Analysis of the effect of mobile terminal speed on WLAN/3G vertical handovers

Proceedings of IEEE Global Telecommunications Conference, GLOBECOM '06, San Francisco, California, 27 november - 1 december, 2006.WLAN hot-spots are becoming widely spread. This, combined with the availability of new multi-mode terminals integrating heterogeneous technologies, opens new business opportunities for mobile operators. Scenarios in which 3G coverage is complemented by WLAN deployments are becoming available. Thus, true all-IP based networks are ready to offer a new variety of services across heterogeneous access. However, to achieve this, some aspects still need to be analyzed. In particular, the effect of the terminal speed on the detection and selection process of the preferred access network is not yet well understood. In fact, efficiency of vertical handovers depends on the appropriate configuration of mobile devices. In this paper we present a simulation study of handover performance between 3G and WLAN access networks showing the impact of mobile users’ speed. The mobile devices are based on the IEEE 802.21 cross layer architecture and use WLAN signal level thresholds as handover criteria. A novel algorithm to dynamically adjust terminals’ configuration is presented.Publicad

Wireless Energy Efficiency Evaluation for Buildings Under Design Based on Analysis of Interference Gain

In this paper, we present part of our ground-breaking work that bridges building design and wireless network deployment. The original contributions lie in: i) defining interference gain (IG) as an intrinsic figure of merit (FoM) of a building & x2019;s wireless performance in terms of interference signal blockage; ii) developing analytic models to calculate IG; and iii) developing a novel method to calculate the optimum transmitting power to achieve the maximum IG of a building. The IG is derived as an integral transform of the probability density function (PDF) of the distance from a probe user equipment (UE) with a random position relative to a wall, and with a uniformly distributed direction. Furthermore, the PDF of the random distance is derived in closed-form for rectangular rooms to facilitate fast computation of the IG of a building under design (BUD) tiled by rectangular rooms and corridors. For BUD with irregular rooms, a random shooting algorithm (RSA) is proposed to numerically compute the PDF. The closed-form expression and the RSA are compared and validated. Numerical results show the validity of both the model to calculate IG and the methodology to derive the optimum transmitting power to achieve the maximum IG of a given building. The results shed light to architects on how to design buildings with desirable wireless performance and for radio engineers on how densely wireless access points can be deployed to approach the intrinsic wireless performance of a building

Mobility management in multi-tier LiFi networks

Mobility management is an important part of the analysis and design of ultra-dense LiFi networks. This paper presents a two-tier LiFi network and analyses the cross-tier handover rate between the primary and secondary cells. For different conditions of semiangle at half illuminance of the primary and secondary cells, we propose three different coverage models for the secondary cells. Using stochastic geometry, closed-form expressions are derived for the cross-tier handover rate, ping-pong rate and sojourn time in terms of the received optical signal intensity, time-to-trigger and user mobility. The analytical models are validated with simulation results

Location-Enabled IoT (LE-IoT): A Survey of Positioning Techniques, Error Sources, and Mitigation

The Internet of Things (IoT) has started to empower the future of many industrial and mass-market applications. Localization techniques are becoming key to add location context to IoT data without human perception and intervention. Meanwhile, the newly-emerged Low-Power Wide-Area Network (LPWAN) technologies have advantages such as long-range, low power consumption, low cost, massive connections, and the capability for communication in both indoor and outdoor areas. These features make LPWAN signals strong candidates for mass-market localization applications. However, there are various error sources that have limited localization performance by using such IoT signals. This paper reviews the IoT localization system through the following sequence: IoT localization system review -- localization data sources -- localization algorithms -- localization error sources and mitigation -- localization performance evaluation. Compared to the related surveys, this paper has a more comprehensive and state-of-the-art review on IoT localization methods, an original review on IoT localization error sources and mitigation, an original review on IoT localization performance evaluation, and a more comprehensive review of IoT localization applications, opportunities, and challenges. Thus, this survey provides comprehensive guidance for peers who are interested in enabling localization ability in the existing IoT systems, using IoT systems for localization, or integrating IoT signals with the existing localization sensors