Point-multipoint radio transmission system

• US 6,178,330 B1
• Filed: 09/24/1998
• Issued: 01/23/2001
• Est. Priority Date: 03/27/1996
• Status: Expired due to Term

• Current Assignee: Ericsson AB (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Robert Bosch GmbH
• Inventors: Auer, Erich, Alberty, Thomas
• Primary Examiner(s): Bost, Dwayne D.
• Assistant Examiner(s): WASHINGTON, ERIKA ALISE
• Application Number:
  US09/155,222
• Time in Patent Office: 852 Days
• Field of Search: 455/500, 455/450, 455/451, 455/452, 455/454, 455/455, 455/463, 455/464, 455/62, 455/63, 455/67.3, 455/507, 455/509, 455/524, 455/517, 455/501, 455/296, 455/520, 455/554, 455/555, 455/560, 375/222, 370/477, 370/468
• US Class Current: 455/452.2
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0096 Indication of changes in allocation
• CPC Class Codes: H04W 84/14 WLL [Wireless Local Loop]; RLL [Radio Local Loop]

Abstract

In order to permit flexible allocation of transmission capacities in such a radio transmission system, without interrupting or disturbing existing radio links, provision is made for a control device which, in response to a change of transmission channels in the central station and in the subscriber stations in question, adjusts one or a plurality of transmission parameters so that both the band width of the available radio frequency channel is optimally utilized, and a required resistance to interference is attained in the radio frequency channel. To that end, the modems existing in the central station and in the subscriber stations are equipped with L transmission channels and K receiving channels, of which, in each case, a maximum of L-1 in the transmission direction, and a maximum of K-1 in the receiving direction are activated. In response to a change in the transmission channels with respect to the number of carriers and/or the transmission parameters of the individual carriers, the adjustment to the new transmission parameters is effected in the at least one non-activated transmission channel or receiving channel and, after acquisition of the new transmission parameters has been concluded, a switchover is made to this/these transmission channels or receiving channels.

Claims

1. A point-to-multipoint radio transmission system, comprising:

a central station utilizing a first set of transmission channels and including at least one central station modem for each channel of the first set of the transmission channels;

subscriber stations utilizing a second set of transmission channels, each of the subscriber stations including at least one subscriber modem, each respective modem of the station and subscriber modems including a first number of transmitting channels and a second number of receiving channels, each of the first and second numbers being greater than one, the respective modem transmitting at least one signal via a maximum of a third number of the transmitting channels or via a maximum of a fourth number of the receiving channels, the third number being less than the first number by one, the fourth number being less than the second number by one; and

a control device adjusting, for each of the station and subscriber modems and when a change occurs in at least one of the transmission channels and a predetermined interference resistance of the transmission channels, at least one of;

a fifth number of first active channels of the transmitting channels,

a sixth number of second active channels of the receiving channels, and

at least one of a plurality of transmission parameters of at least one of the first active

channels and the second active channels, the fifth number being between one and the third number, the sixth number being between one and the fourth number, the control device performing an adjustment at least one of to optimally utilize a bandwidth of an available radio frequency channel and to achieve the predetermined interference resistance in the transmission channels, the plurality of transmission parameters including at least one of a channel carrier frequency, a data rate, a modulation, a coding, a transmission level and signal quality evaluation parameters,

wherein, when the plurality of transmission parameters are changed,

the control device adjusts further transmission parameters in a non-operating channel of the transmitting or receiving channels, while the at least one signal is transmitted via at least one other channel of the transmitting channels or of the receiving channels, and the control device prevents a switchover to the non-operating channel until further transmission channels are acquired.

2. The point-to-multipoint radio transmission system according to claim 1,

wherein at least one modem of the station modem and subscriber modem includes:

encoders and modulators, a single encoder of the encoders and a single modulator of the modulators being assigned to each of the transmitting channels, and

variable interpolation filters, a single interpolation filter of the variable interpolation filters being assigned to each channel of the transmitting channels,

wherein, for each of the transmitting channels, a particular filter of the interpolation filters is coupled between a respective encoder of the encoders and a respective modulator of the modulators.

3. The point-to-multipoint radio transmission system according to claim 2,

wherein the at least one modem includes interpolators, a single interpolator of the interpolators being assigned to each of the transmitting channels,

wherein, for each of the transmitting channels, a particular interpolator of the interpolators is positioned downstream of a respective modulator of the modulators, the particular interpolator converting a complex digital output signal generated by the respective modulator to a real digital signal.

4. The point-to-multipoint radio transmission system according to claim 3, wherein at least one of the interpolators is a complex half-band filter.

5. The point-to-multipoint radio transmission system according to claim 2,

wherein the at least one modem includes interpolators, a single interpolator of the interpolators being assigned to each of the transmitting channels,

wherein, for each of the transmitting channels, the modulators provide output signals via a respective branching arrangement to a particular interpolator of the interpolators, and

wherein, for each of the transmitting channels, the particular interpolator converts a complex digital output signal generated by a respective modulator of the modulators into a real digital signal.

6. The point-to-multipoint radio transmission system according to claim 5, wherein at least one of the interpolators is a complex half-band filter.

7. The point-to-multipoint radio transmission system according to claim 5, wherein the branching arrangement is a frequency-division multiplexer.

8. The point-to-multipoint radio transmission system according to claim 1,

wherein at least one modem of the station modem and subscriber modem includes encoders, modulators and variable interpolation filters processing all of the transmitting channels in a time-division multiplexing manner,

wherein, for each of the transmitting channels, a particular filter of the variable interpolation filters is positioned between a respective encoder of the encoders and a respective modulator of the modulators.

9. The point-to-multipoint radio transmission system according to claim 8,

wherein the at least one modem includes multiplexers and interpolators, a single interpolator of the interpolators being assigned to each of the transmitting channels, and

wherein, for each of the transmitting channels, a particular multiplexer provides a complex digital output signal generated by a respective modulator of the modulators to a respective interpolator of the interpolators, the respective interpolator converting the complex digital output signal into a real digital signal.

10. The point-to-multipoint radio transmission system according to claim 9, wherein at least one of the interpolators is a complex half-band filter.

11. The point-to-multipoint radio transmission system according claim 8,

wherein the at least one modem includes shared function units, and

wherein, for each of the transmitting channels, a particular one of the multiplexers processes the first number of the transmitting channels in a time-division multiplexing manner using a respective unit of the shared functional units, the respective unit including the variable interpolation filter.

12. The point-to-multipoint radio transmission system according to claim 8,

wherein the at least one modem includes first function units and second functional units, and

wherein, for each of the transmitting channels, a particular one of the multiplexers processes the first number of the transmitting channels in a time-division multiplexing manner using a respective first unit of the first functional units and a respective second unit of the second functional units, the respective first unit including the variable interpolation filter, the respective second unit including the modulator.

13. The point-to-multipoint radio transmission system according to claim 8,

wherein the at least one modem includes first function units and second functional units, and

wherein, for each of the transmitting channels, a particular one of the multiplexers processes the first number of the transmitting channels in a time-division multiplexing manner using a respective first unit of the first functional units and a respective second unit of the second functional units, the respective first unit including the variable interpolation filter, the respective second unit including an interpolator having a fixed interpolation factor.

14. The point-to-multipoint radio transmission system according to claim 1,

wherein at least one modem of the station modem and subscriber modem includes:

demodulators and decoders, a single demodulator of the demodulators and a single decoder of the decoders being assigned to each channel of the receiving channels, and variable decimation filters, a single decimation filter of the variable decimation filters being assigned to each channel of the receiving channels, wherein, for each of the receiving channels, a particular decimation filter of the decimation filters is coupled between a respective decoder of the decoders and a respective demodulator of the demodulators.

15. The point-to-multipoint radio transmission system according to claim 14,

wherein the at least one modem includes:

decimators, a single decimator of the decimators being assigned to each channel of the receiving channels, and

wherein, for each of the receiving channels, a particular decimator of the decimators is coupled upstream to a respective demodulator of the demodulators, the particular decimator converting a real digital receiving signal into a complex digital signal.

16. The point-to-multipoint radio transmission system according to claim 15, wherein at least one of the decimators is a complex half-band filter.

17. The point-to-multipoint radio transmission system according to claim 14,

wherein the at least one modem includes:

decimators, a single decimator of the decimators being assigned to each channel of the receiving channels, and

wherein, for each of the receiving channels, a particular decimator of the decimators converts a real digital receiving signal into a complex digital signal, the complex digital signal being provided to the a respective demodulator of the demodulators via a branching arrangement.

18. The point-to-multipoint radio transmission system according to claim 17, wherein at least one of the decimators is a complex half-band filter.

19. The point-to-multipoint radio transmission system according to claim 17, wherein the branching arrangement is a frequency demultiplexer.

20. The point-to-multipoint radio transmission system according to claim 1,

wherein at least one modem of the station modem and subscriber modem includes:

demodulators, decoders and variable decimation filters positioned between the demodulators and the decoders,

wherein, for each of the receiving channels, a single modulator of the demodulators, a single decoder of the decoders and a single decimation filter are assigned to each of the receiving channels, and

wherein all of the receiving channels are processed in a time-division multiplexing manner using the demodulators, the variable decimation filters and the decoders.

21. The point-to-multipoint radio transmission system according to claim 20,

wherein, for each of the receiving channels, a respective decimator of the decimators converts a real digital receiving signal into a complex digital receiving signal,

wherein the at least one modem includes demultiplexers, a single demultiplexer of the demultiplexers being assigned to each of the receiving channels, and

wherein, for each of the receiving channels, a particular demultiplexer provides the complex digital receiving signal to a respective demodulator of the demodulators.

22. The point-to-multipoint radio transmission system according to claim 21, wherein at least one of the decimators is a complex half-band filter.

23. The point-to-multipoint radio transmission system according claim 20,

wherein the at least one modem includes shared function units, and

wherein, for each of the receiving channels, a particular one of the demultiplexers processes the second number of the receiving channels in a time-division multiplexing manner using a respective unit of the shared functional units, the respective unit including the variable decimation filter.

24. The point-to-multipoint radio transmission system according to claim 20,

wherein the at least one modem includes first function units and second functional units, and

wherein, for each of the receiving channels, a particular one of the demultiplexers processes the second number of the receiving channels in a time-division multiplexing manner using a respective first unit of the first functional units and a respective second unit of the second functional units, the respective first unit including the variable decimation filter, the respective second unit including the demodulator.

25. The point-to-multipoint radio transmission system according to claim 20,

wherein the at least one modem includes first function units and second functional units, and

wherein, for each of the receiving channels, a particular one of the demultiplexers processes the second number of the receiving channels in a time-division multiplexing manner using a respective first unit of the first functional units and a respective second unit of the second functional units, the respective first unit including the variable decimation filter, the respective second unit including a decimator having a fixed decimation factor.