WLAN Standards Research Articles

Performance Evaluation Voice over WLAN Capacity in Three Standards IEEE 802.11

In the modern landscape of telecommunication, wireless mobile connectivity and migrating voice telephone services to IP technology are two of the most prominent developments that are transforming the landscape. These two concepts can be utilized together using networks which carry voice services over wireless LAN (VoWLAN). However, due to the unique characteristics of each, certain issues inevitably arise and must be handled to allow for suc-cessful deployment. In this paper OPNET 14.5 Modeler was used to carry out extensive simulation scenarios to examine the single cell WLAN VoIP ca-pacity in regards to three IEEE 802.11 WLAN standards which are (a, b, and g) as well as applying different packet sizes, data rates and codec types for analysis.

Compact bowtie-shaped microstrip patch antennas with low cross-polarization and wideband harmonic suppression

A compact microstrip-fed bowtie-shaped circular ring slot antenna with a fundamental resonant frequency at 5.5 GHz for WLAN standards is initially studied. By introducing two bilateral triangles (BLT) slits symmetrically on either side of the radiator with a defected ground structure (DGS), wideband harmonic suppression (HMS) has been achieved. To get the dual-band i.e., lower band at 5.5 GHz and the upper band at 17.41 GHz for direct broadcast services (DBS) transmission satellite communication applications and additional suppress the harmonics excited by the insert-fed cut, a single inverted U-shaped slot (DGS) is integrated into the bowtie-shaped patch. Bowtie-shaped single-band patch (BSBP) antenna measured impedance bandwidth (IBW) from 5.218–6.225 GHz (17.6%) and insert-fed bowtie-shaped dual-band monopole (IBDBM) antenna measured IBW from 5.254–6.168 GHz (16.61%) for the lower band and from 17.213–17.856 GHz (3.66%) for the upper band, a wideband HMS up to 3.17 f0 (f0= fundamental resonant frequency) characteristics are achieved in both cases. The proposed antennas have a wideband HMS, compact size, and a significant reduction in cross-polarization levels in E-plane radiation patterns. The design parameters are also predicted using a machine learning regression technique built on an artificial neural network and convolutional neural network algorithm.

Design of Ternary Convolutional Code using Reconfigurable Architecture

The need for trustworthy and efficient digital data transmission and storage systems has increased in recent years. The demand to handle and store digital information has grown in the business sector, the military, and the government as a direct result of the widespread availability of high-speed, large-scale data networks. This requirement must be met in order for the design of these systems to keep up with the rapid pace set by communication and computer technologies. When trying to overcome the variable degradation in real time, one of the most important factors to consider is the dependability of the broadband communication channel. Therefore, the use of convolutional codes and other channel-coding strategies is an essential component of any broadband communication system. DSL, WLAN, and 3G standards all require different configurations of convolutional coding, each of which must achieve a specific level of coding performance despite operating at a unique data rate (constraint length and code rate) Therefore, from the perspective of channel-coding techniques, hardware implementations for the development of an encoder are essential. This encoder should be able to support multiple networks using a reconfigurability approach and should be able to function across a variety of standards. Additionally, flexibility and hardware performance should both be prioritised. This calls for forward error control coding with reconfigurable logic, which provides high-speed, low-power dynamically dedicated hardware architectures under a number of speed/power performance constraints at different time intervals that can function within a variety of channel conditions. The ternary computation system has a number of benefits, the most notable of which are the availability of a high data rate, improved spectral efficiency, enhanced coverage, and lower latency. As a result, there is a growing demand for ternary-based systems that use convolutional encoders as a result of developments in technology

Possibilities of Electronic Jamming of WLAN Networks in the Physical Layer

Wireless local area networks or WLANs are the necessary underlying communication technology of consumer electronics, mobile computers and mobile phones of our days. Thanks to the comfortable operations and ubiquitous applicability for work and entertainment, the demand surged for these devices in the last 15 years. WLAN solutions provide the opportunity for mobility. But these networks communicate via radio waves with devices, which can be eavesdropped on and attacked. One form of attack is jamming. This article analyses the most frequent WLAN standards and the jamming options, particularly the execution of electronic jamming in the physical layer.

WDM-RoFSO transmission: Demonstration based on IEEE 802.11 WLAN standard

We show two experiment setups to verify the applicability of WDM (wavelength division multiplexing)-RoFSO (Radio-over-Free-Space Optics) system: (i) transmission of images files following the data format of IEEE 802.11 wireless local area network; (ii) robust performance analysis of bit error rate for on–off keying signal at a speed of 10 Gbps. Specifically, it is shown that, for 100 m indoor transmission, our testbed satisfies an error-free condition of BER ≤10−12, achieving a total data rate of 20 Gbps. In this paper, we contribute to the evaluation of the practical FSO measurement data by providing experimental measurements.

Robust, Efficient and Low Profile Fractal Enabled EBG Incorporated Wearable Antenna for WLAN Standards

A compact, robust Koch fractal combined triangular monopole antenna incorporated with a Sierpinski fractal EBG unit cell array is proposed for integral solutions of wearable devices in WLAN standards. The fractal enabled EBG-Antenna has a modified triangular microstrip that acts as a radiator and a 2X2 array of Sierpinski square EBG unit cells as a reflective surface to enhance the performance also as a shield linking the antenna and human body. The proposed antenna demonstrations and impedance match bandwidth of 32 MHz, a gain of 7.86 dBi, Front to back ratio of 13 dB, Radiation Efficiency of 90.35 % at 2.45 GHz in free space. The EBG-Antenna performs well under different bending conditions and human tissue loading as verified by measurements. The specific absorption rate (SAR) is also evaluated and found within limits as per standards. The computed results accomplished the SAR of 0.302 W/Kg, 0.1423 W/Kg for 1 g, 10 g of tissue, respectively, which demonstrates about a 95 % drop associated with the antenna without EBG. Furthermore, the fractal loading makes the antenna compact; EBG introduced at the underside of the monopole antenna gives a high gain-bandwidth product and disengages the human body and the antenna, making the realized antenna a potential candidate with possible seamless incorporation of specified wearable applications in WLAN standards.

GFDM frame design for low-latency industrial networks

This paper proposes a short packet GFDM-based physical (PHY) layer for industrial wireless networks to reduce latency. In our proposed PHY layer, the conventional OFDM scheme used in the data field of IEEE 802.11 WLAN standards is replaced by GFDM. The preamble size is also reduced from 10 symbols to 1 symbol. Furthermore, the fields of the overall packet structure are optimized in terms of total number of subcarriers and cyclic prefix length. Additionally, a noise-free GFDM scheme is subjected to concatenated channel coding to minimize error rate. Through simulation, packet transmission time is reduced by about 40 ∼ 72% compared to the OFDM-based PHY layer while achieving a PER of order 10^−3. The obtained results show that the GFDM-based PHY layer outperforms its counterpart by exhibiting a lower latency and high reliability. This performance renders the GFDM-based (proposed) PHY layer suitable for adoption in the development of wireless networks for latency and reliability constrained industrial applications. It should be noted that the simulations presented in this paper express our first step in the direction of using GFDM for industrial wireless networks to achieve low latency and high reliability. We therefore consider building a fully functional GFDM based-testbed as part of our future work.

Low-Power and Low-Delay WLAN Using Wake-Up Receivers

Energy-efficient communication technologies are a key enabler for many IoT applications. Many existing communication protocols are based on duty-cycling techniques, that have an inherent tradeoff between delay and energy consumption. In the field of sensor networks, wake-up receivers have been investigated to overcome these problems and to further reduce energy consumption. We now go one step further and investigate the use of wake-up receivers in combination with IEEE 802.11 WLAN. We extend the protocol used to communicate between the access point and the client to introduce a wake-up signal. This can be implemented in a way that is fully compatible with existing WLAN standards, thus, it can be deployed gradually with little effort and no need to change existing systems. As a proof of concept and to perform first lab experiments, we developed a hardware prototype using a selective wake-up receiver and off-the-shelf USB-WLAN dongles. All experimental results are verified using an analytical model and a detailed simulation study. We show that our wake-up WLAN can provide connectivity for low-power devices with low delays and low energy consumption at the same time.

Adaptive Multi-Channel Clustering in IEEE 802.11s Wireless Mesh Networks.

WLAN mesh networks are one of the key technologies for upcoming smart city applications and are characterized by a flexible and low-cost deployment. The standard amendment IEEE 802.11s introduces low-level mesh interoperability at the WLAN MAC layer. However, scalability limitations imposed by management traffic overhead, routing delays, medium contention, and interference are common issues in wireless mesh networks and also apply to IEEE 802.11s networks. Possible solutions proposed in the literature recommend a divide-and-conquer scheme that partitions the network into clusters and forms smaller collision and broadcast domains by assigning orthogonal channels. We present CHaChA (Clustering Heuristic and Channel Assignment), a distributed cross-layer approach for cluster formation and channel assignment that directly integrates the default IEEE 802.11s mesh protocol information and operating modes, retaining unrestricted compliance to the WLAN standard. Our concept proposes further mechanisms for dynamic cluster adaptation, including subsequent cluster joining, isolation and fault detection, and node roaming for cluster balancing. The practical performance of CHaChA is demonstrated in a real-world 802.11s testbed. We first investigate clustering reproducibility, duration, and communication overhead in static network scenarios of different sizes. We then validate our concepts for dynamic cluster adaptation, considering topology changes that are likely to occur during long-term network operation and maintenance.

High-Speed Millimeter-Wave Mobile Experimentation on Software-Defined Radios

Millimeter-wave (mm-Wave) communications have become an integral part of WLAN standards and 5G mobile networks and, as application data rate requirements increase, more and more traffic will move to these very high frequency bands. Although there is an ample choice of powerful experimental platforms for sub-6 GHz research, building mm-Wave systems is much more difficult due to the very high hardware requirements. To address the lack of suitable experimentation platforms, we propose mm-FLEX, a flexible and modular open platform with real-time signal processing capabilities that supports a bandwidth of 2 GHz and is compatible with current mm-Wave standards. The platform is built around a fast FPGA processor and a 60 GHz phased antenna array at front-end that can be reconfigured at nanosecond timescales. Together with its ease of use, this turns the platform into a unique tool for research on beam training in highly mobile scenarios and full-bandwidth mm-Wave signal processing.

Quality of Service- and Fairness-Aware Resource Allocation Techniques for IEEE802.11ac WLAN

Increased demand for high-quality multimedia applications over IEEE802.11 networks has further motivated service providers to improve the QoS (quality of service) for all types of network services. IEEE802.11ac is one of the advanced WLAN standards that provides wideband transmission channels and higher data rates, which are vital to support very high-throughput services. However, due to the use of the CSMA/CA-based random access packet transmission technique, the QoS and service fairness criteria cannot always be maintained, particularly for variable bit rate services. This paper proposes new packet scheduling algorithms to support consistently high QoS and intra-service fairness for high data rate video streams. We name the proposed algorithms FRA - TXOP (Flow Rate Adaptive Transmission Opportunity) and EAS (Enhanced Access Scheduler). These algorithms offer appropriate QoS and fairness to video services in a CSMA/CA network. The FRA - TXOP algorithm allocates the transmission resources according to the channel congestion levels experienced by video flows to improve and maintain consistent QoS values. At the same time, the EAS algorithm offers service fairness among the video streams by appropriately scheduling them on the downlink channel. The EAS algorithm is implemented on top of the FRA - TXOP algorithm to achieve high QoS and service fairness among video streams. An NS-3 simulation model is developed to evaluate the performance of the proposed algorithms. The performance analysis shows that the proposed algorithms enhance the video flow QoS in terms of throughput and packet delay as well as improve the fairness among the video flows compared to other TXOP algorithms.

A Study on Dual-band Microstrip Rectangular Patch Antenna for Wi-Fi

This paper presents the design of a dual-band microstrip patch antenna for Wi-Fi that operates at 2.5 GHz and 5.8 GHz. The antenna contains a rectangular patch with two rectangular slots. The first slot is incorporated in the patch while the second slot is incorporated in the ground plane. The antenna is based on a microstrip fed rectangular patch printed on the FR-4 epoxy substrate with a dielectric constant of 4.4 and a thickness of 1.6 mm with patch size 24 mm × 21 mm. The simulated result shows that the realized antenna successfully works on dual-band and subsequently achieves a bandwidth of 100 MHz and 200 MHz as well as the return loss about -29.9 dB and -15.16 dB for 2.5 GHz and 5.8 GHz respectively. A stable omnidirectional radiation pattern is observed in the operating frequency bands. The antenna meets the required specifications for 802.11 WLAN standards.

Design and Development of Enhanced Gain Aperture Coupled Broadband Biodegradable Dielectric Resonator Antenna for WLAN Applications

Metamaterial loaded star-shaped dielectric resonator antenna (SDRA) fed by aperture-coupled mechanism is used for the enhancement of bandwidth and gain. The star-shaped structure is made-up using biodegradable poly-lactic acid having a dielectric constant (er) of 3.45 and loss tangent (tan δ) of 0.05, which adopt the cost-effective manufacturing i.e. additive manufacturing technique. The alteration in rectangular dielectric resonator antenna to make SDRA is the foundation for broad bandwidth while hybrid exciting-modes are due to feeding of two apertures (slots) of unequal length. Correspondingly, metamaterial i.e. an arrangement of the split-ring resonators have been used for gain enhancement of antenna. The enhanced peak gain of the metamaterial loaded SDRA is more than 12 dBi and the average radiating efficiency is ~ 81%. The proposed antenna attained a broad bandwidth of 41.1% ranging from 4.15 to 6.3 GHz which is suitable for the IEEE 802.11 WLAN standards and C-band wireless communications. The proposed antenna has also offer circularly polarized characteristics at 6 GHz. Thus such an antenna with a trait of circular polarization can be promising for other wireless applications.

A circularly polarized printed elliptical wide-slot antenna with high bandwidth-dimension-ratio for wireless applications

This paper outlines a simple design of a compact wideband microstrip-line fed antenna having two rotated elliptical wide-slots (EWSs). Here, both the elliptical wide-slots are placed perpendicular to each other which shows the measured 10 dB return loss bandwidth (RLBW) of about 7.78 GHz (4.94–12.72 GHz; 88.11%). The circular polarization (CP) is achieved by varying either the semi-major axis of any of the elliptical wide-slot or angle between the EWSs. The proposed antenna radiates left-handed circularly polarized (LHCP) and shows the measured axial ratio bandwidth (ARBW) of about 2.05 GHz (5.4–7.45 GHz; 31.91%) which falls completely inside the operating frequency band and hence relevant for wireless applications including an upper-frequency band of WLAN, WiMAX and several standards of IEEE 802.11 including a/h/j/n/ac/ax. The proposed antenna also achieves a high bandwidth dimension ratio (BDR) of about 1062 which along with the ARBW is the highest among the recently reported antenna structures. A peak gain of about 4.39 dBi is reported within the entire operating band while the overall size of the antenna is only $$18\,\times \,17\,{\text {mm}}^2$$ (or $$0.29\lambda _o \times 0.28\lambda _o$$ ; where $$\lambda _o$$ is the wavelength corresponding to the lowest operating frequency, i.e., 4.94 GHz). The performance of the proposed antenna in terms of RLBW, ARBW, gain, and efficiency are validated experimentally which are in concordance with the simulated results.

Virtual Reality Architecture Oriented Wireless Connection For Future Generation Virtual Reality Devices

In order to enhance the user experience of virtual reality (VR) devices, VR multi-user environments and wireless connections must support as the latest generation of VRdevices. Wireless network-based wireless communication devices (WLANs) are popular consumer devices with high throughput and low cost using incompatible bands. However, the use of WLANs can cause packet delivery delays, due to their distributed nature when accessing channels. In this paper, we carefully discuss wireless VR via WLAN, and we request an efficient wireless multiuser VR communication architecture, as well as providing communication for VR. Because the architecture proposed in this paper uses many WLAN standards, based on the characteristics of each VR traffic chain, it is agreed that it supports the efficient sending of massive uplink data generated by several VR devices, and provides adequate frame rates and video control frames. rate for high-quality VR services. We conduct evaluations that are supported to improve exceptional applications than are supported

A Compact Grounded Asymmetric Coplanar Strip-Fed Flexible Multiband Reconfigurable Antenna for Wireless Applications

A compact grounded asymmetric coplanar strip (GACS)-fed flexible multiband frequency reconfigurable antenna with two PIN diodes is proposed. The investigated antenna is backed by a flexible polyamide substrate with compact dimensions of 24 mm $\times19$ mm and a thickness of 1.53 mm. The investigated antenna structure contains a monopole patch that facilitates operation for wireless LAN applications, whereas inverted L-shaped and F-shaped monopoles facilitate operation for Bluetooth and 5G NR applications. The investigated antenna operates at 2.4, 3.8, and 5.6 GHz with measured impedance bandwidths of 5.8%, 6.3%, and 6.6%, respectively, over the three frequency bands, thus facilitating coverage for Bluetooth, 5G NR, and WLAN standards. The two PIN diodes are employed to tune the investigated antenna among four modes, including a single band mode (WLAN 5.5 GHz), two dual-band modes (5G NR 3.8/5.6 GHz, and Bluetooth 2.48/5.6 GHz), and one multiband mode with Bluetooth (2.4 GHz), 5G New Radio (NR) N77 band (3.8 GHz), and WLAN (5.6 GHz) modes. The investigated antenna radiates unidirectionally with a peak gain of 3.73 dBi at 5.6 GHz. Measurements are carried out on the human body to investigate the behaviour of the wearable antenna. The simulated SAR values are in a safe limit of 1.6 W/kg for 1 g of tissue, according to the FCC. Moreover, the investigated antenna shows extremely low vulnerability to degradation in performance as a result of bending effects concerning impedance matching with acceptable acquiescence between measurements and simulations.

A Microstrip Patch Antenna with Defected Ground Structure(DGS) for WiMAX and WLAN Applications

A rectangular microstrip patch antenna with defected ground structure with E-shaped and square shaped slot on the patch is proposed here. The proposed antenna design consists of H-shaped defect on the ground plane. The complete antenna system is constructed on 45.4mm X 45.4mm X 1.6mm, FR-4 substrate with dielectric constant of 4.4 and substrate height of 1.6mm. The antenna mainly works in 4-6 GHz band. The various characteristics parameters of the antenna like return loss, voltage standing wave ratio, impedance, gain, bandwidth and radiation pattern are studied. The antenna is simulated using high frequency structured simulator software , simulated < -10dB, in the entire operating range of 4-6 GHz.The proposed antenna design is mainly focused for the wireless applications and is suitable for IEEE 802.11 WLAN standards in the bands 5.2/5.8 GHz and WiMAX standards in the bands at 5.5 GHz. In this design microstrip line feeding is used.

Metamaterial loaded aperture coupled biodegradable star‐shaped dielectric resonator antenna for WLAN and broadband applications

AbstractThe design and development technique for the enhancement of bandwidth and gain using biodegradable star‐shaped dielectric resonator antenna (SDRA) electrified by two cross‐coupled apertures for broadband applications is presented in this article. The SDRA is fabricated using biodegradable PLA, which is a special type of polymer and made from renewable resources instead of nonrenewable petroleum‐based resources using additive manufacturing technique. Broad bandwidth of 37% is achieved by modifying rectangular dielectric resonator antenna with feeding it by two apertures (slots) of unequal length to excite different modes. The combination of the circular‐shaped split‐ring resonator has been used as a metamaterial for gain enhancement, which enhanced the maximum gain of the antenna by ∼5.4 dB (82.7%). The computed average efficiency within the operating band is ∼80.51%. The proposed antenna is circularly polarized at 5.8 GHz. The proposed antenna fulfills the bandwidth requirements for the IEEE 802.11a WLAN standards (5.15‐5.35 and 5.725‐5.825 GHz), and it is also suitable for various other applications such as satellite navigation systems, aeronautical and meteorological radio navigation services in C‐band.

MAC improvements for very high throughput WLANs

Here we present the first amendments of high throughput networks identified as IEEE 802.11n originated in 2009 to achieve 150 Mbps speed for typical wireless systems to provide better wireless technology. At the same time, to further improve the medium access control (MAC) throughput, a pair of new amendments for WLAN standard are developed which are IEEE 802.11ac and IEEE 802.11ad. The 802.11ac is designed to achieve 1.3 Gbps speed due to its larger frame sizes, improved queuing and enhance the quality of service (QoS) features with the help of multi-user MIMO. The 802.11ad is designed to allow around 7 Gbps while using the possibility of transmitting in the 60 GHz band that can offer the chance to get the high gain and fewer interference features of directional antennas. Lastly, simulation results show the study of QoS requirements for interactive multimedia transport flow is readily achievable in 802.11ac/ad when compared to 802.11n and other legacy standards.

MAC improvements for very high throughput WLANs

Here we present the first amendments of high throughput networks identified as IEEE 802.11n originated in 2009 to achieve 150 Mbps speed for typical wireless systems to provide better wireless technology. At the same time, to further improve the medium access control (MAC) throughput, a pair of new amendments for WLAN standard are developed which are IEEE 802.11ac and IEEE 802.11ad. The 802.11ac is designed to achieve 1.3 Gbps speed due to its larger frame sizes, improved queuing and enhance the quality of service (QoS) features with the help of multi-user MIMO. The 802.11ad is designed to allow around 7 Gbps while using the possibility of transmitting in the 60 GHz band that can offer the chance to get the high gain and fewer interference features of directional antennas. Lastly, simulation results show the study of QoS requirements for interactive multimedia transport flow is readily achievable in 802.11ac/ad when compared to 802.11n and other legacy standards.