Communication terminal apparatus and base station apparatus

Abstract

An allocation section 101 in a base station apparatus of the present invention sets the transmission rate of a transmit signal for a communication terminal apparatus based on a DRC signal transmitted from that communication terminal apparatus. A power margin information detector 117 detects power margin information from a demodulated signal generated by a demodulator 115, and, using that power margin information, a power setting section 118 makes a setting so as to give the minimum transmission power value at which received signal characteristics in each communication terminal apparatus meet the desired quality. Using the set transmission power value, the base station apparatus transmits a transmit signal of the set transmission rate to a communication terminal apparatus. By this means it is possible to suppress interference to a communication terminal apparatus that performs adaptive modulation communication with another base station apparatus and a communication terminal apparatus that performs adaptive modulation communication with the local base station apparatus at the same time.

1 . A base station apparatus comprising: 
 transmission rate setting means for setting a transmission rate of a data channel signal for a communication terminal apparatus based on reception quality of said communication terminal apparatus;    power value setting means for setting a minimum transmission power value at which reception quality of a data channel signal of a set transmission rate in said communication terminal apparatus meets a desired value; and    transmitting means for transmitting a data channel signal of said set transmission rate to said communication terminal apparatus using a set transmission power value.    
     
     
         2 . The base station apparatus according to  claim 1 , wherein said power value setting means is provided with reference reception quality detecting means for detecting a minimum necessary reference reception quality for having received signal characteristics meet a desired quality in a communication terminal apparatus with regard to a data channel signal of a set transmission rate, and sets a transmission power value using a difference between actual reception quality and said reference reception quality.  
     
     
         3 . The base station apparatus according to  claim 1 , wherein: 
 said transmission rate setting means sets a transmission rate notified by a communication terminal apparatus as a transmission rate of a data channel signal for said communication terminal apparatus; and    said power value setting means sets a minimum transmission power value notified by said communication terminal apparatus as a transmission power value for said communication terminal apparatus.    
     
     
         4 . The base station apparatus according to  claim 1 , wherein said power value setting means sets a transmission power value for a communication terminal apparatus using a difference between a transmission power value necessary to minimally meet a set transmission rate notified by said communication terminal apparatus and a normal transmission power value.  
     
     
         5 . The base station apparatus according to  claim 1 , wherein said power value setting means sets a transmission power value necessary to minimally meet a set transmission rate as a transmission power value for a communication terminal apparatus only when a high-speed transmission rate is applied.  
     
     
         6 . The base station apparatus according to  claim 1 , wherein said transmitting means transmits a control channel signal using an almost fixed transmission power value.  
     
     
         7 . The base station apparatus according to  claim 1 , wherein said power value setting means sets a transmission power value selected from a predetermined plurality of transmission power value candidates as a transmission power value for a communication terminal apparatus.  
     
     
         8 . The base station apparatus according to  claim 7 , wherein: 
 said plurality of transmission power value candidates is reported to a communication terminal apparatus; and    said power value setting means selects a transmission power value specified by said communication terminal apparatus from said plurality of transmission power values.    
     
     
         9 . A base station apparatus comprising: 
 transmission rate setting means for setting a transmission rate of a data channel signal for a communication terminal apparatus based on reception quality of a control channel signal in said communication terminal apparatus;    selecting means for selecting a communication terminal apparatus that should be a data channel signal transmission destination based on a set transmission rate;    determining means for determining whether or not data channel signal transmissions to communication terminal apparatuses with good communication quality among communication terminal apparatuses selected as transmission destinations have become predominant in a data channel; and    transmitting means for transmitting a control channel signal and a data channel signal for a communication terminal apparatus selected as a transmission destination using a transmission power value set based on a result of determination by said determining means.    
     
     
         10 . The base station apparatus according to  claim 9 , wherein said determining means is provided with detecting means for detecting a number of communication terminal apparatuses whose control channel signal reception quality exceeds a predetermined value among communication terminal apparatuses selected as transmission destinations, and performs determination using a number of communication terminal apparatuses exceeding said predetermined value.  
     
     
         11 . The base station apparatus according to  claim 10 , wherein said determining means is provided with calculating means for calculating a number of communication terminal apparatuses exceeding a predetermined value as a proportion of communication terminal apparatuses selected as transmission destinations, and performs determination using the calculated proportion.  
     
     
         12 . The base station apparatus according to  claim 9 , wherein said determining means is provided with distribution detecting means for detecting a distribution of control channel signal reception quality in communication terminal apparatuses selected as transmission destinations, and performs determination using the detected distribution.  
     
     
         13 . The base station apparatus according to  claim 12 , wherein said transmitting means is provided with change amount setting means for setting a change amount of transmission power based on a distribution detected by said distribution detecting means, and transmits a control channel signal and a data channel signal for a communication terminal apparatus selected as a transmission destination using a transmission power value set based on the set change amount.  
     
     
         14 . The base station apparatus according to  claim 9 , further comprising estimating means for estimating a change in throughput with regard to a data channel signal based on a transmission rate corresponding to a communication terminal apparatus selected as a transmission destination of a data channel signal; 
 wherein said transmitting means transmits a control channel signal and a data channel signal for a communication terminal apparatus selected as a transmission destination using a transmission power value set based on the estimated change in throughput.    
     
     
         15 . A communication terminal apparatus that performs radio communication with a base station apparatus, said base station apparatus comprising: 
 transmission rate setting means for setting a transmission rate of a data channel signal for said communication terminal apparatus based on actual reception quality of a control channel signal in said communication terminal apparatus;    power value setting means for setting a minimum transmission power value at which reception characteristics of a data channel signal of a set transmission rate in said communication terminal apparatus meet a desired quality; and    transmitting means for transmitting a data channel signal of said set transmission rate to said communication terminal apparatus using a set transmission power value.    
     
     
         16 . The communication terminal apparatus according to  claim 15 , wherein a transmission rate and minimum transmission power value, or a difference between a transmission power value necessary to minimally meet a set transmission rate and a normal transmission power value, is notified to a base station apparatus only when a high-speed transmission rate is applied.  
     
     
         17 . A communication terminal apparatus that performs radio communication with a base station apparatus, said base station apparatus comprising: 
 transmission rate setting means for setting a transmission rate of a data channel signal for a communication terminal apparatus based on reception quality of a control channel signal in said communication terminal apparatus;    selecting means for selecting a communication terminal apparatus that should be a data channel signal transmission destination based on a set transmission rate;    determining means for determining whether or not data channel signal transmissions to communication terminal apparatuses with good communication quality among communication terminal apparatuses selected as transmission destinations have become predominant in a data channel; and    transmitting means for transmitting a control channel signal and a data channel signal for a communication terminal apparatus selected as a transmission destination using a transmission power value set based on a result of determination by said determining means.    
     
     
         18 . A communication method comprising: 
 a transmission rate setting step of setting a transmission rate of a data channel signal for a communication terminal apparatus based on actual reception quality of a control channel signal in said communication terminal apparatus;    a power value setting step of setting a minimum transmission power value at which reception signal characteristics in said communication terminal apparatus with regard to a data channel signal of a set transmission rate meet a desired quality as a transmission power value for said communication terminal apparatus; and    transmitting means for transmitting a data channel signal of a set transmission rate to said communication terminal apparatus using a set transmission power value.