Abstract: A Hardware implementation of LDLT decomposition is proposed for MMSE detection in MIMO system. A systolic array of triangle shape is adopted for matrix inversion. By making use of the property of the Hermitian matrix to be inversed, the input and output can just be lower triangular matrix. Moreover, aiming at the divisions in the LDLT decomposition algorithm, a reciprocal architecture is proposed to avoid dividers. By arranging the timing, time-division multiplexing of the reciprocal architecture can be achieved. And by using look-up table compression technique, the hardware utilization of the reciprocal architecture can be reduced obviously. The simulation result and the implementation result show that the proposed hardware implementation can compute LDLT decomposition of MMSE detection in low hardware utilization, under the premise of high throughput and good bit error rate performance.