A high throughput unified SVD/QRD precoder design for MIMO OFDM systems

Precoding is an effective scheme in pre-compensating the wireless channel impairments and the singular value decomposition (SVD) scheme is a popular choice. This paper presents a unified high throughput SVD/QRD precoder chip design for MIMO OFDM systems. A hardware-implementation-friendly Givens Rotation (GR) based SVD computing scheme is developed first. It starts with a bi-diagonalization phase followed by an iterative diagonalization phase consisting of successive nullification sweeps. A convergence detection mechanism is employed to terminate the computations if the required precision is achieved. The design successfully integrates the SVD module (for precoding) with the QR decomposition (QRD) module (for MIMO signal detection) under a unified hardware framework. The design features a two-level pipelined, fully parallel architecture and CORDIC processors are employed to implement the GR modules efficiently. Various design optimization techniques are applied to reduce the circuit complexity and the power consumption. The implementation using TSMC 90nm process technology indicates a 35.75M SVDs per second throughput rate when operating at 143MHz. Both the throughput rate and the gate count efficiency of the proposed one outperform previous designs significantly.