Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
  • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
  • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
  • H04B7/2643—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using time-division multiple access [TDMA]
  • H04B7/2656—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using time-division multiple access [TDMA] for structure of frame, burst
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
  • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
  • H04B7/2615—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using hybrid frequency-time division multiple access [FDMA-TDMA]
• • 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
  • H04J—MULTIPLEX COMMUNICATION
  • H04J4/00—Combined time-division and frequency-division multiplex systems

Definitions

• the present invention relates to a device and a method for radio transmission of user data arranged in data words of a fixed length in time-division multiplex frames, which have active time slots in which data are transmitted and inactive time slots in which no data are transmitted.
• the invention is particularly suitable for use in digital cordless telephone systems.
• the DECT Digital Enhanced Cordless Telephone
• the DECT Digital Enhanced Cordless Telephone
• This system has ranges from less than 300 meters to about 10 km, depending on the antenna and environment, and is particularly suitable for use inside buildings. Both voice signals and data signals can be transmitted.
• Ten carrier frequencies each with a channel spacing of 1728 kHz, are available in a frequency range from 1880 MHz to 1900 MHz.
• each carrier frequency is divided into 24 time slots.
• the first twelve channels are reserved for the downlink from a base station to a mobile part of a mobile telephone system and the following twelve time slots are reserved for the uplink from the mobile part to the base station.
• the 24 time slots form a frame with a total duration of 10 ms.
• the duration of a single time slot is thus 417 ⁇ s, in which 320 bit user data and 104 bit synchronization data, signaling data and error correction bit can be transmitted.
• the user data rate is thus 32 kbit / s.
• FIG. 2 of the accompanying drawings An alternative structure of a time-division multiplex frame is shown schematically in Figure 2 of the accompanying drawings.
• the frame duration is again 10 ms.
• inactive time slots Between the upward and downward time slots, in which the data is transmitted from the base station to the handset or vice versa, there are inactive time slots arranged between two active time slots, in which no data are transmitted. These inactive time slots (blind slots) allow the frequency of the RF transmit / receive module (frequency hopping) to be programmed between two successive active time slots.
• the duration of each active time slot is 833 ⁇ s and each inactive time slot 417 ⁇ s, that is to say half of an active time slot.
• the active time slot has twice the duration and the inactive time slot the same duration as a time slot in the DECT system.
• This alternative time-division multiplex frame structure can be used, for example, in the US ISM (Industrial, Scientific, Medical) band at a carrier frequency of 2.4 GHz.
• the continuous flow of information in both transmission directions must be compressed into the comparatively narrow time slots in each time division multiplex system in a cordless telephone system.
• the voice data coming from a landline for example, is continuously stored in a memory and then in so-called bursts, ie with a significantly higher data rate in the selected one Time slot implemented for radio transmission.
• bursts ie with a significantly higher data rate in the selected one Time slot implemented for radio transmission.
• the time delay that occurs should be as small as possible.
• the present invention is therefore based on the object of proposing a device and a method for radio transmission of user data arranged in data word length in time-division multiplex frames consisting of active and inactive time slots, with a minimal time delay in the transmission regardless of the selected time slot Implementation of user data occurs.
• n (n integer> 1) data words of the user data being stored during the period from the beginning of an active time slot to the beginning of the next active time slot.
• the storage of a data word in the memory is always just completed at the beginning of the respective time slot, so that the data can be converted and transmitted into the time slot with the least possible time delay.
• the data word length can be one byte corresponding to 8 bits of the user data.
• 5 bytes of the user data can be stored in each case during the time from the beginning of an active time slot to the beginning of the next time slot.
• the data rate at which the user data are temporarily stored in the memory is 32 kbit / s and the readout data rate from the memory is 576 kbit / s.
• the time-division multiplex frame can have a total duration of 10 ms and be divided into four active time slots each with a duration of 833 ⁇ s for data transmission between a base station and a mobile device, four active time slots each with a duration of 833 ⁇ s for transmission from the mobile device to the base station and eight inactive time slots with a duration of 417 ⁇ s each.
• the amount of data transmitted per time slot is preferably 320 bits of user data.
• the carrier frequency of the radio transmission can be 2.4 GHz, for example.
• the device according to the invention and the method according to the invention can be used for the transmission of voice signals and data signals.
• FIG. 1 is a schematic illustration of a base station of a cordless telephone system to which the invention is applicable;
• 3 and 4 are schematic representations to explain the operation of the memory device according to the invention.
• Fig. 1 shows schematically the structure of a base station generally designated 1 of a cordless telephone system, to which the invention is applicable.
• 2 with a connection to a fixed telephone network is designated, on which the user data, for example as 32 kbit / s ADPCM (Adaptive Delta Pulsed Code Modulation) coded signals can be received.
• This user data is continuously written into the memory 3 at the data rate of 32 kbit / s.
• the memory is called a ring memory.
• the memory can be designed as a random access memory (RAM), for example.
• the user data controlled by the burst mode controller 4, is read out as a burst at a higher data rate of 576 kbit / s, coded by means of the encoder / decoder 5 and via the RF module 6 and the antenna 7 with the respectively selected carrier frequency transmitted to the associated handset.
• the time-division multiplex frame structure used in the present exemplary embodiment is shown schematically in FIG. 2.
• the four active time slots RX 1 to RX 4 each with a duration of 833 ⁇ s, are available for the downlink from the base station to a handset.
• the active time slots TX 1 to TX 4, also 833 ⁇ s long, are reserved for the uplink from a handset to the base station.
• the designations Rx x and Tx x stand for "receive" or "transmit" from the handset's point of view.
• An inactive time slot of 417 ⁇ s duration is provided between two active time slots.
• a channel pair consisting of an active time slot and an inactive time slot therefore has a total duration of 1.25 ms.
• 320 bit user data can be transmitted.
• the outer circumference is the user data in units of bytes.
• the outer arrow symbolizes the storage process of user data from the fixed network into the ring memory 3.
• the data are continuously processed at a data rate of 32 bit / s, ie. H. 320 bits or 40 bytes saved in 10 ms. After 10 ms, the "oldest" data is overwritten again.
• a complete turn of the outer arrow corresponds to a storage of 40 bytes of user data for a period of 10 ms.
• the inner arrow symbolizes the reading process of the user data from the ring memory by means of the burst mode control 4.
• the beginning of an active time slot of the time division multiplex frame is plotted on the inside of the circle in such a way that the position of the outer arrow indicates the current time slot.
• the storage of 5 bytes of user data in the ring buffer has just been completed. The data can then be read out of the memory and converted into the respective time slot without any time delay, regardless of the choice of the time slot.
• the radio transmission device and the radio transmission method according to the invention thus make it possible to convert continuously arriving user data into time-division multiplex frames, which is synchronized in such a way that, regardless of the selected time slot, there is a minimal delay and the same in all time slots.

Landscapes

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

Applications Claiming Priority (1)

Publications (1)

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ID=6918509

Family Applications (2)

Family Applications After (1)

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• 1997
  • 1997-06-24 CA CA002294542A patent/CA2294542C/en not_active Expired - Fee Related
  • 1997-06-24 US US09/446,198 patent/US6678262B1/en not_active Expired - Fee Related
  • 1997-06-24 EP EP97931651A patent/EP0992129A1/de not_active Ceased
  • 1997-06-24 WO PCT/DE1997/001315 patent/WO1998059436A1/de not_active Application Discontinuation
  • 1997-08-14 CA CA002294535A patent/CA2294535C/en not_active Expired - Fee Related
  • 1997-08-14 BR BR9714778-8A patent/BR9714778A/pt not_active Application Discontinuation
  • 1997-08-14 WO PCT/DE1997/001739 patent/WO1998059438A1/de active Application Filing
  • 1997-08-14 US US09/446,545 patent/US7079496B1/en not_active Expired - Fee Related
  • 1997-08-14 WO PCT/DE1997/001731 patent/WO1998059437A1/de active Application Filing
  • 1997-08-14 CA CA002295313A patent/CA2295313C/en not_active Expired - Fee Related
  • 1997-08-14 CN CNB971823529A patent/CN1143457C/zh not_active Expired - Fee Related
  • 1997-08-14 CN CNB971823537A patent/CN1192517C/zh not_active Expired - Fee Related
  • 1997-08-14 EP EP97938764A patent/EP0992130A1/de not_active Ceased
  • 1997-08-14 CN CNB971823502A patent/CN1192516C/zh not_active Expired - Fee Related
  • 1997-08-14 JP JP50350399A patent/JP3444901B2/ja not_active Expired - Lifetime
  • 1997-08-14 KR KR10-1999-7012301A patent/KR100430134B1/ko not_active IP Right Cessation
  • 1997-08-14 CA CA002294915A patent/CA2294915C/en not_active Expired - Fee Related
  • 1997-08-14 US US09/446,654 patent/US6693885B1/en not_active Expired - Fee Related
  • 1997-08-14 WO PCT/DE1997/001740 patent/WO1998059439A1/de not_active Application Discontinuation
• 1998
  • 1998-12-30 US US09/446,752 patent/US6967934B1/en not_active Expired - Fee Related
• 2001
  • 2001-02-15 HK HK01101117A patent/HK1030313A1/xx not_active IP Right Cessation
  • 2001-02-15 HK HK01101114A patent/HK1030312A1/xx unknown
  • 2001-03-15 HK HK01101876A patent/HK1032491A1/xx unknown

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