DE 41 02 408 A1
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`[barcode]
`(19)
`Federal Republic
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`of Germany
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`[emblem]
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`German
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`Patent Office
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`Patent Publication
`(12)
`(10) DE 41 02 408 A 1
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`(21)
`Reference:
`P 41 02 408.7
`(22)
`Filing date:
`01/28/1991
`(43)
`Publishing date: 08/06/1992
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`(51)
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`Int. Cl.5:
`H 04 H 3/00
`H 04 H 1/00
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`(71) Applicant:
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`Grundig E.M.V. Elektro-Mechanische
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`Versuchsanstalt Max Grundig holländ.
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`Stiftung & Co. KG, 8510 Fürth, DE
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`An application for examination has been filed according to Section 44 PatG (German Patent Act)
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`(54)
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`The invention concerns a procedure for use in common-wave radio broadcasting.
`(57)
`For common-wave broadcasting, it is necessary for the modulation content of the transmitter frequencies
`of the individual broadcasting stations to be identical.
`In order to make transmitter or regional identification possible, however, one or more additional carrier
`frequencies, which differ from each other from region to region, are emitted, reception of these additional
`carrier frequencies making it possible to select at the receiver specialized regional news.
`The number of additional carrier frequencies required can be reduced to four individual frequencies or
`groups of frequencies if the additional carrier signals are modulated with identification signals.
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`Procedure for the identification of transmitter or region in common-wave broadcasting networks
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`DE 41 02 408 A1
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`1
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`Federal printing office, 06.92
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`208 032/51
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`7/40
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`(72)
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`Inventor
`Saalfrank, Werner, Dr.-Ing. 8522
`Herzogenaurach, DE
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`1
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`Petitioner Samsung - SAM1015
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`DE 41 02 408 A1
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`Description
`A high-quality radio transmission meeting the quality standards
`required by digital storage media (compact disk, DAT) is
`impossible using present analogue FM-transmission procedures,
`particularly in case of reception in moving motor vehicles or in
`mobile devices. Fluctuations in field strength and multipath
`reception lead to distorted signals, with their consequences can be
`reduced only partially by tricky alternating strategies using
`alternative receiver frequencies (e.g., in connection with the radio
`data system, RDS).
`Digital radio transmission for the mobile reception using satellites
`is presently still prevented by the mandatory use of receiver
`antennas with a distinct alignment capacity, necessary due to the
`relatively low transmission power.
`For this reason, for several years a standard is being developed for
`a novel, terrestrial, digital transmission process, known under the
`title “DAB” (Digital Audio Broadcasting) (here see: “Funkschau –
`Spezial”: “Digitaler Ton – von Hörfunk bis Mobiltelefon”, (Radio
`show – special, digital sound – from radio to mobile telephone),
`1989, pages 9 – 18).
`One of the specifics of the planned transmission network is the
`common-wave radio operation of transmitter stations participating
`within the scope of a nationwide radio program. This means that in
`a certain region all transmitter stations simultaneously emit
`transmission signals with the same modulation content on the very
`same transmission frequency and/or the same carrier frequencies.
`Here, the so-called COFDM-method (Coded Orthogonal
`Frequency Division Multiplex) is provided as the transmission
`procedure, by which within a region, e.g., the transmission area of
`a statewide radio station, utilizing a carrier frequency – bandwidth
`of e.g., 1.5 MHz, simultaneously approx. 5…6 stereo programs
`can be broadcasted (in addition to data related to or independent
`from said programs). Within the channel bandwidth available here
`a plurality of individual carriers (e.g., 448 carrier frequencies
`equidistantly spaced over the frequency axis) is impinged with a 4-
`DPSK-modulation (DPSK –
`Differential Phase Shift Keying). By scrambling the digital
`program data within the sequence and the allocation to individual
`carrier frequencies it is prevented that any transmission errors,
`caused by fluctuations in field strength, extend over long,
`temporarily continuous signal sections, and thus they can be
`corrected more easily.
`A detailed explanation of the principle transmission and coding
`procedures is discernible from the article “Digital Sound
`Broadcasting to Mobil Receivers” in the publication “IEE
`Transactions in Consumer Electronics”, Vol. 35, no. 3, Aug. 89,
`pages 439 – 503.
`In order to design a radio network covering several states it is
`necessary to provide a minimum of 4 different transmission
`channels of a certain bandwidth B such that the different programs
`of the individual transmission regions are prevented from
`interfering each other. With the help of these four different
`transmission channels it is possible to plan the individual
`transmission regions in the form of a 4-part cluster such that an
`inter-regional and/or international transmission network shows no
`abutting zones to different programs with simultaneously an
`identical transmission frequency.
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`Therefore a frequency band with a bandwidth totaling 4 x B is
`required to implement the common-wave broadcasting of the DAB
`– radio transmission. Of course, by using the other 3 cluster
`frequencies a network of locally limited transmitters can be
`installed within a certain transmission region, so that in addition to
`the 5…6 nationwide programs additionally 6 to 18 local programs
`can be broadcasted.
`As mentioned at the outset, the common-wave broadcasting of
`e.g., a nationwide transmission network requires the 100-percent
`consistency of the modulation content of the frequency portions
`simultaneously emitted by the individual transmitter stations, in
`order to allow a flawless decoding of the program data. Due to the
`fact that the future DAB-network shall additionally handle the
`tasks of the present FM-radio network e.g., any nationwide
`broadcasting of traffic news contradicts the necessity to transmit to
`the vehicle operators targeted regional or local traffic information.
`Additionally, the vehicle operator transferring from one
`transmission region to an adjacent one shall be provided with
`rough information of location in order to allow him/her to
`automatically or manually adjust the receiver to the receiver
`channel or the neighboring region.
`Accordingly the objective of the invention is to provide a
`procedure for the identification of transmitter or region, which
`abstains from interfering with the common-wave operation of the
`transmission network. The method shall additionally be capable to
`transmit additional transmission data, unrelated to the region.
`This objective is attained in the common-wave transmission
`procedure defined in the preamble of claim 1 by the features
`mentioned in the characterizing part of claim 1. Additional
`advantageous embodiments of the invention are disclosed in the
`dependent claims 2 - 6.
`In the following the invention is explained in greater detail based
`on the drawings:
`They show:
`Fig. 1a
`the arrangement of the carrier frequencies for a
`statewide common-wave network;
`Fig. 1b
`the arrangement of the carrier frequencies according to
`Fig. 1a, however with additional transmitter and/or
`regional identification;
`the frequency distribution diagram in the form of a 4-
`Fig. 2
`part cluster.
`According to Fig 1a, in the DAB – broadcasting method within a
`statewide transmission region (e.g., 448) carrier frequencies are
`transmitted simultaneously with equidistant frequency distances Δf
`in a frequency range with the bandwidth B. The individual carriers
`are each modulated with one part of the digital data, with the
`modulation content of the individual carries being identical for all
`transmitter stations of the transmission region. When operation
`occurs in the time multiplex system here the data of different
`programs are transmitted within the data packages in a temporal
`sequence such that for a program change within the programs
`offered by a certain transmitter station no change of the adjustment
`frequencies is necessary in the receiver but only a switch of the
`time - allocated decoding of the data packages. The data content of
`a program is not limited to radio signals but can also comprise
`partially or entirely information or control data (e.g., image
`transmission or control data (e.g., image transmission or traffic
`control information).
`Outside the transmission region of a state broadcast station with
`the carrier frequency range B1, of course a transmitter with a
`different program offer cannot use the same carrier frequencies,
`because in the overlapping area of both transmission regions then
`any unambiguous program decoding is no longer possible.
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`Accordingly, a separate carrier frequency range B2 must be
`allocated to this adjacent broadcast region. It is discernible from
`Fig. 2 that, assuming at least four different frequency ranges
`B1…B4, a frequency planning can be prepared in which regions
`with identical carrier frequency ranges are not abutting each other
`(cf. 4-color display of political maps).
`However, within one transmission region additionally locally
`limited transmitters can be embedded with different program
`offers, if the other three cluster frequencies are allocated thereto
`and it is ensured that their transmission cannot penetrate into the
`adjacent transmission regions with the same carrier frequency
`range.
`In order to ensure a flawless common-wave operation within a
`transmission region it is mandatory that all carrier frequencies
`used for transmitting programs or data are impinged with
`respectively identical modulation content, i.e. a regional or
`transmitter-specific identification is impossible within the program
`information. However, in order to allow e.g. a targeted selection
`from the nationwide prepared traffic information for traffic news
`or the detection of a regional standard alarm message it is
`necessary to allow via particular transmitter identification a rough
`local orientation to the receiver. Here, all transmitters of a certain
`region may be provided with the same identification when the
`message is not only of regional importance. In order to detect
`which particular transmitter station is the closest within the
`nationwide common-wave broadcast network of the receiver the
`field strength and/or the number or temporal sequence of the
`received echo of the receiver signal provided with particular
`identification can be evaluated.
`According to Fig. 1b the identification can occur via n non-
`modulated carrier frequencies (dot-dash frequency lines n·3…n),
`which are transmitted in addition to the carrier frequencies l…m
`used for program transmission according to Fig. 1a. These
`additional n carriers may be inserted within or outside the
`frequency band required for program transmission at any position,
`however only within the predetermined frequency grid. In any case
`here the bandwidth to be transmitted expands from B to B’. The
`arrangement of the additional carrier frequencies in the frequency
`range to be transmitted allows a plurality of variations of the
`identification.
`transmitter
`The additional carrier frequencies required for
`identification lead to a large number of transmitter stations within
`a transmission region and to a considerable expansion of the
`frequency bandwidth B’ to be transmitted. This disadvantage can
`be avoided when one or more of these additional carriers are
`modulated with a particular identification signal. In order to
`prevent interfering with common-wave broadcasting, similar to
`Fig. 2 here at least four groups of additional carriers may be
`provided, with their regional use being planned such that no
`mutual interference develops. The identification signals are
`modulated on the additional carriers in the same manner as the
`COFDM procedure.
`By the modulation of the additional carriers with identification
`signals here arbitrary numbers of secondary common-wave
`networks can be formed in reference to the additional carriers
`within wide-area common-wave broadcasting.
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`4
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`In order to transmit regionally independent data the additional
`carriers may also be modulated e.g., with switching or
`synchronizing signals. Due to the fact that sufficient time is
`provided for the evaluation of the additional signals and/or error
`safety is ensured within the transmission capacity of an individual
`additional carrier by sufficient redundancy, here the additional
`frequencies required can be limited in most cases to one additional
`carrier each, instead of an entire group.
`By using the transmitter or regional identification it is additionally
`possible during mobile reception in the international traffic to
`detect in due time the transfer into an adjacent broadcasting region
`with a different program offer. Here, the orientation occurs by a
`comparison of the received identification with the identification
`list allocated to the broadcast landscape, stored in an internal
`device storage. This way the receiver can be adjusted manually or
`automatically to the group of carrier frequencies of the new
`broadcasting region as soon as the receiver quality of the
`previously received transmitter signal is no longer sufficient.
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`Claims
`A method for the wireless transmission of digital
`1.
`information and/or control signals in common-wave broadcasting
`with a plurality of individual carriers, respectively modulated with
`a portion of the desired signal, characterized in that one or more
`additional, regionally different individual carrier frequencies are
`transmitted for identifying the respective transmitting station or for
`marking a certain broadcast region, with their presence being
`evaluated for transmitter identification, and which prevent any
`interference of information in the common-wave broadcasting.
`2.
`A method according to claim 1, characterized in that the
`additional carrier frequencies in the common-wave broadcasting
`network allocated to the individual transmitter stations or regions
`are distributed over at least four groups (4-part cluster) such that
`the same frequencies can be used simultaneously in transmitting
`regions sufficiently distant from each other, and that this additional
`carrier frequencies are modulated with particular identification
`signals for the identification of the transmitter or region.
`3.
`A method according to claim 2, characterized in that in
`common-wave broadcast networks, modulated according to the
`COFDM method, the identification signals are modulated on the
`additional carriers according to the same method.
`4.
`A method according to claim 2, characterized in that for
`the identification of transmitters or regions only a single additional
`carrier is used per group, modulated with an identification signal.
`5.
`A method according to one of claims 2 to 4,
`characterized in that the additional carrier frequencies allocated to
`the individual transmitter stations or regions are not only provided
`with identification signals but are also modulated with additional
`data, not necessarily related to the region.
`6.
`A method according to one of claims 1 to 4,
`characterized in that secondary common-wave networks are
`formed within one common-wave broadcast network, designed in
`the form of clusters, using one or more identification carriers per
`cluster.
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`Here, 2 page(s) of drawings
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`DE 41 02 408 A1
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`Drawings page 1
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`Number
`Int. Cl5:
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`Publishing date:
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`DE 41 02 408 A1
`H 04 H 3/00
`August 6, 1992
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`DE 41 02 408 A1
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`Drawings page 2
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`Number
`Int. Cl5:
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`Publishing date:
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`DE 41 02 408 A1
`H 04 H 3/00
`August 6, 1992
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`5
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