Research On Key Technologies Of Space Time Delay Sensitive Communication

With the development of related industries such as industrial Internet,self-driving and reusable self-landing rockets,the concept of delay-sensitive networks has attracted more and more attention,and the release of related technical standards is in progress.On the other hand,space networks are also developing in an orderly manner,and Space-Earth Integration Network will be realized in the future.In this context,this paper mainly studies the time-sensitive communication technology in space,focusing on the research of two key technologies: space time synchronization and space network resource allocation.In terms of space-time synchronization,a time-synchronization model was established and it is found that the existing time synchronization technology has sunder high dynamic motion scenarios.Therefore,this paper analyzes the whole process of time show poor performance in high dynamic motion scenarios,and proposes a clock difference estimation method based on radial velocity.Considering the acquisition of radial velocity,a time synchronization scheme based on pulsar positioning is proposed.The scheme includes two stages of coarse synchronization and fine synchronization.The coarse synchronization synchronization stage does not need to rely on pulsar positioning.The pseudo-delay of continuous measurement can obtain a rough estimate of the clock difference.Using this estimate to adjust the time,you can reduce the clock difference to at least 1ms.Fine synchronization uses pulsar positioning to obtain the approximate position and velocity of the spacecraft,thereby obtaining the radial velocity.Using the estimated value of the clock difference based on the radial velocity,further time adjustment is performed to reduce the clock difference and achieve accurate time synchronization.Through simulation,it was found that within the positioning error range,through two-stage time adjustment,the clock difference can be stabilized within 1 μs.Moreover,the scheme proposed in this paper is more adaptable than the existing scheme,that is,time synchronization can be performed in all visible time.In terms of resource allocation,this paper introduces a hybrid service-resourceallocation model for delay-sensitive services,bandwidth-sensitive services,and besteffort services.Due to the advantages of the utility function in terms of efficiency and fairness,this paper proposes a resource allocation scheme based on the utility function.The optimization goal of this scheme is to maximize the total utility(ie,total user satisfaction).The simulation found that the scheme meets the respective needs of the delay-sensitive and bandwidth-sensitive services,and avoids the best-effort service from being hungry because of its low priority.Moreover,within each services,proportional fair among users is achieved.