SYSTEM FOR REDUCING THE EFFECTS OF SIGNAL FADING ON RECEIVED SIGNALS

• Main Authors: STIERNVALL, JAN-ERIK, BAECKSTROEM, THOMAS OLOF, KAHRE, RAGNAR E
• Format: Patent
• Language: English; Korean
• Published: 10.10.1996
• Edition: 6
• Subjects: ANTENNAS, i.e. RADIO AERIALS; BASIC ELECTRIC ELEMENTS; BASIC ELECTRONIC CIRCUITRY; CODE CONVERSION IN GENERAL; CODING; DECODING; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

Signals in synchronizing sequences and data sequences are transmitted over a fading channel to a Viterbi-receiver (11, 12). The signals are received by antennas and sampled to received antenna signals (sin,r(k)). Part channel estimates (hest,r) for the individual antennas are formed. For Viterbi-analysis, assumed input signals (sa,r( DELTA Tij,k)) for the data sequence are produced with the aid of the part channel estimates (hest,r). Part metric values (mr( DELTA Tij,k)) are formed as a difference between the received antenna signal (s,in,r(k)) and corresponding assumed input signals (sa,r( DELTA Tij,k)) for Viterbi state transitions ( DELTA Tij). For one state transition there is formed a metric value such as the sum of a metric value ((M(Tj,k-1)) for an old state (Tj) at a preceding sampling time point (k-1) increased with a weighted (Kr) sum of the part metric values (mr( DELTA Tij,k)) belonging to individual part channel estimates (hest,r). Corresponding metric values are formed for all state transitions to the new state (Ti) and the smallest of these metric values is chosen in accordance with the Viterbi-algorithm.