Simplified Decoding And Applications Of Polar Code In MIMO Systems

The research focus of wireless communications has been shifted to the fifth generation mobile communication system(5G)for 2020 and beyond.5G will be integrated into more areas in a broader space-time environment,and ultimately to achieve the vision “information delivered as soon as in the mind,all objects within reach”.In the future,diversification,high dynamic,high-capacity requirements will guide the technology,and 5G should face the challenge of reliable and efficient transmission in complex environments.Thus,efficient channel coding has become an important research direction.Polar code proposed recently can approach the Shannon capacity limit,while it has low encoding and decoding complexities.Polar code has arised a great concern in the academia and the industry.However,the practical applications of polar code are not sufficient.Polar code still requires a series of research work in the practical application scenario.Thus,based on studying the existing encoding and decoding algorithms of polar code,a simplified decoding algorithm is designed,which effectively reduces the decoding complexity.Moreover,Polar code and Multiple-Input Multiple-Output system are combined.A channel coding scheme is proposed based on the concatenation of polar code and space-time coding(Polar-STBC),which initially demonstrates the practical feasibility of proposed scheme in MIMO system.The main research work is as follows:Firstly,generation matrix of polar encoding is derived.Based on the analyses of combination and separation of channels,capacity of each separation channel is calculated,and the reason which causes polarization is analyzed.The encoding theory of polar codes is shown.According to the characteristics of the polarization,construction methods based on Bhattacharyya parameters and density evolution are studied.Then,a simplify decoding algorithm is proposed based on tree pruning.The conventional decoding algorithm of polar code,successive cancellation and belief propagation decoding,are modeled and analyzed.It is proved that there exists redundant decoding calculation process,which results in heavy computational complexity and decoding delay.Based on the erasure and substitution of the redundant calculation process,a simplify decoding algorithm is designed to reduces the computational complexity of the existing decoding algorithm significantly,while the error performance is ensured at the same time.Finally,a channel coding scheme is proposed based on concatenation system of polar code and space-time coding(Polar-STBC system).A Polar-STBC system is designed based on the concatenation of polar code and space-time coding.Based on the analyses for space-time block coding in Rayleigh fading and Rice fading MIMO channels,the Polar-STBC system can be equivalented to a single transmission channel,and the construction of polar codes in Polar-STBC system is proposed,which improves the system performance greatly.The initial exploration of the polar codes' applications in MIMO system is completed.