Integrated cellular communications system

• US 5,446,756 A
• Filed: 10/28/1993
• Issued: 08/29/1995
• Est. Priority Date: 03/19/1990
• Status: Expired due to Term

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: Celsat America, Inc.
• Inventors: Mallinckrodt, Albert J.
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US08/145,246
• Time in Patent Office: 670 Days
• Field of Search: 455/19, 455/54.1, 455/69, 455/33.1, 375/1, 375/14, 379/59
• US Class Current: 375/130
• 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 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. Two-way adaptive power control and signal quality monitoring and power control responsive thereto are provided for controlling the power output levels of transmitters to the minimum necessary for satisfactory communications. Each transmission includes a code representative of the transmitter output power level. Receivers compare this code to the received signal strength and adjust their associated transmitter power output level accordingly. Bit error rate and SNR are monitored by receivers to develop a measure of signal quality. A signal quality code is transmitted to remote units and transmission output power level is adjusted in response. Timing signals are provided by one or more nodes to obtain user position information.

Claims

1. A cellular communication system comprising:

(a) a first transceiver comprising

a first receiver for receiving a first signal,

quality measurement means for determining the quality of said first signal and for generating a first quality signal representative of the quality of said first signal, and

a first transmitter for transmitting a second signal and said first quality signal;

(b) a second transceiver comprising

a second transmitter for transmitting said first signal,

a second receiver for receiving said second signal and said first quality signal,

a history compilation means for compiling history data relating to received first quality signals,

signal strength measurement means for measuring the signal strength of said second signal,

a processor means for processing said first quality signal, said compiled history data and said signal strength of said second signal for providing a path loss signal, and

controller means for controlling the output power level of said first signal in accordance with said path loss signal.

2. A cellular communication system as in claim 1 wherein:

said second transceiver further comprises;

a quality means for determining the quality of said second signal and for producing a second quality signal representative of the quality of said second signal, and

said second transmitter for transmitting said first signal and said second quality signal;

said first transceiver further comprises;

said first receiver for receiving said first signal and said second quality signal,

a history compilation means for compiling history data relating to received second quality signals,

a measurement means for measuring the signal strength of said first signal,

a processor means for processing said second quality signal, said compiled history data and said signal strength of said first signal for providing a path loss signal, and

a controller means for controlling the output power level of said second signal in accordance with said path loss signal.

3. A method for communicating between first and second transceivers, each transceiver comprising a transmitter and a receiver, the method comprising:

generating a quality signal representative of the quality of a received first signal;

transmitting the quality signal of the respective transceiver and a second signal to the other transceiver;

receiving the transmitted quality signal and second signal from the other transceiver;

measuring the signal strength of the received second signal;

compiling history data relating to the received quality signals;

processing the quality signal the compiled history data and the signal strength of the second signal to provide a path loss signal; and

controlling the associated transmitter output power level in response to path loss signal.