System and method for controlling transmission power

• US 6,144,860 A
• Filed: 10/27/1997
• Issued: 11/07/2000
• Est. Priority Date: 10/28/1996
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Komatsu, Masahiro
• Primary Examiner(s): Hunter, Daniel S.
• Assistant Examiner(s): WYCHE, MYRON
• Application Number:
  US08/958,492
• Time in Patent Office: 1,107 Days
• Field of Search: 455/572, 455/69, 455/423, 455/522, 455/70, 370/342
• US Class Current: 455/522
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters

Abstract

A transmission power control system suitable in use for a mobile communications system in which communications are performed through a many-valued encoding operation in which codes are represented with symbols. CIR calculating means is disposed in the transmission station and calculates a CIR by subtracting an interference signal level from a desired signal level of a transmission signal, wherein the desired signal level is obtained based on an average power of inverse-modulated pilot symbols each obtained by inverse-modulating a pilot symbol with a theoretical value of the pilot symbol, and wherein the interference signal level is obtained based on a distribution of inverse-modulated pilot symbols each obtained by inverse-modulating a pilot symbol with a theoretical value of the pilot symbol. Transmission power indicating means is disposed in the transmission station and transmits an indication for transmission power control according to the CIR of the transmission signal from the remote call station. Transmission power adjusting means is disposed in the remote call station and varies transmission power according to the indication for transmission power control from the transmission station. The quality of a receive signal can be maintained by improving the measurement accuracy of a received signal level.

Claims

1. A transmission power control system suitable in use for a mobile communications system, in which communications between a base station and a mobile station are performed through a many-valued encoding operation in which codes are represented with symbols, said base station acting as a transmission station or a remote call station, said mobile station acting as a remote call station or a transmission station, said base station having a transmitter and a receiver and said mobile station having a transmitter and a receiver, comprising:

CIR calculating means disposed in said transmission station, for calculating a CIR by subtracting an interference signal level from a desired signal level of a transmission signal, wherein said desired signal level is obtained based on an average power of inverse-modulated pilot symbols each obtained by inverse-modulating a pilot symbol with a theoretical value of said pilot symbol, and wherein said interference signal level is obtained based on a distribution of inverse-modulated pilot symbols each obtained by inverse-modulating a pilot symbol with a theoretical value of said pilot symbol,

transmission power indicating means disposed in said transmission station, for transmitting an indication for transmission power control according to the CIR of said transmission signal from said remote call station, and

transmission power adjusting means disposed in said remote call station, for varying transmission power according to the indication for transmission power control from said transmission station.

2. A transmission power control system suitable in use for a mobile communications system, in which communications between a base station and a mobile station are performed through a many-valued encoding operation in which codes are represented with symbols, said base station acting as a transmission station or a remote call station, said mobile station acting as a remote call station or a transmission station, said base station having a transmitter and a receiver and said mobile station having a transmitter and a receiver, comprising:

CIR calculating means disposed in said transmission station, for calculating a CIR by subtracting an interference signal level from a desired signal level of a transmission signal, wherein said desired signal level is obtained based on an average power of inverse-modulated data each obtained by inverse-modulating known data among received data with a theoretical value and by inverse-modulating unknown data with a decision value judged after demodulation, and wherein said interference signal level is obtained based on a distribution of inverse-modulated data each obtained by inverse-modulating known data among said received data with a theoretical value and by inverse-modulating unknown data with a decision value judged after demodulation,

transmission power indicating means disposed in said transmission station, for transmitting an indication for transmission power control according to the CIR of said transmission signal from said remote call station, and

transmission power adjusting means disposed in said remote call station, for varying transmission power according to the indication for transmission power control from said transmission station.

3. A transmission power control system suitable in use for a mobile communications system, in which communications between a base station and a mobile station are performed through a many-valued encoding operation in which codes are represented with symbols, said base station acting as a transmission station or a remote call station, said mobile station acting as a remote call station or a transmission station, said base station having a transmitter and a receiver and said mobile station having a transmitter and a receiver, comprising:

CIR calculating means disposed in said transmission station, for calculating a CIR by subtracting an interference signal level from a desired signal level of a transmission signal, wherein said desired signal level is obtained based on an average power of inverse-modulated pilot symbols each obtained by weighting a pilot symbol with a fading estimated value and then inverse-modulating the weighted pilot symbol with a theoretical value, and wherein said interference signal level is obtained by weighting pilot symbols with a fading estimated value, then square averaging the weighted pilot symbols, and then subtracting the squared result from said desired signal level,

transmission power indicating means disposed in said transmission station, for transmitting an indication for transmission power control according to the CIR of said transmission signal from said remote call station, and

transmission power adjusting means disposed in said remote call station, for varying transmission power according to the indication for transmission power control from said transmission station.

4. A method for controlling transmission power of a mobile communications system, in which communications between a base station and a mobile station are performed through a many-valued encoding operation in which codes are represented with symbols, said base station acting as a transmission station or a remote call station, said mobile station acting as a remote call station or a transmission station, said base station having a transmitter and a receiver and said mobile station having a transmitter and a receiver, comprising the steps of:

calculating a CIR by subtracting an interference signal level from a desired signal level of a transmission signal, wherein said desired signal level is obtained based on an average power of inverse-modulated pilot symbols each obtained by inverse-modulating a pilot symbol with a theoretical value of said pilot symbol, and wherein said interference signal level is obtained based on a distribution of inverse-modulated pilot symbols each obtained by inverse-modulating a pilot symbol with a theoretical value of said pilot symbol,

transmitting an indication for transmission power control according to the CIR of said transmission signal from said remote call station, and

varying transmission power according to the indication for transmission power control from said transmission station.

5. A method for controlling transmission power of a mobile communications system, in which communications between a base station and a mobile station are performed through a many-valued encoding operation in which codes are represented with symbols, said base station acting as a transmission station or a remote call station, said mobile station acting as a remote call station or a transmission station, said base station having a transmitter and a receiver and said mobile station having a transmitter and a receiver, comprising the steps of:

calculating a CIR by subtracting an interference signal level from a desired signal level of a transmission signal, wherein said desired signal level is obtained based on an average power of inverse-modulated data each obtained by inverse-modulating known data among received data with a theoretical value and by inverse-modulating unknown data with a decision value judged after demodulation, and wherein said interference signal level is obtained based on a distribution of inverse-modulated data each obtained by inverse-modulating known data among said received data with a theoretical value and by inverse-modulating unknown data with a decision value judged after demodulation,

transmitting an indication for transmission power control according to the CIR of said transmission signal from said remote call station, and

varying transmission power according to the indication for transmission power control from said transmission station.

6. A method for controlling transmission power of a mobile communications system, in which communications between a base station and a mobile station are performed through a many-valued encoding operation in which codes are represented with symbols, said base station acting as a transmission station or a remote call station, said mobile station acting as a remote call station or a transmission station, said base station having a transmitter and a receiver and said mobile station having a transmitter and a receiver, comprising the steps of:

calculating a CIR by subtracting an interference signal level from a desired signal level of a transmission signal, wherein said desired signal level is obtained based on an average power of inverse-modulated pilot symbols each obtained by weighting a pilot symbol with a fading estimated value and then inverse-modulating the weighted pilot symbol with a theoretical value, and wherein said interference signal level is obtained by weighting pilot symbols with a fading estimated value, then square averaging the weighted pilot symbols, and then subtracting the squared result from said desired signal level,

transmitting an indication for transmission power control according to the CIR of said transmission signal from said remote call station, and

varying transmission power according to the indication for transmission power control from said transmission station.