Multiplex communications – Duplex – Communication over free space
Reexamination Certificate
1999-01-28
2002-05-14
Nguyen, Chau (Department: 2663)
Multiplex communications
Duplex
Communication over free space
C370S337000
Reexamination Certificate
active
06388996
ABSTRACT:
BACKGROUND OF THE INVENTION
In communication systems having a communication transmission path between a communication source and a communication sink, transmitting and receiving devices are used for communication processing and transmission in which
1) the communication processing and communication transmission can take place in a preferred transmission direction (simplex operation) or in both transmission directions (duplex operation),
2) the communication processing is analogue or digital,
3) the communication transmission via the long-distance transmission path takes place wire-free on the basis of various communication transmission methods FDMA (Frequency Division Multiple Access), TDMA (Time Division Multiple Access) and/or CDMA (Code Division Multiple Access) for example in accordance with radio standards such as DECT, GSM, WACS or PACS, 1S-54, PHS, PDC etc. (see IEEE Communications Magazine, January 1995, pages 50 to 57; D. D. Falconer et al: “Time Division Multiple Access Methods for Wireless Personal Communications”) and/or by wire.
“Communication” is a generic term which covers both the message content (information) and the physical representation (signal). Despite a communication having the same message content—that is to say the same information—different signal forms may occur. Thus, for example, a communication relating to an item may be transmitted in any of the following forms
(1) an image,
(2) as the spoken word,
(3) as the written word,
(4) as an encrypted word or image.
The type of transmission according to forms (1), (2) and (3) is in this case normally characterized by continuous (analogue) signals, while the type of transmission according to forms (4) normally takes place by means of discontinuous signals (for example pulses, digital signals).
On the basis of this general definition of a communication system, the invention relates to a base station having a fast channel changing function in a cellular TDMA/FDMA radio system, in particular in a cellular DECT system.
A cellular radio system, as a subset of the previously defined communication system is, for example, the cellular DECT-System (Digital Enhanced (previously: European) Cordless Telecommunication; see (1): Nachrichtentechnik Elektronik 42 (Electronic telecommunication 42) (1992) January/February No. 1, Berlin, DE: U. Pilger “Struktur des DECT-Standards” (Structure of the DECT Standard), pages 23 to 29 in conjunction with the ETSI Publication ETS 300175-1 . . . 9, October 1992; (2): Telcom Report 16 (1993), No. 1, J. H. Koch: “Digitaler Komfort für schnurlose Telekommunikation—DECT-Standard eröffnet neue Nutzungsgebiete” (Digital convenience for cordless telecommunications—DECT Standard opens up new application areas), pages 26 and 27; (3): tec 2/93—the Technical Magazine from Ascom “Wege zur universellen mobilen Telekommunikation” (Universal mobile telecommunication techniques), pages 35 to 42; (4): Philips Telecommunication Review, Vol. 49, No. 3, September 1991, R. J. Mulder: “DECT, a universal cordless access system”; (5): WO 93/21719 (
FIGS. 1
to
3
with associated description)) or the cellular GAP-System (Generic Access Profile; ETSI-Publikation prETS 300444, April 1995, Final Draft, ETSI, FR), which may be designed, for example, on the basis of a monocellular DECT/GAP system (Single Cell System) according to FIG.
1
and in accordance with the illustration in
FIGS. 4 and 5
.
According to the DECT/GAP Standard and in accordance with the illustration in
FIG. 1
, a DECT/GAP radio interface which is designed for the frequency band between 1.88 and 1.90 GHz can be used to set up on a DECT/GAP base station BS a maximm of 12 links, using the TDMA/FDMA/TDD method (Time Division Multiple Access/Frequency Division Multiple Access/Time Division Duplex) in parallel with DECT/GAP mobile parts MT1 . . . MT12. The figure of 12 results from a number “kg” of time slots or telecommunications channels available for duplex operation of a DECT/GAP system (k=12). The links may in this case be internal and/or external. In the case of an internal link, two mobile parts which are registered at the base station BS, for example the mobile part MT2 and the mobile part MT3, can communicate with one another. In order to set up an external link, the base station BS is connected to a telecommunications network TKN, e.g. in cable form via a telecommunications line unit TAE, or a private branch exchange is connected to a cable telecommunications network, or (according to PCT Reference WO 95/05040 in wire-free form as a repeater station) to a higher-level telecommunications network. In the case of the external link, it is possible to communicate with a mobile part, for example with a mobile part MT1, via the base station BS and the telecommunications line unit TAE, or for the private branch exchange NStA to communicate with a subscriber in the telecommunications network TKN. If—as in the case of Gigaset 951 (Siemens cordless telephone, see Telcom Report 16, (1993) Issue 1, pages 26 and 27)—the base station BS has only one connection to the telecommunications line unit TAE or to the private branch exchange NStA, then only one external link can be set up. If—as in the case of Gigaset 952 (Siemens cordless telephone; see Telcom Report 16, (1993), Issue 1, pages 26 and 27)—the base station BS has two connections to the telecommunications network TKN then, in addition to the external link to the mobile part MT1, a further external link is possible from a cable telecommunications terminal TKE connected to the base station BS. In this case it is also in principle feasible for a second mobile part, for example the mobile part MT12, to use the second connection for an external link, instead of the telecommunications terminal TKE. While the mobile parts MT1 . . . MT12 are operated using a battery or a rechargeable battery, the base station BS, which is designed as a small cordless exchange, is connected to a voltage network SPN via a network interface unit NAG.
Based on the document Components 31 (1993), Issue 6, pages 215 to 218; S. Althammer, D. Brückmann: “Hochoptimierte IC's für DECT-Schnurlostelefone” (Highly optimized ICs for DECT cordless telephones),
FIG. 2
shows the basic circuit design of the base station BS and of the mobile part MT according to FIG.
1
. According to this figure, the base station BS and the mobile part MT have a radio part FKT with an antenna ANT used for transmitting and receiving radio signals, a signal processing device SVE and a central controller ZST, which are connected to one another in the illustrated manner. The radio part FKT essentially contains the known devices such as the transmitter SE, the receiver EM and the synthesizer SYN. The signal processing device SVE contains, inter alia, a coding/decoding device CODEC. Both for the base station BS and for the mobile part MT, the central controller ZST has a microprocessor &mgr;P with a program module PGM designed in accordance with the OSI/ISO layer model (see (1): Instruction Sheets—Deutsche Telekom, Year 48, 2/1995, pages 102 to 111; (2): ETSI Publication ETS 300175-1 . . . 9, October 1992), a signal control section SST and a digital signal processor DSP, which are connected to one another in the illustrated manner. Of the layers defined in the layer model, only the first four layers, which are absolutely essential for the base station BS and for the mobile part MT&lgr; are illustrated. The signal control section SST in the base station BS is designed as a Time Switch Controller TSC, and that in the mobile part MT is designed as a Burst Mode Controller BMC. The major difference between the two signal control sections TSC, BMC is that the base-station-specific signal control section TSC also carries out switching functions that the mobile-part-specific signal control section BMC does not.
The basic method of operation of the circuit units mentioned above is described, for example, in the document cited above, Components 31 (1993), Issue 6, pages 215 to 218.
The circuit layout described according to
FIG. 2
is supplemented by ad
Baumeister Josef
Biedermann Rolf
Nguyen Chau
Trinh D.
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