) * | 2005-07-13 | 2007-01-17 | Skipper Wireless Inc. | Method and system for providing an active routing antenna |
US7778149B1 (en) | 2006-07-27 | 2010-08-17 | Tadaaki Chigusa | Method and system to providing fast access channel |
US8160096B1 (en) | 2006-12-06 | 2012-04-17 | Tadaaki Chigusa | Method and system for reserving bandwidth in time-division multiplexed networks |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5889816A (en) * | 1996-02-02 | 1999-03-30 | Lucent Technologies, Inc. | Wireless adapter architecture for mobile computing |
US5924039A (en) * | 1996-08-13 | 1999-07-13 | Telesis Technologies Laboratory | Digital multichannel multipoint distribution system (MMDS) network that supports broadcast video and two-way data transmissions |
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1998
- 1998-10-09 TW TW087116766A patent/TW420909B/en active
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1999
- 1999-07-23 EP EP99937424A patent/EP1112631A1/en not_active Withdrawn
- 1999-07-23 BR BR9913603-1A patent/BR9913603A/en not_active Application Discontinuation
- 1999-07-23 AU AU52263/99A patent/AU5226399A/en not_active Abandoned
- 1999-07-23 WO PCT/US1999/016748 patent/WO2000016508A1/en not_active Application Discontinuation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5889816A (en) * | 1996-02-02 | 1999-03-30 | Lucent Technologies, Inc. | Wireless adapter architecture for mobile computing |
US5924039A (en) * | 1996-08-13 | 1999-07-13 | Telesis Technologies Laboratory | Digital multichannel multipoint distribution system (MMDS) network that supports broadcast video and two-way data transmissions |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1744467A1 (en) * | 2005-07-13 | 2007-01-17 | Skipper Wireless Inc. | Method and system for providing an active routing antenna |
US7778149B1 (en) | 2006-07-27 | 2010-08-17 | Tadaaki Chigusa | Method and system to providing fast access channel |
US8160096B1 (en) | 2006-12-06 | 2012-04-17 | Tadaaki Chigusa | Method and system for reserving bandwidth in time-division multiplexed networks |
Also Published As
Publication number | Publication date |
---|---|
AU5226399A (en) | 2000-04-03 |
TW420909B (en) | 2001-02-01 |
BR9913603A (en) | 2001-09-25 |
EP1112631A1 (en) | 2001-07-04 |
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