A new hybrid broadcast scheduling algorithm for asymmetric communication systems

Author(s):  
Yufei Guo ◽  
Sajar K. Das ◽  
Cristina M. Pinotti
2020 ◽  
Vol 53 (7-8) ◽  
pp. 1238-1249
Author(s):  
Geng Liang ◽  
Xin An

With the application of digital information technology and communication technology, industrial intelligence and integration also began to develop rapidly, and the importance of the research on bus communication in industrial control communication also increased. As the first international bus standard, PROFIBUS has been widely used in the field of industrial control; in recent years, it was mainly used to connect devices to the control layer and convert data through token transmission. Based on the understanding of the transmission mechanism of PROFIBUS fieldbus protocol, this article carries out a simulation study on its communication performance. Through analysis of the data link layer, changing the target token cycle time (high and low priority) and random setting each site message number, as well as the number of master station and slave station, how the main token latency and packet loss rate and efficiency of bus affect the change of performance parameters was observed. For multiple communication systems, the relationship between the address value on the main token ring and transport performance is found by experiments on the site address value on the main token ring and the target token cycle time value. Finally, the scheduling algorithm is applied to the communication scheduling of PROFIBUS fieldbus. The results confirm that the scheduling algorithm has better transmission efficiency than the traditional MAC media access protocol under the condition that the load rate does not exceed 100%, which makes up for the shortcomings of the original PROFIBUS bus system and makes the communication performance better.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Shengfeng Xu ◽  
Gang Zhu ◽  
Chao Shen ◽  
Yan Lei ◽  
Zhangdui Zhong

We investigate the downlink service scheduling problem in relay-assisted high-speed railway (HSR) communication systems, taking into account stochastic packet arrivals and quality-of-service (QoS) requirements. The scheduling problem is formulated as an infinite-horizon average cost constrained Markov decision process (MDP), where the scheduling actions depend on the channel state information (CSI) and the queue state information (QSI). Our objective is to find a policy that minimizes the average end-to-end delay through scheduling actions under the service delivery ratio constraints. To address the challenge of centralized control and high complexity of traditional MDP approaches, we propose a distributed online scheduling algorithm based on approximate MDP and stochastic learning, where the scheduling policy is a function of the local CSI and QSI only. Numerical experiments are carried out to show the performance of the proposed algorithm.


Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3783 ◽  
Author(s):  
Trong-Yen Lee ◽  
I-An Lin ◽  
Jun-Jie Wang ◽  
Ju-Tse Tsai

FlexRay is a next-generation in-vehicle communication protocol which works in real time with flexibility. The most common applications in FlexRay are high bandwidth. X-by-wire applications, such as brake by wire and throttle by wire. However, there is no mechanism which can prevent transient faults in the application layer of FlexRay. If a transient fault occurs during driving, this would be very dangerous; therefore, we propose a fast reliability scheduling algorithm (FRSA) to improve the communication reliability of FlexRay. The proposed method reduces the probability of transient faults in one clock cycle by using a retransmission mechanism to recover the transient errors, and further improves computational complexity using the lookup table method to ensure system reliability. In this paper, we analyze a related literature to establish the system reliability constraints needed to evaluate the necessary time and slot usage, and the proposed cost function is used to evaluate the performance and efficiency when the number of messages is increased. Experimental results show that the proposed FRSA reduces execution time by an average 70.76% and cost by an average 13.33% more than the other existing methods. This method can be useful to others, especially regarding research about periodic time-triggered communication systems.


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