Base station apparatus, communication terminal apparatus, and communication method

Abstract

An assignment section 101 determines communication resource assignment to communication terminals based on a transmission rate at which communication is possible for each subcarrier of each communication terminal, and instructs a buffer section 102 to output forward transmission data. In addition, the assignment section 101 instructs a frame creation section 103 to perform forward transmission data symbolization, and also outputs a signal indicating communication resource assignment to each communication terminal. The buffer section 102 holds forward transmission data, and outputs forward transmission data to the frame creation section 103 in accordance with instructions from the assignment section 101. The frame creation section 103 symbolizes a resource assignment signal and transmission data to create a frame, which it outputs to a spreading section 104.

The invention claimed is: 
     
       1. A base station apparatus comprising:
 a receiver that receives a signal representing communication quality estimated per subcarrier in a communication terminal apparatus of a communicating party;   an assigner that assigns subcarriers for use in communication with the communication terminal apparatus in accordance with the signal representing communication quality; and   a transmitter that transmits data to the communication terminal apparatus using the subcarriers assigned by the assigner.   
     
     
       2. The base station apparatus of  claim 1  wherein the transmitter transmits subcarrier assignment information per subcarrier. 
     
     
       3. The base station apparatus of  claim 1 , wherein the assigner assigns the subcarriers, for use in communication with the communication terminal apparatus, per time slot. 
     
     
       4. The base station apparatus of  claim 1 , wherein the assigner determines a spreading factor, of the data transmitted from the transmitter, in accordance with the signal representing communication quality. 
     
     
       5. A communication terminal apparatus comprising a demodulator that demodulates a signal, addressed to said communication terminal apparatus and carried by subcarriers, in accordance with the subcarrier assignment information transmitted from the base station apparatus of  claim 2 . 
     
     
       6. The communication terminal apparatus of  claim 5 , wherein the demodulator performs threshold determination of quality of the signal addressed to said communication terminal apparatus and demodulates said signal when the quality is above a predetermined threshold. 
     
     
       7. A communication method comprising:
 receiving a signal at a base station apparatus, said signal representing communication quality estimated per subcarrier in a communication terminal apparatus of a communicating party;   assigning subcarriers for use in communication with the communication terminal apparatus in accordance with the signal representing communication quality;   transmitting subcarrier assignment information and data to the communication terminal apparatus using the assigned subcarriers; and   demodulating a signal addressed to the communication terminal apparatus and carried by the subcarriers, in accordance with the subcarrier assignment information transmitted from the base station apparatus.   
     
     
       8. A communication method comprising:
 receiving a signal at a base station apparatus, said signal representing communication quality estimated per subcarrier in a communication terminal apparatus of a communicating party;   assigning subcarriers for use in communication with the communication terminal apparatus in accordance with the signal representing communication quality;   transmitting data to the communication terminal apparatus using the assigned subcarriers; and   performing threshold determination of quality of a signal addressed to the communication terminal apparatus and demodulating said signal when the quality is above a predetermined threshold.   
     
     
       9. A communication method comprising:
 receiving, at a base station apparatus, a signal transmitted from a terminal apparatus, the signal indicating communication quality calculated in said terminal apparatus for each of bands, into which a frequency domain comprised of subcarriers is divided, and each of the bands comprising a subcarrier;   assigning, to said terminal apparatus, a resource comprised of consecutive subcarriers in a part of the bands;   transmitting, from said base station apparatus to said terminal apparatus, assignment information indicating the resource assigned to said terminal apparatus; and   transmitting, from said base station apparatus to said terminal apparatus, data using the resource,   wherein the assignment information is transmitted using another resource which is different from the resource assigned to said terminal apparatus.   
     
     
       10. A communication method comprising:
 receiving, at a base station apparatus, a signal transmitted from a terminal apparatus, the signal indicating communication quality calculated in said terminal apparatus for each of bands, into which a frequency domain comprised of subcarriers is divided, and each of the bands comprising a subcarrier;   assigning, to said terminal apparatus, a resource comprised of consecutive subcarriers in a part of the bands;   transmitting, from said base station apparatus to said terminal apparatus, assignment information indicating the resource assigned to said terminal apparatus; and   transmitting, from said base station apparatus to said terminal apparatus, data using the resource,   wherein the assignment information is transmitted with a modulation scheme which is different from that for the data.   
     
     
       11. A communication method comprising:
 transmitting, from a terminal apparatus to a base station apparatus, a signal indicating communication quality calculated for each of bands, into which a frequency domain comprised of subcarriers is divided, and each of the bands comprising a subcarrier;   receiving, at said terminal apparatus, assignment information, which indicates a resource assigned to said terminal apparatus and which is transmitted from said base station apparatus to said terminal apparatus, the resource being comprised of consecutive subcarriers in a part of the bands; and   receiving, at said terminal apparatus, data transmitted from said base station apparatus using the resource, which said base station apparatus assigns to said terminal apparatus, in accordance with the assignment information,   wherein the assignment information is transmitted using another resource which is different from the resource assigned to said terminal apparatus.   
     
     
       12. A communication method comprising:
 transmitting, from a terminal apparatus to a base station apparatus, a signal indicating communication quality calculated for each of bands, into which a frequency domain comprised of subcarriers is divided, and each of the bands comprising a subcarrier;   receiving, at said terminal apparatus, assignment information, which indicates a resource assigned to said terminal apparatus and which is transmitted from said base station apparatus to said terminal apparatus, the resource being comprised of consecutive subcarriers in a part of the bands; and   receiving, at said terminal apparatus, data transmitted from said base station apparatus using the resource, which said base station apparatus assigns to said terminal apparatus, in accordance with the assignment information,   wherein the assignment information is transmitted with a modulation scheme which is different from that for the data.   
     
     
       13. A base station apparatus comprising:
 a receiver configured to receive a signal transmitted from a terminal apparatus, the signal indicating communication quality calculated in said terminal apparatus for each of bands, into which a frequency domain comprised of subcarriers is divided, and each of the bands comprises a subcarrier;   an assigner configured to assign, to said terminal apparatus, a resource comprised of consecutive subcarriers in a part of the bands;   a transmitter configured to transmit, to said terminal apparatus, assignment information indicating the resource assigned to said terminal apparatus, and configured to transmit, to said terminal apparatus, data using the resource,   wherein the assignment information is transmitted using another resource which is different from the resource assigned to said terminal apparatus.   
     
     
       14. A base station apparatus comprising:
 a receiver configured to receive a signal transmitted from a terminal apparatus, the signal indicating communication quality calculated in said terminal apparatus for each of bands, into which a frequency domain comprised of subcarriers is divided, and each of the bands comprises a subcarrier;   an assigner configured to assign, to said terminal apparatus, a resource comprised of consecutive subcarriers in a part of the bands;   a transmitter configured to transmit, to said terminal apparatus, assignment information indicating the resource assigned to said terminal apparatus, and configured to transmit, to said terminal apparatus, data using the resource,   wherein the assignment information is transmitted with a modulation scheme which is different from that for the data.   
     
     
       15. A terminal apparatus comprising:
 a transmitter configured to transmit, to a base station apparatus, a signal indicating communication quality calculated for each of bands, into which a frequency domain comprised of subcarriers is divided, and each of the bands comprises a subcarrier; and   a receiver configured to receive assignment information, which indicates a resource assigned to said terminal apparatus and which is transmitted from said base station apparatus, the resource being comprised of consecutive subcarriers in a part of the bands, and configured to receive data transmitted from said base station apparatus using the resource, which said base station apparatus assigns to said terminal apparatus, in accordance with the assignment information,   wherein the assignment information is transmitted using another resource which is different from the resource assigned to said terminal apparatus.   
     
     
       16. A terminal apparatus comprising:
 a transmitter configured to transmit, to a base station apparatus, a signal indicating communication quality calculated for each of bands, into which a frequency domain comprised of subcarriers is divided, and each of the bands comprises a subcarrier; and   a receiver configured to receive assignment information, which indicates a resource assigned to said terminal apparatus and which is transmitted from said base station apparatus, the resource being comprised of consecutive subcarriers in a part of the bands, and configured to receive data transmitted from said base station apparatus using the resource, which said base station apparatus assigns to said terminal apparatus, in accordance with the assignment information,   wherein the assignment information is transmitted with a modulation scheme which is different from that for the data.