AU2008201941A1 - High speed HF wireless data communication system - Google Patents

High speed HF wireless data communication system Download PDF

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Publication number
AU2008201941A1
AU2008201941A1 AU2008201941A AU2008201941A AU2008201941A1 AU 2008201941 A1 AU2008201941 A1 AU 2008201941A1 AU 2008201941 A AU2008201941 A AU 2008201941A AU 2008201941 A AU2008201941 A AU 2008201941A AU 2008201941 A1 AU2008201941 A1 AU 2008201941A1
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AU
Australia
Prior art keywords
signal
frequency
data
carrier
block
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
AU2008201941A
Inventor
Wilfred Kiapin Kilepak Amai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
WACI TECH Pty Ltd
Original Assignee
WACI TECH Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2007902414A external-priority patent/AU2007902414A0/en
Application filed by WACI TECH Pty Ltd filed Critical WACI TECH Pty Ltd
Priority to AU2008201941A priority Critical patent/AU2008201941A1/en
Publication of AU2008201941A1 publication Critical patent/AU2008201941A1/en
Abandoned legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H04L27/12—Modulator circuits; Transmitter circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code
    • H04L25/40—Transmitting circuits; Receiving circuits
    • H04L25/49—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems
    • H04L25/4917—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems using multilevel codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H04L27/14—Demodulator circuits; Receiver circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/28—Systems using multi-frequency codes with simultaneous transmission of different frequencies each representing one code element
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices

Description

P/00/011 Regulation 3.2
AUSTRALIA
Patents Act 1990
ORIGINAL
COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Applicant: HIGH SPEED HF WIRELESS DATA COMMUNICATION SYSTEM Waci Tech Pty Ltd The following statement is a full description of this invention, including the best method of performing it known to me: 1 828267 cmm patent req 00 O HIGH SPEED HF WIRELESS DATA COMMUNICATION SYSTEM eThe present invention relates generally to a data transmission system, and in particular to a system for transmitting and receiving data very high speed over a standard wireless HF communication link. The invention is suitable for use in mobile communication devices, and it will be convenient to describe the invention in relation to that exemplary, but non-limiting application.
HF radio frequency data transmission systems have been in existence 00 for many years. Data transmission and reception techniques have been Sdeveloped to improve data throughput and minimise the occurrence of data transmission and reception errors. However, the requirement to transmit and receive increasing volumes of audio, video and data content in a real time, high speed environment exceeds the capabilities of current HF radio frequency data transmission systems.
There currently exists a need to provide a data communication system that ameliorates or overcomes one or more disadvantages of known HF data communication systems. Moreover, there exists a need to provide a high speed and reliable wireless data communication system that is simply, robust, economical to manufacture and use, and is suitable for use in a variety of geographical environments and more importantly uses less of the RF spectrum while giving more data throughput Internet speed). This need is for an alternative form of communication to satellite. This need is for a system that provides long distance (over-the-horizon), high speed (in the order of megabit per-second or greater), narrow modulation bandwidth (less than 1 kHz) system.
With this in mind, one aspect of the invention provides data transmitting apparatus for transmitting data over a standard wireless communications link, including: a signal generator for generating a modulating signal with N digital states, where N is an integer greater than 2; a signal modulator block for using the modulating signal to shift the outward frequency of a carrier system between predetermined values; and 8287 sped AU CAP 00 O a wireless transmission block for transmitting the frequency-shifted N carrier signal.
Preferably, the data transmitting apparatus includes a multilevel square wave regenerator to optimise straight edge transmission of the modulating signal between the N digital states.
The wireless transmission block may include a power amplifier for amplifying the modulated carrier signal; a high Q filter block; and an antenna.
The signal modulator block may include a first and second signal 0 modulator for using the modulating signal to shift the output frequency of a 00 carrier signal between predetermined values respectively about first and Ssecond carrier frequencies.
Another aspect of the invention includes data receiving apparatus for receiving data transmitted by the above-described data transmitting apparatus.
The data receiving apparatus may include a filter block for detecting the presence of the frequency-shifted carrier signal at each of the predetermined values; and an N-state frequency triggered waver generator for reconstituting the modulating signal with N digital states.
The data receiving device may further include a signal switching device for enabling selective reception of a transmitted signal at a particular carrier frequency having the best signal strength.
The wireless transmission block may act to transmit a circular polarised frequency-shifted carrier signal. In this case, the signal switching device may switch between signal polarities to determine the carrier frequency having the best signal strength.
The data receiving apparatus may further include a directive antennae to minimise inter-signal interference.
Various aspects and features of the invention will be described in the accompanying drawings which are incorporated into and constitute a part of the description of the invention, illustrate the best mode so far contemplated for carrying out the invention and serves to explain the principles of the invention.
Figure 1 is a schematic diagram depicting one embodiment of a data communication system; 828267 specd AU CAP 00 O Figure 2 is a schematic diagram illustrating functional components Sforming part of a data transmitting device forming part of the data Ccommunication system shown in Figure 1; Figure 3 is a schematic diagram illustrating various components of a data receiving device forming part of the data communication system shown in Figure 1; Figure 4 is a graphical representation of the frequency spectrum of a carrier signal shifted by an N digital state modulating signal to a number of Spredetermined frequency values.
00oo Referring now to Figure 1, there is shown generally a data Scommunication system 10 including an exemplary mobile transceiver 12 and base stations 14, 16 and 18 respectively associated with transceiver systems 22 and 24. Base stations 14, 16 and 18 are interconnected by means of a HF communications network 26. The communications network may confirm to any one of a number of suitable telecommunication standards, such as W- CDMA, GSM and the like. Since the communication network is using HF frequencies, the locations of base stations 14, 16 and 18 can be beyond lineof-sight distances.
Figure 2 shows a number of functional components forming part of a data transmitting device 30 forming part of one or more of the elements of the data communication system 10 shown in Figure 1. The functional components shown in Figure 2 may be included in the mobile transceiver 12 and/or the base stations 14 to 18. The data transmitting apparatus 30 includes an Nstate digital signal generating device 32, a signal shaping block 34, a signal modulating block 36 and a wireless transmission block 38.
The signal modulator block 36 includes a first N-level frequency modulator 40 functioning about a first carrier signal operating at a frequency fj 1 and a second N-level frequency modulator 42 operating about a carrier signal at a frequency fc2. The wireless transmission block includes a first linear amplifier 44 coupled to a first high Q filter block 46 and transmission antennae 48. The wireless transmission block 38 also includes a second linear amplifier connected to the output of the N-level frequency module 42 and a filter block 52 coupled to the transmission antennae 48.
882287 sped AU CAP 00 The N-state digital signal generator 32 generates a modulating digital c signal with N digital states where N is an integer greater than 2. Rather than a binary digital signal having two states (typically two different voltage levels) representing a binary and the N-state digital signal generator produces a signal having a state, such as voltage, that correlates to one of a predetermined number N of values.
The signal generated is then shaped by the signal shaping block 34.
Typically, the signal generated by the N-state digital signal generator 32 is not "square", namely does not have vertical or straight edge transitions between oO each of the digital states able to be adopted by the signal. The signal shaping Sblock 34 functions as a multi-level square wave regenerator to optimise straight-edge transition of the modulating signal between the N possible digital states.
The output from the signal shaping block 34 is used by the N-level frequency modulator block 40 to modulate a high frequency carrier signal between multiple narrow band frequencies. In other words, the modulating signal is used to shift the output frequency of the carrier signal at a nominal frequency fl between predetermined values. Narrow bandwidth is achieved by using high Q components in the circuit elements constituting the N-level frequency modulator block 40. The modulated carrier signal is then amplified by the linear amplifier block 44. Fine high Q filters in the filter block 46 are added to filter unwanted harmonics or signal images before transmission by the transmission antennae 48.
In order to improve the transmission diversity of the data transmission device 30, the N-state digital signal is used to modulate a carrier signal at a second output frequency. Accordingly, the modulating signal is used to shift the output frequency fc 2 between predetermined values by the N-level modulator block 42. Once again, a linear amplifier 50 and high Q filter block 52 amplify and then filter the modulated carrier signal before transmission by the transmission antenna 48. In this way, the same digital signal is used to two different carrier frequencies in order to improve the transmission diversity of the dial a transmission device Turning now to Figure 3, there is shown a series of elements forming part of a data receiving device 60. The data receiving device 60 and the data 828287 ped AU CAP 00 O transmitting device 30 may both form part of a same entity in the data Scommunication system shown in Figure 1. The data receiving device tincludes a reception antenna 62, a signal switching device 64, and RF amplifier 66, high Q filter block 68, N-state frequency triggered wave generator
(N
70, wave refiner 72 and a regenerated N-state digital signal block 74. As will be appreciated from Figure 1, a single mobile transceiver including the data receiving device 60 may be in a position to receive signals transmitted from various base stations. The signal switching device 64 acts to automatically Sswitch to a received signal having the best signal strength. Dynamic routing 00oo algorithms are used to choose between reception locations so that the system Sis dynamically switching between reception nodes. A dynamic communications protocol such as TCP/IP is used in conjunction with systems so that standard routers are used in the data communication system 10. Moreover, the signal switching device acts to automatically switch to the carrier frequency (either f, 1 or f, 2 that is determined to have the best signal strength.
Depending upon noise or fading effects between various locations, a circular polarised signal may be transmitted by the data transmitting device A circular polarised transmission will allow the data receiving device 60 to be able to receive in vertical, horizontal or any other polarisation angle where the signal is best received. In this case, the signal switching device 64 may act to automatically switch between signal polarities to determine the carrier frequency having the best signal strength. The RF amplifier block 66 acts to amplify the incoming radio frequency signal from the antenna 62 to a reasonable level to be able to be discerned by the next stage. The high Q filter block 68 acts to filter out all signals except for the predetermined narrow band frequencies corresponding to the various N digital states.
The N-state frequency triggered wave generator block 70 effectively toggles between the various N digital states (eg voltage levels) depending upon the presence of the frequency-shifted carrier signal at each of the predetermined values corresponding to the N digital states. The wave refiner block 72 acts to optimise the straight edge transmission of the multi-level signal generated by the preceding block 70. The output from the wave refiner block 72 is then used by the regenerated N-states digital signal block 74 to 828267 sped AU CAP 00 reconstitute the N-state digital generated in block 32 at the data transmitting C device The above-described modulation technique enables the transmission of data at a high throughput rate via use of multiple state digital signal modulation of a carrier frequency on narrow radio frequency channels. The higher the Q factor of the components used in the circuit elements constituting the data transmission and receiving devices, the narrower the radio frequency channels or the more N-state that can be transmitted about a particular carrier signal 0 frequency. Figure 4 shows an example of how a particular outward frequency oo (N of a carrier signal has been shifted to predetermined frequency values fI, f 2 ,f 3 ,f 4 and f 5 The presence of a signal peak within the band pass regions centred at each of these frequencies represents the presence of a digital state within, in this example, a five digital state signal. In a practical example, the output frequency of a carrier signal may have a nominal value of 7.0000 MHz. Three narrowly separated frequencies, such as 7.0050 MHz, 7.0051 MHz and 7.0052 MHz can be used to transmit each of the, in this example, three digital states corresponding to the modulating signal. In this case, the predetermined values by which the output frequency of the carrier signal are shifted are separated by only 100 Hz.
In order to improve the coverage provided by the data communication system 10, one or both of the antennas of the data transmitting device 30 and data receiving device 60 may be directive antennas. Directive antennas are mostly used to reduce interference between neighbouring RF spectrum users.
Both these antennas have the effect of increasing radiated power in the direction of the receiver. Two most commonly used directive antennas are the dipol and the Yagi antennas. However, it will be appreciated that other forms of antennae can be used.
Although in the above described embodiments, the invention is implemented using electronic circuitry, in other embodiments of the invention may be implemented primarily using computer software, using digital signal techniques, using application specific integration circuits (ASICs) or other equivalent hardware, software or combination thereof. Implementation of a hardware state machine so as to perform the functions described herein will be apparent to persons skilled in the relevant art.
828287 sped AU CAP r 00 O While the present invention has been described in conjunction with a Cl limited number of embodiments, it will be apparent to those skilled in the art that many alternatives, modifications and variations in line with the foregoing description are possible. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variations as may fall within the spirit and scope of the invention.
oo 828267 sped AU CAP

Claims (9)

1. Data transmitting apparatus for transmitting data over a wireless communications link, including: a signal generator for generating a modulating signal with N digital states, where N is an integer greater than 2; a signal modulator block for using the modulating signal to shift the output frequency of a carrier signal between predetermined values; and 0 a wireless transmission block for transmitting the frequency-shifted 00oo carrier signal.
2. Data transmitting apparatus according to claim 1, and further including: a multilevel square wave regenerator to optimize straight-edge transition of the modulating signal between the N digital states.
3. Data transmitting apparatus according to either one of claims 1 or 2, wherein the wireless transmission block includes: a power amplifier for amplifying the modulated carrier signal; a high Q filter block; and an antenna.
4. Data transmitting apparatus according to any one of the preceding claims, wherein the signal modulator block includes: first and second signal modulator for using the modulating signal to shift the output frequency of a carrier signal between predetermined values respectively about first and second carrier frequencies.
Data transmitting apparatus according to any one of the preceding claims, wherein the wireless transmission block acts to transmit a circular polarized frequency-shifted carrier signal.
6. Data receiving apparatus for receiving data transmitted by data transmitting apparatus according to any one of the preceding claims, the data receiving apparatus including: 828267 sped AU CAP 00 a filter block for detecting the presence of the frequency-shifted carrier signal Sat each of the predetermined values; and an N-state frequency triggered wave generator for reconstituting the modulating signal with N digital states.
7. Data receiving apparatus according to claim 6, and further including: a signal switching device for enabling selective reception of a transmitted signal at a particular carrier frequency having the best signal strength. 00
8. Data receiving apparatus according to claim 7 when dependant upon N claim 5, wherein the signal switching device switches between signal polarities to determine the carrier frequency having the best signal strength.
9. Data receiving apparatus according to any one of claims 6 to 8, and further including: a directive antenna to minimizing inter-signal interference. 828257 sped -AU CAP
AU2008201941A 2007-05-07 2008-05-02 High speed HF wireless data communication system Abandoned AU2008201941A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2008201941A AU2008201941A1 (en) 2007-05-07 2008-05-02 High speed HF wireless data communication system

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AU2007902414A AU2007902414A0 (en) 2007-05-07 High speed HF wireless data communication system
AU2007902414 2007-05-07
AU2008201941A AU2008201941A1 (en) 2007-05-07 2008-05-02 High speed HF wireless data communication system

Publications (1)

Publication Number Publication Date
AU2008201941A1 true AU2008201941A1 (en) 2008-11-27

Family

ID=40292346

Family Applications (1)

Application Number Title Priority Date Filing Date
AU2008201941A Abandoned AU2008201941A1 (en) 2007-05-07 2008-05-02 High speed HF wireless data communication system

Country Status (1)

Country Link
AU (1) AU2008201941A1 (en)

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