Research Of Spatial Coupling On 5G

With the rapid development of mobile communication technology and mobile Internet technology in Twenty-first Century,the knowledge and information between different human civilizations,intersects inte-grates and develops around the world.At present,the 4G mobile commu-nication system has been popularized in the world,and has been put into commercial operation.4G communication technology has the advantages of fast data transmission,high spectrum efficiency,good compatibility,etc.,but it still has some shortcomings,including resources wasting,lim-ited communication capacity,and so on.According to the increase in the number of commercial communications users in recent years,the future demand for the capacity of the communication system will be greater and the mobile Internet business will grow explosivly.As a result of this rea-son 5G mobile communication technology came into being.The main de-mand of 5G mobile communication system is to improve the data trans-mission capacity and system capacity.Spatially Coupled LDPC code is a code which is close to the Shannon capacity limit in theory.It is beneficial to increase the system capacity of 5G mobile communication system,and it also can be used in the non-orthogonal multiple access technology of 5G mobile communication.At present the researches on the practical application of Spatially Coupled LDPC codes are mainly focused on two aspects:the construction of the Spatially Coupled LDPC codes and the encoding and decoding augrithm with low complexity.In terms of the first aspect,a structure based on the parity check matrix has been proposed,while in terms of the second aspects the recursive encoding algorithm with low complexity has been designed.However,this kind of recursive encoding algorithm can only be used at certain design rates,besides,in order to bring the register to zero state after recursive encoding,some computational complexity will be sacrificed to calculate the added tail bits.According to the above points,it is still difficult to put Spatially Coupled LDPC code into practice.In order to solve these problems above,we will talk about the practi-cal constructure of Spatially Coupled LDPC codes and the encoding augrithm with low complexity and low time consumption in this paper.Based on the traditional Spatially Coupled LDPC codes,we propose a modified structure of Spatially Coupled LDPC code with arbitrary rates,which allows recursive encoding.we also modify the tail structure of the terminated Spatially Coupled LDPC codes,which makes the termination more effecient.The corresponding encoding augrithm with low complexi-ty will also be provided for these two modified structure.The previous structure can solve the problem of recursive encoding for Spatially Cou-pled LDPC codes with arbitrary rate,and the later structure can terminate the Spatially Coupled LDPC codes with finite length effectivly.We also provide the performance analysis of Spatially Coupled LDPC codes with the two modified structure in terms of the design rate and density evolu-tion.It can be observed that both of the modified structures lead to a better belief-propagetion threshold.Besides,some finite-length simulation re-sults of the corresponding Spatially Coupled LDPC codes over the binary erasure channel(BEC)are provided to verify the theoretical analysis.In summary,our study implements the recursive encoding of the Spa-tial Coupling LDPC codes with arbitrary rates with low complexity and terminates the Spatial Coupled LDPC codes effciently,which reduces the calculate consumption of the encoding of the Spatial Coupled LDPC codes and drives the practical application of Spatial Coupled LDPC codes in 5G communication systems.