Low Priority Nodes Research Articles

Priority-Based Dynamic IoT-Downlink Communications with Blind Transmission-Mode Recognition

In downlink Internet of things (IoT) applications, certain nodes can be given a higher transmission priority than others, and hence might be allocated more transmission resources. Consequently, some nodes may face a resource-starvation problem. To overcome such a predicament, this article proposes an opportunistic non-orthogonal multiple access (NOMA) scheme to enable low priority (LP) nodes (LPNs) to share the transmission resources of high priority (HP) nodes (HPNs) while prioritizing the quality of service (QoS) requirements of the HPNs. In the proposed scheme, the control center (CC) may decide to multiplex the data of one or more LPNs with the HPN data using NOMA, which can improve the network throughput substantially. Such a decision is based on the channel conditions and QoS requirements for the HPNs and LPNs. Hence, the proposed system may operate in one of the following four modes, HPN orthogonal multiple access (OMA), LPN-OMA, (HPN, LPN)-NOMA, and the OFF mode where all nodes are muted. To improve the network efficiency and reduce overhead, the network is considered uncoordinated where the receiving nodes do not receive side information about the selected transmission-mode by the CC, leaving it to the receiving nodes to blindly recognize the transmission-mode. The network complexity and throughput trade-off is considered for fixed and adaptive power assignments. The results show that the proposed system can provide substantial throughput improvement over conventional NOMA transmission. For the example of a pair of HPN and LPN, the maximum throughput gain with opti-mal power allocation is about 0.85 bits/symbol, which implies that the throughput relative improvement is about 9 folds. The article also discuss the challenges and potential solutions of the proposed framework.

Design and Implementation of a CAN Data Analysis Test Bench based on Raspberry Pi

With the development of Cyber-Physical Systems(CPS), several technologies such as automation control, automotive and intelligent house systems have been developed. To enable communication among various components of such systems, several wired and wireless communication protocols are used. The Controller Area Network(CAN) is one of such wired communication protocols that is popularly used for communication in automobiles and other machinery in the industry. In this paper, we designed and implemented a response time analysis system for CAN communication. The reliable data transfer among various electronic components in a significant time is crucial for the smooth operation of an electric vehicle. Therefore, this system is designed to conveniently analyze the response time of various electronic components of a CAN enabled system. The priority for transmission of the messages in the CAN bus is determined by the message identifier. As the number of nodes increases the transmission of low priority messages is delayed due to the existence of higher priority messages on the bus. We used Raspberry Pi3 and PiCAN2 board to simulate the data transfer for studying the comparative delay in low priority nodes.

Accurate Delay Analysis in Prioritised Wireless Sensor Networks for Generalized Packet Arrival

This letter presents an accurate delay analysis in prioritised wireless sensor networks (WSN). The analysis is an enhancement of the existing analysis proposed by Choobkar and Dilmaghani, which is only applicable to the case where the lower priority nodes always have packets to send in the empty slots of the higher priority node. The proposed analysis is applicable for any pattern of packet arrival, which includes the general case where the lower priority nodes may or may not have packets to send in the empty slots of the higher priority nodes. Evaluation of both analyses showed that the proposed delay analysis has better accuracy over the full range of loads and provides an excellent match to simulation results.

Priority-based model for network partition problems for mobile ad hoc networks

In mobile ad hoc networks, it is collection of nodes used for communication among the nodes. Due to the node mobility, the network may be divided into a number of parts. This paper proposes a priority-based model for mobile ad hoc networks, which assigns the weights to all nodes. Here, the high-priority nodes must maintain connections against those of low-priority nodes. The proposed model has been simulated with the help of 100 mobile nodes in the network using Network Simulator (NS-2.34). The proposed model was simulated and tested under the various environments. It was compared with Goyal model and Hahner model. The simulation results have shown that the proposed model has reached the top position in terms of the network size, percentage of path reconstruction and average delay.

The hierarchical traveling salesman problem

The distribution of relief aid is a complex problem where the operations have to be managed efficiently due to limited resources. We present a routing problem for relief operations whose primary goal is to satisfy demand for relief supplies at many locations taking into account the urgency of each demand. We have a single vehicle of unlimited capacity. Each node (location) has a demand and a priority. The priority indicates the urgency of the demand. Typically, nodes with the highest priorities need to be visited before lower priority nodes. We describe a new and interesting model for humanitarian relief routing that we call the hierarchical traveling salesman problem (HTSP). We compare the HTSP and the classical TSP in terms of worst-case behavior. We obtain a simple, but elegant result that exhibits the fundamental tradeoff between efficiency (distance) and priority and we provide several related observations and theorems.

Channel Adaptive Prioritized Network Coding

We propose a channel adaptive prioritized network coding technique that provides a variable quality of service (QoS) to different nodes in multiple access relay networks (MARN). The basic idea is to exclude the low priority nodes in the network encoder when their channel gains towards the destination are above a threshold, and vary the threshold to provide a variable QoS. The proposed technique can provide a soft-level prioritized service to different nodes depending on their assistance needs. They are a natural generalization of current prioritized network coding techniques which can provide only a hard-level (fixed) prioritized service. We derive the outage probability for the prioritized and non-prioritized nodes in Rayleigh flat fading channel with additive white Gaussian noise and derive optimum threshold based on QoS constraints.

DQDB: an overload cycle analysis of Generalized Bandwidth Balancing with strict priority

This paper uses a state-space approach and an analysis of overload cycle constraints to show that a simple extension of Generalized Bandwidth Balancing ( GBWB), can be used to strictly enforce non-preemptive priorities. The extension associates a Bandwidth Balancing Machine and counter with each queue access machine rather than with the node in order to implement priorities. The entire DQDB network is modeled as a large Finite State machine. Overload cycles are those cycles in the state space that correspond to the situation that all nodes attempting to access the bus are attempting to do so continuously. Simple analytical constraints on the node counters allow derivation of the bandwidth sharing amongst the nodes and give insight into how the system structure results in such sharing. GBWB may be viewed as a mechanism that implements “rate-based” priorities that result in predictable apportioning of the bandwidth. In this paper, a system is presented that enforces “access-based” priorities where a single high priority node may prevent all access to the bus of low priority nodes.

Polling with a General-Service Order Table

This paper derives exact results for a polling system such as a token bus or token ring with exhaustive service and priority polling. The results can also be used to analyze a terminal controller with a generalservice order table. There are <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</tex> stations in the system and the token is passed among them according to a polling table of length <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M (\geq N)</tex> . Stations are given higher priority by being listed more frequently in the polling table. By a straightforward extension of results of Ferguson and Aminetzah [5] for systems with circular polling and exhaustive service, it is shown that in general, the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</tex> mean waiting times require the solution of a set of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M - N</tex> simultaneous equations and a set of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M(M - 1)</tex> simultaneous equations. We show that partial symmetry in the polling table and the station characteristics can be used to significantly reduce the number of equations which must be solved. We present the reduced equation set for a two-priority class system and apply the results to a large token-passing bus network in which a few nodes account for a substantial portion of the network traffic. We show that in the latter case, the overall_ average message waitmg time can be significantly reduced by using priority polling: average waiting times at the high-priority nodes have large reductions in return for a smaller increase at low-priority nodes.