APPLICATION OF NON-TEST METHODS FOR CHANEL ESTIMATION

Abstract

The possibilities  of increasing  the data  rate of adaptive HF communication systems by reducing  redundancy in the  form  of test  signals  used  for its operation are  considered. The problem is currently  pressing  due  to increasing  demands of modern adaptive data  transmission systems to efficient  use of allocated  frequency-time resource  of radio channel. For the  problem solution,  methods based  on the  analysis  of the  received  information signal, taking  into  account the used  signal-code  construction, are proposed. Approaches for solving problems of non-test adaptive signals correction  and channel state  estimation in serial data  communication systems using  convolutional encoder  are  proposed. Search  algorithm  for segments used  for channel impulse response and  equalizer coefficients calculation is shown.  In this case, neither a change in decoding algorithms nor calculating of equalizer  impulse response is required.  Expressions for estimation of the bit error rate for a convolution encoder of general form  are given. The presented approaches maintain operating of adaptive HF data  transmission systems in channels with intersymbol interference, ensuring  the  operative change  of its parameters when the state of the radio channel changes  significantly reducing the use of test signals, or completely abandoning them.