Initial synchronization acquiring device and method for parallel processed DS-CDMA UWB system and DS-CDMA system's receiver using the same

An initial synchronization acquiring method in a parallel processed DS-CDMA UWB system, the method comprising the steps of:

• (a) correlating input signals and outputting correlation result values;
• (b) performing a symbol synchronization coherent combining with respect to a reception signal of the correlation result values and then outputting a combining mark result value;
• (c) calculating an energy value by using the combining mark result value and performing a noncoherent combining with respective to the calculated energy value and thereby outputting a discrimination result value;
• and
• (d) storing the discrimination result value in a buffer and then, if the combining mark result values within the buffer are changed, obtaining a synchronization position value and storing the obtained synchronization position value and combining mark result values in a register for data demodulation, wherein
• the step (b) respectively multiplies successive symbol input signals by preamble patterns received from a matched filter and coherently combines the multiplication result values;
• and
• said combining mark result values and the synchronization position value are values resulting after an initial synchronization acquisition;
• wherein multiplying successive symbol input signals further comprises receiving a plurality of input signals upon reception of despread complex values from the correlator and then respectively multiplying the input signals by preamble patterns received from a symbol matched filter;
• wherein the coherent combining of step (b) includes combining multiplication values received from a multiplier and outputting M pairs of coherent combining result values, wherein M is a positive integer;
• wherein the calculating of an energy value of step (c) includes calculating M energy values using the coherent combining result values and noncoherently combining the M energy values, and outputting a noncoherent combining result value;
• and
• wherein step (d) includes comparing the noncoherent combining result value with a threshold value, and then, if the noncoherent combining result value is identical to or below the threshold value, continuously performing a filtering function with a predetermined preamble pattern, and, if the noncoherent combining result value is above the threshold value, resetting a N×M symbol out of a N×M+A symbol period as a preamble pattern and performing a filtering function with the reset preamble pattern, wherein N is a positive integer and A is a positive integer.

A receiver using an initial synchronization acquiring device in a parallel processed DS-CDMA UWB system, the receiver comprising:

• an ADC (analog-to-digital converter) for receiving an analog signal into which a signal received from a transmitter is baseband-converted by an RF (Radio Frequency) processing block of a receiver, and then converting the analog signal into a digital signal;
• a correlator for correlating the digital signals received from the ADC and outputting correlation result values;
• an initial synchronizer for tuning initial symbol synchronization and frame synchronization by using the correlation result values received from the correlator, generating and then storing combining mark values and a synchronization position value in a register,
• wherein the initial synchronizer comprises:
• a synchronization discriminator for determining whether signals received from the correlator are synchronized and then outputting result values;
• a combining mark/synchronization position detector for storing the result values received from the synchronization discriminator in a buffer and then, if the generated combining mark values within the buffer are changed, obtaining a synchronization position value and storing the obtained synchronization position value and the changed combining mark values in the register;
• and said combining mark values and the synchronization position value are values resulting after an initial synchronization acquisition;
• wherein the synchronization discriminator comprises:
• a multiplier for receiving a plurality of input signals upon reception of despread complex values from the correlator and then respectively multiplying the input signals by preamble patterns received from a symbol matched filter;
• a coherent combining adder for coherently combining multiplication values received from the multiplier and thereby outputting M pairs of coherent combining result values, wherein M is a positive integer;
• an energy calculator for calculating M energy values by using the coherent combining result values received from the coherent combining adder;
• a noncoherent combining adder for noncoherently combining the M energy values received from the energy calculator and thereby outputting a noncoherent combining result value;
• a comparator for comparing the noncoherent combining result value received from the noncoherent combining adder with a threshold value, and then, if the noncoherent combining result value is identical to or below the threshold value, continuously performing a filtering function with a predetermined preamble pattern, and, if the noncoherent combining result value is above the threshold value, resetting a N×M symbol out of a N×M+A symbol period as a preamble pattern and performing a filtering function with the reset preamble pattern, wherein N is a positive integer and A is a positive integer;
• a max finder for measuring the energy values received through the noncoherent combining adder and then storing up to P(P≧1) grade discrimination result values and thereby determining whether synchronization is performed;
• and
• a max storage for storing the up to P-grade discrimination result values received from the max finder.