Experimental statistical channel modelling for advanced wireless communication systems in indoor environments

Draadloze communicatiesystemen voor mobiele telefonie en draadloos internet zijn onmisbaar geworden in het dagelijkse leven. De grootste troef van draadloze communicatie over bedrade communicatie is de toegenomen mobiliteit. Draadloze communicatie heeft evenwel ook één groot nadeel, namelijk de onzekerheid over de kwaliteit van de link tussen zender en ontvanger. Waar bedrade communicatie een doorgedreven ontwerp van het kanaal tussen zender en ontvanger (d.i. de kabel) toelaat, is het ontwerp van het draadloze kanaal (d.i. de omgeving) bijna onmogelijk. Desondanks kunnen wel modellen van de propagatie van draadloze signalen opgesteld worden voor verschillende types omgevingen. Deze modellen laten toe om de betrouwbaarheid en de performantie van een draadloze link in te schatten. Modellering van draadloze propagatie voor indooromgevingen is het algemeen onderwerp van dit proefschrift. De propagatiemodellering in dit proefschrift betreft drie types indooromgevingen, nl. industriële en kantooromgevingen, en de omgeving binnen in een voertuig. De modellering bestaat uit statistische modellen gebaseerd op veldmetingen in deze omgevingen. Verschillende parameters van draadloze signalen worden onderzocht, zoals de variabiliteit van het signaalvermogen met de afstand en in de tijd, het signaalbereik, de dispersie in het tijdsdomein, de dispersie in het spatiaal domein en het vermogensverlies bij propagatie van buiten naar binnen een voertuig

Modelling the energy efficiency of microcell base stations

The power consumption of wireless access networks will become a major issue in the coming years. Therefore, it is important to have a realistic idea about the power consumption of each element in those access networks. In this paper, an energy efficiency model for microcell base stations is proposed. Based on this model, the energy efficiency of microcell base stations is compared for various wireless technologies, namely mobile WiMAX, HSPA and LTE. The power consumption of microcell base stations is about 70-77% lower than for macrocell base stations but a macrocell base station is more energy-efficient than a microcell base station for the same bit rates. However, for the considered case and assuming our parameters are correct, a reduction in power consumption can be obtained by using microcell base stations to fill coverage holes

Circuit model for diffuse multipath and electromagnetic absorption prediction in rooms

We present a room electromagnetics-based theory which primarily models the diffuse multipath components (DMC) power density with a simple circuit model, and afterwards includes the line-of-sight (LOS) component to predict the total exposure in a realistic environment. Given a human absorption cross section (ACS) and its location from a transmitter (Tx), the average whole-body specific absorption rate (SAR(wb)) can be determined by the proposed circuit model for ultra-wideband (UWB) and wireless local area network (WLAN) systems. The SAR(wb) in humans in a realistic office environment for both UWB and WLAN systems is investigated as part of application. The theory is simulated with the Advanced Design System (ADS) software, and excellent agreement between theoretical and simulated values are obtained in terms of relative errors (<2%). The model may be very useful for SAR(wb) prediction in realistic complex indoor environments

Intra-, inter-, and extra-container path loss for shipping container monitoring systems

This letter presents empirical path loss models for an environment of stacked shipping containers. Specifically, a system for wireless monitoring of containers is considered for which three different types of wireless links are identified, namely intra-, inter-, and extra-container links. Furthermore, the inter-container link is investigated for the two most common types of container stacking: row and block stacking. Intra-and inter-container path loss are investigated at IEEE 802.15.4 frequencies of 433, 868, and 2400 MHz. Extra-container path loss is examined at GSM/UMTS frequencies of 900, 1850, and 2100 MHz. Distance-dependent path loss models are proposed for the inter-and extra-container links ( high-correlation coefficients between 0.76 and 0.86). The resulting path loss models can be used in link budget calculations for container monitoring systems

Development of path loss model for 802.11n in large conference rooms

In this paper, a path loss (PL) model for 802.11n in large conference rooms is determined, based on PL measurements. The PL can be described accurately by a one-slope model with one standard deviation. PL exponents varying from 1.2 to 1.7 are found. Based on this PL model, the effect of frequency (2.4 vs 5 GHz), configuration (SISO vs MIMO (spatial diversity)), bandwidth (20 vs 40 MHz) and transmit power on number of access points, total power consumption and possible (physical) throughputs is investigated. According to the determined PL model, a higher range (by tuning the transmit power) requires less access points, as well as a lower total power consumption, due to a PL exponent lower than 2