Research On Key Technologies Of Low Latency Wireless Communication In Industrial Automation

These days,a growing number of new types of services and applications such as automatic drive,remote surgery/control,virtual/augment reality,tactile internet and fac-tory automation come into people's sight and will have a enormous impact on people's lives.One thing these services and applications have in common is that the machine-type-communications?MTC?is a typical type of data transmission and they have a strict constraints on the transmission reliability and the end-to-end?E2E?transmission latency:the constraint on E2E latency is 1 ms and the constraint on reliability is up to 1-10^-9,which is called ultra-reliable and low-latency communications?URLLC?.In many traditional wireless communication applications with a approximately infi-nite blocklength channel coding,the Shannon capacity is used to characterize the maxi-mum achievable rate of the transmission.However,for many URLLC applications which generate short packets and have a strict constraint on transmission delay,a finite block-length channel coding is needed and a resource allocation strategy based on Shannon capacity is not feasible to guarantee the strict QoS constraints on transmission reliabil-ity and latency.Based on the theory of finite blocklength channel coding rate,this text studies the optimal resource allocation policy in the downlink and uplink transmission respectively.Firstly,in the uplink transmission,with a limited system resources,we study how to optimize the the system performance through a reasonable resource allocation strat-egy under a strict QoS constraint on reliability and latency.Based on the feature that the transmission experiences a quasi-static channel,we setup a two-state transmission model.We see the delay-sensitive area spectral efficiency?DASE?as a performance metric,by studying the properties of the target function,a search algorithm based on dichotomy and golden section method for optimal resource allocation is proposed.Based on the pro-posed algorithm,we obtain a feasible region of the wireless resource allocation scheme which satisfies the QoS constraint of uplink transmission.Then,We search for the op-timal resource allocation scheme that maximizes the DASE within the feasible region.Through simulations,we analyze the impact of frequency diversity,array gain and differ-ent optimization indexes on the resource allocation scheme in ultra-reliable and low delay communication.Secondly,in the downlink transmission,the random arrival of packets at the base station will cause queue delays.To satisfy the data transmission queueing delay and queueing delay error probability,the minimum transmission rate is set as the effective bandwidth.To satisfy the data transmission error probability of short packets,the maxi-mum transmission rate is set as the finite blocklength channel coding rate.Due to the fact that the transmission experiences a quasi-static channel,a two-state transmission model is proposed.We study how to design a suitable resource allocation scheme to meet the queuing delay and transmission reliability of downlink transmission.We propose a search algorithm based on dichotomy,golden section method,and genetic algorithm to find the optimal resource allocation strategy firstly.Then,We search for the optimal resource al-location scheme that maximizes the DASE.Through simulations,we analyze the impact of frequency diversity,array gain and different optimization indexes on the resource allo-cation scheme in ultra-reliable and low delay communication.