Optimized synchronization preamble structure

Abstract

This proposal describes an optimized synchronization (SYNCH) symbol sequence to be used in transmission systems, which are currently under standardization. The synchronization symbol is constructed using specially designed OFDM (orthogonal frequency division multiplexing) symbols with an optimized sequence, which is mapped onto the modulated subcarriers. The resulting synchronization symbol consists of several repetitions in the time domain. Using the proposed sequence the resulting synchronization symbol achieves a high timing detection and frequency offset estimation accuracy. Furthermore the burst is optimized to achieve a very low envelope fluctuation (low Peak-to-Average Power Ratio) and a very low dynamic range to reduce complexity on the receiver and to save time and frequency acquisition time in the receiver. The proposed sequence is furthermore optimized with respect to all other synchronization symbols that are used to construct the synchronization and training preambles for the BCCH-DLCHs.

1 - 7 . (canceled)  
     
     
         8 . A method for generating a synchronization preamble signal comprising OFDM symbols, the method comprising the steps of: 
 generating at least one OFDM symbol by modulating 12 subcarriers of an OFDM scheme according to the following sequence:      S   −26.26   =N*{ 0,0,(1 +j ),0,0,0,(−1 −j ),0,0,0,(1 +j ),0,0,0,(−1 −j ),0,0,0,(−1 −j ), 0,0,0,(1 +j ),0,0,0,0,0,0,0,0,(−1 −j ),0,0,0,(−1 −j ),0,0,0,(1 +j ),0,0,0,(1 +j ),(1 +j ),0 0,0,(1 +j ),0,0}   where N is a normalization factor; and    inverse Fourier transforming the generated OFDM symbol thereby generating a time domain signal.    
     
     
         9 . The method according to  claim 8 , wherein the step of inverse Fourier transforming comprises a step of applying a 64-point inverse fast Fourier transform (IFFT) to the sequence S, with the remaining 15 input values to the IFFT being set to zero.  
     
     
         10 . The method according to  claim 8 , further comprising a step of cyclically extending the time domain signal.  
     
     
         11 . A device for generating a synchronization preamble signal comprising OFDM symbols, comprising: 
 means for generating at least one OFDM symbol by modulating 12 subcarriers of an OFDM scheme according to the following sequence:      S   −26.26   =N*{ 0,0,(1 +j ),0,0,0,(−1 −j ),0,0,0,(1 +j ),0,0,0,(−1 −j ),0,0,0,(−1 −j ), 0,0,0,(1 +j ),0,0,0,0,0,0,0,(−1 −j ),0,0,0,(−1 −j ),0,0,0,(1 +j ),0,0,0,(1 +j ), (1 +j ),0, 0,0,(1 +j ),0,0}   wherein N is a normalization factor; and    means for inverse Fourier transforming the generated OFDM symbol thereby generating a time domain signal.    
     
     
         12 . A method for synchronizing a receiver of an OFDM transmission system, the method comprising the following steps: 
 receiving a preamble signal;    autocorrelating the received preamble signal, wherein the preamble signal has been obtained by generating at least one OFDM symbol by modulating 12 subcarriers of an OFDM scheme according to the following sequence:      S   −26.26   =N*{ 0,0,(1 +j ),0,0,0,(−1 −j ),0,0,0,(1 +j ),0,0,0,(−1 −j ),0,0,0,(−1 −j ), 0,0,0,(1 +j ),0,0,0,0,0,0,0,(−1 −j ),0,0,0,(−1 −j ),0,0,0,(1 +j ),0,0,0,(1 +j ),(1 +j ),0, 0,0,(1 +j ),0,0}   where N is a normalization factor; and    inverse Fourier transforming the generated OFDM symbol thereby generating a time domain signal.    
     
     
         13 . An OFDM receiver, comprising means for receiving and means for autocorrelating; the receiving and autocorrelating means being designed for a preamble signal obtainable by the following steps: 
 generating at least one OFDM symbol by modulating 12 subcarriers of an OFDM scheme according to the following sequence:      S   −26.26   =N*{ 0,0,(1 +j ),0,0,0,(−1   31  j ),0,0,0,(1 +j ),0,0,0,(−1 −j ),0,0,0,(−1 −j ), 0,0,0,(1 +j ),0,0,0,0,0,0,0,(−1 −j ),0,0,0,(−1 −j ),0,0,0,(1 +j ),0,0,0,(1 +j ),(1 +j ),0, 0,0,(1 +j ),0,0}   where N is a normalization factor; and    inverse Fourier transforming the generated OFDM symbol.