US 2004/0006733 A1 · Method for repairing received signal and equalizer

Abstract

A method for repairing a channel-encoded phase modulation signal deteriorated in radio path, and an equalizer and receiver operating according to said method. In the repairing of the received signal (r) is utilized data corrected with respect to bit errors, which data is achieved by channel coding and decoding and interleaving. For this purpose, a feedback signal is formed by re-encoding and reinterleaving the decoded signal. This way bits ({circumflex over (b)}), correspoding to symbol bits of the signal received from the channel but in addition estimating the original data, are provided. The equalizer (EQ) is an iteration-type. After each iteration cycle, to the result is added the corresponding bit estimate being included in the feedback signal for the next cycle. When the result has settled, it is taken forward on the signal path without said bit estimate. A wide iteration cycle, accompanied by parts belonging to channel coding and interleaving (DEIL, DEC, ENC, IL), can be repeated for a few times with the same data for further reducing errors. In the equalizer as well as in the decoder (DEC) analog technology, instead of digital iteration, can be used in searching for the equilibrium of bit values.

Claims23

Dependent claims

A method for repairing in a receiver symbols of a channel-encoded signal, deteriorated in radio path of a transmission system, in which receiver bits of repaired symbols are channel-decoded, the method comprising the following steps;

the channel used for transmission is modeled by seeking coefficients to be applied to consecutive samples,
a certain number of samples of received signal are stored,
initial values for bits of symbols corresponding to said samples are set in a memory,
an iterative settling of values of symbol bits to states, where a cost function describing a degree of intersymbol interference achieves a minimum, is arranged, using for each bit said coefficients of the channel model and information about states of other bits of the symbol in question and states of bits of adjacent symbols,
a decision is made about bits of at least one symbol and
for a new calculation, symbol queue in the memory is shifted by the number of steps being the same as a number of decided symbols,
wherein
the decoded bits are re-encoded and
during said iterative settling the bits provided by re-encoding are further used in repairing of symbols to utilize bits corrected by means of decoding.

6 more elements

Dependencies are inferred from the claim text.

Method for repairing received signal and equalizer

Life of this patent

Method for repairing received signal and equalizer

Life of this patent

Abstract

Claims23