A decoder to search a tree graph to decode a received signal. The tree graph may have a plurality of levels, each level having a plurality of nodes and each node representing a different value of an element of a candidate transmit signal corresponding to the received signal. The decoder may include a first module to execute a branch prediction at each branch node to select one of a plurality of candidate nodes stemming from the branch node that has a smallest distance increment, and a second module, running in parallel to the first module, to evaluate the branch prediction made by the first module at each branch node by computing an accumulated distance of the selected node. If the accumulated distance of the selected node is greater than or equal to a search radius, the first module may override the branch prediction and select an alternative candidate node.