The Orbital Channel Resource Control on Non-Markov Priority Systems of Mass Service Basis. Part 2. Dispatch Method

The article develops a methodology for scheduling an orbital channel resource with operational priority assignment based on the calculation of the parameters of a non-Markov service model with a limited residence time of a request in the system, which differs from known methods in that it takes into account the priority of various network subscribers, taking into account the high dynamics of their movement and the average waiting time in the service system with priority in the allocation of the orbital channel resource of the satellite command-relay system. The analysis of the influence of service quality indicators of information data flows is carried out.It is shown that the developed method of priority scheduling makes it possible to meet the requirements for the quality of service. A complex of experimental studies was carried out, which showed the possibility of ensuring the required level of stability with the deterioration in difficult conditions of radio electronic equipment, which made it possible to formulate practical proposals for improving the complex of coordination and distribution of resources of in the satellite command relay system.

Research and Design of Adaptive Networking Method Based on LoRa

An adaptive networking method based on LoRa(Long Range) technology is proposed. The data transmission of wireless sensor networks widely used in the Internet of things is studied. A star network composed of Lora wireless transmission technology is designed to build an adaptive data transmission network. The design process of network topology, hardware and adaptive networking method of adaptive networking are introduced. Aiming at solving the problems of limited node capacity, adjacent frequency interference, and unreasonable channel resource allocation in the LoRa network, an adaptive frequency hopping mechanism is used for networking. The system uses I. MX6ULL as the main control and integrates 8 LoRa modules at the same time, which greatly improves the node capacity of the gateway. The server can realize real-time viewing and monitoring of node equipment, and real-time evaluation of channel communication quality.

The Orbital Channel Resource Control on NonMarkov Priority Systems of Mass Service Basis. Part 1.Operational Distribution Model

In work systems analysis of process of target functioning of the satellite command relay system (SCRS) in the conditions of a difficult radio-electronic situation is carried out. The carried-out analysis of perspectives of development of a subsystem of relaying of SKRS of orbital grouping of spacecrafts of remote sensing of Earth, allowed to draw a conclusion on features of a stage of coordination planning of the means of a subsystem of relaying consisting in distribution of SKRS the orbital channel resource (OCR) on the basis of the non-Markov priority systems of service. The model of operational distribution of ROC of a subsystem of relaying on the basis of the priority systems of service in which, unlike the known models, time of stay of the request in a system is limited is received, limits for a type of distribution of holding time of requests are lifted and also expression for calculation of the initial moments of distribution of waiting time of messages of different priorities is received. Use of model allows to evaluate the probability of untimely delivery of details and also to provide required figures of merit of service of priority flows and at the expense of it to provide the required connectivity and stability of SKRS in general.

An multi-BSS multi-user full duplex MAC protocol based on AP cooperation for the next generation WLAN

Aiming at the problems of low efficiency of buffer information collection and sharp drop of system throughput caused by the aggravation of conflicts in the multi basic service set (BSS) high density deployment overlap coverage scenario of next generation wireless local access network (WLAN), an access point cooperation based multi-BSS multi-user full duplex multiple access protocol named as CMMFD is proposed. Firstly, a channel resource allocation algorithm for stations (STA) in overlapping coverage area is designed, in which, the access control (AC) equipment allocates the channel resources for all STA in response to buffer state and interference information (BI) according to the proportion of STA in the overlapped coverage area. Secondly, a BI information collection protocol process based on access point (AP) cooperation sending trigger frame is designed to collect all STA information. After receiving trigger frame, STA will access the channel and report BI information in p-probability according to the channel resources allocated by AC. Finally, a multi-BSS multi-user channel resource allocation algorithm based on full duplex is designed. AC allocates channel resources according to all BI information reported by AP, and schedules STA in the multi-BSS to carry out multi-user full duplex transmission over the sub-channel. Simulation results show that the throughput of the CMMFD protocol improves by 29.6%, compared with Mu-FuPlex protocol and EnFD-OMAX protocol.

Highly Reliable MAC Protocol Based on Associative Acknowledgement for Vehicular Network

IEEE 1609/802.11p standard obligates each vehicle to broadcast a periodic basic safety message (BSM). The BSM message comprises a positional and kinematic information of a transmitting vehicle. It also contains emergency information that is to be delivered to all the target receivers. In broadcast communication, however, existing carrier sense multiple access (CSMA) medium access control (MAC) protocol cannot guarantee a high reliability as it suffers from two chronic problems, namely, access collision and hidden terminal interference. To resolve these problems of CSMA MAC, we propose a novel enhancement algorithm called a neighbor association-based MAC (NA-MAC) protocol. NA-MAC utilizes a time division multiple access (TDMA) to distribute channel resource into short time-intervals called slots. Each slot is further divided into three parts to conduct channel sensing, slot acquisition, and data transmission. To avoid a duplicate slot allocation among multiple vehicles, NA-MAC introduces a three-way handshake process during slot acquisition. Our simulation results revealed that NA-MAC improved packet reception ratio (PRR) by 19% and successful transmission by 30% over the reference protocols. In addition, NA-MAC reduced the packet collisions by a factor of 4. Using the real on-board units (OBUs), we conducted an experiment where our protocol outperformed in terms of PRR and average transmission interval by 82% and 49%, respectively.

Conceptual model of a data transmission network for a polymodal control system in critical state infrastructure

Approaches to modeling a data transmission network in a remotely controlled system for distributed critical state facilities are considered in the article. To solve the problem of increasing the efficiency of channel resource costs, a new analytical model of the information distribution system from the standpoint of teletraffic theory is proposed. The model describes the service of extraordinary calls with absolute priorities, failures and gradient reservation of the channel resource for messages of modalities with the characteristics of operators in the data transmission network of critical facilities.

The Lyapunov Optimization for Two-Tier Hierarchical-Based MAC in Cloud Robotics

Cloud robotics can largely enhance the robot intelligence by offloading tasks to the cloud dynamically. However, the robots differ in their own hardware configuration such as battery and processing capacity, while the transmission frames are also a mixture of different quality of service (QoS) requirements. As the competition for limited channel resource is inevitable, how to optimize the system performance by effective resource allocation is a key problem. The paper proposes a two-tier hierarchical-based MAC (Two-Tier MAC) which means the classification exists not only in frames but also in robots. The Lyapunov optimization technique is used to maximize the time-averaged quality satisfaction. The experiments show the superior performance of the Two-Tier MAC compared with other MAC protocols especially in overloaded networks. Meanwhile, the system also presents a longer lifetime because the Two-Tier MAC takes energy balance into consideration.