Determination of data rate, based on power spectral density estimates

Abstract

The present invention relates to a method and a circuitry for estimating data transmission rate in a communication system. The communication system utilises variable data transmission rates. A transmission signal between two stations of the system includes a plurality of data symbols over a sequence of data frames. A data frame of a received transmission signal is classified in accordance with a predefined classification of the data transmission rates, whereafter the data transmission rate of the received data frame is estimated on basis of said classification.

1 - 24 . (canceled)  
   
   
       25 . A method for estimating data transmission rate in a communication system with variable data transmission rates wherein a transmission signal includes a plurality of data symbols over a sequence of data frames, comprising: 
 classifying a data frame of a received transmission signal in accordance with a predefined classification of the data transmission rates; and    estimating the data transmission rate of the received data frame on basis of said classification;    wherein the data frames are classified based on a power spectral density function estimate of the received transmission signal; and    the estimation of the power spectral density function comprises a step of dividing the total number of received data symbols into blocks, wherein each block includes predefined amount of consecutive points of the signal.    
   
   
       26 . A method according to  claim 25 , wherein the data frames are classified based on frequency content of the received transmission signal.  
   
   
       27 . A method according to  claim 25 , wherein the power spectral density function estimate of the received transmission signal is calculated using a Fast Fourier Transform algorithm and coherent averaging of the data symbol sequence of the received transmission signal.  
   
   
       28 . A method according to  claim 27 , wherein a modified Fast Fourier Transform algorithm is used, said modified Fast Fourier Transform algorithm taking predefined symmetries of the transmitted data symbols into account.  
   
   
       29 . A method according to  claim 25 , wherein the estimation of the power spectral density function further comprises the steps of: 
 calculating an individual Fourier Transform for each of said blocks for receiving squared real and imaginary points for each frequency of the signal;    calculating an individual power spectral function estimate of each of the blocks by summing the squared real and imaginary points; and    calculating the power spectral density function estimate by averaging the individual power spectral function estimates.    
   
   
       30 . A method according to  claim 25 , wherein the power spectral density function estimate is normalised by summing the elements of the power spectral density function for obtaining a sum of the elements and by dividing each of said elements by the sum.  
   
   
       31 . A method according to  claim 25 , wherein the classification further comprises a step of removing effects of noise.  
   
   
       32 . A method according to  claim 31 , wherein the data frames are classified based on a power spectral density function estimate of the received transmission signal, the noise removal comprising subtracting an inverse of the number of elements of the power spectral density function from the power spectral density function.  
   
   
       33 . A method according to  claim 25 , wherein the classification comprises further: 
 calculating a variable from the power spectral density function for characterising the frequency content of the power spectral density function; and    comparing the variable against limit values of a classification decision structure.    
   
   
       34 . A method according to  claim 33 , wherein the variable characterising the frequency content of the received transmission signal comprises center-of-moment of the power spectral density function.  
   
   
       35 . A method according to  claim 33 , wherein the magnitude of the variable indicates the relative amount of high frequencies present in the power spectral density function.  
   
   
       36 . A method according to  claim 25 , wherein the communication system comprises a cellular code division multiple access communications network, and the data is transmitted between a mobile station and a base station of the network over a radio interface.  
   
   
       37 . A method according to  claim 25 , wherein the number of data transmission rate classes of the predefined classification equals the number of possible data transmission rates.  
   
   
       38 . A method according to  claim 25 , wherein the number of data transmission rate classes of the predefined classification is lower than the number of the possible data transmission rates.  
   
   
       39 . A method for channel estimation is a cellular code division multiple access communication system wherein a plurality of data symbols is spread over a sequence of data frames in a transmission signal with variable data transmission rates, comprising: 
 classifying a data frame of a received transmission signal in accordance with a predefined classification of the data transmission rates; and    estimating the data transmission rate of the received data from on basis of said classification;    wherein the data frames are classified based on a power spectral density function estimate of the received transmission signal; and    the estimation of power spectral density function comprises a step of dividing the total number of received data symbols into blocks, wherein each block includes a predefined amount of consecutive points of the signal.    
   
   
       40 . A method according to  claim 39 , wherein the estimate of the data transmission rate is used to assist in rate selection for Viterbi decoding of the received data symbols.  
   
   
       41 . A method according to  claim 39 , wherein a data rate information received from a transmitting station and the estimate data transmission rate are both used for the channel estimation.  
   
   
       42 . Signal receiving circuitry for use in a communication system with variable data transmission rates wherein data is transmitted as a plurality of data symbols over a sequence of data frames, the signal receiving circuitry comprising a rate estimation unit for receiving an incoming transmission signal, for classifying a data frame of the signal in accordance with a predefined classification of the data transmission rates, and for determining from the results of the classification an estimate of the data transmission rate of the received data frame; 
 wherein the rate estimation unit is arranged to classify the received signal based on a power spectral density function estimate of the received transmission signal, and to estimate the power spectral density function by dividing the total number of received data symbols into blocks, wherein each block includes a predefined amount of consecutive points of the signal.    
   
   
       43 . Signal receiving circuitry according to  claim 42 , wherein the rate estimation unit estimates the data transmission rate based on the frequency content of the received signal.  
   
   
       44 . Signal receiving circuitry according to  claim 42 , comprising a channel estimation unit which utilises the estimate data transmission rate of the received signal in channel estimation.  
   
   
       45 . A mobile station including signal receiving circuitry arranged for use in communication via a communication system with variable data transmission rates wherein data is transmitted as a plurality of data symbols over a sequence of data frames, the signal receiving circuitry comprising a rate estimation unit for receiving an incoming transmission signal, for classifying a data frame of the signal in accordance with a predefined classification of the data transmission rates, and for determining from the results of the classification an estimate of the data transmission rate of the received data frame; 
 wherein the rate estimation unit is arranged to classify the received signal based on a power spectral density function estimate of the received transmission signal, and to estimate the power spectral density function by dividing the total number of received data symbols into blocks, wherein each block includes a predefined amount of consecutive points of the signal.    
   
   
       46 . A base station including signal receiving circuitry for use in communication with variable data transmission rates wherein data is transmitted as a plurality of data symbols over a sequence of data frames, the signal receiving circuitry comprising a rate estimation unit for receiving an incoming transmission signal, for classifying a data frame of the signal in accordance with a predefined classification of the data transmission rates, and for determining from the results of the classification an estimate of the data transmission rate of the received data frame; 
 wherein the rate estimation unit is arranged to classify the received signal based on a power spectral density function estimate of the received transmission signal and to estimate the power spectral density function by dividing the total number of received data symbols into blocks, wherein each block includes a predefined amount of consecutive points of the signal.    
   
   
       47 . Signal receiving circuitry for use in a communication system with variable data transmission rates wherein data is transmitted as a plurality of data symbols over a sequence of data frames, the signal receiving circuitry comprising means for receiving an incoming transmission signal, for classifying a data frame of the signal in accordance with a predefined classification of the data transmission rates, and for determining from the results of the classification an estimate of the data transmission rate of the received data frame; 
 wherein the means is arranged to classify the received signal based on a power spectral density function estimate of the received transmission signal, and to estimate the power spectral density function by dividing the total number of received data symbols into blocks, wherein each block includes a predefined amount of consecutive points of the signal.    
   
   
       48 . A mobile station including signal receiving circuitry arranged for use in communication via a communication system with variable data transmission rates wherein data is transmitted as a plurality of data symbols over a sequence of data frames, the signal receiving circuitry comprising means for receiving an incoming transmission signal, for classifying a data frame of the signal in accordance with a predefined classification of the data transmission rates, and for determining from the results of the classification an estimate of the data transmission rate of the received data frame; 
 wherein the means is arranged to classify the received signal based on a power spectral density function estimate of the received transmission signal, and to estimate the power spectral density function by dividing the total number of received data symbols into blocks, wherein each block includes a predefined amount of consecutive points of the signal.    
   
   
       49 . A base station including signal receiving circuitry for use in communication with variable data transmission rates wherein data is transmitted as a plurality of data symbols over a sequence of data frames, the signal receiving circuitry comprising means for receiving an incoming transmission signal, for classifying a data frame of the signal in accordance with a predefined classification of the data transmission rates, and for determining from the results of the classification an estimate of the data transmission rate of the received data frame; 
 wherein the means is arranged to classify the received signal based on a power spectral density function estimate of the received transmission signal and to estimate the power spectral density function by dividing the total number of received data symbols into blocks, wherein each block includes a predefined amount of consecutive points of the signal.