Communication apparatus and communication system

Abstract

A communication apparatus includes a reference signal generating section, a transmitting section, a propagation estimating section, a first data acquiring section, and a decoding section. The reference signal generating section generates a first reference signal to enable a communicating party to estimate a propagation environment. The transmitting section transmits the first reference signal. The propagation estimating section estimates a first propagation estimation value of the propagation environment using a second reference signal transmitted from the communicating party. The first data acquiring section generates first data using the first propagation estimation value. The decoding section decodes a transmission signal encoded using a second propagation estimation value that is estimated by the communicating party using the first reference signal, to obtain second data using the first data.

The invention claimed is: 
     
       1. A communication apparatus, comprising:
 a reference signal generating section that generates a first reference signal to enable a communicating party to estimate a propagation environment;   a transmitting section that transmits the first reference signal;   a storing section that stores a known signal known between the apparatus and the communicating party   a propagation estimating section that obtains correlation between the known signal and a second reference signal transmitted from the communicating party, and generates a delay profile as an estimation value of propagation environment;   a first data acquiring section that reads out first data associated with the delay profile generated in the propagation estimating section, from a reference table that associates the delay profile with the first data; and   a decoding section that decodes a transmission signal encoded and transmitted using an estimation value of the propagation environment estimated by the communicating party using the first reference signal, to obtain second data using the first data read out by the first data acquiring section.   
     
     
       2. The communication apparatus according to  claim 1 , wherein the first data acquiring section calculates convolution of correlation between the known signal and the second reference signal, and a quantization vector stored in the reference table, and selects and reads out a vector code as the first data by performing metric calculation using the delay profile and the quantization vector subjected to the convolution. 
     
     
       3. The communication apparatus according to  claim 1 , wherein the first data acquiring section performs orthogonal conversion on the delay profile generated in the propagation estimating section to condense signal components, and reads out the first data using signal components. 
     
     
       4. A communication method, comprising:
 generating, in a first communication apparatus, a first reference signal to enable a second communication apparatus to estimate a propagation environment;   transmitting the first reference signal from the first communication apparatus to the second communication apparatus;   storing, in the first communication apparatus, a known signal known between the first communication apparatus and the second communication apparatus;   obtaining, in the first communication apparatus, correlation between the known signal and a second reference signal transmitted from the second communication apparatus, and generating, in the first communication apparatus, a delay profile as an estimation value of the propagation environment;   reading out, in the first communication apparatus, first data associated with the generated delay profile, from a reference table that associates the delay profile with the first data; and   decoding, in the first communication apparatus, a transmission signal encoded and transmitted using an estimation value of the propagation environment estimated by the second communication apparatus using the first reference signal, to second data using the first data read out.   
     
     
       5. A transmitting signal generating apparatus, comprising:
 A first transmission antenna and a second transmission antenna;   a plurality of outputs that output, to the first transmission antenna and to the second transmission antenna, a plurality of outputting signals simultaneously using a same frequency; and   a plurality of weighting coefficient sets stored in one or more buffers;   wherein the communication apparatus generates the plurality of outputting signals by multiplying a plurality of data by one weighting coefficient set of the plurality of weighting coefficient sets;   each of the outputting signals is a non-multiplexed signal or is a multiplexed signal into which the plurality of data is multiplexed;   the multiplexed signal and the non-multiplexed signal are multiplied by the one weighting coefficient set, selected from the plurality of weighting coefficient sets, for each of the outputting signals;   each of the plurality of weighting coefficient sets includes a weighting coefficient for each of the plurality of outputting signals; and   the plurality of weighting coefficient sets are vectors having no correlation with each other.   
     
     
       6. The transmitting signal generating apparatus according to claim 5, wherein,
 the one or more buffers store a relationship between the plurality of weighting coefficient sets and a polarization code indicating polarization information obtained from a plurality of inputs received by a plurality of reception antennas within the communication apparatus, and   each weighting coefficient set is calculated based on the polarization code and includes the weighting coefficient for each of the plurality of outputting signals.   
     
     
       7. A transmitting signal generating method, comprising:
 outputting to a first and a second transmission antenna within a communication apparatus a plurality of outputting signals simultaneously using a same frequency;   storing a plurality of weighting coefficient sets in one or more buffers; and   generating, by the communication apparatus, the plurality of outputting signals by multiplying a plurality of data by one weighing coefficient set of the plurality of weighting coefficient sets, wherein:   each of the outputting signals is a non-multiplexed signal or is a multiplexed signal into which the plurality of data is multiplexed;   the multiplexed signal and the non-multiplexed signal are multiplied by the one weighting coefficient set, selected from the plurality of weighting coefficient sets for each of the outputting signals;   each of the plurality of weighting coefficient sets includes a weighting coefficient for each of the plurality of outputting signals; and   the plurality of weighting coefficient sets are vectors having no correlation with each other.   
     
     
       8. The transmitting signal generating method according to claim 7, further comprising,
 storing a relationship between the plurality of weighting coefficient sets and a polarization code indicating polarization information obtained from a plurality of inputs received by a plurality of reception antennas within the communication apparatus, and   wherein each weighting coefficient set is calculated based on the polarization code and includes the weighting coefficient for each of the plurality of outputting signals.