Research On High-dimensional Modulation Rate-adaptive Technology Based On Sphere Packing

With the global bandwidth increasing exponentially,how to make effective use of bandwidth resources becomes more and more important.Rate-adaptive technology can adjust the spectral efficiency and signal transmission rate adaptively according to user's requirements and channel quality to achieve the purpose of improving bandwidth utilization.Studies have shown that using high-dimensional modulation formats to achieve rate-adaptive transmission can improve the performance of the modulation formats while achieving a more finer granularity in spectral efficiency and signal transmission rate adjustment.Therefore,it is of great significance to study high-dimensional modulation rate-adaptive technology.Based on the sphere packing theory,this paper proposes high-dimensional modulation rate-adaptive technology based on sphere packing and builds a high-dimensional modulation rate-adaptive system based on sphere packing.Subsequently,the variable-rate technology is verified by simulation.The simulation results show that the rate-adaptive technology proposed in this paper can achieve a finer adjustment of spectral efficiency,transmission rate and transmission distance by switching the symbol set of the high-dimensional modulation formats.This article carries out the following research work:1.The research purpose and research results of high-dimensional modulation rate-adaptive technology are reviewed.According to the developing history and current situation of rate-adaptive technology,we summarize the research results both home and abroad systematically.The advantage of using high-dimensional modulation formats to realize variable rate has been analyzed.It points out that it is of great significance to study high-dimensional modulation rate-adaptive technology.2.The principle and implementation methods of high-dimensional modulation technology are studied.The advantages of high-dimensional modulation formats are analyzed and three typical methods for generating high-dimensional modulation formats are explored.The process of generating,transmitting,and receiving of high-dimensional modulation formats based on the sphere packing theory is analyzed in detail.3.The performance of variable-rate technology and its implementation methods are analyzed in depth.Several typical variable-rate implementation methods are analyzed in detail from the aspects of principle,implementation and performance,andtheir performances are compared.The comparison results show that the rate-adaptive method based on the modulation format mSP-QAM and the rate-adaptive method based on the modulation format PM-k SC-mQAM can realize a finer adjustment of spectral efficiency only by introducing a small number of additional devices.Therefore,they are effective methods for realizing the variable rate.4.High-dimensional modulation rate-adaptive technology based on sphere packing is proposed.The principle of high-dimensional modulation rate-adaptive technology based on sphere packing is introduced in detail,and three key technical problems faced in realizing the variable-rate technology are solved.They are:selecting the lattice points for generating symbol sets of high-dimensional modulation formats,defining high-dimensional mapping rules and flexible switching of high-dimensional modulation formats.Then,the advantages of high-dimensional modulation rate-adaptive technology based on sphere packing are analyzed by simulation.The results show that the variable-rate technique can achieve a finer spectral efficiency adjustment,at the same time,the high-dimensional modulation formats adopted by the rate-adaptive technology can better achieve the trade-off between spectral efficiency and CFM.5.A high-dimensional modulation rate-adaptive system based on sphere packing is built,and the performance of the high-dimensional modulation rate-adaptive technology based on sphere packing is simulated on this system.Simulation results show that the variable-rate technology can easily achieve a finer adjustment of spectral efficiency and bit rate.When the variable-rate transmission are implemented using four-dimensional modulation formats,the adjustable granularity of the SE is 0.5 bit/symbol/pol.At a symbol rate of 7 Gbaud,it allows variation of the bit rate from 14 Gb/s to 70 Gb/s.When the variable-rate transmission are implemented using eight-dimensional modulation formats,the adjustable granularity of the SE is 0.25 bits/symbol/pol.At a symbol rate of 7 Gbaud,it allows variation of the bit rate from 28 Gb/s to 84 Gb/s.