Patent ID: 6396878
Filing Date: 2002-05-28
Classification: H03M

Abstract:
A reception method in which received symbols are functions of bits, which are determined by means of temporally successive trellis levels A and B, which comprise a predetermined number of states, a transition from each of the states to a state at the next level B being performed on the bases of a received symbol, comprising:forming, at more than one known state of the level B, a transition metric for a received symbol, the transition metric corresponding to a conditional probability and being used in the transition for moving from known states of the preceding level A to each said known state of the next level B, a state of a preceding level being determined as symbols in the transition metric, the symbols each having a predetermined number of symbol alternatives; forming a cumulative transition metric by multiplying the transition metric by a cumulative metric relating to each known state of the preceding level A; forming a cumulative metric relating to the states of the level B by summing cumulative transition metrics relating to the states of the level B over the symbol alternatives of a symbol, with a known location, determining a state of the preceding level A; and determining the bits of the received symbols separately for each bit of a symbol, irrespective of each other, by using the cumulative transition metrics.