Coexistence Of IEEE Research Articles

Analysis of Congestion Control Mechanisms for Cooperative Awareness in IoV Environments

Traditional vehicle ad hoc networks (VANETs) have evolved toward the Internet of Vehicles (IoV) during the past ten years with the introduction of 5G communication technology and the growing number of vehicles linked to the Internet. The coexistence of IEEE 802.11p and 5G becomes critical to build a heterogeneous IoV system that benefits from both technologies, being that the IEEE 802.11p standard remains the best option for direct communications and safety-critical applications. The IEEE 1609 standard family and the ETSI ITS-G5 standard family both use the IEEE 802.11p standard as a MAC mechanism. To avoid dangerous situations, vehicles require the periodic exchange of awareness messages. With the increase in vehicle density, the MAC layer will suffer from radio channel congestion problems, which in turn will have a negative impact on the safety application requirements. Therefore, the decentralized congestion control (DCC) mechanism has been specified by ETSI to mitigate channel congestion; this was achieved by adapting transmission parameters such as transmit power and data rate. However, several studies have demonstrated that DCC has drawbacks and suffers from poor performance when the channel load is very high. This paper investigates a new promising DCC technique called transmission timing control (TTC), to reduce the channel load for periodic cooperative awareness. It consists of spreading the transmissions over time to avoid contention on the transmission channel. The objective of the paper is to propose an analytical study to calculate the probability of successful transmission using TTC. Obtained results showed a convergence between the applied experiments and our mathematical model, achieving an error margin of only 5%, which confirms the validity of the equation proposed.

Harmonious Coexistence of IEEE 802.11af Wireless LAN and Digital TV

ABSTRACT Congested Industrial, Scientific, and Medical (ISM) band stifles the growth of Wireless Local Area Network (WLAN). The recent switchover from analog to digital TV (DTV) broadcast frees from the conventional TV bands a sizeable amount of spectrum, which is commonly called TV white space (TVWS). TVWS is very attractive to many wireless technologies, including WLAN. IEEE came up with 802.11af, the standard for the WLAN technology that operates in TVWS. Nevertheless, it is unsure how best to guarantee its operation not causing harmful interference to DTV. In this paper, we present the conditions required for harmless coexistence of IEEE 802.11af WLAN and DTV. We make use of the standard prediction method based on radio propagation characteristics, i.e. the ITU-R P.1411-9 method which has been adopted in communication system planning. Based on our findings, we suggest the followings: (1) Operate IEEE 802.11af WLAN at any adjacent channel other than the first (i.e. except the closest neighbour channel). (2) The height of IEEE 802.11af installation does play a part when there is a relatively large separation distance between the WLAN and DTV (e.g. 50 m). (3) For outdoor operation, IEEE 802.11af WLAN should be installed at the second, third, or fourth channels adjacent to the DTV’s; fifth or sixth adjacent channel for indoor operation.

On the coexistence of IEEE 802.11ac and WAVE in the 5.9 GHz Band

The IEEE Wireless Access in Vehicular Environment, or WAVE, system uses 5.9 GHz band. Recently, however, the FCC announced its intention to share the band for WLANs based on new standards such as IEEE 802.11ac. In this article, we discuss the problems in the possible coexistence scenario of WAVE and WLAN, such as direct competition between WLAN and WAVE devices for bandwidth and the hidden terminal problem. The problems are exacerbated by the different bandwidth used by the two technologies, so the only usable sensing method between them is energy detection. In this article, we consider one way to address the problems within the current standards framework, which is the combined control of interframe space and the receiver sensitivity on the WLAN devices cued by the energy detection.

CHAMELEON: A Framework for Coexistence of Wireless Technologies in an Unlicensed Band

The recent increase in the number of technologies operating in the 2.4 GHz ISM band has drawn attention towards the impact they can have on each other. In this paper, we have conducted a case study about coexistence of IEEE 802.11 and IEEE 802.15.4 which has led us to discover previously unknown interactions. We show through extensive experiments that CCA method used by a wireless device can significantly change the coexistence scenario. We also highlight the ways in which coexistence can be improved by making runtime adjustments to some MAC/PHY layer parameters and show their effectiveness. Furthermore, we propose a framework which exploits the pervasiveness and ubiquity of Wi-Fi to improve coexistence among wireless technologies in the 2.4 GHz ISM band. Our framework has the capability to detect the presence of wireless technologies operating anywhere in the 2.4 GHz ISM band and also accounts for devices whose signatures do not exist in the database. It facilitates the Wi-Fi AP to make decisions such as changing the channel or making MAC/PHY layer adjustments which are compliant with the configured coexistence policy thus improving the performance of the wireless devices. We have implemented our framework on real hardware and evaluated its performance in the presence of ZigBee.

Performance of Ad-Hoc Wireless Network on 2.4GHz Band in Real Fields

This paper describes the performance of ad-hoc wireless network on 2.4 GHz band in the real buildings and homes. The communication module based on the IEEE 802.15.4 standard was developed and installed into four kinds of buildings with different structures to estimate the performance of the network in the real field. The attenuation of the signal resulting from obstacles and the coexistence of IEEE 802.15.4 with other products on the same radio frequency band were evaluated. Thus, the guidelines for applying the network to building and home control systems and practical solutions for constructing a ubiquitous network for these systems are established.