Point to multipoint communication system with subsectored upstream antennas

• US 6,304,762 B1
• Filed: 12/22/1997
• Issued: 10/16/2001
• Est. Priority Date: 12/23/1996
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Robinson, Eugene A., Chalkley, Hatcher E., Brobston, Michael L., Weiner, Douglas B., Myers, William K.
• Primary Examiner(s): Nguyen, Lee
• Application Number:
  US08/996,258
• Time in Patent Office: 1,394 Days
• Field of Search: 455/422, 455/424, 455/449, 455/517, 455/524, 455/561, 455/562, 455/62, 455/63, 455/67.1, 455/447, 455/446, 343/824, 343/853
• US Class Current: 455/562.1
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 84/14 WLL [Wireless Local Loop]; RLL [Radio Local Loop]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A point-to-multipoint communication system wherein the base station broadcasts the same frequency band signals over multiple sectors of given node. The base station includes a plurality of channel receivers (ch. 1-ch. n) for each sector and a plurality of antennas 36a and 36b selectively coupled to said channel receivers. The subsector antennas have these radiation centers offset from each other to present different coverage over the node.

Claims

1. A point to multipoint communications system comprising:

a base station nodal transmitter and base station transmit antenna and a base station receiver system and base station receive antenna system located at each node, said base station transmitter and base station transmit antenna broadcasting signals over a given downstream sector of said node;

remote transceiver stations located at the downstream sector of said node capable of receiving said signals from said base station transmitter broadcasting signals over said downstream sector of said node and capable of transmitting polarized return upstream signals to said base station nodal receiver system and base station receive antenna system;

said base station nodal receiver system including one or more receivers for each downstream sector for receiving said return upstream signals from said remote stations;

said base station nodal receive antenna system including a plurality of offset subsector antennas for said given downstream sector of said node such that the center of the coverage area in said downstream sector of each of the antennas is separated and offset to present different coverage over the downstream sector by the offset subsector antennas and said plurality of offset subsector antennas for each given downstream sector are of orthogonal polarization to the plurality of offset subsector antennas for the adjacent downstream sector such that the polarization of the receive antenna system alternates from sector to sector about the node; and

means for selectively coupling said offset subsector antennas of said downstream sector of said node to said one or more base station nodal receivers for each downstream sector.

2. The system of claim 1 wherein said remote transceiver stations include a directional transmit antenna.

3. The system of claim 1 wherein said directional transmit antenna at said remote station has a beam width of less than 5 degrees.

4. The system of claim 3 wherein said offset subsector antennas for each downstream sector are coupled to separate receivers and adapted to receive different receive frequencies.

5. The system of claim 1 wherein said plurality of offset subsector antennas is two and said centers of radiation are centered with a first subsector antenna coverage centered at the left half of the downstream sector and a second subsector antenna coverage centered at the right half of the downstream sector.

6. The system of claim 5 wherein said selective means includes switching the one of the two offset subsector antennas with the best signal to the base station receiver for that sector.

7. The system of claim 6 wherein said selective means includes means for receiving the signal from both offset subsector antennas, and detecting the best signal.

8. The method of claim 7 wherein the means for detecting the best signal includes a comparator comparing both subsector antenna signals signals and the means for selecting includes a switch for switching that is responsive to a control signal from said comparator.

9. The system of claim 1 wherein said selective means includes switching the offset subsector antenna with the best signal in the downstream sector to the base station receiver for that sector.

10. A point to multiunit communications system comprising:

a plurality of base station transmitters and alternating orthogonal polarized sector antennas located at each node broadcasting signals such that the polarization of the downstream signals transmitted about the node from sector to sector of the node changes orthogonal polarization;

polarized remote transceiver stations capable of receiving polarized signals in each sector of the node where the polarization alternates about the node and capable of transmitting polarized return upstream signals back to a base station receiver system at the base station where the polarized upstream signals alternate polarization from sector to sector about the node;

said base station receiver system including one or more base station receivers for each downstream sector;

a base station receive antenna system including a plurality of polarized offset subsector antennas for each downstream sector such the center of the coverage area of the subsector antennas at each downstream sector is separated and offset to present different coverage over the downstream sector and the polarization of the plurality of offset subsector antennas for each downstream sector are orthogonal to the plurality of offset subsector antennas for the adjacent downstream sector such that the polarization of the base station receive antennas alternate from sector to sector about the node; and

means for selectively coupling said offset subsector antennas for said downstream sector to said one or more base station receivers for that downstream sector.

11. The system of claim 10 wherein said offset subsector antennas are coupled to separate base station receivers for that sector and adapted to receive different receive frequencies.

12. The system of claim 11 wherein said plurality of offset subsector antennas is two and said centers of radiation are centered with a first subsector antenna adapted to receive a first band of frequencies at the left half of the downstream sector and a second subsector antenna adapted to receive a different second band of frequencies centered at the right half of the downstream sectors and said first subsector antenna is coupled to a first of said base station receivers in said sector and said second subsector is coupled to a second of said base station receivers.

13. The system of claim 10 wherein said plurality of offset subsector antennas is two and said center of radiation of a first subsector antenna is centered at the left of each sector and said center of radiation of a second subsector antenna is centered at the right of each sector.

14. The system of claim 13 wherein said selective means includes switching the one of the two offset subsector antennas with the best signal to the base station receiver for that sector.

15. The system of claim 14 wherein said selective means includes means for receiving the signal from both offset signal and detecting the best signal.

16. The system of claim 15 wherein the means for detecting the best signal includes a comparator comparing both signals and the means for selecting includes a switch for switching that is responsive to a control signal from a comparator.

17. The system of claim 10 wherein said selective means includes switching the offset subsector antenna with the best signal in the sector to the base station receiver for that sector.

18. A point multipoint communications system comprising:

a base station nodal transmitter and base station transmit antenna and a base station receiver system and base station receive antenna system located at each node, said base station transmitter and base station transmit antenna broadcasting signals over a given downstream sector of said node;

remote transceiver stations located at the downstream sector of said node capable of receiving said signals from said base station transmitter broadcasting signals over said downstream sector of said node and capable of transmitting return upstream signals at different frequencies to said base station nodal receiver system and base station receive antenna system;

said base station nodal receiver system including for each downstream sector at least two receivers with said at least two receivers adapted to receive different receive frequencies;

said base station nodal receive antenna system including for each sector at least two offset subsector antennas with one of said subsector antennas coupled to a corresponding one of at least two base station receivers and a second one of said subsector antennas coupled to a second of said two base station receivers and said offset subsector antennas are offset such that the centers of coverage of the subsector antennas is separated and offset.

19. The system of claim 18 wherein said plurality of offset subsector antennas is two and said centers of radiation are centered with a first subsector antenna adapted to receive a first band of frequencies at the left half of the downstream sector and a second subsector antenna adapted to receive a different second band of frequencies centered at the right half of the downstream sectors and said first subsector antenna is coupled to a first of said base station receivers in said sector and said second subsector antenna is coupled to a second of said base station receivers.