In this paper, we generalize the concept of signal space detection to construct a fixed delay tree search (FDTS) detector which estimates a block of n channel symbols gt a time. This technique is useful for high speed implementation. Two approaches are discussed both of which are based on signal space partitioning. In the first approach, symbol detection is performed based on a multi-class partitioning of the signal space. This approach is a generalization of binary symbol detection based on two-class pattern classification. In the second approach, binary signal detection is combined with a look-ahead technique, resulting in a highly parallel detector architecture.