EP1088402A1 - Procede et dispositif a diversite en frequence porteuse destines a la transmission d'informations - Google Patents

Procede et dispositif a diversite en frequence porteuse destines a la transmission d'informations

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Publication number
EP1088402A1
EP1088402A1 EP98936225A EP98936225A EP1088402A1 EP 1088402 A1 EP1088402 A1 EP 1088402A1 EP 98936225 A EP98936225 A EP 98936225A EP 98936225 A EP98936225 A EP 98936225A EP 1088402 A1 EP1088402 A1 EP 1088402A1
Authority
EP
European Patent Office
Prior art keywords
carrier frequency
frequency values
subgroup
carrier
frequencies
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Withdrawn
Application number
EP98936225A
Other languages
German (de)
English (en)
Inventor
Jürgen KOCKMANN
Olaf Dicker
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.)
Siemens AG
Original Assignee
Siemens AG
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
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP1088402A1 publication Critical patent/EP1088402A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • 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
    • 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

Definitions

  • the present invention relates to a method and a device for transmitting information in different carrier frequencies by means of a frequency hopping method.
  • the device and the method can, for. B. can be implemented in a mobile station or a base station of a mobile radio system.
  • the so-called frequency hopping spread spectrum system is known as a method for transmitting data on a plurality of carrier frequencies.
  • a frequency hopping spread spectrum system is to be understood as a system in which a plurality of carrier frequencies are provided for the radio transmission of data and the carrier frequency currently used is changed at periodic intervals.
  • the carrier frequency can be changed after each time slot or time frame of the time division multiplex transmission.
  • TDMA time division multiplex
  • Such a frequency hopping spread spectrum system has advantages in that the energy of the entire radio transmission is distributed over all carrier frequencies. This is particularly important if a generally available frequency band, such as the 2.4 GHz ISM (Industrial, Scientific, Medical) band, is used.
  • an upper limit for the maximum energy occurring per carrier frequency is set for this frequency band in order to keep interference to other participants as low as possible.
  • the frequency change it is mandatory that at least 75 different frequencies must be used within a period of 30 seconds. Furthermore, each frequency may be used for a maximum of 0.4 seconds in 30 seconds. On average, all frequencies must be used equally.
  • 24 time slots, 12 each for uplink and for downlink are defined in a 10 ms frame.
  • the FCC part 15 only provides a bandwidth of less than 1 MHz in the ISM band. In order to meet this requirement, the number of time slots was reduced to 12 time slots in a 10 ms time frame, ie 6 time slots each for uplink and for downlink.
  • each time slot would have a length of 833 ⁇ s.
  • the time slots in the DECT standard have a length of 417 ⁇ s.
  • Time slots in which data are transmitted are required. With such systems, only 6 active time slots in each direction are used for data transmission. If such systems, which operate on the basis of slow frequency hopping, are also to meet the requirements of FCC part 15 in the ISM band, an inactive blind time slot of 417 ⁇ s must again be present between adjacent active time slots.
  • This blind time slot thus has half the length of a full time slot of 833 ⁇ s, which means that if a base time frame of 10 ms is maintained, four active time slots are available in each frame for uplink and for downlink, between which blind time slots are sent.
  • the four active time slots each have a length of 833 ⁇ s, while the blind time slots each have a length of 417 ⁇ s.
  • frequency programming for frequency hopping in the next following active time slot can also be carried out at the end of the previous active time slot.
  • the programmed start frequency can be set in the next active time slot.
  • the object of the present invention is to create a method and a device for transmitting information in different carrier frequencies by means of a frequency hopping method, in which the different carrier frequencies are provided in a simple and effective manner.
  • a random sequence of a number of N possible carrier frequency values fx in addresses 1 to N of a table is provided for transmitting information in different carrier frequencies by means of a frequency hopping method, the N possible carrier frequencies be divided into n sub-groups. Then at least a part M of the N carrier frequency values fx is read out repeatedly from the table periodically, the carrier frequency values fx being read out sequentially from the corresponding addresses and the subgroups in a specific sequence within each subgroup, where M ⁇ N. Then information is transmitted in the carrier frequencies corresponding to the carrier frequency values read out.
  • the method and the device according to the present invention can, for. B. be implemented in a mobile or a base station of a mobile radio system.
  • a carrier frequency is first sampled. A decision is then made as to whether a specific message has been received on this carrier frequency during a certain period of time. If the decision is negative, a new carrier frequency is selected and this new carrier frequency is sampled. If the decision is positive, the table is provided using the message. In particular, the random sequence is generated starting from the position at which the mobile radio unit that sent the specific message is currently located, so that the random sequences of the two mobile radio units are synchronized.
  • a carrier frequency is first sampled. Then it is decided whether these carrier frequency is received. If the decision is negative, a new carrier frequency is selected and this new carrier frequency is sampled. If the decision is positive, the address corresponding to this carrier frequency is searched in the table and the carrier frequency values are periodically read out repeatedly from this address.
  • FIG. 1 shows a mobile radio transmission system with a base station according to the invention
  • FIG. 2 shows a time frame of a data transmission standard as can be used in the present invention
  • 3 shows in detail the internal structure of a base station according to the invention
  • FIG. 4 shows a schematic illustration of a frequency-hoping spread spectrum system, in particular also in the case of a jammer avoidance mode
  • FIG. 5 shows a table from which carrier frequency values within each subgroup are read out repeatedly, the subgroups being read out in a specific order
  • Fig. 6 shows a flow chart illustrating a method for synchronizing, for example, two mobile radio units
  • FIG. 7 is a flowchart illustrating a method of establishing a connection, for example, between two mobile radio units
  • FIG. 9 shows a flowchart which represents a method for the synchronization of, for example, two mobile radio units, in which disturbed carrier frequency values are replaced by undisturbed carrier frequency values;
  • FIG. 10 shows a flow chart illustrating a method for
  • 11 shows a table in which only a part of the possible carrier is read out, the remaining part of the unread carrier frequency values within each sub-group is used to replace disturbed carrier frequency values;
  • FIG. 13 shows a table in which another disturbed carrier frequency value in the read-out part of the subgroup is replaced by an undisturbed carrier frequency value.
  • the arrangement for radio transmission of data has a base station 1 and several mobile parts (mobile stations), wireless telephones 2, 3 ....
  • the base station 1 is with a
  • Terminal line 10 connected to the landline.
  • An interface device which is not shown, can be provided for communication between the base station 1 and the terminal line 10.
  • the base station 1 has an antenna 6, by means of which communication with the mobile part 3 takes place, for example, via a first radio transmission path 8 with the mobile part 2 or via a second radio transmission path 9.
  • the handsets 2, 3 ... each have an antenna 7 for receiving or transmitting data.
  • Fig. 1 the state is schematically shown in which the base station 1 actively communicates with the mobile part 2 and thus exchanges data.
  • the handset 3, on the other hand, is in the so-called idle locked mode, in which it waits stand-by for a call from the base station 1. In this state, the mobile part 3 does not actually communicate with the base station 1, but rather receives the data from the base station 1 only at periodic intervals, for example of a time slot in order to be able to re-synchronize its carrier frequencies fx.
  • base station 1 The internal structure of base station 1 is shown schematically in FIG. 1.
  • the voice information data are supplied to an RF module 4, which is controlled by a carrier frequency sequence unit.
  • RF module 4 which is controlled by a carrier frequency sequence unit.
  • the exact structure of a base station 1 according to the invention will be described later.
  • data are transmitted in several time slots in succession on a plurality of carrier frequencies fx, ten of which are shown, in the illustrated case 24 time slots Zx, using a time division multiplex method TDMA (Time Division Multiple Access).
  • TDMA Time Division Multiple Access
  • work is carried out in alternating mode (duplex), i. i.e., after the first twelve time slots Zx have been transmitted, reception is switched and the second twelve time slots (Z13 to Z24) are received in the opposite direction by the base station.
  • the time duration of a time frame is 10 ms, and 24 time slots Zx are provided, namely twelve time slots for the transmission from the base station to handsets and a further twelve time slots Zx for transmission from the handsets to the base station.
  • ten carrier frequencies fx between 1.88 GHz and 1.90 GHz are provided.
  • the present invention is used in particular for transmissions in the so-called 2.4 GHz ISM (Industrial, Scientific, Medical) frequency band.
  • the generally accessible ISM frequency band has a bandwidth of 83.5 MHz. According to the FCC part 15 regulation, at least 75 carrier frequencies must be distributed over this 83.5 MHz. A division of the bandwidth from 83.5 MHz to 96 carrier frequencies, ie a channel spacing of 864 kHz, is particularly advantageous.
  • the frequency bands and standards mentioned above are given purely as an example.
  • the basic requirement for applicability in the present invention is only that a so-called frequency hopping spread spectrum is used, ie that several carrier frequencies are available and that the carrier frequency selected for transmission is changed from time to time.
  • a prerequisite for such a change is that the data are transmitted in time slots Zx (time-division multiplex method).
  • the DECT standard and any other modified standard based on this DECT standard are suitable.
  • the RF module 4 is supplied with information data when the base station 1 is to transmit to a handset 2, 3... By means of the antenna 6, and the RF module 4 outputs information data when Data can be received from handsets.
  • the RF module 4 modulates the di ⁇ gitalen encoded information data onto a carrier frequency fx.
  • the carrier frequency fx currently to be used is predetermined by a carrier frequency sequence unit, which is generally designated 20.
  • a detection device 24 is provided in the carrier frequency sequence unit 20, to which the demodulated signal is supplied by the RF module 4.
  • a fault means that there is either a fault in the actual sense or an assignment by another transmitter.
  • a disturbance in the sense of the present description can thus be detected in that a received signal on a Carrier frequency is demodulated and it is detected whether there is a signal level on this carrier frequency or not.
  • a disturbed carrier frequency is therefore a carrier frequency onto which a signal is modulated that exceeds a certain threshold value.
  • the A-CRC value, the X-CRC value, a loss of synchronization or the RSSI value can be used for blocking.
  • the detection device 24 determines, for example on the basis of the demodulated signal from the RF module 4, how high the signal component modulated onto a specific carrier frequency fx is. If the detected signal component is above a predetermined limit value, the detection device 24 outputs a fault detection signal to a blocking / release unit 21. Depending on the interference detection signal from the detection device 24, the blocking / release unit 21 provides blocking / release information to a processor 23. This blocking / release information indicates which of the carrier frequencies fx are blocked or released again due to the detection of a fault by the detection device 24, as will be explained later.
  • the processor 23 is supplied with a sequence from a random generator 22.
  • the random number generator 22 generates a randomly distributed sequence of carrier frequency values within the usable frequency band in order to store a random series of carrier frequency values in a table 25 of the processor. The random generator 22 thus carries out one of the
  • the processor 23 reads the in operation Carrier frequency values serially from the table and finally outputs a control signal to the RF module 4, which specifies the carrier frequency value to be used for the RF module 4.
  • the processor 23 has the table 25 provided in a memory, the function and management of which will be explained later.
  • a carrier frequency fl is used, for example, during a frame Rx of a mobile radio transmission, as is shown hatched in FIG. 4.
  • This frequency fl is thus the first value of the random sequence stored in the table, which is fed to the processor 23, which in turn controls the RF module 4 accordingly.
  • the table 25 prescribes a frequency hopping Pl to a carrier frequency f3 due to the sequence stored in it.
  • the detection means has detected, for example, in a previous transmission 24, that the carrier frequency f is disturbed 2, and thus has been the detection device 24 is a corresponding thereto interference signal to the locking / unlocking unit 21, which in turn is a Sper ⁇ tion the frequency f2 which has indicated to the processor 23. Furthermore, it is assumed that the random number generator 22 is based ⁇ ner sequence determined previously for the frame requires R3 acquired as disturbed carrier frequency f2.
  • the processor 23 On the basis of the coincidence of the prescribed carrier frequency f2 according to the sequence in table 25 and at the same time the blocking signal from the blocking / release unit 21 for the same carrier frequency f2, the processor 23 now replaces the carrier frequency f2 for the frame R3 which is actually prescribed but is detected as being disturbed Carrier frequency detected by the detection device 24 as not disturbed, for example the carrier frequency f4, as indicated by the frequency hopping arrow P3. Instead of of the carrier frequency 2 actually prescribed by the sequence, the RF module 4 is therefore driven to the substitute carrier frequency f4. By replacing the carrier frequency detected as disturbed, a modified sequence of carrier frequencies is created. The modified sequence only has undisturbed carrier frequencies. The fact that a carrier frequency detected as disturbed is replaced and is not skipped by a transition to the following carrier frequency means that the positions of the undisturbed carrier frequencies in the modified sequence are not changed compared to the original sequence.
  • This blocking can be released again by the blocking / release unit 21 as soon as a new detection by the detection device 24 indicates that the previously disturbed carrier frequency is no longer disturbed.
  • the blocking / release unit 21 issues an enable signal to the processor 23, which indicates that the processor 23 no longer has to replace the previously disturbed carrier frequency by another carrier frequency.
  • the blocking / release unit 21 can automatically output a release signal to the processor 23 without a renewed detection by the detection device 24 as soon as a predetermined time period has expired.
  • Each of the procedures mentioned thus ensures that the entire predetermined frequency spectrum is used in an evenly distributed manner. By adjusting the times in the procedure for blocking frequencies, standards can thus be met.
  • Base station 1 is the master in frequency allocation, i. H. at the start of a connection establishment, the random number generator is initialized in a mobile part with the state of the random number generator 22 of the fixed station 1. The same random number generator 22 then generates in the mobile part the same random sequence of carrier frequency values as is stored in table 25 of the base station and also stores it in a corresponding table 25.
  • the mobile stations have a very similar structure to that in FIG. 3 shown base station.
  • the mobile stations do not include the blocking / release device 21 and the detection device 24, but the random number generator 22 and the processor 23 with the table 25 and the RF module 4. It is also conceivable that the mobile station detects the disturbed carrier frequencies and notifies the base or base station.
  • the present invention can thus be used or implemented both in a base station and in a mobile station.
  • the procedure for frequency blocking which is carried out by the detection device 24 and the blocking / releasing unit 21, uses a unidirectional protocol on the air interface during the entire connection time between the base station 1 and a handset 2, 3. If the detection device 24 finds one of the end possible frequencies fx as disturbed by the base station 1, the base station 1 thus informs all the mobile parts with which it operates active connections that this disturbed frequency, when it is read from the table , is to be replaced by another carrier frequency which is not detected as being disturbed. The frequency lock is canceled by the lock / release unit 21 when the locked carrier frequency for transmission is suitable again or if it was blocked for longer than a previously defined time.
  • FIG. 3 it can be seen that the processor 23 is assigned the table 25, for example provided in a memory.
  • FIGS. 5 to 13 it will now be explained how the carrier frequencies fx are provided according to the invention.
  • all of the available N carrier frequencies fx for example 96, are entered in a table 25.
  • the distribution of the carrier frequency values shown is only an example and any other distributions can be selected.
  • FIGS. 5 to 7 show the table 25 stored in the processor 23.
  • a corresponding carrier frequency fx is assigned to each address 1 to 96, all 96 carrier frequencies fx being different.
  • the subgroups within the table 25 the advertising thereby read out in a particular order, for example in the order of the first subset, third subset, fifth subset, sixth subgroup fourth Un ⁇ terange and last second subgroup.
  • the order given has advantages in terms of frequency hopping. It provides a maximum frequency jump of 47 carrier frequency values (3-16-1 carrier frequency values), the minimum fre- Quenzprungentferung is 17 carrier frequency values (16 + 1 carrier frequency values).
  • the carrier frequency values are written into the n subgroups of table 25 on the basis of a random number sequence generated by the random number generator 22.
  • a random sequence of carrier frequency values is first written into the first group until it is full, then into the second subgroup, etc.
  • the carrier frequency values fx are read out serially within each subgroup during operation, the subgroups in a specific, e.g. B. the order mentioned above can be read out one after the other.
  • the carrier frequency values read out are converted in the RF module into corresponding carrier frequencies and used for the transmission of data.
  • the particular order in which the subgroups are successively read from table 25 can be any other suitable order besides the advantageous order described above.
  • the read-out method described above considerably reduces the computing effort in the respective mobile radio unit during operation, since a new carrier frequency or a new carrier frequency value fx does not always have to be determined.
  • the random sequence of carrier frequencies fx in the table is generated each time the connection between mobile radio units is established and is written into corresponding tables 25. Thereafter, when transmitting data, the carrier frequency values which are permanently written into the table and which are read out in the manner according to the invention are used.
  • each base station of a mobile radio system can have a random sequence of carrier frequency values fx exclusively assigned to it in its table 25.
  • a shift register or the like can be used, for example, to generate the random sequence of carrier frequency values fx in the random number generator 22.
  • a mobile station When establishing a connection to a base station, a mobile station receives a specific message from the base station that the creation initialized against the random sequence of carrier frequency values fx, so that the identical table 25 of carrier frequency values fx as in the base station is generated.
  • a carrier frequency fx is first sampled in a corresponding device in a step 26.
  • the sampled carrier frequency corresponds to one of the carrier frequency values fx already stored in table 25.
  • a decision is made in a corresponding device or ascertained whether this sampled carrier frequency was received during a specific period. If the decision is negative, for example, since the carrier frequency is disturbed, a new carrier frequency is selected, as shown in step 28, and this new Trä ⁇ gerfrequenz is scanned.
  • This new carrier frequency is advantageously selected from a different subgroup than the first sampled carrier frequency.
  • the frequency of the received carrier corresponding address is overall in the Table 25 searches, in a step 29 in a corresponding device of the processor 23. Then, in a step 30 in a corresponding device, the random sequence of the carrier frequency values fx stored in the table 25 is read out from this address in the manner according to the invention.
  • no additional information about the frequency hopping algorithm is therefore necessary, since no changes occur in the periodically repeated frequency value table 25.
  • a specific selected carrier frequency is first sampled in a corresponding device in a step 31.
  • a corresponding device is used to determine or decide whether a specific message has been received on this scanned carrier frequency.
  • the specific message can be, for example, the N t message in the A field of the DECT standard. Other corresponding messages can be used in other standards.
  • step 32 If it is determined in step 32 that the particular message is not received WUR ⁇ de, is replaced after the lapse of a certain period of time, which is determined in a step 33 in a corresponding device in a subsequent step 34 in a corresponding device a new carrier frequency selects which is scanned.
  • the new carrier frequency is advantageously selected from a different subgroup than the first sampled carrier frequency. Steps 32 and 33 can be carried out in a single device.
  • a corresponding corresponding device If it is decided in step 32 that the specific message has been received, then in a step 35 a corresponding corresponding device generates the table 25.
  • the various carrier frequency values are generated in a random sequence by the random number generator 22 and are written into the table 25 in subgroups.
  • the specific message or a part thereof can be used to generate the random sequence, thereby ensuring that, for example, the same random sequence of carrier frequency values fx is written into Table 25 in a mobile station as in the corresponding Table 25 in the assigned base station are available.
  • the carrier frequency values fx are then periodically read out repeatedly from the table 25 in order to transmit data in the corresponding carrier frequencies.
  • the mobile station knows from the specific message received in the scanned carrier frequency at which address of the table 25 the base station is located, and can use this address to read out the subsequent carrier frequency values fx synchronously with the base station.
  • the carrier frequency values stored in table 25 in the mobile stations are periodically read out repeatedly and used for the transmission of data.
  • the disturbed frequencies are e.g. B. determined by the respective base station.
  • the information about the disturbed carrier frequencies is communicated to the respective mobile stations by the assigned base station, whereupon the disturbed carrier frequencies are replaced by undisturbed carrier frequencies.
  • the remaining 18 carrier frequency values in the last three addresses of each subgroup are only used for the transmission of data if one of the carrier frequencies of the first 13 addresses in each subgroup is recognized and communicated by the respective base station.
  • the generation of the random sequence of carrier frequency values for each subgroup is also carried out here in such a way that all 16 carrier frequency values for each subgroup are generated in a random sequence by the random number generator 22 and are stored in each subgroup of table 25, the subgroups being filled in successively .
  • Each carrier frequency value fx is contained in table 25 only once. If one of the carrier frequencies of the first 13 becomes
  • the base station sends the mobile station a corresponding message to replace the disturbed carrier frequency with an undisturbed carrier frequency from the last three carrier frequency values of the corresponding subgroup. In this way, disturbed frequencies during transmission can be avoided. If more than 18 carrier frequencies are disturbed, a periodic background noise is caused by the disturbed carrier frequencies used.
  • FIG. 9 shows a flowchart which explains the method steps for synchronizing a mobile station with a base station when only 78 carrier frequency values fx are repeatedly read out from the table 25 periodically.
  • Steps 26 to 30 correspond to the steps shown in FIG. 6 and are also implemented in corresponding devices in processor 23. 9, after step 29, in which the address in table 25 is found, which corresponds to the sampled and received carrier frequency, an additional method step 37 is carried out in a corresponding device.
  • step 37 a specific message is received by the base station, by means of which the table 25 is updated.
  • the base station if it detects a particular carrier frequency in a subgroup as being disturbed, replaces the corresponding carrier frequency value in its own table 25 with an undisturbed carrier frequency value from one of the last three addresses of the subgroup and transmits this information to the mobile station.
  • the mobile station replaces the same carrier frequency value, so that since the tables 25 of the base station and the mobile station are identical, the carrier frequency values read out periodically from the table 25 in the mobile station continue to exactly match those of the base station.
  • the specific message for updating table 25 can be, for example, the P t or M t message of the A field.
  • the carrier frequency values are read from the table 25 in the updated form. In contrast to FIG. 6, however, only 78 of the 96 available carrier frequency values are used here.
  • FIG. 10 shows a flowchart which explains the establishment of a connection between a mobile station and a base station.
  • the flow diagram shown in FIG. 10 essentially comprises the same process steps like the flowchart shown in FIG. 7, but here too a step 38 for updating the table 25 is inserted.
  • Method steps 31 to 36 correspond to the method steps shown in FIG. 7. All of the method steps shown in the flowchart in FIG. 10 are implemented in corresponding devices in the processor 23 of the mobile station.
  • step 35 in which table 25 was generated by means of random number generator 22, the mobile station receives a specific message for updating table 25 in order to replace faulty carrier frequency values from addresses 1 to 75 with undisturbed carrier frequency values from addresses 76 to 96 .
  • the specific message for updating table 25 can be the P t or M t message of the A field in the DECT standard.
  • FIGS. 11 to 13 show the manner in which disturbed carrier frequency values from the sequentially read out first 13 addresses of each subgroup can be replaced by undisturbed carrier frequency values from the undisclosed last three addresses of the subgroup.
  • 11 shows a table 25 with six subgroups, each with 16 carrier frequency values.
  • the first subgroup contains a random sequence of 16 carrier frequency values fx in its addresses 1 to 16. Of these 16 carrier frequency values, 13 carrier frequency values are read out sequentially from addresses 1 to 13.
  • the base station If the base station detects, for example, that the carrier frequency corresponding to the carrier frequency value f 27 , which is stored in address 3 of the first subgroup of table 25 of the base station and the mobile station, is disturbed, it transmits this information to the mobile station simultaneously with the instruction given to exchange the carrier frequency value f 12 located in the address 16 of the first subgroup of table 25 with the carrier frequency value f 2 7.
  • FIG. 12 shows an updated table 25 in which the carrier frequency values f 12 and f 27 in the first subgroup of table 25 in FIG. 11 have swapped places. It the first 13 carrier frequency values in the addresses 1 to 13 are therefore always read out sequentially in each subgroup, the subgroups being read out in succession in a specific order, as explained above. Even if disturbed carrier frequencies are determined, the first 13 carrier frequency values from each subgroup are still read out, the disturbed carrier frequency values being replaced with undisturbed carrier frequency values from the last three addresses of the corresponding subgroup.
  • the base station determines that the carrier frequency corresponding to the carrier frequency value f 27 is no longer disturbed, but now the carrier frequency corresponding to the carrier frequency value f 54 is disturbed, it first exchanges the carrier frequency value f 27 back into its address 3 and accordingly the carrier frequency value f 12 to its address 16 and also gives the mobile station the appropriate instruction for this. The next disturbed carrier frequency value f 54 from its address 13 is then exchanged with the carrier frequency value f 54 from address 16.
  • the original carrier frequency values if they are no longer disturbed, are therefore always written back to their old locations or to their old addresses before new, disturbed carrier frequency values are replaced.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé et un dispositif à diversité en fréquence porteuse destinés à la transmission d'informations par un procédé à sauts de fréquence. Une séquence aléatoire fournit un nombre N de valeurs de fréquences porteuses fx possibles aux adresses 1 à N d'une table (25). Les N fréquences porteuses possibles sont subdivisées en n sous-groupes. Au moins une partie M des N valeurs de fréquences porteuses fx de la table (25) est périodiquement répétée. Dans chaque sous-groupe, les valeurs de fréquences porteuses fx sont extraites séquentiellement des adresses correspondantes et les sous-groupes sont extraits dans un ordre chronologique déterminé, sachant que M≤N. Des informations sont ensuite transmises à des fréquences porteuses qui correspondent aux valeurs de fréquences porteuses extraites. Le procédé et le dispositif selon l'invention peuvent, par exemple, être appliqués dans une station mobile ou une station de base d'un système radio mobile.
EP98936225A 1998-06-18 1998-06-18 Procede et dispositif a diversite en frequence porteuse destines a la transmission d'informations Withdrawn EP1088402A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/DE1998/001682 WO1999066651A1 (fr) 1998-06-18 1998-06-18 Procede et dispositif a diversite en frequence porteuse destines a la transmission d'informations

Publications (1)

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EP1088402A1 true EP1088402A1 (fr) 2001-04-04

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EP98936225A Withdrawn EP1088402A1 (fr) 1998-06-18 1998-06-18 Procede et dispositif a diversite en frequence porteuse destines a la transmission d'informations

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Publication number Priority date Publication date Assignee Title
FR2640448B1 (fr) * 1980-10-13 1992-01-03 Trt Telecom Radio Electr Systeme de transmission d'informations forme de reseaux exploitant par sauts de frequence un ensemble de canaux
DE3415032C2 (de) * 1983-04-27 1985-06-20 Siemens AG, 1000 Berlin und 8000 München Verfahren zur störresistenten Funkübertragung
SE445698B (sv) * 1984-11-19 1986-07-07 Ericsson Telefon Ab L M Forfarande att reducera smalbandiga storares inverkan vid radiokommunikation mellan tva stationer, vilka utnyttjar frekvenshopp
US5471503A (en) * 1992-12-29 1995-11-28 Apple Computer, Inc. Scanning method for receiving a transmission in a communication system with slow frequency hopping and coding
US5515369A (en) * 1994-06-24 1996-05-07 Metricom, Inc. Method for frequency sharing and frequency punchout in frequency hopping communications network
US5586120A (en) * 1995-07-05 1996-12-17 Motorola, Inc. Method for a channel hopping communication system with variable transmission bandwidth

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