High-speed complex-number multiplications based on redundant binary representation of partial products

The complex-number multiplier is one of the key arithmetic components for the baseband signal processing of modern digital communication systems such as channel equalization, timing recovery, modulation and demodulation. This paper presents two algorithms suitable for a high-speed complex-number multiplier, which are based on redundant binary (RB) representation of partial products. The basic idea behind our approach is to convert a pair of binary partial products into a RB form so that the post-addition/subtraction which is inevitable in the conventional methods based on binary multiplication, is eliminated. With the proposed algorithms, the complex-number multiplication is reduced to two RB multiplications, one for the real part and the other for the imaginary part. The RB multiplication is defined by an addition of RB partial products, and is performed in parallel without carry propagation from the least-significant digit to the most-significant digit. This work results not only in simplified arithmetic operations, but also in highly parallel and simple architecture when compared with conventional methods using binary multiplications. To demonstrate the algorithms, two test chips have been implemented using a 0.8µm CMOS technology.