CA2306485A1 - Dual mode mobile telephone - Google Patents
Dual mode mobile telephone Download PDFInfo
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- CA2306485A1 CA2306485A1 CA002306485A CA2306485A CA2306485A1 CA 2306485 A1 CA2306485 A1 CA 2306485A1 CA 002306485 A CA002306485 A CA 002306485A CA 2306485 A CA2306485 A CA 2306485A CA 2306485 A1 CA2306485 A1 CA 2306485A1
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- transmission
- time
- division multiplex
- mobile telephone
- reception
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- 230000009977 dual effect Effects 0.000 title abstract description 12
- 230000005540 biological transmission Effects 0.000 claims abstract description 96
- 238000000034 method Methods 0.000 claims description 15
- 238000006243 chemical reaction Methods 0.000 claims description 5
- 230000001419 dependent effect Effects 0.000 claims 1
- 230000008054 signal transmission Effects 0.000 description 4
- 238000004891 communication Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 230000011664 signaling Effects 0.000 description 2
- 230000010267 cellular communication Effects 0.000 description 1
- VJYFKVYYMZPMAB-UHFFFAOYSA-N ethoprophos Chemical compound CCCSP(=O)(OCC)SCCC VJYFKVYYMZPMAB-UHFFFAOYSA-N 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
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
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
- H04B1/403—Circuits using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency
- H04B1/406—Circuits using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency with more than one transmission mode, e.g. analog and digital modes
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- 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
- H04W88/02—Terminal devices
- H04W88/06—Terminal devices adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
- Transceivers (AREA)
- Time-Division Multiplex Systems (AREA)
Abstract
A mobile telephone, as well as a radio transmission process, are particularly suitable for so-called dual use appliances. The mobile telephone has a first transmitter/receiver (3) for transmitting/receiving mobile radio signals in a time multiplex frame of a duration t1 with a number of time slots of a duration t2 in a first frequency range, and a second transmitter/receiver (4) for transmitting/receiving signals in a second frequency range. A converter (2) converts the signals received by the second H.F. unit (4) in reception time slots of a time multiplex frame into useful signals, and useful signals for transmission in transmission time slots of a time multiplex frame by means of the second transmitter/receiver (4). The duration of a time multiplex frame equals n x t1, n being an integer 1, and the transmission and reception time slots are transmitted with the same H.F. carrier frequency. The mobile telephone and radio transmission process make it possible to use a mobile telephone in a dual mode as a mobile and as a cordless telephone, with as little as possible technical complexity and therefore low cost.
Description
DUAL MODE MOBILE TELEPHONE
The invention is directed to a dual mode mobile telephone that can be employed both as mobile telephone, for example according tot he GSM Standard, as well as as mobile part of a cordless telephone system. To that end, the mobile telephone comprises a first transmission/reception means for transmitting/receiving mobile telephone signals in time-division multiplex frames having a duration t, with a plurality of time slots having a duration of t2 in a first frequency range, and comprises a second transmission/reception means for transmitting/receiving signals in a second frequency range wherein the cordless telephone system works.
The invention is also directed to a radio transmission method for cordless telephones, whereby signals between a mobile part and a base station are transmitted in one or more frequency channels in time-division multiplex frames having a defined length with reception time slots and transmission time slots, and is also directed to an air interface for cordless telephony.
The mobile telephone standard GSM (Global system for Mobile Communications) has enjoyed worldwide acceptance. What is thereby involved is an internationally applied specification wherein the critical system features of the mobile radio telephone system are standardized. As a result thereof, it is possible to use mobile telephones internationally (roaming). The completely digital GSM system 2 0 also enables a high subscriber density, high dependability against tapping and a satisfactory voice quality. In addition to the transmission of voice signals, a data transmission to/from, for example, mobile fax devices or the like is also possible.
The air interface, i.e. the transmission protocol for the radio signal transmission, is briefly explained below with reference to Figure 3. The GSM
2 5 networks operated in Germany and in most European countries work in two transmission bands between 890 and 915 MHZ and 935 and 960 MHZ. However, it is also possible to select other frequencies. For example, the DCS-1800 System likewise works according to the GSM Standard in a frequency range of 1800 MHZ
(E-networks).
For assuring an adequate use comfort, the voice signals must be transmitted quasi-simultaneously in both directions between the respective participants in the call (fully capable of duplex). In the GSM system, the lower frequency band from 890 through 91 S MHZ serves for the signal transmission from the mobile part to the transmission station (upstream connection or, respectively, uplink), and the upper frequency band between 935 and 960 MHZ serves for the signal transmission from the transmission station to the mobile part (downstream connection or, respectively, downlink). A total of 124 frequency channels having a spacing of 200 kHz from one another are available in each of the two bands.
Each of 1 o these frequency channels is in turn divided into time-division multiplex frames or TDMA frames having a duration of 4.615 ms. Each time-division multiplex frame is in turn composed of eight time slots having a duration of 577 bus. For a signal transmission between a mobile part and a transmission/reception station, a respective time slot is required in the lower frequency band for transmission (from the point of view of the mobile part) and a time slot is required in the upper frequency band for the reception of signals. In addition to the frequency spacing of 45 MHZ (FDD =
Frequency Division Duplex), transmission and reception slot exhibit a time offset of three time slots, i.e. approximately 1.73 ms. Further details are described, for example, in DavidBenkner, "Digitale Mobilfunksysteme", Stuttgart, 1996, Chapter 8.1.
The DECT (Digital European Cordless Telephone) Standard is widespread in Europe for cordless telephony. The air interface defined therein employs a different time-division multiplex frame format having a frame duration of 10 ms that is in turn divided into 24 time slots having a duration of 416.6 ~s.
2 5 For a telephone user who employs both a cordless telephone system at home and/or at the workplace as well as a mobile telephone underway, it would be advantageous to offer a mobile telephone that can be utilized both as mobile part of a cordless telephone system as well as as a GSM mobile telephone. Since, however, the GSM mobile telephone system and, for example, the DECT cordless telephone system are not compatible with one another, such a dual use mobile telephone must have not only two RF transmission/reception units but, additionally, must have two different converter devices for signal conversion into/from the respectively different time-division multiplex frame structures. Such a dual mode mobile telephone is therefore very complicated in design and is thus comparatively heavy, has large dimensions and is expensive.
EP-0 415 502 A2 discloses a cellular communication system, whereby at least one base station to which a plurality of mobile stations can be respectively connected is provided in each cell of the communication system. The communication system is thereby fashioned such that, for example, a GSM signalling protocol is adapted to DECT channels. To that end, the mobile stations can preferably be fashioned such that they function both as GSM mobile stations and DECT mobile stations.
The present invention is therefore based on the object of proposing a mobile telephone of the species initially cited that allows a dual mode operation as GSM mobile telephone and as mobile part of a cordless telephone system with optimally little outlay.
The invention is also based on the object of proposing a radio transmission method for cordless telephones that facilitates the employment of dual mode mobile 2 0 parts.
This object is achieved by a mobile telephone defined in claim 1 that comprises a converter device for converting signals received by the second transmission/reception means in reception time slots of a time-division multiplex frame into payload signals and for converting payload signals into transmission time 2 5 slots of a time-division multiplex frame for transmitting the signals with the second transmission/reception means, whereby the duration of a time-division multiplex frame amounts to n x t" whereby n is a whole number z 1, and whereby the duration of a transmission and reception time slot amounts to m x tz, whereby m is a whole numbers 1, and whereby the respectively appertaining transmission and reception 3 0 time slots are transmitted with the same RF Garner frequency.
3a Transmission and reception time slots, in contrast to the GSM system, inventively comprise no frequency difference. This enables a simpler structure of the second RF unit for the connection with the cordless telephone fixed station.
The inventive mobile telephone has the advantage that the time-division multiplex frame structure processed by the converter means is derived from that of the mobile radio telephone system, preferably GSM, so that a common clocking can be employed both for the conversion of the mobile radio telephone signals as well as of the cordless telephone signals. The converter means is advantageously fashioned such that this can process both the GSM signals as well as the cordless telephone signals. The structure of the inventive mobile telephone is thus simplified further.
The second transmission/reception means preferably works at a transmission/reception frequency of approximately 2.4 GHz. This corresponds to what is referred to as the ISM (Industrial, Scientific and Medical) frequency band that is internationally reserved for cordless telephone applications and the like.
The inventive mobile telephone can thus be internationally used.
Preferably, a time-division multiplex frame has a duration of 4.61 S ms.
However, multiples of this time duration are also possible. A transmission and reception time slot can preferably have a duration of 577 us. However, whole-multiples of this duration are likewise possible here, for example 1154 ~s.
Like the GSM system, the converter means preferably works with a data rate of 271 kBit/s. Since, however, fewer signaling and matching data are required, the usable data rate can be higher than in GSM.
Transmission and reception time slots can respectively follow one another in alternation. However, it is also possible that a group of two or four reception slots follows a group of - likewise - two or four transmission slots. The sequence of 2 0 transmission and reception slots thereby plays no part. A further possibility is to provide only transmission slots in one time-division multiplex frame and only reception time slots in the time-division multiplex frame following thereupon.
Advantageously, the inventive mobile telephone comprises a switchover means for automatically switching between a first operating condition as mobile 2 5 telephone and a second operating condition as mobile part of a cordless telephone system. This enables a very comfortable use of the dual mode mobile telephone since the user need not switch between mobile telephone and cordless telephone operation himself. The switchover means acquires the level of a signal of the cordless telephone fixed station received by the second transmission/reception means. When this signal level lies above a defined value, the dual mode mobile telephone works as cordless telephone mobile part; otherwise, it works as mobile telephone.
The inventive mobile telephone can be employed as part of a cordless telephone system. The cordless telephone system can thereby advantageously 5 comprise only one radio frequency unit for connection to the second radio frequency unit of the mobile telephone.
The invention, further, proposes a radio transmission method for cordless telephones, whereby the duration of a time-division multiplex frame is n x t"
the duration of the transmission and reception time slots is m x tz, and the transmission and reception time slots are transmitted with the same Garner frequency, whereby m, n are whole numbers z 1, t, is the duration of a GSM time-division multiplex frame and t2 is the length of a,GSM time slot.
Preferably, a time-division multiplex frame comprises a.duration of 4.615 ms or a multiple thereof, a time slot comprises a duration of 577 ps or a whole multiple thereof. The transmission data rate preferably amounts to 271 kBit/s.
Transmission and reception time slots can thereby respectively follow one another in alternation individually or in groups. It is also possible that one time-division multiplex frame only contains a plurality of transmission slots and the time-division multiplex frame following thereupon contains a plurality of reception slots.
2 0 The inventive mobile telephone and the inventive radio transmission method are explained on the basis of exemplary embodiments with reference to the attached drawings, wherein Figure 1 is a schematic illustration of an inventive mobile telephone;
Figure 2 is a schematic illustration of inventive time-division multiplex 2 5 frame structures; and Figure 3 is a schematic illustration of the time-division multiplex frame structure of the GSM air interface.
As first transmission/reception means, the mobile telephone 1 shown in Figure 1 comprises a known, first RF unit 3 for sending and receiving signals 3 0 according to the GSM Standard that is connected to a transmission/reception antenna S. Further, the inventive mobile telephone contains a central control unit (not shown) for controlling the operating functions, a keyboard as input interface, a display means 6 as well as a power supply means (not shown) and a suitable housing.
Over and above this, the inventive mobile telephone comprises a second RF unit 4 as second transmission/reception means that is connected to the same transmission/reception antenna 5 but transmits and receives at a frequency of approximately 2.4 GHz, what is referred to as the ISM band. First and second RF unit 3, 4, however, can also be fashioned as a shared component. They comprise an 1 o encoder/decoder and are connected to a shared conversion means 2 that converts a signal received and decoded by the first or second RF unit into payload signals, particularly voice signals that are output at a loudspeaker 8 of the mobile telephone.
However, the inventive mobile telephone is not limited to the transmission of voice signals; rather, data signals for a portable computer, fax device or the like that can be connected to the mobile telephone can also be transmitted.
The converter means 2 also serves the purpose of converting payload signals, like voice signals received at a microphone 7 of the mobile telephone or low-frequency data signals as well, into periodically repeating transmission time slots of a multiplex frame, for example with a memory means and what is referred to as a burst 2 0 mode controller. The readout data rate thereby preferably amounts to 271 kBit/s corresponding to the GSM Standard. The burst signals obtained in this way are encoded by the second RF unit 4 and are sent with the 2.4 GHz carrier frequency.
The length of a time-division multiplex frame that the converter means 2 processes amounts to n x t,, whereby n is a whole number z 1 and t, is the frame duration in the 2 5 GSM system, i.e. is approximately 4.615 ms. The length of a transmission slot amounts to m x tz, whereby m is a whole number >_ 1 and t2 is the time slot length of the GSM Standard, i.e. approximately 577 ~s. By employing a time structure of the air interface derived from the GSM Standard, it is possible to employ the converter means in common both for the GSM signals sent/received at the first RF unit 3 as well for the cordless telephone signals sent/received at the second RF unit 4, at least in critical components. In particular, the same time control can be employed for both operating modes of the inventive dual mode mobile telephone.
The inventive mobile telephone 1 preferably comprises a switchover means 9 for automatically switching between GSM operation and cordless telephone operation. The level of a signal received at the second RF module is acquired and compared to a predetermined value. When the level of the received cordless telephone signal lies above the defined value, a determination is made that the mobile telephone is within range of the appertaining cordless telephone system, and the mobile telephone is thus switched into the cordless telephone operating condition.
When a signal level below the limit value is acquired, it is assumed that the inventive mobile telephone is not within the transmission range of the cordless telephone system fixed station, and it is placed into mobile telephone operating mode.
Exemplary time-division multiplex frame structures of the inventive air interface are described below with reference to Figure 2 for cordless telephony.
A cordless telephone signal shown in Figure 2a is composed of time-division multiplex frames having a length of 4.615 ms corresponding to the GSM
frame duration. A frame is divided into four transmission slots TO through T3 having a respective duration of 577 ps and into four following reception slots RO
through R3 2 0 likewise having a duration of 577 ps. Let it be noted that the sequence can also be reversed, so that the reception slots precede the transmission slots (respectively with reference to the mobile telephone). The transmission preferably ensues in the 2.4 GHz ISM band in one or - preferably, more frequency bands. However, what is critical is that, by contrast to the GSM system, the transmission slots and reception 2 5 slots are used in the same frequency channel, so that the second RF unit need not work with different transmission and reception frequencies.
Figure 2) shows a time-division multiplex frame that likewise has a duration of 4.1 S ms, whereby, however, the transmission slots TO and T 1 and the reception slots RO and R1 have a respective length of 1.154 ms.
Given the example of Figure lc), a transmission slot T0, T1,... and a reception slot R0, Rl,... respectively alternate. In the example of Figure ld), a first time-division multiplex frame, likewise having a duration of 4.615 ms, contains eight transmission slots TO through T7, and the following time-division multiplex frame contains eight reception slots RO through R7.
What is critical is that the structure of the time-division multiplex frames employed for the cordless telephone transmission corresponds to that of the mobile telephone standard or, respectively, whole multiples thereof, so that the same time control can be employed for the mobile telephone transmission and the cordless 1 o telephone transmission. Advantageously, the same converter means can be employed for both types of transmission.
The invention is directed to a dual mode mobile telephone that can be employed both as mobile telephone, for example according tot he GSM Standard, as well as as mobile part of a cordless telephone system. To that end, the mobile telephone comprises a first transmission/reception means for transmitting/receiving mobile telephone signals in time-division multiplex frames having a duration t, with a plurality of time slots having a duration of t2 in a first frequency range, and comprises a second transmission/reception means for transmitting/receiving signals in a second frequency range wherein the cordless telephone system works.
The invention is also directed to a radio transmission method for cordless telephones, whereby signals between a mobile part and a base station are transmitted in one or more frequency channels in time-division multiplex frames having a defined length with reception time slots and transmission time slots, and is also directed to an air interface for cordless telephony.
The mobile telephone standard GSM (Global system for Mobile Communications) has enjoyed worldwide acceptance. What is thereby involved is an internationally applied specification wherein the critical system features of the mobile radio telephone system are standardized. As a result thereof, it is possible to use mobile telephones internationally (roaming). The completely digital GSM system 2 0 also enables a high subscriber density, high dependability against tapping and a satisfactory voice quality. In addition to the transmission of voice signals, a data transmission to/from, for example, mobile fax devices or the like is also possible.
The air interface, i.e. the transmission protocol for the radio signal transmission, is briefly explained below with reference to Figure 3. The GSM
2 5 networks operated in Germany and in most European countries work in two transmission bands between 890 and 915 MHZ and 935 and 960 MHZ. However, it is also possible to select other frequencies. For example, the DCS-1800 System likewise works according to the GSM Standard in a frequency range of 1800 MHZ
(E-networks).
For assuring an adequate use comfort, the voice signals must be transmitted quasi-simultaneously in both directions between the respective participants in the call (fully capable of duplex). In the GSM system, the lower frequency band from 890 through 91 S MHZ serves for the signal transmission from the mobile part to the transmission station (upstream connection or, respectively, uplink), and the upper frequency band between 935 and 960 MHZ serves for the signal transmission from the transmission station to the mobile part (downstream connection or, respectively, downlink). A total of 124 frequency channels having a spacing of 200 kHz from one another are available in each of the two bands.
Each of 1 o these frequency channels is in turn divided into time-division multiplex frames or TDMA frames having a duration of 4.615 ms. Each time-division multiplex frame is in turn composed of eight time slots having a duration of 577 bus. For a signal transmission between a mobile part and a transmission/reception station, a respective time slot is required in the lower frequency band for transmission (from the point of view of the mobile part) and a time slot is required in the upper frequency band for the reception of signals. In addition to the frequency spacing of 45 MHZ (FDD =
Frequency Division Duplex), transmission and reception slot exhibit a time offset of three time slots, i.e. approximately 1.73 ms. Further details are described, for example, in DavidBenkner, "Digitale Mobilfunksysteme", Stuttgart, 1996, Chapter 8.1.
The DECT (Digital European Cordless Telephone) Standard is widespread in Europe for cordless telephony. The air interface defined therein employs a different time-division multiplex frame format having a frame duration of 10 ms that is in turn divided into 24 time slots having a duration of 416.6 ~s.
2 5 For a telephone user who employs both a cordless telephone system at home and/or at the workplace as well as a mobile telephone underway, it would be advantageous to offer a mobile telephone that can be utilized both as mobile part of a cordless telephone system as well as as a GSM mobile telephone. Since, however, the GSM mobile telephone system and, for example, the DECT cordless telephone system are not compatible with one another, such a dual use mobile telephone must have not only two RF transmission/reception units but, additionally, must have two different converter devices for signal conversion into/from the respectively different time-division multiplex frame structures. Such a dual mode mobile telephone is therefore very complicated in design and is thus comparatively heavy, has large dimensions and is expensive.
EP-0 415 502 A2 discloses a cellular communication system, whereby at least one base station to which a plurality of mobile stations can be respectively connected is provided in each cell of the communication system. The communication system is thereby fashioned such that, for example, a GSM signalling protocol is adapted to DECT channels. To that end, the mobile stations can preferably be fashioned such that they function both as GSM mobile stations and DECT mobile stations.
The present invention is therefore based on the object of proposing a mobile telephone of the species initially cited that allows a dual mode operation as GSM mobile telephone and as mobile part of a cordless telephone system with optimally little outlay.
The invention is also based on the object of proposing a radio transmission method for cordless telephones that facilitates the employment of dual mode mobile 2 0 parts.
This object is achieved by a mobile telephone defined in claim 1 that comprises a converter device for converting signals received by the second transmission/reception means in reception time slots of a time-division multiplex frame into payload signals and for converting payload signals into transmission time 2 5 slots of a time-division multiplex frame for transmitting the signals with the second transmission/reception means, whereby the duration of a time-division multiplex frame amounts to n x t" whereby n is a whole number z 1, and whereby the duration of a transmission and reception time slot amounts to m x tz, whereby m is a whole numbers 1, and whereby the respectively appertaining transmission and reception 3 0 time slots are transmitted with the same RF Garner frequency.
3a Transmission and reception time slots, in contrast to the GSM system, inventively comprise no frequency difference. This enables a simpler structure of the second RF unit for the connection with the cordless telephone fixed station.
The inventive mobile telephone has the advantage that the time-division multiplex frame structure processed by the converter means is derived from that of the mobile radio telephone system, preferably GSM, so that a common clocking can be employed both for the conversion of the mobile radio telephone signals as well as of the cordless telephone signals. The converter means is advantageously fashioned such that this can process both the GSM signals as well as the cordless telephone signals. The structure of the inventive mobile telephone is thus simplified further.
The second transmission/reception means preferably works at a transmission/reception frequency of approximately 2.4 GHz. This corresponds to what is referred to as the ISM (Industrial, Scientific and Medical) frequency band that is internationally reserved for cordless telephone applications and the like.
The inventive mobile telephone can thus be internationally used.
Preferably, a time-division multiplex frame has a duration of 4.61 S ms.
However, multiples of this time duration are also possible. A transmission and reception time slot can preferably have a duration of 577 us. However, whole-multiples of this duration are likewise possible here, for example 1154 ~s.
Like the GSM system, the converter means preferably works with a data rate of 271 kBit/s. Since, however, fewer signaling and matching data are required, the usable data rate can be higher than in GSM.
Transmission and reception time slots can respectively follow one another in alternation. However, it is also possible that a group of two or four reception slots follows a group of - likewise - two or four transmission slots. The sequence of 2 0 transmission and reception slots thereby plays no part. A further possibility is to provide only transmission slots in one time-division multiplex frame and only reception time slots in the time-division multiplex frame following thereupon.
Advantageously, the inventive mobile telephone comprises a switchover means for automatically switching between a first operating condition as mobile 2 5 telephone and a second operating condition as mobile part of a cordless telephone system. This enables a very comfortable use of the dual mode mobile telephone since the user need not switch between mobile telephone and cordless telephone operation himself. The switchover means acquires the level of a signal of the cordless telephone fixed station received by the second transmission/reception means. When this signal level lies above a defined value, the dual mode mobile telephone works as cordless telephone mobile part; otherwise, it works as mobile telephone.
The inventive mobile telephone can be employed as part of a cordless telephone system. The cordless telephone system can thereby advantageously 5 comprise only one radio frequency unit for connection to the second radio frequency unit of the mobile telephone.
The invention, further, proposes a radio transmission method for cordless telephones, whereby the duration of a time-division multiplex frame is n x t"
the duration of the transmission and reception time slots is m x tz, and the transmission and reception time slots are transmitted with the same Garner frequency, whereby m, n are whole numbers z 1, t, is the duration of a GSM time-division multiplex frame and t2 is the length of a,GSM time slot.
Preferably, a time-division multiplex frame comprises a.duration of 4.615 ms or a multiple thereof, a time slot comprises a duration of 577 ps or a whole multiple thereof. The transmission data rate preferably amounts to 271 kBit/s.
Transmission and reception time slots can thereby respectively follow one another in alternation individually or in groups. It is also possible that one time-division multiplex frame only contains a plurality of transmission slots and the time-division multiplex frame following thereupon contains a plurality of reception slots.
2 0 The inventive mobile telephone and the inventive radio transmission method are explained on the basis of exemplary embodiments with reference to the attached drawings, wherein Figure 1 is a schematic illustration of an inventive mobile telephone;
Figure 2 is a schematic illustration of inventive time-division multiplex 2 5 frame structures; and Figure 3 is a schematic illustration of the time-division multiplex frame structure of the GSM air interface.
As first transmission/reception means, the mobile telephone 1 shown in Figure 1 comprises a known, first RF unit 3 for sending and receiving signals 3 0 according to the GSM Standard that is connected to a transmission/reception antenna S. Further, the inventive mobile telephone contains a central control unit (not shown) for controlling the operating functions, a keyboard as input interface, a display means 6 as well as a power supply means (not shown) and a suitable housing.
Over and above this, the inventive mobile telephone comprises a second RF unit 4 as second transmission/reception means that is connected to the same transmission/reception antenna 5 but transmits and receives at a frequency of approximately 2.4 GHz, what is referred to as the ISM band. First and second RF unit 3, 4, however, can also be fashioned as a shared component. They comprise an 1 o encoder/decoder and are connected to a shared conversion means 2 that converts a signal received and decoded by the first or second RF unit into payload signals, particularly voice signals that are output at a loudspeaker 8 of the mobile telephone.
However, the inventive mobile telephone is not limited to the transmission of voice signals; rather, data signals for a portable computer, fax device or the like that can be connected to the mobile telephone can also be transmitted.
The converter means 2 also serves the purpose of converting payload signals, like voice signals received at a microphone 7 of the mobile telephone or low-frequency data signals as well, into periodically repeating transmission time slots of a multiplex frame, for example with a memory means and what is referred to as a burst 2 0 mode controller. The readout data rate thereby preferably amounts to 271 kBit/s corresponding to the GSM Standard. The burst signals obtained in this way are encoded by the second RF unit 4 and are sent with the 2.4 GHz carrier frequency.
The length of a time-division multiplex frame that the converter means 2 processes amounts to n x t,, whereby n is a whole number z 1 and t, is the frame duration in the 2 5 GSM system, i.e. is approximately 4.615 ms. The length of a transmission slot amounts to m x tz, whereby m is a whole number >_ 1 and t2 is the time slot length of the GSM Standard, i.e. approximately 577 ~s. By employing a time structure of the air interface derived from the GSM Standard, it is possible to employ the converter means in common both for the GSM signals sent/received at the first RF unit 3 as well for the cordless telephone signals sent/received at the second RF unit 4, at least in critical components. In particular, the same time control can be employed for both operating modes of the inventive dual mode mobile telephone.
The inventive mobile telephone 1 preferably comprises a switchover means 9 for automatically switching between GSM operation and cordless telephone operation. The level of a signal received at the second RF module is acquired and compared to a predetermined value. When the level of the received cordless telephone signal lies above the defined value, a determination is made that the mobile telephone is within range of the appertaining cordless telephone system, and the mobile telephone is thus switched into the cordless telephone operating condition.
When a signal level below the limit value is acquired, it is assumed that the inventive mobile telephone is not within the transmission range of the cordless telephone system fixed station, and it is placed into mobile telephone operating mode.
Exemplary time-division multiplex frame structures of the inventive air interface are described below with reference to Figure 2 for cordless telephony.
A cordless telephone signal shown in Figure 2a is composed of time-division multiplex frames having a length of 4.615 ms corresponding to the GSM
frame duration. A frame is divided into four transmission slots TO through T3 having a respective duration of 577 ps and into four following reception slots RO
through R3 2 0 likewise having a duration of 577 ps. Let it be noted that the sequence can also be reversed, so that the reception slots precede the transmission slots (respectively with reference to the mobile telephone). The transmission preferably ensues in the 2.4 GHz ISM band in one or - preferably, more frequency bands. However, what is critical is that, by contrast to the GSM system, the transmission slots and reception 2 5 slots are used in the same frequency channel, so that the second RF unit need not work with different transmission and reception frequencies.
Figure 2) shows a time-division multiplex frame that likewise has a duration of 4.1 S ms, whereby, however, the transmission slots TO and T 1 and the reception slots RO and R1 have a respective length of 1.154 ms.
Given the example of Figure lc), a transmission slot T0, T1,... and a reception slot R0, Rl,... respectively alternate. In the example of Figure ld), a first time-division multiplex frame, likewise having a duration of 4.615 ms, contains eight transmission slots TO through T7, and the following time-division multiplex frame contains eight reception slots RO through R7.
What is critical is that the structure of the time-division multiplex frames employed for the cordless telephone transmission corresponds to that of the mobile telephone standard or, respectively, whole multiples thereof, so that the same time control can be employed for the mobile telephone transmission and the cordless 1 o telephone transmission. Advantageously, the same converter means can be employed for both types of transmission.
Claims (22)
1. Mobile telephone, comprising a first means (3) for sending/receiving mobile radio telephone signals in time-division multiplex frames having a duration t1 with a plurality of time slots having a duration t2 in a first frequency range, a second means (4) for sending/receiving signals in a second frequency range, characterized by a converter means (2) for converting signals received by the second transmission/reception means (4) in reception time slots into payload signals and for converting payload signals in transmission time slots of a time-division multiplex frame for transmission by the second transmission/reception means 94), whereby - the duration of a time-division multiplex frame is n x t1, whereby n is a whole number ~ 1, - the duration of a transmission and reception time slot is m x t2, whereby m is a whole number ~ 1, and - respectively appertaining transmission and reception time slots are transmitted with the same RF carrier frequency.
2. Mobile telephone according to claim 1, characterized in that the converter means (2) is additionally fashioned for the conversion of GSM signals received by the first transmission/reception means (3) into payload signals and for conversion of payload signals into GSM time-division multiplex frames for transmission by the first transmission/reception means (3).
3. Mobile telephone according to claim 1 or 2, characterized in that the second transmission/reception means (4) exhibits a transmission/reception frequency of approximately 2.4 GHz.
4. Mobile telephone according to one of the claims 1 through 3, characterized in that the converter means (2) processes time-division multiplex frames having a duration of n 4.615 ms.
5. Mobile telephone according to one of the claims 1 through 4, characterized in that the converter means (2) processes transmission and reception time slots having a duration of m x 577 µs.
6. Mobile telephone according to one of the claims 1 through 5, characterized in that the converter means (2) exhibits a data rate of 271 kBit/s.
7. Mobile telephone according to one of the claims 1 through 6, characterized in that transmission and reception time slots respectively follow one another in alternation in a time-division multiplex frame.
8. Mobile telephone according to one of the claims 1 through 6, characterized in that a respectively defined plurality of transmission time slots and a defined plurality of reception time slots follow one another in alternation in a time-division multiplex frame.
9. Mobile telephone according to one of the claims 1 through 6, characterized in that a time-division multiplex frame having a defined plurality of transmission time slots and a time-division multiplex frame having a defined plurality of reception time slots respectively follow one another.
10. Mobile telephone according to one of the claims 2 through 9, characterized by a switchover means (9) for automatically switching between - a first operating condition for sending/receiving signals with the first transmission/reception means (3), and - a second operating condition for sending/receiving signals with the second transmission/reception means (4).
11. Mobile telephone according to claim 10, characterized in that the switchover means (9) acquires the level of a signal received by the second transmission/reception means (4) and switches between first and second operating condition dependent on the acquired signal level.
12. Mobile telephone according to one of the claims 1 through 11, characterized in that the first transmission/reception means (3) is fashioned for sending/receiving mobile radio telephone signals according to the GSM
Standard.
Standard.
13. Mobile telephone according to one of the claims 1 through 12, characterized in that the mobile telephone is fashioned as at least one mobile part of a cordless telephone system that comprises a fixed station and at least one mobile part.
14. Mobile telephone according to claim 13, characterized in that the mobile telephone is connected to the fixed station, whereby the fixed station comprises only one transmission/reception means for sending/receiving signals in the second frequency range.
15. Air interface for cordless telephony, comprising time-division multiplex frames to be transmitted at a fixed carrier frequency and having a defined duration with a defined plurality of time slots, whereby - the duration of a time-division multiplex frame is n x t1, whereby n is a whole number to ~ 1 and t1 is the duration of a time-division multiplex frame, particularly of a GSM time-division multiplex frame, - the duration of a time slot is m x t2, whereby m is a whole number ~ 1 and t2 is the time slot duration, and - the respectively appertaining transmission and reception time slots are arranged in the same time-division multiplex frame or in neighboring time-division multiplex frames of the same carrier frequency.
16. Radio transmission method for cordless telephony, whereby radio signals are transmitted between a mobile part and a base station in one or more frequency channels in transmission and reception time slots that are arranged in time-division multiplex frames having a fixed length, characterized in that - the duration of a time-division multiplex frame is n x t1, whereby n is a whole number ~ 1 and t1 is the duration of a predetermined time-division multiplex frame, particularly of a GSM time-division multiplex frame;
- the duration of a time slot is m x t2, whereby m is a whole number ~ 1 and t2 is the time slot length; and - the respectively appertaining transmission and reception time slots are transmitted with the same RF carrier frequency.
- the duration of a time slot is m x t2, whereby m is a whole number ~ 1 and t2 is the time slot length; and - the respectively appertaining transmission and reception time slots are transmitted with the same RF carrier frequency.
17. Radio transmission method according to claim 16, characterized in that the transmission frequency amounts to approximately 2.4 GHz.
18. Radio transmission method according to claim 16 or 17, characterized in that a time-division multiplex frame has a duration of n x 4.615 ms.
19. Radio transmission method according to one of the claims 16 through 18, characterized in that a transmission and reception time slot has a duration of m x 577 µs.
20. Radio transmission method according to one of the claims 16 through 19, characterized in that the transmission data rate amounts to 271 kBit/s.
21. Radio transmission method according to one of the claims 16 through 20, characterized in that a defined plurality of transmission time slots and a defined plurality of reception time slots respectively follow one another in alternation in a time-division multiplex frame.
22. Radio transmission method according to one of the claims 16 through 20, characterized in that a time-division multiplex frame having a defined plurality of transmission time slots and a time-division multiplex frame having a defined plurality of reception time slots respectively follow one another.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19742405.8 | 1997-09-25 | ||
| DE19742405A DE19742405A1 (en) | 1997-09-25 | 1997-09-25 | Dual mode mobile phone |
| PCT/DE1998/002834 WO1999016273A1 (en) | 1997-09-25 | 1998-09-22 | Dual mode mobile telephone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2306485A1 true CA2306485A1 (en) | 1999-04-01 |
Family
ID=7843636
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002306485A Abandoned CA2306485A1 (en) | 1997-09-25 | 1998-09-22 | Dual mode mobile telephone |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP1018278B1 (en) |
| CN (1) | CN1275296A (en) |
| BR (1) | BR9813225A (en) |
| CA (1) | CA2306485A1 (en) |
| DE (2) | DE19742405A1 (en) |
| WO (1) | WO1999016273A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU784074B2 (en) * | 2000-10-20 | 2006-02-02 | Symbol Technologies, Llc. | Dual mode wireless data communications |
| US9408253B2 (en) | 1999-09-21 | 2016-08-02 | Ipr Licensing, Inc. | Subscriber unit for managing dual wireless communication links |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2984669B1 (en) * | 1998-09-11 | 1999-11-29 | 静岡日本電気株式会社 | Local Circuit in Mobile Phone with Built-in Simple Mobile Phone |
| DE19924718A1 (en) * | 1999-05-31 | 2000-12-14 | Gustav Schlaf | Mobile communications unit can switch between different networks to optimize call costs |
| DE20012337U1 (en) | 2000-07-17 | 2000-09-21 | Rampl, Josef, 84181 Neufraunhofen | Telephone system with automatic switchover from mobile network operation to landline operation |
| JP3560149B2 (en) | 2000-09-12 | 2004-09-02 | 日本電気株式会社 | Mobile phone, GPS, Bluetooth integrated composite terminal and control method therefor |
| CN100428808C (en) * | 2002-09-27 | 2008-10-22 | 上海明波通信技术有限公司 | Dual mode terminal device and community searching method |
| JP3909844B2 (en) * | 2003-01-30 | 2007-04-25 | 松下電器産業株式会社 | Wireless communication device |
| CN100463481C (en) * | 2003-06-30 | 2009-02-18 | 中兴通讯股份有限公司 | A method and system for implementing short distance wireless communication in public switched telephone network |
| CN1977556B (en) * | 2004-07-02 | 2011-09-07 | 飞思卡尔半导体公司 | Arrangement and circuit for dual mode operation in a communication system terminal |
| CN1317908C (en) * | 2004-11-16 | 2007-05-23 | 上海市电信有限公司 | Separate type double mode mobile phone |
| CN101222715B (en) * | 2008-01-29 | 2013-04-03 | 展讯通信（上海）有限公司 | Double-card double-standby mobile phone implemented by single communication device |
| CN102123500B (en) * | 2010-01-08 | 2016-08-03 | 华为技术有限公司 | The resource allocation methods of multimode terminal and device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4989230A (en) * | 1988-09-23 | 1991-01-29 | Motorola, Inc. | Cellular cordless telephone |
| GB2236454A (en) * | 1989-09-01 | 1991-04-03 | Philips Electronic Associated | Communications system for radio telephones |
| DE4344702A1 (en) * | 1993-12-27 | 1995-07-06 | Deutsche Bundespost Telekom | Alternative operation procedure for mobile subscriber's appts. |
| GB2288101B (en) * | 1994-03-22 | 1998-04-29 | Nokia Mobile Phones Ltd | Multi-mode radio telephone |
-
1997
- 1997-09-25 DE DE19742405A patent/DE19742405A1/en not_active Withdrawn
-
1998
- 1998-09-22 BR BR9813225-3A patent/BR9813225A/en not_active IP Right Cessation
- 1998-09-22 WO PCT/DE1998/002834 patent/WO1999016273A1/en active IP Right Grant
- 1998-09-22 CA CA002306485A patent/CA2306485A1/en not_active Abandoned
- 1998-09-22 EP EP98956794A patent/EP1018278B1/en not_active Expired - Lifetime
- 1998-09-22 DE DE59803933T patent/DE59803933D1/en not_active Expired - Fee Related
- 1998-09-22 CN CN98809562A patent/CN1275296A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9408253B2 (en) | 1999-09-21 | 2016-08-02 | Ipr Licensing, Inc. | Subscriber unit for managing dual wireless communication links |
| AU784074B2 (en) * | 2000-10-20 | 2006-02-02 | Symbol Technologies, Llc. | Dual mode wireless data communications |
Also Published As
| Publication number | Publication date |
|---|---|
| WO1999016273A1 (en) | 1999-04-01 |
| EP1018278B1 (en) | 2002-04-24 |
| DE59803933D1 (en) | 2002-05-29 |
| BR9813225A (en) | 2000-08-29 |
| EP1018278A1 (en) | 2000-07-12 |
| CN1275296A (en) | 2000-11-29 |
| DE19742405A1 (en) | 1999-04-08 |
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