WLAN Interface Research Articles

Monitoring of pH, Amonia (NH3) and Temperature Parameters Aquaponic Water in the 4.0 Revolution Era

The quality of the water is very important in determining the aquaponics system, including the pH parameter such as the ideal acidity level in aquaponics. The water quality temperature parameter also plays a very important role in determining water quality, especially in the case of temperature changes that are influenced by air temperature, wind speed and solar radiation. A safe maximum level of ammonia (NH3) is required in a good aquaponics system. When making adjustments, the water quality is set manually without the use of a controller that is fed back to the actuator, that is, the manual change of the desired temperature, pH value and ammonia. Temperature changes are made by exposure to sunlight or heating, while ammonia is achieved by adding fish feed or adding new water. Whereas the pH treatment is done with vinegar (for a pH value that is too humid), bicarbonate is used for a pH value that is too acidic for the research object. Based on the aquaponic system literature parameter data for ammonia from less than 0.5 ppm to an ideal of 0 ppm, the pH value is in the ideal range of 6.5 - 8, while at the ideal temperature it is (21-28 ) ° C. In this study, the author develops a solution to monitor the state of water with pH, ammonia and temperature sensors based on the Internet of Things, the Arduino Uno uses as monitoring parameters, pH sensors are They use to detect the acid content of water, temperature sensors for temperature measurements, use the MQ135 gas sensor for ammonia. and ESP8266 as a WLAN interface to send data to Android without using actuators.

Adaptive informant factor-based optimised channel allocation in large-scale mesh networks

The demand for expanded WLAN coverage is increasing more than ever, due to increasing number of computing and communications devices which are equipped with an integrated IEEE 802.11 WLAN interface - including smart-phones, notebook PCs and multimedia components. As wireless mesh networks (WMN) collect and relay the traffic generated by many clients, there have been several research efforts to improve the network capacity. One of the strategies is through the coordinated use of multiple channels and multiple radios. Thus, the channel assignment to a mesh node becomes an important research issue. Therefore, in this paper AIF-based optimised channel allocation is proposed, which acquires the information of channel of a network and then processes it to optimise the RF channel allocation. The proposed AIF-OCA functions for each period when some interference is detected via AIF. The arrangement of Relay Nodes (RN) and RF channels with IEEE 802.11s/u standard is considered in the proposed model. To validate the performance of the proposed model, it is compared with several existing techniques in WMN environment.

Front End to Back End Speech Scrambler

As modern mobile devices are often equipped with a WLAN interface and many buildings are equipped with a WLAN infrastructure, WLAN could be used for localization. The aim of this work is to investigate the quality of different indoor positioning methods based on values of WLAN received signal strength index (RSSI) using commercially available devices (smart phones, personal digital assistants). Three positioning algorithms were considered: minimal Euclidian distance, intersections of RSSI-Isolines and a stochastic model based on Bayes' theorem. A measuring test bed within an empty seminar room, four different types of personal digital assistants (Dell, Fujitsu, HP, T-Mobile) and two types of access points (Netgear, Lancom) were used. No modification of hardware and software was conducted. Furthermore this paper shows how WLAN localization can be applied in a museum guide application. This paper also shows the visualization of spatial user position frequency pattern during a field trial within a museum.

An approach to energy efficient vertical handover technique for heterogeneous networks

Energy consumption is critical issue in heterogeneous networks comprising of proliferation of different types of wireless networks. The next generation mobile terminals are equipped with multiple interfaces to associate themselves with one or more networks at the same time. Vertical handover techniques facilitate the user to have ubiquitous access with desired quality of service but increased energy consumption with time. Thus energy aware vertical handover techniques are highly desirable in present era of heterogeneous networks. In this work, an approach to energy efficient vertical handover technique has been suggested and analyzed for different traffic classes. The proposed approach is based on vector normalized preferred performance based VIKOR algorithm (V-VPP) for performing handover. It resulted in lesser energy consumption in the presence of three interfaces WLAN, WIMAX and cellular interface operating simultaneously.

RSSI-BASED WLAN INDOOR POSITIONING USED WITHIN A DIGITAL MUSEUM GUIDE

As modern mobile devices are often equipped with a WLAN interface and many buildings are equipped with a WLAN infrastructure, WLAN could be used for localization. The aim of this work is to investigate the quality of different indoor positioning methods based on values of WLAN received signal strength index (RSSI) using commercially available devices (smart phones, personal digital assistants). Three positioning algorithms were considered: minimal Euclidian distance, intersections of RSSI-Isolines and a stochastic model based on Bayes' theorem. A measuring test bed within an empty seminar room, four different types of personal digital assistants (Dell, Fujitsu, HP, T-Mobile) and two types of access points (Netgear, Lancom) were used. No modification of hardware and software was conducted. Furthermore this paper shows how WLAN localization can be applied in a museum guide application. This paper also shows the visualization of spatial user position frequency pattern during a field trial within a museum.

WiMAX - WLAN Interface using TORA, DSR and OLSR Protocols with their Evaluation under Wormhole Attack

As it is know that WiMAX and WLAN are two wireless developing technologies. The researchers are working on the integrated scenarios of these two technologies so as to approach the maximum benefits out of these technologies. Therefore in this paper we are performing simulations over the two scenarios i.e. with wormhole attack and without wormhole attack. The evaluation is taken on three different protocols i.e. DSR, OLSR and TORA. The results are shown in graphical figures and according to them results are made.

Smart WLAN Discovery for Power Saving of Dual‐Mode Terminals

Dual‐mode terminals (DMTs) equipped with cellular and WLAN interfaces have become popular in recent years. Users of DMTs can enjoy high‐speed WLAN Internet access and wide area Internet access to cellular networks. However, a DMT may consume power inefficiently when discovering a WLAN with inherently limited service coverage. In this letter, we propose to use smart WLAN discovery (SWD) to minimize the power consumption required for WLAN discovery. To minimize the power consumption of a DMT, an SWD DMT activates its WLAN interface only when the DMT transfers data within the WLAN coverage area. The simulation results of SWD show an improved power‐saving performance compared to previous WLAN discovery schemes.

Modeling and performance analysis of power efficient multi-tier location management in interworked WLAN and cellular network

In multi-radio access networks, it is essential to support multi-tier location management to mobile stations (MSs) with multi-radio interfaces, in order to deliver incoming calls to appropriate radio access networks. In multi-tier location management, the location information of MSs at multi-radio access networks should be managed in an integrated way, and single registration (SR) and multi registration (MR) are widely used multi-tier location management schemes. In SR, MSs register at the registration area (RA) of only one of available access networks. In MR, on the other hand, MSs register at the RAs of all available access networks simultaneously. However, battery power consumption is significant in both SR and MR, since multiple radio interfaces operate simultaneously. Recently, works on efficient power management (EPM) have been carried out in interworked WLAN and cellular network by turning off the WLAN interface when it is not active because the idle state power consumption of WLAN interface is significant. In EPM, if a voice over IP (VoIP) call arrives at WLAN, it is notified through a less power-consuming cellular interface. The paging via cellular interface, however, generates significant signaling load at radio interface because paging has to be performed to all cells within a registration area (RA) of cellular network. In this paper, we propose power efficient multi-tier location management schemes, i.e., power efficient SR (PSR) and power efficient MR (PMR), based on the tradeoff between SR/MR and EPM. The performance of the proposed schemes is analyzed in terms of signaling load and energy consumption. The results show that PSR and PMR have significantly lower signaling load than EPM and have significantly smaller energy consumption than SR/MR.

On Downlink Capacity of Cellular Data Networks With WLAN/WPAN Relays

We consider the downlink of a cellular network supporting data traffic in which each user is equipped with the same type of IEEE 802.11-like WLAN or WPAN interface used to relay packets to further users. We are interested in the design guidelines for such networks and how much capacity improvements the additional relay layer can bring. A first objective is to provide a scheduling/relay strategy that maximizes the network capacity. Using theoretical analysis, numerical evaluation, and simulations, we find that when the number of active users is large, the capacity-achieving strategy divides the cell into two areas: one closer to the base station where the relay layer is always saturated and some nodes receive traffic through both direct and relay links, and the farther one where the relay is never saturated and the direct traffic is almost nonexistent. We also show that it is approximately optimal to use fixed relay link lengths, and we derive this length. We show that the obtained capacity is independent of the cell size (unlike in traditional cellular networks). Based on our findings, we propose simple decentralized routing and scheduling protocols. We show that in a fully saturated network our optimized protocol substantially improves performance over the protocols that use naive relay-only or direct-only policies.

RFID service for non-RFID enabled devices: Embedded hardware implementation

Radio Frequency Identification (RFID) applications require the use of specialized hardware in order to obtain the IDs that are provided by the tags. This condition limits the extension of the information to devices with non-RFID capabilities. In this paper we present the design and implementation of a RFID service conceived for devices with non-RFID hardware but a WLAN interface. More specifically, we utilized embedded hardware to build an affordable and practical device that allows obtaining lists of tag IDs by using a common WLAN interface. Additionally, we performed delay metrics experiments and measurements are provided.

무선랜 환경에서 서비스 연속성 지원을 위한 IMS 기반 핸드오버 지원 방안

본 논문은 단일 무선랜 인터페이스를 갖는 IMS 단말에서 서비스 연속성을 지원하기 위해 패킷 손실을 최소화하는 L3 핸드오버 지원방안을 제안한다. 기존 IMS 서비스 연속성 지원 방안은 하나의 단말 내에 존재하는 다수의 인터페이스를 통해 서로 다른 접속망을 경유하여 IMS 코어 네트워크와의 통신이 가능한 상태에서 이동성 제공이 가능하다. 하지만, 단일 인터페이스를 갖는 무선랜 단말은 동시에 하나 이상의 접속망을 통해 IMS 코어 네트워크와 통신을 할 수 없다. 제안 방안은 Candidate Access Router Discovery(CARD) 매커니즘을 이용하여 타겟 WLAN 영역에서 단말이 사용할 IP를 미리 구성하고, 서비스 연속성 서버가 단말을 대신하여 타겟 WLAN 영역에서의 L3 연결 과정 및 IMS 서버로의 등록절차를 수행한다. 이후 서비스 연속성 제공을 위해 SIP 기반의 세션 제어 메커니즘을 수행한다. 제안된 핸드오버 제공 방안의 성능 검증을 위해 기존 서비스 연속성 제공 방안과 제안 방안에 대한 핸드오버 지연(latency), 시그널링 비용(cost)을 비교 분석하였다. This paper proposes a L3 handover method to minimize packet loss for supporting service continuity to IMS Terminal which has a single WLAN interface. The existing IMS based handover solution is able to support handover between different access networks in case that a terminal has multiple interfaces. That is, WLAN terminals need multiple interfaces to connect with one or more access networks. This proposed method configures IP address for the terminal in target WLAN previously by using Candidate Access Router Discovery(CARD) mechanism. Also, in the proposed method, service continuity server performs L3 connection establishment in target WLAN and registration to IMS server instead of the terminal. And then session control mechanism based on SIP is performed to support service continuity. We analyzed handover latency and signaling cost in the proposed method and existing method to show the improved performance by the proposed method.

Reducing signaling load for power-efficient integrated WLAN/cellular networks

In power-efficient WLAN/cellular dual mode mobile station (MS), WLAN interface is basically turned off when it is not actively transmitting or receiving data because idle state power consumption of WLAN interface is significant and it is much higher than that of cellular interface. Since only cellular interface is turned on to maintain reachability, if a VoIP call is arrived at WLAN it is notified through less power-consuming cellular interface. The paging via cellular interface for VoIP call, however, generates significant signaling load at radio interface because paging has to be performed to all cells within a registered cellular registration area (RA). In this paper, we reduce signaling load of power-efficient WLAN/cellular networks by paging cells only containing WLAN using the network coverage information between WLAN and cellular network, without degrading the performance of power consumption. Numerical results show that the signaling load of power-efficient integrated WLAN/cellular networks is significantly reduced.

Trace-based analysis of Wi-Fi scanning strategies

The number of smartphones in use is overwhelmingly increasing every year. These devices rely on connectivity to the Internet for the majority of their applications. The everincreasing number of deployed 802.11 wireless access points and the relatively high cost of other data services make the case for opportunistic communication using free WiFi hotspots. However, this requires effective management of the WLAN interface, because by design the energy cost of WLAN scanning and interface idle operation is high and energy is a primary resource on mobile devices. We study several heuristic strategies for interface management, and use real-world user traces to evaluate and compare their performance against the optimal algorithm. Trace-based simulations show that simple static scanning with a suitable interval value is very effective for delay-tolerant, background applications.

An energy-efficient interface selection for multi-mode terminals by utilizing out-of-band paging channels

With the advent of a number of wireless network technologies such as WCDMA and WLAN, current mobiles are equipped with multiple network interfaces, so called Multi-Mode Terminal (MMT). MMTs are capable to access different kinds of networks by performing a vertical handover between heterogeneous wireless networks, where during the idle state, the MMTs consume a lot of energy since their WLAN interface must wake up for listening to periodical beacons. However, previous studies on the vertical handover did not address how to select the optimal interface taking into account the characteristics of MMTs, especially energy consumption. Therefore, in this paper, we propose an energy-efficient interface selection scheme for MMTs in the integrated WLAN and cellular networks. The proposed interface selection scheme takes advantage of existing out-of-band paging channel of cellular networks, so that the WLAN interface can be completely turned off during the idle state leading to reduction in energy consumption. Simulation results show that the proposed scheme outperforms conventional approaches in terms of energy consumption with reduced signaling overhead and handover delay.

Power-Efficient Communication Protocol for Integrated WWAN and WLAN

One of the most impending requirements to support a seamless communication environment in heterogeneous wireless networks comes from the limited power supply of small-size and low-cost mobile terminals as in stand-alone WLANs or cellular networks. Thus, it is a challenge to design new techniques so that mobile terminals are able to not only maintain their active connection as they move across different types of wireless networks, but also minimize their power consumption. There have been several efforts aimed at having mobile devices equipped with multiple interfaces connect optimally to the access network that minimizes their power consumption. However, a study of existing schemes for WLAN notes that in the idle state, a device with both a WLAN and a WWAN interface needs to keep both interfaces on in order to receive periodic beacon messages from the access point (AP: WLAN) and downlink control information from the base station (WWAN), resulting in significant power consumption. Therefore, in this paper, we propose a power-efficient communication protocol (PCP) that includes turning off the WLAN interface after it enters the idle state and using the paging channel of WWAN in order to wake up the WLAN interface when there is incoming long-lived multimedia data. This scheme is known to limit the power consumption, while at the same time, it makes use of the paging channel in cellular networks. Further, our proposed scheme is designed to avoid repeatedly turning on and off WLAN interfaces, that consumes a significant amount of power. We propose turning on the WLAN interface when the number of packets in the radio network controller (RNC)'s buffer reaches a certain threshold level. The tradeoffs between the power saving and the number of packets dropped at the buffer are investigated analytically through the study of an on/off traffic model. Simulation results for scenarios of interest are also provided.

PIANO: A power saving strategy for cellular/VoWLAN dual-mode mobiles

The integration of cellular and VoIP over WLAN (VoWLAN) systems recently has attracted considerable interest from both academia and industry. A cellular/VoWLAN dual-mode system enables users to access a low-cost VoIP service in a WLAN hotspot and switch to a wide-area cellular system without WLANs. Unfortunately, cellular/VoWLAN dual-mode mobiles suffer the power consumption problem that becomes one of the major concerns for commercial deployment of the dual-mode service. In this study, we present a novel power saving mechanism, called PIANO (paging via another radio), for the integration of heterogeneous wireless networks, and further apply the proposed methods to implement a cellular/VoWLAN dual-mode system. Based on the proposed mechanisms, a dual-mode mobile can completely switch off its WLAN interface, only leaving the cellular interface awake to listen to paging messages. When a mobile receives a paging message from its cellular interface, it wakes up the WLAN interface and responds to connection requests via WLAN networks. Therefore, a dual-mode mobile reduces the power consumption by turning off the WLAN interface during idle, and can also receive VoWLAN services. Measurement results based on the prototype system demonstrate that the proposed methods significantly extend the standby hours of a dual-mode mobile.

An efficient power-saving mechanism for integration of WLAN and cellular networks

In this letter, we propose an efficient power-saving mechanism using paging of cellular networks for WLAN in heterogeneous wireless networks, where WLAN interface is turned off during idle state without any periodic wake-up in order to save power consumption while at the same time, the existing paging of cellular network is utilized in place of beacons in WLAN. For the proposed mechanism, the mean power consumption is investigated via analytical and simulation results.