Mitigation of Exposed Terminal Problem Using Packet Sensing

Zhang, Kewang; Zhang, Deyun; Jiang, Weihua

doi:10.1109/cnsr.2008.41

Cited by 8 publications

(4 citation statements)

References 8 publications

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“…This scheme improved system performance over distributed MAC protocol, and did not need time synchronization among nodes. Ke-wang Zhang [7] proposed SB-FSMA/CA method for static Ad hoc network. In this method, the correlation coefficient between ongoing…”

Section: Description Of Hidden/exposed Terminals Problemmentioning

confidence: 99%

Directional-transmission-based solution for hidden and exposed terminal problems in inter-vehicular network

Zeng

2013

2013 3rd International Conference on Consumer Electronics, Communications and Networks

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The intrinsic problem of hidden/exposed terminals in inter-vehicular networks may bring about communication conflicts and decrease network throughput. In this paper, we take the unidirectional feature of road into consideration, and design a single-channel transmission scheme for decreasing communication conflicts with nodes' position information and directional antennas. The scheme includes the identification and notification of relative positions among adjacent nodes, the identification of nodes' transmission state, and the scheduling of directional transmissions. By simulation experiments in NS-2, we verify that this scheme can discern hidden/exposed terminal nodes, decrease communication conflicts, and improve network performance. Keywords-inter-vehicular network; exposed terminal; hidden terminal; directional antennaAs a special type of Ad hoc network, the Inter-Vehicular Network [1] can provide convenient wireless Internet access and extended network coverage in places without communication infrastructure. With such functions as safety driving, information service and mobile office, it has become a hot research direction. However, communication conflicts are more prone to occur because of highly overlapping of nodes' coverage, and lead to the problems of hidden terminals and exposed terminals. This paper proposes a solution, i.e. Directional Optimization for Hidden and Exposed Terminal (DOHET for short), to deal with the problem and improve spatial utilization for Inter-Vehicular Network. Used in ground Geo-location RF Signal systems [2], it can identify potential communication conflicts effectively, choose appropriate time for transmission, and avoid the negative influence of hidden/exposed terminals on data transmission. Suggestion on setting proper nodes' distance is also proposed to achieve improved performance. I. DESCRIPTION OF HIDDEN/EXPOSED TERMINALS PROBLEMHidden terminals are the nodes locating within the communication range of data receiver and out of the communication range of data sender. Hidden terminals are unable to detect sender's traffic and try to communicate with the receiver, thus message conflict will happen. Exposed terminals are the nodes located within the communication range of data sender and out of the communication range of data receiver. Exposed terminals can detect sender's traffic and delay sending messages, but its transmission does not actually cause communication conflicts. So it introduces unnecessary delay and decreases the channel utilization rate.As shown in Figure 1, when node (i-1) sends messages to node i, node (i+1) locates in the coverage area of receiver i and becomes the hidden terminal. When node i sends a message to node (i-1), node (i+1) locates at the coverage area of sender i and becomes the exposed terminal. Fig. 1 Topology of one-dimensional inter-vehicular network II. RELATED WORKSCurrently there are a few research works about hiding/exposed terminals for general Ad hoc network, but few for inter-vehicular network. It is known that with single channel, t...

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Section: Description Of Hidden/exposed Terminals Problemmentioning

confidence: 99%

Directional-transmission-based solution for hidden and exposed terminal problems in inter-vehicular network

Zeng

2013

2013 3rd International Conference on Consumer Electronics, Communications and Networks

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“… Type-3: The source of interference is out of the detection range of the transmitter, but causes interferences at the receiver ("Hidden Terminal Problem"). There are several strategies to mitigate these interferences within the same network of operation (Tsertou & Laurenson, 2008;Zhang et al, 2008). However, interferences with foreign networks may still appear.…”

Section: Coexistence In the 24 Ghz Ism Frequency Bandmentioning

confidence: 99%

Wireless Technologies in Factory Automation

Buda¹,

Schuermann²,

Wollert³

2010

Factory Automation

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Wireless technologies are utilised in consumer applications for several years, now. However, the operation of radio based communication systems in automation applications was considered doubtful for a long time. Primarily, the highly fluctuating quality of wireless transmission channels, compared to wired ones, was responsible for this fact. Transmitted electromagnetic waves experience reflexion, scattering, and diffraction, which may cause constructive or destructive interferences of the different signal copies arriving at the receiver. The direct consequences are packet errors and losses, resulting in higher transmission delays. Especially industrial propagation environments, with a lot of metallic surfaces and moving objects, are classified as demanding for wireless transmission. While fluctuations in latency and short losses of connections may be tolerated in consumer applications, exceeding given timelines in automation applications implies intolerable errors. The results are low plant availabilities and decreasing productivity. By means of the development of diverse wireless standards and the adaption of well-suited protocols for industrial applications, the end-users doubts could be reduced dramatically over the last decay. The advantages of wireless solutions are obvious. In harsh environments, mobile and rotating scenarios, or at positions, difficult to access, cable connections and sliding contacts represent a main source of error. In this context the error probability can be decreased and the maintenance intervals increased by the utilisation of wireless technologies. In addition to that, there is a great potential on saving time and money during planning, installation, and commissioning of plant sections. Many domains of the industrial automation already profit from the deployment of wireless solutions. With KNX RF (Konnex, 2006) and ZigBee (ZigBee Standards Organization, 2007) the first standards for building automation have been introduced. Within the scope of the HART 7 specifications (HART Communication Foundation, 2008) the first standard, WirelessHART, for the process automation was released in late 2007. Further standards, especially for the domain of factory automation, are expected to get published in 2010. In order to reduce costs and time during the development of wireless solutions, unlicensed frequency bands are typically used for operation. Moreover an almost worldwide harmonised operation is guaranteed. This tendency is very pronounced for the 2.45 GHz ISM (Industrial, Scientific, and Medical) frequency band. Because of the high availability, transceiver chips of commercial standards are 2 www.intechopen.com Factory Automation 30

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“…Acharya et al 16 proposed the Medium Access via Collision Avoidance with Enhanced Parallelism (MACA-P) protocol, which makes the exposed node concurrently transmit and improves the network throughput by aligning the sending time of the acknowledgement (ACK) and DATA frames. Zhang et al 17 proposed the Signal strengthBased Frame Sensing Multiple Access with Collision Avoidance (SB-FSMA/CA) protocol, which enables the exposed nodes to concurrently transmit if and only if the correlation coefficient calculated by the exposed node is less than a certain threshold. Park et al 18 increased the packet reception ratio using forward error correction schemes (FECS).…”

Section: Introductionmentioning

confidence: 99%

“…To resolve the exposed-node problem in WSNs, researchers have presented many concurrent transmission strategies. [14][15][16][17][18][19][20][21] In a study by Phil, 14 the Multiple Access with Collision Avoidance (MACA) protocol was presented. In this protocol, the required transmission time is only covered in the Clear to Send (CTS) frame.…”

Section: Introductionmentioning

confidence: 99%

Concurrent transmission mechanism to mitigate pan-exposed-node problems in wireless sensor networks

Zhao

Chen

Guo

et al. 2017

International Journal of Distributed Sensor Networks

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Power control technology is widely used in wireless sensor networks to improve network performance. The asymmetric transmission power strategy used in power control technology causes the re-emergence of hidden-node problems and more serious exposed-node problems. This article analyzes the reasons of these problems and proposes the concept of the pan-hidden node and pan-exposed node. To avoid pan-hidden-node problems and mitigate pan-exposednode problems, a concurrent transmission mechanism is presented. The concurrent transmission mechanism contains a strict time schedule for different categories of frames and an interference degree criterion to ensure concurrent transmission. The rigorous time schedule can guarantee that different classes of frames do not interfere with one another. The interference among the frames of the same type is constrained by the interference degree criterion. Finally, the performance of the concurrent transmission mechanism is evaluated using simulation experiments.

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Mitigation of Exposed Terminal Problem Using Packet Sensing

Cited by 8 publications

References 8 publications

Directional-transmission-based solution for hidden and exposed terminal problems in inter-vehicular network

Directional-transmission-based solution for hidden and exposed terminal problems in inter-vehicular network

Wireless Technologies in Factory Automation

Concurrent transmission mechanism to mitigate pan-exposed-node problems in wireless sensor networks

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