Data Collision Problem Research Articles

Design and Implementation of an IoT Gateway for Zigbee and WiFi

This paper proposed a framework called IAPA (Integrated Access Point Architecture) that applied an off-the-shelf AP (Access Point) device on WLAN (Wireless Local Area Network) as an IoT (Internet-of-Things) gateway to integrate Zigbee and Wifi. This Wifi-Zigbee AP (called WiZAP) has the advantages of low cost, small size and low power consumption. However, the coexistence of Wifi and Zigbee in unlicensed bands will introduce a serious data collision problem. In this paper, we propose a linear-time balance-first configuration strategy to adjust Wifi parameters to reduce data collision. A strategy to dynamically configure these parameters for MAC layer communication is also proposed. Experiments test the influence of network transmission in real application scenarios. Results show that our WiZAP can work efficiently with the coexistence of Wifi and Zigbee.

On ℓ2–ℓ∞ output-feedback control scheduled by stochastic communication protocol for two-dimensional switched systems

This paper is concerned with the – output-feedback control problem for a class of two-dimensional (2-D) switched systems described by the general Fornasini–Marchesini second model under the stochastic communication protocol (SCP). In a networked 2-D switched control system, the sensors and the controller are typically connected through a shared communication network of limited bandwidth, which is likely to result in data collision problem. To circumvent this network-induced problem, a new SCP is dedicatedly put forward for the 2-D switched system in order to orchestrate the transmission order of sensor nodes, under which only one sensor node obtains the privilege to access the network at each transmission instant. Then, based on the nominal system information compensation, a set of new mode-dependent output-feedback controllers is designed for 2-D switched systems subject to SCP and external disturbances. Moreover, using the average dwell-time approach, sufficient conditions are established to ensure the existence of the desired controllers that guarantee both the exponential mean-square stability and the – performance. Finally, a numerical example is presented to demonstrate the effectiveness of the proposed controller design method.

Event-triggered sliding mode control under the Round-Robin protocol for networked switched systems

The event-triggered sliding mode control problem is addressed for a class of networked switched systems subject to communication constraints. Not only the problem of network congestion, but also the problem of data collision is taken into account. In order to lighten network overloads and save bandwidth, an event-triggered scheme is utilized to decide whether a datum is transmitted or not and the Round-Robin protocol is employed to determine the priority of the actuator at a certain instant, which is a novel attempt to the sliding mode control problem for networked switched systems. Sufficient conditions are established such that the closed-loop system with sliding mode dynamics is exponentially stable. An event-based sliding mode control law is constructed under the Round-Robin protocol to drive the system trajectory into a bounded sliding vicinity around the sliding surface. Finally, a numerical example is given to demonstrate the effectiveness of the developed methods.

Optimization of Big Data Scheduling in Social Networks

In social network big data scheduling, it is easy for target data to conflict in the same data node. Of the different kinds of entropy measures, this paper focuses on the optimization of target entropy. Therefore, this paper presents an optimized method for the scheduling of big data in social networks and also takes into account each task’s amount of data communication during target data transmission to construct a big data scheduling model. Firstly, the task scheduling model is constructed to solve the problem of conflicting target data in the same data node. Next, the necessary conditions for the scheduling of tasks are analyzed. Then, the a periodic task distribution function is calculated. Finally, tasks are scheduled based on the minimum product of the corresponding resource level and the minimum execution time of each task is calculated. Experimental results show that our optimized scheduling model quickly optimizes the scheduling of social network data and solves the problem of strong data collision.

Deep-learning-based phase control method for tiled aperture coherent beam combining systems

We incorporate deep learning (DL) into tiled aperture coherent beam combining (CBC) systems for the first time, to the best of our knowledge. By using a well-trained convolutional neural network DL model, which has been constructed at a non-focal-plane to avoid the data collision problem, the relative phase of each beamlet could be accurately estimated, and then the phase error in the CBC system could be compensated directly by a servo phase control system. The feasibility and extensibility of the phase control method have been demonstrated by simulating the coherent combining of different hexagonal arrays. This DL-based phase control method offers a new way of eliminating dynamic phase noise in tiled aperture CBC systems, and it could provide a valuable reference on alleviating the long-standing problem that the phase control bandwidth decreases as the number of array elements increases.

Analysis of Mutual Couple Effect of UHF RFID Antenna for the Internet of Things Environment

Asset management was a common RFID-based Internet-of-Things (IoT) application scene. RFID tags in the equipment warehouse were usually large, and the communication between the reader and the tag was prone to data collision problems, which affected the recognition efficiency of the device. In practical applications, due to the structural characteristics of the micro-strip UHF RFID tag antenna, the traditional inter-coupling impedance expression had large errors and insufficient accuracy in predicting the mutual coupling effect, such as system frequency shift. In this paper, the 3D initialization model of the tag was used to indirectly extract the electrical parameter values by the ANSYS HFSS software. At the same time, the dual-tag was taken as an example to derive the transimpedance expression between the dense tags to extract the corresponding coupling parameters. Finally, various tag-intensive scenarios in the actual environment were tested and the derivation formula was verified, and the dual-tag UHF RFID near-field frequency shift affected by the environmental factors, such as relative position, attachment, and the stacking method, was discussed. The mutual coupling effect on the minimum transmit power of the reader antenna was also studied. The experimental results showed that the average error of the formula calculated by this method was significantly smaller than that of the traditional formula. When the tag spacing was less than 30 mm, the derived mutual impedance expression was applied to the frequency shift calculation error range (1.6-7.3 MHz). For dense tag systems, the error was less than 9.8% when the number of tags was greater than 7, and the prediction accuracy was higher than the superposition method. The research results provided a theoretical and practical basis for the rapid identification and location of power assets during the dense RFID tag environment.

An Adaptive Relay Transmission Scheme for Reliable Data Forwarding in Wireless Body Area Networks

The new generation of telemedicine systems enables healthcare service providers to monitor patients not only in the hospital but also when they are at home. In order to efficiently exploit these systems, human information collected from end devices must be sent to the medical center through reliable data transmission. In this paper, we propose an adaptive relay transmission scheme to improve the reliability of data transmission for wireless body area networks. In our proposal, relay nodes that have successfully decoded a packet from the source node are selected as relay nodes in which the best relay with the highest channel gain is selected to forward the failed packet instead of the source node. The scheme addresses both the data collision problem and the inefficient relay selection in relay transmission. Our experimental results show that the proposed scheme provides a better performance than previous works in terms of the packet delivery ratio and end-to-end delay.

전력 효율을 위한 수신자 기반 비동기 센서 MAC 프로토콜 설계

In this paper we describe an asynchronous MAC protocol with receiver-initiated duty cycling for energy-efficiency in wireless sensor networks(WSN). Legacy asynchronous MAC protocols, X-MAC and PW-MAC, has weaknesses which generates too many control packets and has data collision problem between multiple transmitters, respectively. Therefore, we propose a receiver-initiated asynchronous MAC protocol which generates control packets from transmitter to complement these disadvantages. Compared to the prior asynchronous duty cycling approaches of X-MAC and PW-MAC, the proposed protocol shows a improvement in energy-efficiency, throughput and latency from simulation results.

Data Collision Detection Technology of the Electronic Countermeasures' Simulation Scenario

In order to solve the problem of data collision in the electronic countermeasures simulation scenario edition, a scenario data collision detecting algorithm based on productive inferring, whats more, a scenario data collision detection system for electronic countermeasures simulation is designed and actualized. This system can be integrated into electronic countermeasures simulation system regarded as a component, to check the scenario data and ensure the datas rationality.

On a Characteristic of Data Transmission In Bus Network

Bus network is a primary topology in local area network and the network had a problem of data collision on the bus which influenced the efficiency of data transmission. Recently, using switching-hub that establishes a link from a sending station to a receiving station, the number of data collisions extremely decreased. However, in the case that the data buffer of a receiving station is full or the receiving station is sending or receiving data, a sending station has to wait for sending data. This waiting time (stand-by time) influences an efficiency of data transmission. In this paper, a characteristic of data transmission with the stand-by time in bus network is clarified. Taking note of one station with a sending data buffer, the link probability that the link from the station to a receiving station will be established is defined as constant. The station connected to the bus is modeled as a queue with stand-by time, and then state equations of the probability of the number of waiting data at the ready time of sending are expressed. From the equations, probabilities of the number of waiting data, mean of the number of waiting data in the sending buffer and mean waiting time which is the time from the data arrival time at the sending buffer to the beginning time of sending are derived. The calculated values are illustrated with the link probabilities in several cases, and then the influences of the link probability to data transmission are shown.

An Improved Multi-Label Anti-Collision Algorithm of RFID

When there are multiple electronic tags in the reading range of reader, It arises problem of multiple tags data collision in the data communication process of RFID system, causing the data reader have obtained error. This paper will contrapose the problem of tag collision, analysizing the search number and the system throughput rate of the existing anti-collision search algorithm based on binary, to propose an improved anti-collision algorithm. The improved algorithm reduces the redundant information of the sequence number that the reader have sent, and no longer searchs the tags of one bit collided ,but identify the two collided tags directly, thus reducing the search number of algorithm. Matlab simulation show that this algorithm can reduce the search number of reader identifying tags, improving the identifying efficiency of the RFID system, solving the problem of tag collision effectively.

A decentralized minislot scheduling protocol (DMSP) in TDMA-based wireless mesh networks

Wireless mesh network is a promising network topology that can provide high data rate backhaul network access. For achieving high data rate backhaul network access, a well-designed bandwidth scheduling protocol is necessary for wireless mesh networks. This paper takes minislot scheduling problem for IEEE 802.16 mesh networks as an example and formulates the problem as an integer linear programming model in this paper, where minislot is an atomic bandwidth allocation unit for data transmissions among subscriber stations and base station. Due to the high computational complexity for solving integer linear programming model at subscriber stations and the degradation of bandwidth utilization resulted from data collision problems and minislot insufficient problems, this paper proposes a decentralized minislot scheduling protocol to make subscriber stations, rather than base station, schedule minislot usage for throughput gains in the IEEE 802.16 mesh networks. The decentralized minislot scheduling protocol includes minislot usage constraints and minislot decision strategies to alleviate data collisions and minislot insufficient problems as well as to increase bandwidth utilization. The proposed protocol can not only accommodate to the IEEE 802.16 standard, but also makes subscriber stations schedule minislots with the latest minislot usage information. Besides IEEE 802.16 mesh networks, the proposed protocol also can apply to any wireless mesh networks with less or no modifications. From the simulation results, the performance of the proposed protocol outperforms the other related contributions in terms of the transmission delay, control overhead, minislot utilization and the network throughput.

Modified Anti-Binary Collision Protocol (MABS) of Radio Frequency Identification (RFID) System

This paper introduces a modified version of anti-binary collision algorithm. The proposed method enhances data collision problems done among multiple tags in the range of the RFID reader's action. The proposed algorithm is called (MABS). It is one blocking protocol, based on Adaptive binary splitting protocol. MABS not only inherits the essence of ABS which uses the information of recognized tags obtained from the last process of tag identification, but also adopts a blocking technique which prevents recognized tags from being collided by unrecognized tags. Finally, the simulation results show that MABS outperforms ABS.

Dual-reader wireless protocols for dense active RFID identification

Radio Frequency Identification (RFID) becomes increasingly widespread in various applications. However, data collision is one of the most concerns in dense active RFID systems. Data collision will cause serious data loss, slow identification speed and high energy consumption. In this paper, data collision problem is addressed and two communication protocols are presented based on the dual-reader structure. One is the master–slave dual-reader (MSDR) protocol, and the other is called the dual-reader DCMA (DRDCMA) protocol. Both protocols are implemented in the hardware platform and their performances are compared with other conventional anti-collision protocols. Experimental results show that our proposed protocols outperform the conventional ones in terms of identification rate, identification speed and energy consumption. Compared to the Single-reader (SR) protocol, the proposed MSDR protocol can improve the identification rate by 82.9%, reduce the access latency and energy consumption by 47.0%. Besides, the proposed DRDCMA protocol can reduce the access latency and energy consumption by 69.1 and 78.3%, respectively, in comparison with DCMA. Moreover, MSDR has the fastest identification speed and it can improve nearly 100% over SR when the communication load is large enough. DRDCMA presents the highest identification rate with nearly no data loss, while the identification rate in MSDR is 40.6% and decreases dramatically with the increment in communication load. Copyright © 2011 John Wiley & Sons, Ltd.

Application of ICA-based anti-collision algorithm in RFID system

Data collision problem exists in radio frequency identification (RFID) system when tabs are present in the interrogation zone of a single reader at the same time. Though different anti-collision me...

A New Content-Addressing Mechanism of CMAC-Type Associative Memory Systems for Reducing the Required Memory Size

The reduction problem of the required memory size is essential to CMAC-type associative memory system (AMS). Although the conventional hash-coding and hash-addressing scheme can solve the problem effectively, it may cause data collision problem resulting in the loss of useful information previously stored. To overcome this drawback, a new content-addressing mechanism is proposed. The main idea is as follows: One of the data stored in each set of ρ association memory locations is chosen to be a "master weight", and all the remaining "slave weights". It has been found that, in the case of regular training, all the slave weights are identical to the master one, and hence may be simply removed without loss of useful information. Utilizing this tact, a new algorithms for encoding, retrieval and training have been developed, and the required memory size can be reduced to 1/ρ of its original value without the data collision problem.