Power control of an integrated cellular communications system

• US 5,878,329 A
• Filed: 01/08/1997
• Issued: 03/02/1999
• Est. Priority Date: 03/19/1990
• Status: Expired due to Fees

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: Celsat America, Inc.
• Inventors: Mallinckrodt, Albert Jack
• Primary Examiner(s): LE, THANH C
• Application Number:
  US08/780,519
• Time in Patent Office: 783 Days
• Field of Search: 455/33.1, 455/33.4, 455/34.1, 455/53.1, 455/54.1, 455/54.2, 455/62, 455/63, 455/67.1, 455/69, 455/70, 455/422, 455/507, 455/517, 455/522, 455/524, 455/68, 370/311, 370/320, 370/335, 370/342, 375/200
• US Class Current: 455/69
• 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 7/18543 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: 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 1/0042 Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0047 Decoding adapted to other signal detection operation in conjunction with sequence estimation or equalization H04L25/03286
• 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: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/20 using error rate
• 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 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• 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
• 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. 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. Preferably, the invention provides power control of a cellular communications system using code division multiple access (CDMA) employing forward error correction coding (FECC) and spread spectrum waveforms to enhance the effective gain and selectivity of the system.

Claims

1. A cellular communication system having at least first and second transceivers, each transceiver comprising a transmitter and a receiver, the cellular communication system comprising:

a first transceiver comprising;

a first receiver for receiving a second transmitted signal and a second transmitter level signal; and

a first transmitter which transmits a first transmitted signal at a first controllable and variable power level and a first transmitter level signal which is representative of said first power level of said first transmitted signal;

a first measurement means for measuring the signal strength of said second transmitted signal;

a first processor means for processing said second transmitter level signal and said signal strength of said second transmitted signal to produce a path loss estimate for said second transmitted signal;

a first controller means for adjusting and controlling the power level of said first transmitted signal to a desired signal strength in accordance with said path loss for said second transmitted signal to maintain the power level of said first transmitted signal at a minimum power level;

a second transceiver comprising;

a second transmitter for transmitting said second transmitted signal at a second controllable and variable power level and said second transmitter level signal which is representative of said second power level of said second transmitted signal;

a second receiver for receiving said first transmitted signal and said first transmitter level signal;

a second measurement means for measuring the signal strength of said first transmitted signal;

a second processor means for processing said first transmitter level signal and said signal strength of said first transmitted signal to produce a path loss estimate for said first transmitted signal; and

a second controller means for adjusting and controlling the power level of said second transmitted signal in accordance with said path loss estimate for said first transmitted signal to maintain the power level of said second transmitted signal at a minimum power level.

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

transmitting a first transmitted signal by the transmitter of the first transceiver at an adjustable and controllable power level and transmitting a first transmitter level signal which is representative of the output power level of the first transmitted signal;

receiving the first transmitted signal and first transmitter level signal at the receiver of the second transceiver;

measuring the received signal strength of the first transmitted signal of the first transceiver at the receiver of the second transceiver;

comparing the measured signal strength of the first transmitted signal to the received first transmitter level signal at the second transceiver;

providing a path loss estimate representative of the difference between the measured signal strength of the first transmitted signal and the first transmitter level signal;

adjusting the output power level of the transmitter of the second transceiver in accordance with the path loss estimate of the first transmitted signal to maintain the output power level at a minimum power level;

transmitting a second transmitted signal by the transmitter of the second transceiver at an adjustable and controllable power level and transmitting a second transmitter level signal which is representative of the output power level of the second transmitted signal;

receiving the second transmitted signal and second transmitter level signal at the receiver of the first transceiver;

measuring the received signal strength of the second transmitted signal of the second transceiver at the receiver of the first transceiver;

comparing the measured signal strength of the second transmitted signal to the received second transmitter level signal at the first transceiver;

providing a path loss estimate representative of the difference between the measured signal strength of the second transmitted signal and the second transmitter level signal; and

adjusting the output power level of the transmitter of the first transceiver in accordance with the path loss estimate of the second transmitted signal to maintain the output power level at a minimum power level.