A cellular/satellite communications system with generation of a plurality of sets of intersecting antenna beams

• US 5,594,941 A
• Filed: 05/16/1995
• Issued: 01/14/1997
• Est. Priority Date: 01/11/1994
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Dent, Paul W.
• Primary Examiner(s): Pham, Chi H.
• Application Number:
  US08/442,168
• Time in Patent Office: 609 Days
• Field of Search: 455/12.1, 455/13.3, 455/13.4, 455/20, 455/22, 455/33.1, 455/33.4, 455/53.1, 455/54.1, 379/59, 370/95.3, 342/352, 342/354
• US Class Current: 455/13.4
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H01Q 25/007 using two or more primary active elements in the focal region of a focusing device for operation on different wavebands H01Q5/22
• CPC Class Codes: H04B 7/0837 using pre-detection combining H04B7/0868 takes precedence
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message
• CPC Class Codes: H04B 7/18567 Arrangements for providing additional services to the basic mobile satellite telephony service
• CPC Class Codes: H04B 7/2041 Spot beam multiple access
• CPC Class Codes: H04B 7/2046 SS-TDMA, TDMA satellite switching
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/021 Estimation of channel covariance
• CPC Class Codes: H04L 25/03203 Trellis search techniques
• CPC Class Codes: H04L 25/0328 with interference cancellation circuitry adaptations for interference cancellation within a sequence estimator H04L25/03305; interference related aspects of direct sequence spread spectrum H04B1/7097; interference related aspects of frequency hopping spread spectrum H04B1/715; see also H04B1/10
• CPC Class Codes: H04L 25/03299 : with noise-whitening circuitry
• CPC Class Codes: H04L 25/03331 : Arrangements for the joint estimation of multiple sequences
• CPC Class Codes: H04W 16/02 : Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/14 : Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 74/08 : Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 84/025 : with acknowledge back capability
• CPC Class Codes: H04W 84/042 : Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 84/06 : Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

A satellite system includes circuitry for forming at least a first and second set of antenna beams for communication with a respective first and second set of mobile stations. Neighboring beams in the first set intersect at an approximately -4 dB down point relative to the central beam peak, thereby defining for each beam an approximately -4 dB beam circumference having an approximately -4 dB beam diameter. The second set of antenna beams are displaced from the first set of antenna beams by less than the approximately -4 dB beam diameter.

Claims

1. A system for communicating between one or more central ground stations and a plurality of mobile or portable stations via at least one orbiting satellite comprising:

at least one central ground station having transmitter means to transmit a plurality of signals to a satellite for transponding;

at least one satellite having multi-channel transponder means for receiving said plurality of signals, frequency translating, filtering and amplifying said signals and forming weighted combinations of said signals for applying after power amplification to a multiple element antenna such that a first subset of said signals will be radiated using a first set of antenna beams having radiation patterns that touch at approximately a -4 dB down point relative to beam peak, said approximately -4 dB down point defining an approximately -4 dB diameter for each of said beams, and such that at least one other subset of said signals will be radiated by another set of antenna beams displaced from said first set of beams by less than the approximately -4 dB beam diameter.

2. The system of claim 1, wherein said approximately -4 dB down point is -4.5 dB.

3. A system for communicating between one or more central ground stations and a plurality of mobile or portable stations via at least one orbiting satellite comprising:

at least one central ground station having transmitter means to transmit a plurality of signals to a satellite for transponding;

at least one satellite having multi-channel transponder means for receiving said plurality of signals, frequency translating, filtering and amplifying said signals and forming weighted combinations of said signals for applying after power amplification to a multiple element antenna such that said signals are radiated for a first proportion of a time period using a first set of antenna beams having radiation patterns that touch at approximately a -4 dB down point relative to beam peak, said approximately -4 dB down point defining an approximately -4 dB diameter for each of said beams, and such that for at least one other proportion of said time period said signals are radiated by at least one other set of antenna beams displaced from said first set of beams by less than the approximate -4 dB beam diameter.

4. A method of communicating between a fixed ground station and a plurality of mobile stations using an orbiting satellite involving:

at said ground station grouping said mobile stations into a first number of sets each containing not more than a second number of mobile stations;

allocating the same communications channel to each of the mobiles in the same set, said communications channel comprising a frequency or a timeslot or a code or any unique combination of these;

transmitting signals from said ground station to said satellite for transponding to said mobile stations using their respectively allocated communications channels such that mobile stations in a first of said sets receive signals via a first set of satellite antenna beams that cross at approximately -4 dB down points relative to beam peak, said approximately -4 dB down points defining an approximately -4 dB diameter for each of said beams, and a different set of mobile stations receive their intended signals via a different set of satellite antenna beams that are displaced from said first set of beams by less than said approximately -4 dB beam diameter.

5. The method of claim 4, wherein said approximately -4 dB down point is -4.5 dB.

6. A system for communicating between one or more central ground stations and a plurality of mobile or portable stations via at least one orbiting satellite comprising:

at least one central ground station having receiver means to receive a plurality of signals from said mobile stations transponded by said at least one satellite;

at least one satellite having multi-channel transponder means for receiving signals from said plurality of mobile stations using a multiple-element antenna and for frequency translating, filtering and amplifying signals received at said antenna elements and forming weighted combinations of said signals for applying to separate transmitter means for transmission to said ground station receiving means such that a first subset of said transmitted signals corresponds to a first set of mobile signals received in a first set of antenna beams having radiation patterns that touch at approximately a -4 dB down point relative to beam peak, said approximately -4 dB down point defining an approximately -4 dB diameter for each of said beams, and such that at least one other subset of said transmitted signals corresponds to mobile signals received by another set of antenna beams displaced from said first set of beams by less than the approximately -4 dB beam diameter.

7. A system for communicating between one or more central ground stations and a plurality of mobile or portable stations via at least one orbiting satellite comprising:

at least one central ground station having receiver means to receive a plurality of signals from said mobile stations transponded by said at least one satellite;

at least one satellite having multi-channel transponder means for receiving signals from said plurality of mobile stations using a multiple-element antenna and for frequency translating, filtering and amplifying signals received at said antenna elements and sequentially forming groups of differently weighted combinations of said signals that are applied sequentially to a separate transmitter means for each member of the same group for transmission to said ground station receiving means such that a first group of said transmitted signals corresponds for a first proportion of a time period to a first set of mobile signals received in a first set of antenna beams having radiation patterns that touch at approximately a -4 dB down point relative to beam peak, said approximately -4 dB down point defining an approximately -4 dB diameter for each of said beams, and such that at least one other subset of said transmitted signals corresponds for a second proportion of said time period to mobile signals received by another set of antenna beams displaced from said first set of beams by less than the approximately -4 dB beam diameter.

8. A method of communicating between a fixed ground station and a plurality of mobile stations using an orbiting satellite involving:

at said ground station grouping said mobile stations into a first number of sets each containing not more than a second number of mobile stations;

allocating the same communications channel to each of the mobiles in the same set, said communications channel comprising a frequency or a timeslot or a code or any unique combination of these;

receiving signals at said ground station transponded by said satellite from said mobile stations using their respectively allocated communications channels such that mobile stations in a first of said sets are received by said satellite via a first set of satellite antenna beams that cross at approximately their -4 dB down points relative to beam peak, said approximately -4 dB down points defining an approximately -4 dB diameter for each of said beams, and a different set of mobile stations are received via a different set of satellite antenna beams that are displaced from said first set of beams by less than said approximately -4 dB beam diameter.