Adaptive transmitting and receiving device and method in wireless communication system using frequency division duplexing

An adaptive receiver in a wireless communication system using frequency division duplexing, comprising:

• a demodulator and decoder for receiving signals from a transmitter, and demodulating and decoding the signals;
• an SNR (signal to noise ratio) measuring unit for estimating channel gains or SNRs in a single code block through preambles or pilots output by the demodulator and decoder;
• and
• a received log likelihood ratio parameter determining unit for finding parameters from the channel gains or the SNRs estimated by the SNR measuring unit, and feeding the parameters back for adaptive transmission of the transmitter, the parameters including a mean and a normalized standard deviation of the SNRs in the single code block,
• wherein the receiver is to cause the transmitter to adjust transmit power to be equal to a sum of a first compensated power value Pmean, a second compensated power value Pstd, and a pre-determined transmit power, wherein Pmean corresponds to a difference between the mean of the SNRs and a predefined mean SNR for a determined antenna method, a modulation and a encoding method, Pstd corresponds to the normalized standard deviation of the SNRs, and the pre-determined transmit power is used to transmit the pilots or preambles.

An adaptive transmitting method of a wireless communication system using frequency division duplexing, comprising:

• (a) transmitting a pilot or a preamble to a receiver by using a predefined transmit power;
• (b) determining an antenna method, a modulation and encoding method, and a transmit power based on the parameters (received log likelihood ratio parameters) fed back from a receiver, the parameters including a mean and a normalized standard deviation of SNRs (Signal to Noise Ratios) calculated by the receiver, wherein the transmit power is equal to a sum of a first compensated power value Pmean, a second compensated power value Pstd, and a pre-determined transmit power, wherein Pmean corresponds to a difference between the mean of the SNRs and a predefined mean SNR for the determined antenna method, the modulation and the encoding method, Pstd corresponds to the normalized standard deviation of the SNRs and the pre-determined transmit power is used to transmit the pilot or the preamble;
• and
• (c) transmitting traffic data to the receiver by using the determined antenna method, the modulation and encoding method, and the transmit power.

An adaptive receiving method of a wireless communication system using frequency division duplexing, comprising:

• (a) estimating a complex channel gain (the complex channel gain being from a transmit antenna to a receive antenna) of each symbol in a single code block through a pilot or a preamble transmitted from a transmitter;
• (b) calculating parameters (received log likelihood ratio parameters) including a mean and a normalized standard deviation of SNRs (Signal to Noise Ratios) from the estimated complex channel gain (from a transmit antenna to a receive antenna) of each symbol in a single code block;
• and
• (c) feeding the calculated received log likelihood ratio parameters to the transmitter to cause the transmitter to adjust transmit power to be equal to a sum of a first compensated power value Pmean, a second compensated power value Pstd, and a pre-determined transmit power, wherein Pmean corresponds to a difference between the mean of the SNRs and a predefined mean SNR for a determined antenna method, a modulation and a encoding method, Pstd corresponds to the normalized standard deviation of the SNRs, and the pre-determined transmit power is used to transmit the pilot or the preamble.