Search radius of sphere decoding detection algorithm affects complexity of algorithm

an improved algorithm is proposed. The improved algorithm multiplies a constant compression factor on the search radius of the sphere decoding detection algorithm

and influence of noise factor is reduced in each layer. The complexity of the algorithm is reduced by cutting search radius of sphere and narrowing search range. Simulations results show that the new algorithm can effectively reduce calculation complexity by 18 % compared with the traditional sphere decoding detecting algorithm when signal to noise ratio（ SNR） is less than 10 d B and cause the performance loss of bit error rate is small.