Integrated cellular communications system

• US 5,339,330 A
• Filed: 10/24/1991
• Issued: 08/16/1994
• Est. Priority Date: 03/19/1990
• Status: Expired due to Term

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: David D. Otten
• Inventors: Mallinckrodt, Albert J.
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US07/781,972
• Time in Patent Office: 1,027 Days
• Field of Search: 375/1, 380/34, 370/18, 379/59, 379/60, 455/33.1-33.4, 455/53.1, 455/54.1, 455/54.2
• US Class Current: 370/320
• CPC Class Codes: H04B 7/18517 Transmission equipment in earth stations
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity
• CPC Class Codes: H04B 7/18543 for adaptation of transmission parameters, e.g. power control for detecting or preventing errors in the information received H04L1/00
• CPC Class Codes: H04B 7/18558 Arrangements for managing communications, i.e. for setting up, maintaining or releasing a call between stations
• CPC Class Codes: H04B 7/2041 Spot beam multiple access
• CPC Class Codes: H04B 7/216 Code division or spread-spectrum multiple access [CDMA, SSMA]
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04L 1/004 by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 5/02 Channels characterised by the type of signal
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance
• CPC Class Codes: H04W 52/228 using past power values or information
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

A cellular communications system is provided having both surface and satellite nodes which are fully integrated for providing service over large areas. A spread spectrum system is used with code division multiple access (CDMA) employing forward error correction coding (FECC) to enhance the effective gain and selectivity of the system. Multiple beam, relatively high gain antennas are disposed in the satellite nodes to establish a first set of cells, and by coupling the extra gain obtained with FECC to the high gain satellite-node antennas, enough gain is created in the satellite part of the system such that a user need only use a small, mobile handset with a non-directional antenna for communications with both ground nodes and satellite nodes. User position information is also available. A digital data interleaving feature reduces fading. Each transmitter includes a coder representative of its output power level. Receivers compare this code to the received signal strength and adjust their associated transmitter power output level accordingly. An inter-cell bus is formed in a super-surface node which receives signals from a plurality of cells, frequency multiplexes those signals and transmits the multiplexed signal to the plurality of cells.

Claims

1. A cellular communications system comprising:

at least one space node having a multiple beam antenna positioned so to establish a first set of cells, each space node including means for transmitting and receiving different predetermined sets of code division multiple access coded, spread spectrum waveforms digitally modulated and incorporating forward error correction coding with the waveforms being located in a predetermined frequency band common to all space nodes;

the antenna having a reflector with a multiple element feed disposed in the focal region of the reflector;

at least one surface node positioned so to establish a second set of cells, each surface node including means for transmitting and receiving the predetermined sets of code division multiple access coded, spread spectrum waveforms in the predetermined frequency band; and

a plurality of user units within the cells, each unit including means for communicating with each satellite node and with each surface node and being operatively responsive to a predetermined one of the sets of code division multiple access coded waveforms to thereby establish selective communication with at least one of the nodes.

3. The cellular communications system as in any one of the preceding claims further comprising position means for determining the position of a selected user unit by providing a timing signal to the user unit from one or more nodes, measuring the response time of the user unit to each timing signal, and determining the position of the user unit based on such measurements.

4. The cellular communications system as in claim 3 wherein the position means is also for determining which cell a selected user unit is in and for indicating the location of the cell.

5. The cellular communications system as in claims 1 or 2 wherein the user unit comprises a hand-held, portable transceiver having a substantially non-directional antenna for communicating with the nodes.

6. The communications system as in any one of claims 1 through 2 wherein:

a user unit and a node each comprises a transceiver for communicating with each other, each of the transceivers comprising;

a transmitter which outputs a transmitted signal at a controllable power level and includes level data in said signal which is representative of the power level of the transmitter; and

a receiver which receives the transmitted signal including the level data from the transmitter of the other transceiver, and which comprises;

measurement means for measuring the signal strength of the signal received from the other transmitter;

comparison means for comparing the measured signal strength to the received level data; and

means for controlling the output power level of the associated transmitter of the receiver in the transceiver in accordance with said comparison.

7. The cellular communications system of any of claims 1 through 3 wherein a satellite node includes processing means for receiving signals in a first predetermined plurality of beams, for multiplexing the received signals together and for transmitting the multiplexed signals in a second predetermined plurality of beams.

8. The cellular communications system as in claims 1 or 2 wherein the multi-beam antenna of the space node provides beams of relatively narrow beamwidth.

9. The cellular communications system as in claim 8 wherein the beamwidth of at least one of the beams of the antenna is less than one degree.

11. The cellular communications system as in claims 1 or 2 wherein the predetermined frequency band is divided into a plurality of sub-bands and communications with each space node are conducted in a first sub-band and communications with each surface node are conducted in a second sub-band.

2. A cellular communications system comprising:

at least one space node having a multiple beam antenna positioned so to establish a first set of cells, each space node including means for transmitting and receiving different predetermined sets of code division multiple access coded, spread spectrum waveforms digitally modulated and incorporating forward error correction coding with the waveforms being located in a predetermined frequency band common to all space nodes, wherein the antenna comprises a reflector with a multiple element feed disposed in the focal region of the reflector;

at least one surface node positioned so to establish a second set of cells, each surface node including means for transmitting and receiving the predetermined sets of code division multiple access coded, spread spectrum waveforms in the predetermined frequency band;

a plurality of user units within the cells, each unit including means for communicating with each satellite node and with each surface node and being operatively responsive to a predetermined one of the sets of code division multiple access coded waveforms to thereby establish selective communication with at least one of the nodes; and

a network controller operationally connected with each space node and with each surface node to selectively allocate communications with said user units among said space and surface nodes.

10. The cellular communications system as in claim 2 wherein the network controller controls the system such that the user unit communicates with the space node of the cell it is within or with the surface node of the cell it is within based on selectively considering the quality of the signal received from the user unit at each node, the location of the party with which the user unit desires to communicate, and a predetermined allocation of communication resources.

12. A cellular communications system comprising:

at least one space node having a multiple beam antenna positioned so to establish a first set of cells, each space node including means for transmitting and receiving different predetermined sets of code division multiple access coded, spread spectrum waveforms digitally modulated and incorporating forward error correction coding with the waveforms being located in a predetermined frequency band common to all space nodes;

at least one surface node positioned so to establish a second set of cells, each surface node including means for transmitting and receiving the predetermined sets of code division multiple access coded, spread spectrum waveforms in the predetermined frequency band;

a plurality of user units within the cells, each unit including means for communicating with each satellite node and with each surface node and being operatively responsive to a predetermined one of the sets of code division multiple access coded waveforms to thereby establish selective communication with at least one of the nodes; and

a network controller operationally connected with each space node and with each surface node to selectively allocate communications with said user units among said space and surface nodes, said network controller controlling the system such that the user unit communicates with the space node of the cell it is within or with the surface node of the cell it is within based on selectively considering the quality of the signal received from the user unit at each node, the location of the party with which the user unit desires to communicate, and a predetermined allocation of communication resources.