IP-based connection between mobile phones

Indoor positioning methods based on wireless local area network (WLAN) signal measurements have gained popularity because of high localisation accuracy. These methods use radio‐maps obtained from wireless signal measurement surveys on location grids. Measurement sets from various WLAN access points are called fingerprints and they can be used to identify locations where the measurements are collected. WLAN positioning methods face unexpected changes in signal patterns because of attenuation changes or transient faults in WLAN cards or access points that often make signal strength readings unavailable. This study studies the effect of faulty measurements on the performance of popular state‐of‐the‐art WLAN indoor positioning methods. Additionally, an integrity monitoring preprocessing algorithm is provided that demonstrates a possibility of faulty measurements mitigation for conventional methods such as K‐ nearest‐neighbour. This is achieved by detecting and excluding faulty measurements prior to classification. Performance figures are provided for both simulated and empirical environments.

In recent years, there has been a growing demand in 3G data services, leading to deteriorating 3G service quality. Noting that Wireless Local Area Networks (WLANs) as well as 3G cellular networks are widely available today, WLANs could be effectively utilized to relieve the overload in the 3G networks. On the other hand, use of IEEE 802.11 WLAN Access Points (APs) has proliferated tremendously, resulting in a communication device inside a mobile vehicle to access the Internet. However, using Internet through APs in moving vehicles is challenging since WLAN APs have a short range and are typically not deployed to cover all roads. Several studies have investigated the performance of using intermittently available WLAN connectivity from moving vehicles for data transfers and predictive offloading in WLAN/3G networks. However, these works have not addressed mobility pattern from the viewpoint that drivers' mobility is generally known to have a daily routine. Therefore, in this paper, we consider the user's historical mobility to decide to offload data to WLAN instead of switching to 3G network. The user's application usage pattern is also considered into predicting available WLANs. To evaluate the performance of our offloading algorithm, we analyze the prediction error and conduct simulations. The simulation results show that the proposed algorithm achieves shorter transmission time than the existing schemes that do not consider user's mobility pattern by delivering more data to the WLANs.

Indoor positioning methods using location-sensitive features of available wireless signals can achieve high accuracy. In particular, many state-of-the-art methods exploit quite unique sets of location-dependent received signal strength (RSS) measurements from multiple wireless local area network (WLAN) access points (APs), also called as wireless fingerprints. However, reception of signals from WLAN APs is not often stable, and RSS measurements tend to be unavailable due to WLAN card or AP transient effects, limited sensitivity of WLAN cards, and fluctuating attenuation and reflection of signals due to a multipath environment, structural changes and moving objects. In certain hostile scenarios, bogus APs may be installed to disorient WLAN localisation algorithms. In this study, two approaches are proposed to mitigate the impact of faulty signal strength measurements. Performance figures are provided for both simulated and empirical environments in order to support conclusions.

The million dollar question

Wireless Local Area Networks (WLANs) have become commonplace addition to the normal environments surrounding us. Based on IEEE 802.11 technology, WLANs can now be found in the working place, at homes, and in many cities' central district area as open or commercial services. These access points in the public areas are called "hotspots". They provide Internet access in various types of public places such as shopping districts, cafes, airports, and shops. As the hotspots are being used by a growing user base that is also quite heterogeneous, their usability is becoming evermore important. As hotspots can be accessed by a number of devices differing in their capabilities, size, and user interfaces, achieving good usability in accessing the services is not straightforward. This paper reports a user study and usability analysis on WLAN access to discover user's needs and suggest enhancements to fight the usability problems in WLAN access.

Understanding the Design of Mobile Social Networking

Wireless local area networks (WLANs) for public access need to provide privacy between users and also ensure correct charging where access is based on payment. However, by design, conventional LANs and WLANs provide directs unmediated communications between networked devices at the link layer. The paper presents a method to allow networked client devices to communicate with a network comprising routers and other servers while preventing unmediated communication between the clients on the wireless network. An advantage of the method is that it can be implemented entirely within the WLAN access point as a configurable forwarding policy database. No changes are needed to the WLAN client software or the routers and servers and the communication remains completely within the scope of existing industry standards.

We discuss the derivation of an empirical model for spatial registration patterns of mobile users in a campus wireless local area network (WLAN). Such a model can be very useful in a variety of simulation studies of the performance of mobile wireless systems, such as that of resource management and mobility management protocols. We base the model on extensive experimental data from a campus WiFi LAN installation. We divide the empirical data available to us into training and test data sets, develop the model based on the training set, and evaluate it against the test set. The model shows that user registration patterns exhibit a distinct hierarchy, and that WLAN access points (APs) can be clustered based on registration patterns. Cluster size distributions are highly skewed, as are intra-cluster transition probabilities and trace lengths, which can all be modeled well by the heavy-tailed Weibull distribution. The fraction of popular APs in a cluster, as a function of cluster size, can be modeled by exponential distributions. There is general similarity across hierarchies, in that inter-cluster registration patterns tend to have the same characteristics and distributions as intra-cluster patterns. In this context, we also introduce and discuss the modeling of the disconnected state as an integral part of real traffic characteristics. We generate synthetic traffic traces based on the model we derive. We then compare these traces against the real traces from the test set using a set of metrics we define. We find that the synthetic traces agree very well with the test set in terms of the metrics. We compare the derived model to a simple modified random waypoint model, and show that the latter is not at all representative of the real data. We also show how the model parameters can be varied to allow designers to consider 'what-if' scenarios easily. Finally we develop an extended version of Model T that uses an alternative modeling of relative popularity of APs and clusters, with certain generalization advantages, and evaluate its fidelity to the real data also, with positive results.

The global positioning system (GPS) is a popular choice for accurate location sensing and is often used in navigation systems. However, GPS fails to operate inside buildings because satellite signals are blocked. Thus, GPS cannot be used for localization indoors. Moreover, it is difficult to distinguish between the different floors. Research to overcome this problem using the ultrawideband (UWB), radio frequency identification (RFID), and infrared ray (IR) has been conducted. These methods, however, have drawbacks, such as the need for an additional communication module and database. Wireless local area network (WLAN) access point (AP) is widely installed at various locations, and using these WLAN APs can be a viable alternative. The proposed system in this paper indicates the location information in the service set identifier (SSID) of virtual AP. Therefore, merely by scanning the WLAN signals, mobile users can detect their location indoors.

This paper analyzes the interference effect of WLAN(Wireless Local Area Network) service on WiBro(Wireless Broadband) service in adjacent frequency band by using Monte Carlo method. For the analysis, we make scenario that WLAN service operates on frequency band of 2401 MHz ~ 2423 MHz and WiBro service operates on frequency band of 698 MHz ~ 704 MHz. In case of WiBro receiver is close to WLAN AP(Access Point), the interference will be increased. So, we calculate the protection distance between WiBro receiver and WLAN AP to meet interference probability of 5 % below and required interference power of WLAN AP to meet interference probability of 5 % below in the case of fixed protection distance. As a result, the protection distance of 60 m and -9.5 dBm of required interference power of WLAN AP at 10 m of the fixed protection distance are analyzed.

The IEEE 802.11 Wireless Local Area Network (WLAN) is a popular internet access technology, and researchers are continuously working on the quality of service (QoS) improvement by proposing new and efficient schemes. Performance analysis and benchmarking are an integral part of WLAN research. In most of the cases, this is done through computer simulation using popular network simulators such as Network Simulator - 2 (NS-2) or OPNET. The computer simulation of a dynamic system such as a communication network heavily depends upon a set of stochastic models for capturing the real-time behaviors of the system. The choice of a set of stochastic models that represent the most practical scenario is often debated and there is no universal consensus on the choice of these models. This is why, for proper assessment of the merits of a proposal, and any associated commercialization activities, a validation on a hardware platform is highly recommended. Researchers have developed few Field Programmable Gate Array (FPGA) and System-on-Chip (SoC) based hardware, but most of these development platforms are expensive and/or have limited support for networking layers software. This letter proposes an Atheros SoC based hardware platform, and an open-source Linux software stack, called OpenWrt, for WLAN research. The proposed hardware is available off-the-shelf as a WLAN access point (AP), and is a cost-effective way of generating results on a hardware system. A new MAC protocol is implemented on one such WLAN access point to prove the platform.

In spite of rapid worldwide increase in mobile phone use and public concerns about associated potential health effects, little is known about patterns of mobile phone ownership and use in the general population and among children. In April 2005, we conducted a survey of mobile phone ownership and use among fourth grade school children in three Hungarian cities. From 24 schools, 1301 student filled out a short, self-administered questionnaire on basic demographics, mobile phone ownership, pattern of mobile phone use, and after-school activities. Overall, 989 students (76%) owned a mobile phone. Three hundred thirteen students (24%) used a mobile phone daily to make phone calls, and an additional 427 students (33%) used mobile phones for phone calls at least several times per week. Sixty-six students (5%) sent text messages daily and an additional 308 students (24%) sent text messages at least several times per week. Girls, children with no siblings, children who were members of a sport club, and children who played computer games daily were more likely to own and use mobile phones regularly. A higher number of socially disadvantaged children in a class predicted lower likelihood of regular mobile phone use among children. Our results suggest that mobile phone ownership and regular use is highly prevalent among school children in Hungary. Due to rapid changes in ownership patterns follow up surveys will be required to obtain information on temporal trends and changes in mobile phone ownership and pattern of use among school children.

With the dramatic increase in mobile phone usage in recent years, reports of mobile phone addiction have come in public use. While researches on other media addictions have been published, mobile phone addiction is rarely understood. Although scholars have examined in detail how heavy uses of certain media adversely affect students' academic performances, little is known about how mobile phones usage relates to academic performance. For most young people in Taiwan, a country with a high density of mobile phone users, using a mobile phone to network with family and friends has become a daily routine. This exploratory study examines the relationship between mobile phones use, mobile phone addiction, social capital, and academic performance in Taiwanese college students. This study seeks to determine the relationship between mobile phone addiction and depression among college students in Taiwan, the relationships among mobile phones usage, mobile phone addiction, and social capital, and finally, the relationships among mobile phone addiction, mobile phone usage, and students' academic performance. An online survey was designed and administered to 166 Taiwanese college students. The results showed there were no significant relationships between mobile phone addiction and depression in the sample. Heavy mobile phone users reported better relationships with their friends and family. Heavy mobile phone users also reported that frequent use of their mobile phones adversely affected their academic performance and learning, whereas light mobile phone users reported that their academic performance and learning were less negatively impacted by their mobile phones usage. However, respondents who were extremely heavy mobile phone users reported that their mobile phones positively affected their academic performance.

The use of mobile phones and the risk of brain tumors among children and adolescents

Wireless communication has experienced enormous growth during the past decade, primarily driven by mobile cellular systems for voice communications, but more recently by the use of wireless local area networks(WLANs) for corporate enterprises and hot spot areas. However, mobile operators will face many challenges both economically and technically, as WLAN evolve through a bewildering number of different standards during the coming years. Potentially this will require several upgrades to the WLAN infrastructure. A new approach for addressing these challenges is evaluated in this paper. It is based on a radio over fiber (RoF) technology that uses electro-absorption modulator (EAM) and off-the-shelf WLAN access point, and it promises to provide solutions that will be transparent to changes in protocols and frequency of operation as well as reducing radio access infrastructure costs