EP2497191A1 - Frequency hopping method for a radio device - Google Patents
Frequency hopping method for a radio deviceInfo
- Publication number
- EP2497191A1 EP2497191A1 EP10798472A EP10798472A EP2497191A1 EP 2497191 A1 EP2497191 A1 EP 2497191A1 EP 10798472 A EP10798472 A EP 10798472A EP 10798472 A EP10798472 A EP 10798472A EP 2497191 A1 EP2497191 A1 EP 2497191A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- signal
- data
- additional data
- transmission
- frequency hopping
- 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.)
- Withdrawn
Links
Classifications
-
- 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
- H04B1/713—Spread spectrum techniques using frequency hopping
- H04B1/715—Interference-related aspects
-
- 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
- H04B1/713—Spread spectrum techniques using frequency hopping
- H04B1/7143—Arrangements for generation of hop patterns
-
- 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
- H04B1/713—Spread spectrum techniques using frequency hopping
- H04B1/715—Interference-related aspects
- H04B2001/7154—Interference-related aspects with means for preventing interference
Definitions
- the invention relates to a frequency hopping method for a radio.
- Radios using frequency hopping are well known today. This method is used to reduce transmission errors (for example by fading) and also to prevent recovery of transmitted information (voice or data) from unauthorized third party sites.
- This method is already possible with known receivers to record the individual jumps of these frequency hopping broadband and then recover the information contained in the signal by classification method ("de-hopping").
- de-hopping The object of the present invention is to provide a method by which this information recovery from the received signal can be prevented.
- Embodiments of the invention and a method for receiving the generated signal are the subject of further claims.
- one or more of the following signal parameters is pseudo-randomly changed in the individual frequency hops:
- Insertion of an information sequence known to the receiver for example a pseudo random bit sequence (eg pseudo noise (PN) sequences) or bits of an error detection or error correction code (eg CRC or parity) - these additional bits can also be used by the receiver to perform mathematical calculations Procedure to correct transmission errors.
- PN pseudo noise
- CRC error correction code
- the positioning of the additional data (additional bits) in the overall data stream can be done by one of the following alternatives:
- n and z are specified by the controller and are in one another embodiment of the invention can change dynamically during transmission;
- the bandwidth can also be varied by selectively transmitting the data in a shorter or a longer transmission duration of a hop, with a shorter hop duration providing a higher bandwidth and a longer hop duration less bandwidth. For this purpose, no additional data must be inserted in the signal. However, a correlation between bandwidth and transmission time must be accepted.
- Variation of the transmission duration of a hop wherein in a special embodiment, the pause duration between the individual hops can additionally be varied as a further parameter.
- additional data can be added to the user data, with the above-mentioned methods in principle being able to be used.
- the changes in the signal parameters mentioned are advantageously carried out during the switching times of the frequency switchover and thus apply to the entire duration of a hops.
- the change of the mentioned signal parameters can, but does not have to be, done with every new hop. It can also be provided, for example, to make a change only every second or third hop. Of course, here are also any other consequences of jumps to which changes are to take place, possible. In this case, pseudo-random change patterns are also advantageous in order to make the classification more difficult.
- the switching between the individual types of modulation and the bandwidths as well as the setting of the transmission duration of a hop is carried out on the basis of a pseudo-random pattern, which is e.g. can be generated with a key generator (e.g., via a linear feedback shift register).
- This pattern must be the same for both transmitter and receiver and is advantageously chosen to minimize correlations between modulation type, bandwidth, hop duration and frequency range.
- the method according to the invention can be used not only for the transmission of speech but also for general data transmission (arbitrary bit streams).
- the invention has the following advantages: - Avoiding de-hoping and thus possible decoding of the signal based on the parameters signal bandwidth, power density distribution or modulation type. For a potential de-hopping, therefore, only the direction (and possibly also the signal strength) is available as the sole selection criterion. However, as soon as the frequency hopping area of the transmitter is larger than the scan bandwidth of a direction finder, the direction of the individual transmission packets could be determined, but in the best case they would be perceived as different bursts from a particular direction. - Modulation type recognizers require a certain amount of time to robustly recognize a modulation type. Although this period of time is becoming increasingly shorter as a result of advancing technology, rapid change, as is possible with the method according to the invention, makes detection impossible as long as the (arbitrarily adjustable) transmission duration of the frequency hopping is less than the time necessary for detection.
- the high dimensionality of the adjustable parameters makes it difficult or impossible to register such a radio in an emitter database. This in turn makes difficult or makes automatic identification of the radio impossible.
- FIG. 1 shows the signal flow in the transmitter in a first embodiment of the method according to the invention
- FIG. 4 shows the signal flow in the receiver according to the method of the invention
- Fig. 5 the control logic for the inventive variation of the signal parameters in the receiving device.
- Fig. 1 illustrates the signal flow in the transmitter.
- additional bits from an additional data source such as generated pseudo-random bits
- additional data source such as generated pseudo-random bits
- the distribution of useful and additional data in the data stream is carried out according to the predetermined by the controller
- the data stream extended in this way is forwarded via a multiplexer in parallel to all modulators (one modulator per modulation type), which generate IQ data in the baseband.
- modulators one modulator per modulation type
- only one of the modulator output signals reaches a mixer by means of a switch.
- This mixer modulates the IQ data into the given RF band according to the center frequency of the current hop.
- the payload data to be transmitted is thus modulated onto an HF carrier.
- the controller controls the signal generation and provides the components required for the production of the horns. As can be seen from FIG. 1, the control also provides the modulators with the signal clock, since this is required for the variation of the signal bandwidth.
- the received signal is mixed down into the baseband with knowledge of the hop control described in FIG. 1 and demodulated by the predetermined demodulator.
- the payload is based on the pattern of the inserted Additional data extracted.
- the inserted additional data can also be used in order to be able to more robustly determine the user data.
- the modulators can be applied in parallel (insofar identical to FIG. 1).
- the baseband signals generated by the modulators are added together and the sum signal is mixed up to the intended RF frequencies.
- the individual baseband signals have different IF frequencies in order to simulate a plurality of radios for an unauthorized receiver in the RF signal.
- Fig. 2 shows the signal flow in the transmitter for a further embodiment of the method according to the invention.
- the difference to the embodiment according to FIG. 1 is based on the fact that the data stream (user data and optionally inserted additional data) according to FIG. 2 is not supplied to all modulators in parallel, but only to the modulator currently provided for the modulation generation. This is done with an additional, the multiplexer downstream demultiplexer, which forwards the output signal of the multiplexer only to the respective active modulator. The remaining modulators are deactivated.
- a universal modulator can be provided which can generate all the required types of modulation.
- Fig. 3 the control logic for the switching of the individual signal parameters is shown, as implemented in the controller (Fig.1, 2).
- a decoder for the Modulationartenumscnies, a decoder for bandwidth switching, a decoder for Hopsendedauerumscnies, a decoder for the Hoppausendauerumscnies and a decoder for switching the center frequency is controlled via a pseudo-random number generator (eg designed as 16bit linear feedback shift register).
- a pseudo-random number generator eg designed as 16bit linear feedback shift register.
- the decoder for the Bandwidth switching requires the data rate of the original signal, the modulation type, the hop duration and the hop duration as further inputs.
- the respective output signal of the decoder is, as described in FIGS. 1 and 2, used to control the signal flow in the transmitter.
- the control logic according to FIG. 3 is synchronized with the control logic present in the receiving device, which will be explained in more detail below.
- the driving of the individual decoders may be e.g. This is done by using individual bits of the pseudo-random generator exclusively to drive a particular decoder, e.g.
- Number of bits per decoder log 2 (number of possible states, eg number of modulation types or number of bandwidths, etc.), rounded up in whole numbers.
- individual outputs (bits) of the pseudo-random generator can be used for several decoders, but this can lead to an undesirable correlation of the parameters to be varied.
- the pseudo-randomly switched operating parameters in the receiver must be exactly simulated and set in the receiver. This must first one
- Synchronization between radio and radio receiver done. This can be done by a training or synchronization sequence (bit pattern) and / or a pulse pattern, which are exchanged on a user-defined (adjustable) channel between transmitter and receiver (handshake) before the actual transmission.
- bit pattern bit pattern
- pulse pattern a training or synchronization sequence
- the following methods are used to extract the user data when the signal is received: 1.
- Switching the modulation type The relevant demodulator is used according to the type of modulation used during transmission, eg (QPSK, FSK, ASK.FM,. ..) switched.
- Equalizer by channel estimation.
- the amount of additional data to be filtered out results from the modulation alphabet and the clock rate of the modulator.
- the bandwidth in the transmitter has been varied in such a way that the data has optionally been transmitted in a shorter or longer hops-end duration, no additional data need to be inserted into the signal.
- the hop duration must be configured accordingly in the receiver by the controller.
- the signal mixed down into the baseband by a mixer is advantageously routed in parallel to a plurality of demodulators.
- the demodulators correspond to the possible modulation types of the transmission signal.
- a multiplexer selects the data stream of the respective demodulator required at this time and supplies it to the further signal processing.
- the output signal of the demodulator currently required is then subjected to data extraction.
- the additional bits inserted during the transmission are removed.
- the signal can be subsampled here according to the oversampling factor.
- An advantage here is an integer oversampling during transmission, since thereby the additional samples can be easily sorted out when receiving. If error detection or error correction bits have been added as additional bits for bandwidth enlargement, these can be used after their extraction for error detection or avoidance.
- Fig. 5 shows the control logic for the inventive variation of the signal parameters in the receiving device. This corresponds to the control of the radio, as shown in Fig. 3.
- the controls in the radio device and in the receiving device must be synchronized with one another. This can happen, for example, in which the pseudo- Random generators of radio and receiver are subjected before transmission with a training or synchronization sequence (bit pattern) and / or a pulse pattern.
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102009052107.0A DE102009052107B4 (en) | 2009-11-05 | 2009-11-05 | Frequency hopping for a radio |
PCT/DE2010/001266 WO2011054338A1 (en) | 2009-11-05 | 2010-10-29 | Frequency hopping method for a radio device |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2497191A1 true EP2497191A1 (en) | 2012-09-12 |
Family
ID=43530807
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP10798472A Withdrawn EP2497191A1 (en) | 2009-11-05 | 2010-10-29 | Frequency hopping method for a radio device |
Country Status (4)
Country | Link |
---|---|
US (1) | US8964810B2 (en) |
EP (1) | EP2497191A1 (en) |
DE (1) | DE102009052107B4 (en) |
WO (1) | WO2011054338A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2963836A1 (en) * | 2014-07-03 | 2016-01-06 | ETH Zurich | Spread spectrum methods and devices |
CN116886124B (en) * | 2023-09-05 | 2023-11-14 | 成都九华圆通科技发展有限公司 | Frequency hopping signal tracking and suppressing method |
Family Cites Families (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3781818A (en) * | 1972-05-08 | 1973-12-25 | Univ Johns Hopkins | Data block multiplexing system |
DE69125613T2 (en) * | 1991-12-18 | 1997-07-17 | Hewlett Packard Ltd | Method and device for generating test signals |
FR2705176B1 (en) * | 1993-05-12 | 1995-07-21 | Suisse Electronique Microtech | FM RADIO RECEIVER COMPRISING A SUPERCHAMPLE CIRCUIT. |
US5623312A (en) * | 1994-12-22 | 1997-04-22 | Lucent Technologies Inc. | Compressed-domain bit rate reduction system |
JP2998659B2 (en) * | 1996-10-11 | 2000-01-11 | 日本電気株式会社 | Error control device |
US5832026A (en) * | 1996-12-04 | 1998-11-03 | Motorola, Inc. | Method for correcting errors from a fading signal in a frequency hopped spread spectrum communcation system |
US20020021745A1 (en) * | 2000-04-07 | 2002-02-21 | Negus Kevin J. | Multi-channel-bandwidth frequency-hopping system |
US7092427B1 (en) * | 2001-05-21 | 2006-08-15 | Rockwell Collins, Inc. | Direct sequence modulation using time, frequency, and/or on-off keying |
SE521746C2 (en) * | 2002-04-05 | 2003-12-02 | Ericsson Telefon Ab L M | Multi Modulation Transmitter |
US8243779B2 (en) | 2005-04-29 | 2012-08-14 | Alcatel Lucent | Method of quality-based frequency hopping in a wirelesscommunication system |
US8223817B2 (en) * | 2005-12-29 | 2012-07-17 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and arrangement for frequency hopping in wireless communication systems with carriers of varying bandwidth |
JP5226185B2 (en) * | 2006-02-15 | 2013-07-03 | 富士通株式会社 | Detecting and ranging device |
US8369424B2 (en) * | 2006-07-14 | 2013-02-05 | Qualcomm Incorporated | Frequency selective and frequency diversity transmissions in a wireless communication system |
GB2443869B (en) * | 2006-11-17 | 2010-05-12 | Imagination Tech Ltd | OFDM receivers |
US8625655B2 (en) * | 2007-09-24 | 2014-01-07 | Intel Corporation | Adaptive radio frequency interference mitigation during channel scanning or hopping |
US8428100B2 (en) * | 2007-10-08 | 2013-04-23 | Honeywell International Inc. | System and methods for securing data transmissions over wireless networks |
US8081691B2 (en) * | 2008-01-14 | 2011-12-20 | Qualcomm Incorporated | Detection of interferers using divergence of signal quality estimates |
US8060028B1 (en) * | 2009-05-07 | 2011-11-15 | The United States Of America As Represented By The Secretary Of The Navy | Multi-spectrum high data rate communications system with electromagnetic interference cancellation |
-
2009
- 2009-11-05 DE DE102009052107.0A patent/DE102009052107B4/en not_active Expired - Fee Related
-
2010
- 2010-10-29 WO PCT/DE2010/001266 patent/WO2011054338A1/en active Application Filing
- 2010-10-29 EP EP10798472A patent/EP2497191A1/en not_active Withdrawn
- 2010-10-29 US US13/508,054 patent/US8964810B2/en not_active Expired - Fee Related
Non-Patent Citations (2)
Title |
---|
None * |
See also references of WO2011054338A1 * |
Also Published As
Publication number | Publication date |
---|---|
US20120300813A1 (en) | 2012-11-29 |
US8964810B2 (en) | 2015-02-24 |
DE102009052107B4 (en) | 2015-10-29 |
DE102009052107A1 (en) | 2011-05-12 |
WO2011054338A1 (en) | 2011-05-12 |
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