1. A nonlinear multiple input, multiple output orthogonal frequency-division multiplexing (MIMO-OFDM) detector comprising: a vector arithmetic unit configured to sequentially compute first metrics corresponding to a first current tree level of a first search tree and second metrics corresponding to a second current tree level of a second search tree; and a sorting and indexing unit configured to sort the first metrics and the second metrics sequentially received from the vector arithmetic unit and configured to sequentially provide first indices of lowest first metrics and second indices of lowest second metrics to the vector arithmetic unit, the lowest first metrics being first inputs to the vector arithmetic unit for a first next tree level of the first search tree and the lowest second metrics being second inputs to the vector arithmetic unit for a second next tree level of the second search tree, wherein the vector arithmetic unit and the sorting and indexing unit are coupled in a pipeline that computes the second metrics concurrently with sorting and indexing of the first metrics, and wherein the first search tree corresponds to a first subcarrier of an OFDM symbol.