Antenna array for a cellular RF communications system

• US 4,128,740 A
• Filed: 02/14/1977
• Issued: 12/05/1978
• Est. Priority Date: 02/14/1977
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Graziano, Victor
• Primary Examiner(s): Claffy, Kathleen H.
• Assistant Examiner(s): Brigance, Gerald L.
• Application Number:
  US05/768,260
• Time in Patent Office: 659 Days
• Field of Search: 179/2 EB, 179/2 EA, 179/15 BZ, 325/51, 325/52, 325/53, 325/55, 325/64
• US Class Current: 455/447
• CPC Class Codes: H04B 7/2621 using frequency division multiple access [FDMA] H04B7/2615 takes precedence
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/24 Cell structures

Abstract

An array of antennas for a cellular RF communications system for providing communications to randomly placed transceivers in a given area. The antenna array includes a plurality of antenna sites located in the centers of cells. Each antenna site has a plurality of sectored antennas for providing a plurality of communication channels. A predetermined number of sites are used to constitute a subarray of cells to provide a set of communication channels and channel allocations are repeated from subarray to subarray. Channels are also so allocated as to minimize channel interference and optimize channel utilization. An omnidirectional antenna may be provided for each antenna site for signalling purposes.

Claims

1. A cellular RF Communications System for a plurality of mobile transceivers in a given geographical area of a cellular communications system, the system comprising:

an array of antennas made of a plurality of subarrays, each subarray having a number of cells,

a plurality of sector antennas located substantially at the center of each cell,

means for operating each of the sector antennas of cells of each subarray to provide a predetermined communication channel to the mobile transceivers which is different from that provided by the other sector antennas of the same cell, and

means for repeating channel allocations to sector antennas for subarray to subarray in a predetermined pattern,

means for positioning co-channel antennas with respect to one another so as to eliminate substantially side lobe and frontal lobe interferences from adjacent side and front co-channel sector antennas, and

means for physically spacing and spatially relating co-channel antennas so as to minimize frontal lobe interference from the back co-channel.

2. The system according to claim 1, wherein co-channel sector antennas are positioned so that a given sector antenna is subjected to only one co-channel interfering signal uninhibited by antenna beam restrictions wherein said one co-channel is selected so that its interference is minimal.

3. The system according to claim 2, comprising:

said subarray made of a predetermined number of cells and each cell having a predetermined number of sector antennas.

4. The system according to claim 2, including means for operating each of the sector antennas to provide a plurality of communication channels.

5. The system according to claim 2, wherein certain of cells include six sector antennas, each for providing six sections of illumination of about 60°

each.

6. The system according to claim 2, wherein four cells are used to form a subarray.

7. The antenna array according to claim 3, wherein two or more of sector antennas are allocated channels in a given sequence in a given subarray and the remaining antennas of the same subarray are allocated channels in a different sequence.

8. The antenna array according to claim 2, including an omnidirectional antenna in each cell for providing a signalling channel.

9. A method of providing communications channels to a plurality of mobile transceivers in a given area serviced by a cellular RF telecommunication system, the communications system having a plurality of antennas arranged in an array made of subarrays, each subarray having a plurality of cells, each cell provided with a centrally located antenna site, each site having a plurality of sector antennas, comprising the steps of:

operating the plurality of sector antennas of each array to provide different communications channels.

repeating channel allocations from subarray to subarray to increase utilization of channels available for the given area,

allocating communications channels among the sector antennas so as to eliminate substantially side lobe and frontal lobe interferences from adjacent side and front co-channel sector antennas, and

positioning co-channel antennas so that they are physically spaced and spatially related to one another so as to minimize frontal lobe interference from a back co-channel.

10. The method according to claim 9, including the step of positioning co-channel sector antennas so that a given sector antenna is subjected to only one co-channel interfering signal uninhibited by antenna beam restrictions wherein said one co-channel is selected so that its interference is minimal.

11. The method according to claim 9, including the steps of allocating channels for sector antennas in a given pattern for a given sequence and allocating channels in a different sequence in the same subarray.

12. The method according to claim 9, including the step of operating individual sector antennas to provide multiple communication channels.

13. The method according to claim 9, including the step of providing an onmidirectional antenna for each of the cells for providing a signalling channel.