WO2000019674A1 - Conversion of gfsk-modulated signals into qpsk-modulated signals - Google Patents
Conversion of gfsk-modulated signals into qpsk-modulated signals Download PDFInfo
- Publication number
- WO2000019674A1 WO2000019674A1 PCT/DE1999/003057 DE9903057W WO0019674A1 WO 2000019674 A1 WO2000019674 A1 WO 2000019674A1 DE 9903057 W DE9903057 W DE 9903057W WO 0019674 A1 WO0019674 A1 WO 0019674A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- qpsk
- modulated data
- controller
- gfsk
- dect
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/18—Phase-modulated carrier systems, i.e. using phase-shift keying
- H04L27/20—Modulator circuits; Transmitter circuits
- H04L27/2003—Modulator circuits; Transmitter circuits for continuous phase modulation
- H04L27/2007—Modulator circuits; Transmitter circuits for continuous phase modulation in which the phase change within each symbol period is constrained
- H04L27/2017—Modulator circuits; Transmitter circuits for continuous phase modulation in which the phase change within each symbol period is constrained in which the phase changes are non-linear, e.g. generalized and Gaussian minimum shift keying, tamed frequency modulation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/18—Phase-modulated carrier systems, i.e. using phase-shift keying
- H04L27/22—Demodulator circuits; Receiver circuits
Definitions
- the present invention relates to a mobile radio device and a method for wireless transmission of QPSK-modulated data using a DECT baseband controller.
- the DECT standard was adopted in the early 1990s. It is the first common European standard for cordless telecommunications.
- a DECT network is a microcellular, digital mobile network for high subscriber densities. It is primarily designed for use in buildings. However, the DECT standard can also be used outdoors. The capacity of the DECT network of around 10,000 subscribers per square kilometer makes the cordless standard an ideal access technology for network operators. According to the DECT standard, both the transmission of voice and the transmission of data signals are possible. This means that cordless data networks can also be set up on a DECT basis.
- DECT Digital European Cordless Communication
- a digital, cordless telecommunications system for ranges below 300 m has been standardized for Europe. This system is therefore suitable in connection with the switching function of a telecommunications system for mobile telephone and data traffic in an office building or on a company site.
- the DECT functions supplement a telecommunications system and thus make it the base station FS of the cordless telecommunications system.
- Digital radio connections can be made on up to 120 channels. conditions between the base station FS and the maximum of 120 mobile stations MS are established, monitored and controlled.
- the frequency range is 1.88 GHz to 1.9 GHz on a maximum of ten different carrier frequencies (carriers).
- This frequency multiplex method is called FDMA (Frequency Division Multiple Access).
- the data is modulated according to the GMSK (Gauss Minimum Shift Keying) method.
- GMSK Gaus Minimum Shift Keying
- TDMA Time Division Multiple Access
- a time-division multiplex frame thus consists of 24 channels (see
- Channel 1 to channel 12 are transmitted from the base station FS to the mobile stations MS, while channel 13 to channel 24 are transmitted in the opposite direction from the mobile stations MS to the base station FS.
- the frame duration is 10 ms.
- the duration of a channel (time slot, slot) is 417 ⁇ s.
- 320 bit information e.g. voice
- 100 bit control data synchronization, signaling and error control
- the useful bit rate for a participant (channel) results from the 320 bit information within 10 ms. It is thus 32 kilobits per second.
- each time slot contains, in addition to the 320 information bits mentioned above, a further 104 bits required for signal transmission and 56 bits of a guard field, so that each time slot contains a total of 480 bits.
- the DECT standard may have to be modified and adapted to local conditions.
- the transmission cannot take place in the normal DECT range between 1.88 and 1.90 GHz, but rather the generally accessible one
- the FCC part 15 stipulates how much transmission power can be transmitted on a certain channel during a certain period of time. This requirement could also not be met by directly adopting the DECT standard.
- One way of realizing an air interface that meets the above-mentioned regulations is to use a higher-quality modulation method, e.g. a QPSK-based system in which the carrier frequency is changed at predetermined time intervals (frequency hopping spread spectrum).
- the use of the higher-quality modulation method halves the bandwidth required, for example when using a QPSK system.
- the object of the present invention is therefore to provide a mobile radio device and a method which make it possible to create a QPSK air interface using an existing DECT controller.
- a mobile radio device for wireless transmission of QPSK data.
- the mobile radio device has a controller which is designed and developed for the transmission of GFSK-modulated data, for example in accordance with the DECT standard.
- a ballast module is provided which converts GFSK-modulated data output by the controller into QPSK-modulated data to be transmitted or converts the received QPSK-modulated data into GFSK-modulated data and sends it to the controller.
- the ballast module must be designed so that after the conversion of the QPSK-modulated data into GFSK-modulated data according to the DECT standard, the QPSK-modulated data is synchronized, which can be done by a synchronization signal from the ballast module to the controller.
- the ballast module can control an RF module in such a way that the data is modulated onto a carrier frequency FX that lies outside the DECT band.
- the carrier frequency can be, for example, in a 2.4 GHz band (ISM band).
- the ballast module can be implemented by an ASIC.
- the ballast module can convert GFSK-modulated data into ⁇ / 4-QPSK-modulated data or convert received ⁇ / 4-QPSK-modulated data into GFSK-modulated data.
- a method for wireless transmission of QPSK-modulated data by means of a controller is also provided, which is designed for the transmission of GFSK-modulated data, for example in accordance with the DECT standard.
- a ballast module converts GFSK-modulated data output by the controller into QPSK-modulated data to be transmitted or converts received QPSK-modulated data into GFSK-modulated data and transfers it to the controller.
- the carrier frequency fx can be changed after a predetermined time period, the predetermined time period being a time slot or a frame (or a multiple thereof) of the DECT time frame.
- Fig. 1 shows an arrangement for digital
- 4 shows a state transition diagram of the ⁇ / 4 DQPSK modulation
- 5 shows a detailed illustration of a section of a mobile radio device according to the invention
- FIG. 6 shows a further development of the device from FIG. 5, in which a ballast module sends a synchronization signal to the controller.
- FIG. 1 An arrangement for digital radio transmission of data is provided in FIG. 1.
- a base station 1 is connected to the fixed network by means of a terminal line 10.
- Base station 1 has an RF module 4, by means of which data can be transmitted or received by means of an antenna 6.
- radio transmission to a mobile station 2 can take place via a radio transmission link 8 or radio transmission to a mobile station (cordless telephone) 3 via a second radio transmission link 9.
- All of the mobile stations shown in FIG. 1 have the same structure, so that a more detailed explanation is only to be given on the basis of the mobile station 2 shown.
- this mobile station 2 has an antenna 7 for receiving or transmitting data from or to the base station 1.
- An RF module 5 is provided in the mobile station 2, which essentially corresponds to the RF module 4 used in the base station 1.
- base station 1 denotes a modulator, the exact function of which is explained below.
- mobile station 2 21 denotes a demodulator, which performs the inverse function of that of the modulator 20.
- the base station 1 and each mobile station 2, 3 naturally have a modulator and a demodulator, as is known for radio transmission systems.
- the present invention is intended to provide an air interface possibility in order to adapt the known DECT standard to the regulations which apply to the American ISM band. The problem arises here that the base bandwidth of 1.2 MHz, which is required according to the DECT standard to provide the bit rate of 1.152 megabits per second, the maximum base bandwidth prescribed by the American regulation FCC part 15 of Exceeds 1 MHz.
- a higher-value modulation method (in comparison to the GMSK modulation method of the DECT standard) is a modulation method in which there are more than two (ie 4, 8, ...) discrete carrier states and thus at least two bits combined into one symbol and transmitted together as one symbol in one step.
- a higher-order modulation method in this sense is, for example, the quadrature phase shift keying QPSK (4 PSK), which is shown in FIG. 3.
- QPSK modulation method the input data are provided as bipolar pulses, i. H. the logical 1 is represented by + 1 and the logical 0 by -1.
- serial / parallel conversion the serial data stream is initially divided into bits of even and odd positions. After this conversion, two data signals are present, each with half the data rate of the original signal.
- FIG. 4 Another example of a higher-value modulation method is the ⁇ / 4-DQPSK modulation method shown in FIG. 4.
- the aim of this modulation method is to avoid phase jumps of 180 °, which lead to amplitude drops.
- two bits are combined to form a symbol and cause a phase jump compared to the last transmission phase by ⁇ 45 ° or ⁇ 135 °, as shown in the state transition diagram in FIG. 4.
- the 8 PSK or 16 PSK modulation methods in which there are 8 or 16 discrete carrier states and thus 3 or 4 bits are combined and transmitted to form a symbol, should be mentioned as further examples of higher-value modulation methods.
- Components developed and produced for the DECT standard can continue to be used in a cost-effective manner since the time slot and frame structure of the transmission are not changed compared to the DECT standard.
- a suitable module which enables signals from an existing DECT controller to be to transfer based systems (e.g. PWT).
- This module can be implemented, for example, in the form of an ASIC or in any other form.
- This module must implement the following functions:
- FIG. 5 shows a mobile radio device which can be a base station or a mobile station.
- a DECT baseband controller 22 is provided.
- This baseband controller 22 has, among other things, a modulator / demodulator.
- an additional ballast module 23 is provided, which can be implemented, for example, by an ASIC.
- the DECT baseband controller 22 transmits GFSK-modulated data to the ASIC 23 in the transmission state.
- the ASIC 23 converts the GFSK-modulated data into QPSK-modulated data and transmits it to the high-frequency module 4, 5.
- the high-frequency module 4, 5 then outputs this QPSK-modulated data to the antenna 6, 7.
- the base- band controller 22 is also connected to the ballast module 23 by means of a control line 24, which is used for setting the DECT carrier.
- the ASIC 23 continues to transmit carrier frequency information f x by means of a control line 25 to the high-frequency module 4, 5 in order to control it to the corresponding carrier frequency. For example, transmission in the ISM-2.4 GHz band can thus take place.
- the ASIC 23 When receiving QPSK-modulated data, which the high-frequency module 4, 5 transmits to the ASIC 23 and which can also contain a synchronization word in addition to the user data, the ASIC 23 continues to provide synchronization information together with the actual user data GFSK-modulated to the DECT base station. band controller 22.
- the GFSK modulator / demodulator 20, 21 of the DECT baseband controller 22 outputs GFSK-modulated data to the ASIC 23.
- the ASIC 23 converts the GFSK-modulated data into QPSK-modulated data and transmits it them to the high-frequency module 4, 5 of the DECT baseband controller.
- the high-frequency module 4, 5 then outputs this QPSK-modulated data to the antenna 6, 7.
- the ASIC 23 continues to transmit carrier frequency information f x to the high-frequency module 4, 5 in order to drive it to the corresponding carrier frequency. For example, transmission in the ISM 2.4 GHz band can thus take place.
- the ASIC 23 When QPSK-modulated data is received, which the high-frequency module 4, 5 transmits to the ASIC 23, the ASIC 23 continues to provide synchronization information to the QPSK modulator / demodulator 20, 21 of the DECT baseband controller 22.
- the problem may arise that the synchronization method as used in the DECT baseband controller 22 must continue to function, ie the DECT controller must now synchronize itself with the data stream converted by the ballast module 23.
- the QPSK-modulated data is sent / received at half the data rate, since a QPSK symbol corresponds to exactly 2 DECT bits. This means that some DECT bits can be lost on reception that are generated by the
- DECT baseband controllers 22 are required for synchronization.
- the ballast module 23 which implements the conversion between the QPSK and the GFSK modulation method, transmits the DECT baseband controller 22 in its synchronized state permanently to a DECT synchronization signal (1, 0 - Episode).
- the DECT baseband controller 22 can thus synchronize with this sequence of the DECT synchronization signal from the ballast module 23.
- the ballast module 23 can synchronize with the received QPSK signal (symbol synchronization). If the timing of the synchronization changes, as detected by the ballast module 23 on the basis of the received QPSK signal, the timing of the DECT synchronization signal which the ballast module 23 outputs to the DECT baseband controller 22 is adjusted accordingly. So there is only the synchronization word
- an inexpensive module can thus be created using a DECT baseband controller in accordance with a QPSK modulation method.
- Antenna mobile station 8 first radio transmission link
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP99969868A EP1116366A1 (en) | 1998-09-25 | 1999-09-23 | Conversion of gfsk-modulated signals into qpsk-modulated signals |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19844097.9 | 1998-09-25 | ||
DE1998144097 DE19844097A1 (en) | 1998-09-25 | 1998-09-25 | Mobile radio communications device |
DE19844165 | 1998-09-25 | ||
DE19844165.7 | 1998-09-25 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000019674A1 true WO2000019674A1 (en) | 2000-04-06 |
Family
ID=26049092
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/DE1999/003057 WO2000019674A1 (en) | 1998-09-25 | 1999-09-23 | Conversion of gfsk-modulated signals into qpsk-modulated signals |
Country Status (2)
Country | Link |
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EP (1) | EP1116366A1 (en) |
WO (1) | WO2000019674A1 (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4513315A (en) * | 1981-06-25 | 1985-04-23 | U.S. Philips Corporation | Community antenna television arrangement for the reception and distribution of TV - and digital audio signals |
US4592009A (en) * | 1983-11-17 | 1986-05-27 | E-Systems, Inc. | MSK surface acoustic wave convolver |
US5499047A (en) * | 1993-12-30 | 1996-03-12 | Northern Telecom Limited | Distribution network comprising coax and optical fiber paths for transmission of television and additional signals |
-
1999
- 1999-09-23 WO PCT/DE1999/003057 patent/WO2000019674A1/en not_active Application Discontinuation
- 1999-09-23 EP EP99969868A patent/EP1116366A1/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4513315A (en) * | 1981-06-25 | 1985-04-23 | U.S. Philips Corporation | Community antenna television arrangement for the reception and distribution of TV - and digital audio signals |
US4592009A (en) * | 1983-11-17 | 1986-05-27 | E-Systems, Inc. | MSK surface acoustic wave convolver |
US5499047A (en) * | 1993-12-30 | 1996-03-12 | Northern Telecom Limited | Distribution network comprising coax and optical fiber paths for transmission of television and additional signals |
Also Published As
Publication number | Publication date |
---|---|
EP1116366A1 (en) | 2001-07-18 |
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