In order to decode dual-antenna space division multiplexing data of Long Term Evolution（LTE）transmission mode 3（TM3）by a single-antenna LTE user equipment, a reference constellation which can be used for calculating the log-likelihood ratio（LLR）was generated from single-antenna data on the basis of the calculation principle of LLR. The formula for computing the LLR of turbo decoder＇s input, using single-antenna data, was deduced. The dual-antenna TM3 LTE space division multiplexing data decoding as specified by LTE protocol was achieved using a single-antenna algorithm. The simulation results show that the performance loss of single-antenna decoding algorithm is very small as compared with the normal dual-antenna decoding method. And the decoding speed of the single-antenna algorithm is verified by using Texas Instruments C6670 digital signal processing chip（DSP）.It is shown that the algorithm can reduce the complexity of the LTE system design by reducing two receiving links to single receiving link. Production cost and power consumption can be reduced, which has a great value to the internet of things equipment and the special network equipment.