CDMA/TDD radio communication system

Abstract

In addition to a structure of a conventional CDMA/TDD radio communication system, a base station includes a pilot signal generating circuit for generating a pilot signal that has a constant transmission power level and is known in mobile units and a pilot channel spreading circuit for transmitting the pilot signal to the mobile units through a transmission line. Each of the mobile units includes a pilot signal reception level measuring circuit for measuring reception power of the received pilot signal and a transmission power control circuit for controlling transmission power of a power amplification circuit based on the measured reception power of the received pilot signal.

We claim:  
     
       1. A code-division multiple access/time division duplex radio communication system comprising a base station and one or more mobile units, wherein: 
       said base station comprises:  
       pilot signal generating means for generating a pilot signal which has a constant transmission power level and which has contents that are previously known in said one or more mobile units;  
       pilot signal spreading means for spreading said pilot signal in accordance with spreading codes to generate a spread pilot signal; and  
       pilot signal transmitting means for transmitting said spread pilot signal in a bursting manner to said one or more mobile units; and  
       each of said mobile units comprises:  
       pilot signal despreading means for despreading said spread pilot signal to obtain said pilot signal;  
       pilot signal level measuring means for measuring a reception power of said pilot signal obtained by said despreading means; and  
       transmission power control means for controlling a transmission power based on the measured reception power of said pilot signal obtained by said despreading means.  
     
     
       2. A radio communication system according to  claim 1 , wherein each of said mobile units further comprises synchronization acquisition means for acquiring synchronization of the spreading codes by the spread pilot signal transmitted from said base station. 
     
     
       3. A radio communication system according to  claim 1 , wherein each of said mobile units further comprises synchronization holding means for holding synchronization of said spreading codes by the spread pilot signal transmitted from said base station. 
     
     
       4. A radio communication system according to  claim 1 , wherein each of said mobile units further comprises: 
       phase detecting means for obtaining a phase of a carrier wave by the spread pilot signal transmitted from said base station; and  
       despreading means for demodulating data utilizing an output of said phase detecting means.  
     
     
       5. A radio communication system according to  claim 1 , wherein each of said mobile units further comprises: 
       a local oscillator;  
       frequency offset detecting means for obtaining an offset of a carrier frequency in said local oscillator based on the spread pilot signal transmitted from said base station; and  
       frequency adjusting means for adjusting a frequency of the local oscillator using an output of said frequency offset detecting means.  
     
     
       6. A radio communication according to  claim 1 , wherein each of said mobile units further comprises: 
       synchronization acquisition means for acquiring synchronization of the spreading codes by the spread pilot signal transmitted from said base station;  
       synchronization holding means for holding synchronization of the spreading codes by the spread pilot signal transmitted from said base station;  
       phase detection means for obtaining a phase of a carrier wave by the spread pilot signal transmitted from said base station;  
       despreading means for demodulating data utilizing an output of said phase detection means;  
       frequency offset detection means for obtaining an offset of a carrier frequency in a local oscillator of said mobile unit based on the spread pilot signal transmitted from said base station; and  
       frequency adjusting means for adjusting a frequency of the local oscillator of said mobile unit using an output of said frequency offset detection means.  
     
     
       7. A radio communication system according to any one of  claim 1  to  claim 6 , wherein an output of said pilot signal generating means is a data sequence of all “1's” or a data sequence of all “0's”. 
     
     
       8. A radio communication system according to any of  claim 1  to  claim 6 , wherein said base station further comprises pilot signal transmission level setting means for setting a transmission power of the pilot signal, which is to be transmitted, larger than a transmission power of a signal of another spreading channel. 
     
     
       9. A radio communication system according to  claim 8 , wherein an output of said pilot signal generating means is a data sequence of all “1's” or data sequence of all “0's”. 
     
     
       10. A radio communication system according to  claim 1 , wherein: 
       each of said mobile units further comprises data signal level measuring means for measuring a reception power of a data signal transmitted thereto; and  
       said transmission power control means controls the transmission power based on outputs of said pilot signal level measuring means and said data signal level measuring means.  
     
     
       11. A radio communication system according to  claim 10 , wherein each of said mobile units further comprises: 
       synchronization acquisition means for acquiring synchronization of the spreading codes by the spread pilot signal transmitted from said base station;  
       synchronization holding means for holding synchronization of the spreading codes by the spread pilot signal transmitted from said base station;  
       phase detection means for obtaining a phase of a carrier wave by the spread pilot signal transmitted from said base station;  
       despreading means for demodulating data utilizing an output of said phase detection means;  
       a local oscillator;  
       frequency offset detection means for obtaining an offset of a carrier frequency in said local oscillator based on the spread pilot signal transmitted from said base station; and  
       frequency adjusting means for adjusting a frequency of the local oscillator using an output of said frequency offset detection means.  
     
     
       12. A radio communication system according to  claim 10  or  claim 11 , wherein an output of said pilot signal generating means is a data sequence of all “1's” or a data sequence of all “0's”. 
     
     
       13. A radio communication system according to  claim 1 , wherein: 
       each of said mobile units further comprises data quality measuring means for measuring a quality of received data; and  
       said transmission power control means controls the transmission power based on outputs of said pilot signal level measuring means and said data quality measuring means.  
     
     
       14. A radio communication system according to  claim 13 , wherein each of said mobile units further comprises: 
       synchronization acquisition means for acquiring synchronization of said spreading codes by the spread pilot signal transmitted from said base station;  
       synchronization holding means for holding synchronization of said spreading codes by the spread pilot signal transmitted from said base station;  
       phase detection means for obtaining a phase of a carrier wave by the spread pilot signal transmitted from said base station;  
       despreading means for demodulating data utilizing an output of said phase detection means;  
       a local oscillator;  
       frequency offset detection means for obtaining an offset of a carrier frequency in said local oscillator based on the spread pilot signal transmitted from said base station; and  
       frequency adjusting means for adjusting a frequency of the local oscillator using an output of said frequency offset detection means.  
     
     
       15. A radio communication system according to  claim 13  or  claim 14 , wherein an output of said pilot signal generating means is a data sequence of all “1's” or a data sequence of all “0's”. 
     
     
       16. A radio communication system according to  claim 1 , wherein: 
       each of said mobile units further comprises data signal level measuring means for measuring a reception power of a data signal transmitted thereto and data quality measuring means for measuring a quality of received data; and  
       said transmission power control means controls the transmission power based on outputs of said pilot signal level measuring means, said data signal level measuring means and said data quality measuring means.  
     
     
       17. A radio communication system according to  claim 16 , wherein each of said mobile units further comprises: 
       synchronization acquisition means for acquiring synchronization of said spreading codes by the spread pilot signal transmitted from said base station;  
       synchronization holding means for holding synchronization of said spreading codes by the spread pilot signal transmitted from said base station;  
       phase detection means for obtaining a phase of a carrier wave by the spread pilot signal transmitted from said base station;  
       despreading means for demodulating data utilizing an output of said phase detection means;  
       a local oscillator;  
       frequency offset detection means for obtaining an offset of a carrier frequency in said local oscillator based on the spread pilot signal transmitted from said base station; and  
       frequency adjusting means for adjusting a frequency of the local oscillator using an output of said frequency offset detection means.  
     
     
       18. A radio communication system according to  claim 16  or  claim 17 , wherein an output of said pilot signal generating means is a data sequence of all “1's” or a data sequence of all “0's”. 
     
     
       19. A radio communication system according to  claim 1 , wherein: 
       said base station further comprises single tone transmission means for transmitting a single tone having a constant transmission power level and a single frequency to said mobile units;  
       each of said mobile units further comprises single tone level measuring means for measuring a reception power of said single tone; and  
       said transmission power control means controls the transmission power based on outputs of said pilot signal level measuring means and said single tone level measuring means.  
     
     
       20. A radio communication system according to  claim 19 , wherein each of said mobile units further comprises synchronization acquisition means for acquiring synchronization of said spreading codes by the spread pilot signal transmitted from said base station. 
     
     
       21. A radio communication system according to  claim 19 , wherein each of said mobile units further comprises synchronization holding means for holding synchronization of said spreading codes by the spread pilot signal transmitted from said base station. 
     
     
       22. A radio communication system according to  claim 19 , wherein each of said mobile units further comprises: 
       phase detection means for obtaining a phase of a carrier wave by the spread pilot signal transmitted from said base station; and  
       despreading means for demodulating data utilizing an output of said phase detection means.  
     
     
       23. A radio communication system according to  claim 19 , wherein each of said mobile units further comprises: 
       a local oscillator;  
       frequency offset detection means for obtaining an offset of a carrier frequency in said local oscillator based on the spread pilot signal transmitted from said base station; and  
       frequency adjusting means for adjusting a frequency of the local oscillator using an output of said frequency offset detection means.  
     
     
       24. A radio communication system according to  claim 19 , wherein each of said mobile units further comprises: 
       synchronization acquisition means for acquiring synchronization of the spreading codes by the spread pilot signal transmitted from said base station;  
       synchronization holding means for holding synchronization of the spreading codes by the spread pilot transmitted from said base station;  
       phase detection means for obtaining a phase of a carrier wave by the spread pilot signal transmitted from said base station;  
       despreading means for demodulating data utilizing an output of said phase detection means;  
       a local oscillator;  
       frequency offset detection means for obtaining an offset of a carrier frequency in said local oscillator based on the spread pilot signal transmitted from said base station; and  
       frequency adjusting means for adjusting a frequency of the local oscillator using an output of said frequency offset detection means.  
     
     
       25. A radio communication system according to any one of  claim 19  or  claim 24 , wherein an output of said pilot signal generating means is a data sequence of all “1's” or a data sequence of all “0's”. 
     
     
       26. A radio communication system according to any of  claim 19  to  claim 24 , wherein said base station further comprises pilot signal transmission level setting means for setting a transmission power of the pilot signal, which is to be transmitted, larger than a transmission power of a signal of another spreading channel. 
     
     
       27. A radio communication system according to  claim 8 , wherein an output of said pilot signal generating means is a data sequence of all “1's” or data sequence of all “0's”. 
     
     
       28. A radio communication system according to  claim 10 , wherein: 
       said base station further comprises single tone transmission means for transmitting a single tone having a constant transmission power level and a single frequency to said mobile units;  
       each of said mobile units further comprises single tone level measuring means for measuring a reception power of said single tone; and  
       said transmission power control means controls the transmission power based on outputs of said pilot signal level measuring means, said data signal level measuring means and said single tone level measuring means.  
     
     
       29. A radio communication system according to  claim 28 , wherein each of said mobile units further comprises: 
       synchronization acquisition means for acquiring synchronization of said spreading codes by the spread pilot signal transmitted from said base station;  
       synchronization holding means for holding synchronization of said spreading codes by the spread pilot signal transmitted from said base station;  
       phase detection means for obtaining a phase of a carrier wave by the pilot signal transmitted from said base station;  
       despreading means for demodulating data utilizing an output of said phase detection means;  
       a local oscillator;  
       frequency offset detection means for obtaining an offset of a carrier frequency in said local oscillator based on the spread pilot signal transmitted from said base station; and  
       frequency adjusting means for adjusting a frequency of the local oscillator using an output of said frequency offset detection means.  
     
     
       30. A radio communication system according to  claim 28  or  claim 29 , wherein an output of said pilot signal generating means is a data sequence of all “1's” or a data sequence of all “0's”. 
     
     
       31. A radio communication system according to  claim 13 , wherein: 
       said base station further comprises single tone transmission means for transmitting a single tone having a constant transmission power level and a single frequency to said mobile units;  
       each of said mobile units further comprises single tone level measuring means for measuring a reception power of said single tone; and  
       said transmission power control means controls the transmission power based on outputs of said pilot signal level measuring means, said data quality measuring means and said single tone level measuring means.  
     
     
       32. A radio communication system according to  claim 31 , wherein each of said mobile units further comprises: 
       synchronization acquisition means for acquiring synchronization of the spreading codes by the spread pilot signal transmitted from said base station;  
       synchronization holding means for holding synchronization of said spreading codes by the spread pilot signal transmitted from said base station;  
       phase detection means for obtaining a phase of a carrier wave by the spread pilot signal transmitted from said base station;  
       despreading means for demodulating data utilizing an output of said phase detection means;  
       a local oscillator;  
       frequency offset detection means for obtaining an offset of a carrier frequency in said local oscillator based on the spread pilot signal transmitted from said base station; and  
       frequency adjusting means for adjusting a frequency of the local oscillator using an output of said frequency offset detection means.  
     
     
       33. A radio communication system according to  claim 31  or  claim 32 , wherein an output of said pilot signal generating means is a data sequence of all “1's” or a data sequence of all “0's”. 
     
     
       34. A radio communication system according to  claim 16 , wherein: 
       said base station further comprises single tone transmission means for transmitting a single tone having a constant transmission power level and a single frequency to said mobile units;  
       each of said mobile units further comprises single tone level measuring means for measuring a reception power of said single tone; and  
       said transmission power control means controls the transmission power based on outputs of said pilot signal level measuring means, said data single level measuring means, said data quality measuring means and said single tone level measuring means.  
     
     
       35. A radio communication system according to  claim 34 , wherein each of said mobile units further comprises: 
       synchronization acquisition means for acquiring synchronization of said spreading codes by the spread pilot signal transmitted from said base station;  
       synchronization holding means for holding synchronization of said spreading codes by the spread pilot signal transmitted from said base station;  
       phase detection means for obtaining a phase of a carrier wave by the spread pilot signal transmitted from said base station;  
       despreading means for demodulating data utilizing an output of said phase detection means;  
       a local oscillator;  
       frequency offset detection means for obtaining an offset of a carrier frequency in said local oscillator based on the spread pilot signal transmitted from said base station; and  
       frequency adjusting means for adjusting a frequency of the local oscillator using an output of said frequency offset detection means.  
     
     
       36. A CDMA/TDD radio communication system according to  claim 34  or  claim 35 , wherein an output of said pilot signal generating means is a data sequence of all “1's” or a data sequence of all “0's”. 
     
     
       37. A code division multiple access/time division duplex radio communication system comprising a base station and, a mobile unit, wherein: 
       
         said base station comprises means for transmitting a data signal and a pilot signal, which has a constant transmission power level, to said mobile unit through at least one spreading channel; and  
       
       
         said mobile unit comprises means for controlling transmission power based on a reception power of said pilot signal and a reception power of said data signal transmitted to said mobile unit.  
       
     
     
       38. A code division multiple access/time division duplex radio communication system comprising a base station and a mobile unit, wherein: 
       
         said base station comprises means for transmitting a pilot signal, which has a constant transmission power level, to said mobile unit through at least one spreading channel; and  
       
         said mobile unit comprises means for controlling transmission power based on  ( i )  a reception power of said pilot signal and  ( ii )  a quality of received data, said quality being determined by measuring an error rate comprising at least one of a bit error rate and a frame error rate.    
     
     
       39. A code division multiple access/time division duplex radio communication system comprising a base station and a mobile unit, wherein: 
       
         said base station comprises means for transmitting a data signal and a pilot signal, which has a constant transmission power level, to said mobile unit through at least one spreading channel; and  
       
         said mobile unit comprises means for controlling transmission power based on  ( i )  a reception power of said pilot signal,  ( ii )  a reception power of said data signal transmitted to said mobile unit and  ( iii )  a quality of received data, said quality being determined by measuring an error rate comprising at least one of a bit error rate and a frame error rate.    
     
     
       40. A code division multiple access/time division duplex mobile unit comprising: 
       
         means for determining a reception power of a pilot signal which is transmitted from a base station at a constant level and a reception power of a data signal which is transmitted from said base station; and  
       
       
         means for controlling transmission power based on said determined reception power of said pilot signal and said determined reception power of said data signal.  
       
     
     
       41. A code division multiple access/time division duplex mobile unit comprising: 
       means for determining a reception power of a pilot signal which is transmitted from a base station at a constant level, a reception power of a data signal which is transmitted from said base station, and a quality of received data transmitted from said base station, said quality being determined by measuring an error rate comprising at least one of a bit error rate and a frame error rate; and  
       
         means for controlling transmission power based on said determined reception power of said pilot signal, said determined reception power of said data signal, and said determined quality of said received data.  
       
     
     
       42. A mobile unit according to  claim 40  or  41  further comprising synchronization acquisition means for acquiring synchronization of a spreading signal by said pilot signal transmitted from said base station.  
     
     
       43. A mobile unit according to  claim 40  or  41  further comprising synchronization holding means for holding synchronization of a spreading signal by said pilot signal transmitted from said base station.  
     
     
       44. A mobile unit according to  claim 40  or  41  further comprising: 
       
         phase detecting means for obtaining a phase of a carrier wave by said pilot signal transmitted from said base station; and  
       
       
         despreading means for demodulating data utilizing an output of said phase detecting means.  
       
     
     
       45. A mobile unit according to  claim 40  or  41  further comprising: 
       
         frequency offset detecting means for obtaining an offset of a carrier frequency in a local oscillator of said mobile unit by said pilot signal transmitted from said base station; and  
       
       
         frequency adjusting means for adjusting a frequency of said local oscillator of said mobile unit using an output of said frequency offset detecting means.  
       
     
     
       46. A code division multiple access/time division duplex base station comprising: 
       
         means for generating a pilot signal which has a constant transmission power level and which has contents that are previously known in a mobile unit; and  
       
       
         means for transmitting said pilot signal in a burst manner through at least one spreading channel.  
       
     
     
       47. A base station according to  claim 46  further comprising pilot signal transmission level setting means for setting a transmission power of said pilot signal, which is to be transmitted, larger than a transmission power of a signal of another spreading channel.  
     
     
       48. A base station according to  claim 46  or  47  wherein an output of said means for generating a pilot signal is a data sequence of all “ 1 's” or a data sequence of all “ 0 's”.  
     
     
       49. A code division multiple access/time division duplex radio communication method between a base station and a mobile unit comprising the steps of: 
       
         transmitting, in said base station, a data signal and a pilot signal through at least one spreading channel, said pilot signal having a constant transmission power level; and  
       
       
         controlling, in said mobile unit, transmission power based on a reception power of said pilot signal and a reception power of said data signal transmitted from said base station.  
       
     
     
       50. A code division multiple access/time division duplex radio communication method between a base station and a mobile unit, comprising the steps of: 
       
         transmitting, in said base station, a pilot signal through at least one spreading channel, said pilot signal having a constant transmission power level; and  
       
       
         controlling, in said mobile unit, transmission power based on a reception power of said pilot signal and a quality of received data, said quality being determined by measuring an error rate comprising at least one of a bit error rate and a frame error rate.  
       
     
     
       51. A code division multiple access/time division duplex radio communication method between a base station and a mobile unit, comprising the steps of: 
       
         transmitting, in said base station, a data signal and a pilot signal through at least one spreading channel, said pilot signal having a constant transmission power level; and  
       
       
         controlling, in said mobile unit, transmission power based on a reception power of said pilot signal, a reception power of said data signal transmitted from said base station, and a quality of received data, said quality being determined by measuring an error rate comprising at least one of a bit error rate and a frame error rate.