Point-to-multipoint radio transmission system

(54) POINT-TO-MULTIPOINT RADIO TRANSMISSION SYSTEM

(75) Inventors: Heinz Gockler; Thomas Alberty, both of Backnang (DE)

(73) Assignee: Robert Bosch GmbH, Stuttgart (DE)

( * ) Notice: Under 35 U.S.C. 154(b), the term of this patent shall be extended for 0 days.

(21) Appl. No.: 09/155,391

(22) PCT Filed: Dec. 7, 1996

(86) PCT No.: PCT/DE96/02349 § 371 Date: Feb. 11, 1999

§ 102(e) Date: Feb. 11, 1999

(87) PCT Pub. No.: W097/36433 PCT Pub. Date: Oct. 2, 1997

(30) Foreign Application Priority Data Mar. 27, 1996 (DE) 196 12 108

(51) Int. CI.7 H04J 1/00; H04B 7/208

(52) U.S. CI 370/344; 370/281; 370/344

(58) Field of Search 370/281, 295,

370/344, 343, 468, 341, 282; 375/219, 220, 222, 276, 277; H04B 7/208

(56) References Cited

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4,965,852 * 10/1990 Sasaki 455/82

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5,365,545 * 11/1994 Blackwell et al 375/8

5,512,898 * 4/1996 Norsworthy et al 341/155

5,768,311 * 6/1998 Betts et al 375/222

FOREIGN PATENT DOCUMENTS

36 21 737 1/1988 (DE) .

44 26 183 10/1995 (DE) .
2098029 11/1988 (GB) .

OTHER PUBLICATIONS

R. McGuire, "Technologies for an Exchange Radio", Proceedings of the National Communications Forum, vol. 43, No. 2, Oct. 2, 1989, pp. 869-882.

T. Le-Ngoc et al., "ISDN Implementation for a Point-To-Multipoint Subscriber Radio System", Computer Communications, vol. 13, No. 3, Apr. 1, 1990, pp. 131-135 "Mikrowellenmagazin", vol. 10, No. 6, 1984, pp. 629-630. H. Gockler et al., "Digitale Mehrtrager-Demultiplexer fur den mobilen Satellitenfunk", Frequenz publication, vol. 42 (1988), No. 6-7, pp. 181-189.

(List continued on next page.)

Primary Examiner—Ajit Patel

Assistant Examiner—Hanh Nguyen

(74) Attorney, Agent, or Firm—Kenyon & Kenyon

In order to allow a flexible allocation of transmission capacities in a radio transmission system, without disrupting or interrupting existing radio connections, a control device is provided which, in the event of a change in the transmission channels, adjusts one or more of the transmission parameters in a central station and in affected subscriber stations in such a way that the bandwidth of the available radio channel is optimally utilized. For this purpose, the modems present in the central station and in the subscriber stations are equipped with two transmitted signal paths and two paths and two received signal paths, only one of received signal paths (ENC1, ENC2, IF1, IF2, MODI, MOD2, DEMI, DEM2, DF1, DF2, DEC1, DEC2), only one of which is activated in each case for a signal transmission. The outputs of the transmitted signal paths and the inputs of the received signal paths are equipped with frequency splitters. In the event of a change in the transmission channels, the adjustment to the new transmission parameters takes place in the signal path that is not currently activated, and after acquisition of the new transmission parameters is complete, operation switches over to that signal path.

18 Claims, 6 Drawing Sheets

OTHER PUBLICATIONS

E. Auer et al., "Advanced Modem Equipment for Intelsat IDR/IBS Services", Proceedings of Second European Conference on Satellite Communications, Liege, Belgium, Oct. 1991, ESA SP-332, pp. 457-464.

H. Nicholas et al., "An Analysis of the Output Spectrum of Direct Digital Frequency Synthesizers in the Presence of Phase-Accumulator Truncation," IEEE 1987, 41st Annual Frequency Control Symposium, pp. 495-502.

* cited by examiner