Ratelass Code Decoding Estimation Of Gaussian Channel Capacity With Digital Modulations

The AWGN channel is an important communication channel model,which is commonly used to simulate constant channels,such as fiber-optic communication,satellite communication,and coaxial cable communication.The channel capacity is the maximum transmission rate to ensure the error-free transmission of information.Therefore,when studying the coding and decoding scheme of the communication system in practice,it is of great guiding significance to determine the channel capacity to ensure the reliability of data transmission.Therefore,this paper conducts in-depth research on the modulation technology and coding technology of Gaussian channel,which is summarized as follows:For the AWGN channel with a power constraint of P,the achievable transmission rate of an equally-probably evenly distributed input signal always has a 1.53 dB loss problem from the channel capacity limit.This paper proposes two solutions based on dimensions,and the shaping gain can be obtained without using the shaping coding method.In the low dimension,the channel capacity can be realized by the geometric Gaussian distribution equal probability signal set,and the Gaussian channel capacity can be realized by the BM-APSK model in the high dimension.At the same time,the model and constraint proofing process of two shaping schemes are given.The correctness of the theorem is verified by Matlab simulation results.When the number of constellation points tends to infinity,the performance loss of capacity can be reduced to zero.Aiming at the problem that the LT code has a coding node with a degree of 1 under the AWGN channel connected to the channel and generating an error platform,a concatenated coding structure different from the Raptor code is proposed.This is a new coding structure that uses an accumulator to eliminate the coding node with a degree of one,and is named AR(Accumulate Rateless)code.The BER performance of the LT code after adding the accumulator with or without the accumulator is compared by simulation.The results show that the AR code is updated continuously with the decoding,and there is no fixed error injection.Then,through simulation,the degree distribution of the optimized information node or check node edge and the selection of the edge are verified,which can improve the performance of the AR code in the waterfall area.Through the AWGN channel simulation satellite communication environment,the non-rate code coding and decoding technology is combined withdifferent modulation techniques to simulate.The results show that the actual decoding start length is basically the same as the theoretical code word length condition when starting the decoding by channel capacity calculation.Studying the channel capacity has a good estimation effect on the initial starting code rate when the actual communication system is decoded.