Integer least squares

This paper considers the problem of integer least squares, where the least squares solution is an integer vector, whereas the coefficient matrix is real. In particular, we discuss the sphere decoding method in communications. One of the key issues in sphere decoding is the determination of the radius of search sphere. We propose a deterministic method for finding a radius of search sphere. Also, we investigate the impact of the LLL algorithm on the computational complexity of the sphere decoding method.