Low power, short range point-to-multipoint communications system

• US 6,112,056 A
• Filed: 01/11/2000
• Issued: 08/29/2000
• Est. Priority Date: 06/07/1995
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Systems, Inc.
• Inventors: Langston, J. Leland
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): BANKS HAROLD, MARSHA DENISE
• Application Number:
  US09/481,054
• Time in Patent Office: 231 Days
• Field of Search: 455/62, 455/63, 455/67.1, 455/25, 455/101, 455/103, 455/60, 455/422, 455/517, 455/524, 455/561, 455/562, 455/41, 343/853, 343/797, 343/891, 343/890, 348/6, 342/361, 342/362, 342/363, 342/364, 342/365, 342/366
• US Class Current: 455/62
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 52/0203 in the radio access network or backbone network of wireless communication networks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A point-to-multipoint or two-way communications system is provided by a nodal transmitter located in a node with a plurality of nodal antennas radiating different polarization signals about the node. The system includes subscriber stations with directional antennas adapted to receive signals radiated from the nodal transmitter. The system may additionally include capability for transmitting and radiating subscriber signals to the nodal transmitter location for two-way communications.

Claims

1. A short range, wireless, point-to-multipoint communications system comprising:

a plurality of transmitter systems each broadcasting over a same given frequency band wherein each of said transmitter systems comprises a plurality of contiguous sub-frequency band transmitters;

a plurality of unidirectional transmitting antennas located at a common location of a node coupled to said transmitter systems and positioned to radiate in different directions about said node;

said unidirectional antennas being of orthogonal polarization types and positioned such that one polarization type is spaced about said node between orthogonal polarization types so the polarization of the transmitted signal alternates orthogonal polarization about said node;

each of said unidirectional antennas comprising a plurality of linear arrays of radiating elements with a phase shifter between each radiating element, each of said linear arrays of said unidirectional antennas coupled to one of said contiguous sub-frequency band transmitters; and

plurality of receiver stations with each of said receiver stations having a directional receiver station antenna directed and polarized to receive signals from said unidirectional transmitting antennas.

2. The system of claim 1 wherein there is an amplifier for each linear array.

3. The system of claim 1 wherein the phase shifters provide proportional phasing between each radiating element.

4. The system of claim 1 wherein each of said sub-frequency band transmitters includes a modulator and an amplifier.

5. The system of claim 4 wherein each modulator is a QPSK modulator.

6. The system of claim 4 wherein each of said sub-frequency band transmitters include a time division multiplexer.

7. The system of claim 6 wherein said time division multiplexer receives multiple compressed digital video channels and multiplexes them into a single bit stream for application to said modulator.

8. The system of claim 7 wherein said video channels transmit ATM packets.

9. The system of claim 8 wherein said receiver stations includes a receiver/transmitter at the node wherein said receiver/transmitter is assigned bandwidth on demand using TDMA techniques in conjunction with time slots assigned on demand.

10. The system of claim 9 wherein said transmitter/receiver includes an ATM switch.

11. The system of claim 10 wherein said sub-frequency transmitters transmit ATM packets and said transmitter/receiver sends ATM packets using TDMA and on demand time slots.

12. The system of claim 10 wherein each of said sub-frequency band transmitters is a CDMA transmitter.

13. The system of claim 1 wherein the linear arrays are vertical linear arrays.

14. A short range, wireless, point-to-multipoint transmission system comprising:

a plurality of transmitter systems each broadcasting over a frequency band with each of said transmitter systems comprising a plurality of contiguous sub-frequency band transmitters;

a plurality of unidirectional transmitting antennas located in said node and coupled to said transmitter systems and positioned to radiate in different directions about said node;

said unidirectional antennas being of orthogonal polarization types and positioned such that one polarization type is spaced about said node between orthogonal polarization types so the polarization of the transmitted signal alternates orthogonal polarization about said node; and

each of said unidirectional antennas comprising a plurality of vertical linear arrays of radiating elements with a phase shifter between each radiating element, each of said vertical linear arrays of said unidirectional antennas coupled to one of said sub-frequency band transmitters.

15. The system of claim 14 wherein there is an amplifier for each linear array.

16. The system of claim 14 wherein the phase shifters provide proportional phasing between each radiating element.

17. The system of claim 14 wherein each of said sub-frequency band transmitters includes a separate modulator and an amplifier.

18. The system of claim 17 wherein each modulator is a QPSK modulator.

19. The system of claim 18 wherein each of said sub-frequency band transmitters includes a time division multiplexer.

20. The system of claim 19 wherein said time division multiplexer receives multiple compressed digital channels and multiplexes them into a single bit stream for application to said modulator.

21. The system of claim 20 wherein said digital channels transmit ATM packets.

22. The system of claim 14 including a polarizer for each linear array.

23. The system of claim 14 wherein said system is a telephony system and said sub-frequency transmitters are modulated with telephony.

24. The system of claim 14 wherein said system is a video system and said sub-frequency transmitters are modulated with video information.

25. The system of claim 14 wherein said transmitters are modulated with data signals.

26. The system of claim 14 wherein SONET OC-n signals are demultiplexed to OC-1 signals and the OC-1 signals are multiplexed at a central office and sent to the node which includes a node receiver where the OC-1 signals are demultiplexed and applied to said sub-frequency transmitters.

27. A short range, wireless, point-to-multipoint communications system comprising:

a base station transmitter/receiver system comprising a base station transmitter and associated base station receiver located within a given node;

a base station antenna system having alternating polarization type transmit antennas and receive antennas about said node;

said transmit antennas coupled to said base station transmitter to separately radiate said given frequency band signals at alternating orthogonal polarizations from sector to sector about said node;

said receive antennas coupled to said associated base station receiver for receiving signals from subscriber stations which transmit alternating orthogonal polarization signals from sector to sector about the node;

a plurality of subscriber stations with each of said subscriber stations including a subscriber transmitter/receiver coupled to a subscriber directional antenna system directed and polarized to receive signals from said base station transmitting antennas and for transmitting subscriber signals to said base station receiver antennas such that the polarization of said signals from said subscriber stations from sector to sector about said node alternates polarization, wherein said base station transmitter comprises a plurality of contiguous sub-frequency band transmitters together transmitting over said given frequency band for each sector, wherein each said base station transmit antennas comprises a plurality of linear arrays of radiating elements with a phase shifter between each radiating element, each of said linear arrays of said base station transmit antennas are coupled to one of said sub-frequency band transmitters.

28. The system of claim 27 wherein the phase shifters provide proportional phasing between each radiating element.

29. The system of claim 28 wherein said sub-frequency band transmitters transmit ATM packets and said subscriber transmitter of said transmitter/receiver sends ATM packets using TDMA in on demand time slots controlled by an ATM switch.

30. The system of claim 27 wherein the phase shifters are used to form a narrow vertical antenna pattern.

31. The system of claim 27 wherein said subscriber stations wherein a subscriber transmitter of said subscriber receiver/transmitter provides means for modulating a carrier with signal intelligence;

said intelligence including time division multiple access (TDMA).

32. The system of claim 31 wherein said subscriber transmitter transmits in packet bursts.

33. A wireless point-to-multipoint transmission system comprising:

a transmitter means for generating signals over a given band of frequencies; and

an antenna system located at a point in a node and coupled to said transmitter means for radiating signals over said given band of frequencies about said node;

said antenna system comprising a plurality of spaced unidirectional antennas and said unidirectional antennas including one polarization type spaced between two opposite polarization types so the polarization alternates about the node, each of said unidirectional antennas comprising a plurality of linear arrays of radiating elements with a phase shifter between each radiating element, each of said linear arrays of said unidirectional antennas coupled to one of said contiguous sub-frequency band transmitters.

34. The system of claim 33 wherein each of said unidirectional antennas includes a plurality of vertical linear arrays.

35. The system of claim 34 wherein there is an amplifier for each linear array.

36. The system of claim 34 wherein the phase shifters provide proportional phasing between each radiating element.

37. The system of claim 34 including a polarizer for each linear array.

38. The system of claim 33 wherein said system is a telephony system and said transmitter means is modulated with telephony.

39. The system of claim 33 wherein said system is a video system and said transmitter means is modulated with video information.

40. The system of claim 33 wherein said transmitter means is modulated with data signals.

41. The system of claim 33 wherein SONET OC-n signals are demultiplexed to OC-1 signals and the OC-1 signals are multiplexed at a central office and sent to the node which includes a node receiver where the OC-1 signals are demultiplexed and applied to said transmitter means.