A spherical probability distribution model of the user-induced mobile phone orientation

This paper presents a statistical modeling approach of the real-life user-induced randomness due to mobile phone orientations for different phone usage types. As well-known, the radiated performance of a wireless device depends on its orientation and position relative to the user. Therefore, realistic handset usage models will lead to more accurate over-the-air characterization measurements for antennas and wireless devices in general. We introduce a phone usage classification based on the network access modes, e.g., voice (circuit switched) or non-voice (packet switched) services, and the use of accessories, such as wired or Bluetooth handsets, or a speaker-phone during the network access session. The random phone orientation is then modeled by the spherical von Mises-Fisher distribution for each of the identified phone usage types. A finite mixture model based on the individual probability distribution functions and heuristic weights is also presented. The models are based on data collected from built-in accelerometer measurements. Our approach offers a straightforward modeling of the user-induced random orientation for different phone usage types. The models can be used in the design of better handsets and antenna systems as well as for the design and optimization of wireless networks

Analyzing smart phones\u27 3D accelerometer measurements to identify typical usage positions in voice mode

Smart phone sensors provide new possibilities to understand how devices are actually used and handled in real-life situations. Such information can possibly be used to design better handsets, but also to improve network performance. For example, the radiated performance of a wireless device depends on its orientation and position relative to the user. Hence, knowing realistic handset usage plays a major role in the Over-The-Air characterization of antennas and wireless devices in general. This paper presents an analysis of usage positions for voice service. A simplified statistical model based on data collected from devices acceleration sensors is presented. The analysis shows interesting results from which we can identify some typical ways the user is handling the phone when in a voice conversation. Our analysis shows clear differences of the orientation of the handset when used with a handsfree set and when not

Finding the Distribution of Users in a Cell from Smart Phone Based Measurements

Mobile users are assumed to be positioned within the cell or sector boundaries of the serving cell in the network. Measurements of location done by the smart phones combined with the network layout show differently. There is a significant amount of users which are actually outside the nominal sector boundaries. Knowledge about the statistical location distribution of users inside or outside the serving cell intended coverage may prove valuable in finding more optimal resource management methods. Another application is the development of over-theair characterization of base station antennas. Distance and directional statistics are shown for samples of relative positions within the cell sectors of a real network using smart phone based measurements. Samples for LTE in 800 and 1800 MHz non-voice usage and 3G at 2100 MHz voice usage is included. The distance distributions show clearly that the usage density rapidly decrease with the distance, and there is a clear confirmation that lower frequencies have longer range, also in terms of usage density. Mean usage distance for 800 MHz is 1.62 km, while for 2100 MHz it is only 580 m. It also shows that 90% of the usage is within 3.47 and 1.35 km for the two cases, respectively. The directional distributions relative to the sector centre direction shows that 80% of the users are within 153 degrees for lowest frequency, and 109 degrees for the highest

Rádio cognitivo

Resumo O acesso oportunista ao espectro representa uma grande perspectiva para as redes sem fio do futuro, ao possibilitar o acesso às bandas subutilizadas do espectro licenciado. Veja quais são os cenários mais promissores para usuários que estão em movimento e os requisitos para uma qualidade de serviço gerenciada, sem interferências junto a outros usuários

Identifying scenarios with high potential for future cognitive radio networks

Abstract Opportunistic spectrum access is a great prospect for future wireless networks. The key requirements for an opportunistic user are to avoid interference with any licensed users of the same spectrum and also to cooperate fairly with other opportunistic users. There are many scenarios where an opportunistic network could provide a system that has the potential to provide a better business case than conventional wireless networks. The most promising scenarios for opportunistic users that are on the move and have a requirement for managed quality of service are identified in this paper. The processes used to develop these scenarios are also presented

Cognitive architecture and system solutions to offload LTE networks in TVWS

Abstract This paper presents an application of cognitive radio system concepts for the off-loading operation of LTE networks by the opportunistic use of TV whitespace (TVWS). A flexible functional architecture based on two cognitive managers for spectrum management and resource management respectively, and developed for various mobile scenarios, is mapped to the LTE network architecture. Corresponding system solutions for incumbent protection and quality of service management (including spectrum sensing, interference monitoring and flexible transceiver techniques) are introduced and described in more details for that scenario. Finally, a possible system realisation is shown with enhancements to evolved node B’s and User Equipments accessing the TVWS in an opportunistic way. A timeline for rolling out this realisation taking standardisation plans and regulatory constraints into account is also given

Requirements for a CR-system:challenges compared to conventional wireless technology

Abstract Cognitive Radio (CR) technology is a promising enabler towards a more efficient and dynamic use of the frequency spectrum. The challenges related to using the vacant frequencies in an opportunistic manner put extra constraints on the system if it is going to provide reliable services to the end user. When, in addition, we want a system to provide managed quality of service (QoS) and mobility, the challenges are even more demanding. There are two major challenges for cognitive radio systems based on opportunistic spectrum access: the need to keep track of the spectrum; and the aim of providing managed QoS and mobility. Both these are external constraints generally not present for licensed wireless operation and they call for additional functionality and flexibility in the system as well as the need for additional interfaces to handle the new information. The EU-project QoSMOS has addressed this in defining the overall requirements for the system and we show how these responds to the challenges