1 Post Processing Procedures for Channel Estimation Younglok Kim Dept. of Electrical Engineering Sogang University

Dept. of Electrical Engineering Sogang University 2 Channel estimation output Too many number of noise only data. Only a few coefficients of the channel estimates includes the channel component. Input-to-output noise power ratios (G) are about 26dB (  400) and 22.3dB (  169) for all basic midamble codes of burst type 1 and 2 respectively.

Dept. of Electrical Engineering Sogang University 3 Cross Correlation between Miamble Codes

Dept. of Electrical Engineering Sogang University 4 Post Processing of Channel Estimation Output of Steiner Block Interference + noise Channel components Remove noise based on the threshold threshold

Dept. of Electrical Engineering Sogang University 5 Noise Power Estimation using Channel Estimation Output Threshold based on the noise power for Post Processing Midamble detection Code detection Many others Only a few noise only data is available in guard period of DCH TS. Interference from the data field. ON/OFF ramping time. Timing advance.

Dept. of Electrical Engineering Sogang University 6 Noise Estimation Algorithm: Find the index n(i) satisfying Compute mean square of N smaller coefficients out of L total channel estimates and multiply by the scaling factors: Processing gain G = 400 or 169 for burst type 1 or 2.  is the factor to adjust the sample mean with smaller values.

Dept. of Electrical Engineering Sogang University 7 Block Diagram of Rx Module

Dept. of Electrical Engineering Sogang University 8 Work Procedure 1. Survey the algorithm for the linear solution with cyclic properties 2. Complexity analysis with the number of operations. 3. Write the report including everything above & select the most likely efficient algorithm 4. Algorithm verification with software C language with floating point simulations (testbench could be in MatLab). 5. Determine the word size via the fixed point simulations (can be omitted depending on the schedule) 6. Generation and verification of the VHDL 7. Test by using the FPGA master kit 8. Final documentations

Dept. of Electrical Engineering Sogang University 9 Midamble Generation Issues For Tx and Rx Efficient method to save/retrieve 128 number of the basic midamble of binary length 456 Basic code will be provided For Tx only Efficient Midamble shift generation methods

Dept. of Electrical Engineering Sogang University 10 Efficient Channel Estimation Algorithms Correlator DFT based methods Need non-radix 2 FFT algorithm Prime factor algorithm (PFA) Others Levinson algorithm Other algorithms

Dept. of Electrical Engineering Sogang University 11 Other Algorithm Issues Noise Estimation Partial sample algorithm Efficient SORTING algorithm Adaptive algorithm including post processing Others Post Processing Efficient comparison algorithm Midamble detection Efficient square sum algorithm with many zeros out of W=57 coefficients