Gradient based algorithm is used to find the prefilter weight with MPOE as cost function

1.  Prefiltering in down link with minimum probability of error as cost function (MPOE) •  MPOE a more appropriate cost function than MMSE • Receiver is a simple matched filter (Single user detector) •  Channel •  Completely known at the transmitter •  Partially known: Statistical channel parameters known at the transmitter  Common prefilter for all users  Joint probability of error optimized  Performance not quite satisfactory • Different (optimized) prefilter for each user • Individual probability of error minimized  Excellent performance MPOE based Prefiltering for DS-CDMA Systems Mohit Garg, G Kannan, S N Merchant, U B Desai Idea: System Model: Joint prefilter model Individual prefilter model Approach: Gradient based algorithm is used to find the prefilter weight with MPOE as cost function

2. General Channel Model with MAI+ISI  Multipath, complex Gaussian channel  Number of users 4  Correlated spreading codes with ρ = 0.1015  FIR prefilter of length 4  10,000 bits of data used for each channel Simulations: Performance plot with known channel model Performance plot using statistical parameters of channel Conclusion:  Prefiltering based on MPOE is superior to MMSE prefiltering  Individual prefiltering performs much better than joint prefiltering www.ee.iitb.ac.in/~ubdesai, www.ee.iitb.ac.in/~spann