Contributions to channel modelling and performance estimation of HAPS-based communication systems regarding IEEE Std 802.16TM

New and future telecommunication networks are and will be broadband type. The existing terrestrial and space radio communication infrastructures might be supplemented by new wireless networks that make and will make use of aeronautics-technology. Our study/contribution is referring to radio communications based on radio stations aboard a stratospheric platform named, by ITU-R, HAPS (High Altitude Platform Station). These new networks have been proposed as an alternative technology within the ITU framework to provide various narrow/broadband communication services. With the possibility of having a payload for Telecommunications in an aircraft or a balloon (HAPS), it can be carried out radio communications to provide backbone connections on ground and to access to broadband points for ground terminals. The latest implies a complex radio network planning. Therefore, the radio coverage analysis at outdoors and indoors becomes an important issue on the design of new radio systems. In this doctoral thesis, the contribution is related to the HAPS application for terrestrial fixed broadband communications. HAPS was hypothesised as a quasi-static platform with height above ground at the so-called stratospheric layer. Latter contribution was fulfilled by approaching via simulations the outdoor-indoor coverage with a simple efficient computational model at downlink mode. This work was assessing the ITU-R recommendations at bands recognised for the HAPS-based networks. It was contemplated the possibility of operating around 2 GHz (1820 MHz, specifically) because this band is recognised as an alternative for HAPS networks that can provide IMT-2000 and IMT-Advanced services. The global broadband radio communication model was composed of three parts: transmitter, channel, and receiver. The transmitter and receiver parts were based on the specifications of the IEEE Std 802.16TM-2009 (with its respective digital transmission techniques for a robust-reliable link), and the channel was subjected to the analysis of radio modelling at the level of HAPS and terrestrial (outdoors plus indoors) parts. For the channel modelling was used the two-state characterisation (physical situations associated with the transmitted/received signals), the state-oriented channel modelling. One of the channel-state contemplated the environmental transmission situation defined by a direct path between transmitter and receiver, and the remaining one regarded the conditions of shadowing. These states were dependent on the elevation angle related to the ray-tracing analysis: within the propagation environment, it was considered that a representative portion of the total energy of the signal was received by a direct or diffracted wave, and the remaining power signal was coming by a specular wave, to last-mentioned waves (rays) were added the scattered and random rays that constituted the diffuse wave. At indoors case, the variations of the transmitted signal were also considering the following matters additionally: the building penetration, construction material, angle of incidence, floor height, position of terminal in the room, and indoor fading; also, these indoors radiocommunications presented different type of paths to reach the receiver: obscured LOS, no LOS (NLOS), and hard NLOS. The evaluation of the feasible performance for the HAPS-to-ground terminal was accomplished by means of thorough simulations. The outcomes of the experiment were presented in terms of BER vs. Eb/N0 plotting, getting significant positive conclusions for these kind of system as access network technology based on HAPS

On the Performance of Imt-2000 Communication Link Based on Stratospheric Platforms

A new means for providing wireless communication has been currently proposed. It is based on aerial vehicle known asHigh Altitude Platform or Stratospheric Platforms (SPF). The SPF will be operated at an altitude of 17-22 km above theground. Therefore, the channel condition may be different compared with those of the conventional terrestrial orsatellite wireless channel. In this paper, the channel propagation characteristic of such a system is firstly investigated bymeans of ray tracing algorithm. We emphasize our investigation in a typical urban environment, in which the mobileusers mostly exist. We developed building block model for simulation based on building height distribution, which isobtained from measurement inside Tokyo. As a result, propagation loss model and Ricean channel parameter for theSPF channel is reported in different scenarios. By using this result we then estimate the required transmitted power ofSPF to serve the mobile users in a several transmission rate that is used in IMT-2000 services. Finally, an evaluation ofBER of IMT-2000 link is performed in order to estimate the system level performance. From this evaluation, the maincontribution of this paper is to clearly show the critical limitations of both power requirement as well as system levelperformance of mobile communication IMT-2000 by using the concept of the SPF

A Method of Mobile Base Station Placement for High Altitude Platform Based Network with Geographical Clustering of Mobile Ground Nodes, Journal of Telecommunications and Information Technology, 2009, nr 2

High altitude platforms (HAPs) such as unmanned aerial vehicles (UAVs) which can be deployed as stratospheric infrastructures enable a sort of new configurations of wireless networks. Ground nodes must be clustered in multiple sets and one dedicated UAV is assigned to each set and act as an mobile base station (MBS). For the intra-set nodes, UAVs must communicate each other in order to establish network links among intra-set nodes. Here we find a geographical clustering problem of networking nodes and a placement problem of MBSs. The clustering technique of mobile ground nodes can identify the geographical location of MBSs as well as the coverage of MBSs. In this paper we proposed a clustering mechanism to build such a configuration and the effectiveness of this solution is demonstrated by simulation. For a selected region with a relatively big island, we modeled mobile ground nodes and showed the result of dynamic placement of MBSs by our clustering algorithm. The final results will be shown graphically with the mobility of ground nodes as well as the placement of MBSs

ON THE PERFORMANCE OF IMT-2000 COMMUNICATION LINK BASED ON STRATOSPHERIC PLATFORMS

A new means for providing wireless communication has been currently proposed. It is based on aerial vehicle known asHigh Altitude Platform or Stratospheric Platforms (SPF). The SPF will be operated at an altitude of 17-22 km above theground. Therefore, the channel condition may be different compared with those of the conventional terrestrial orsatellite wireless channel. In this paper, the channel propagation characteristic of such a system is firstly investigated bymeans of ray tracing algorithm. We emphasize our investigation in a typical urban environment, in which the mobileusers mostly exist. We developed building block model for simulation based on building height distribution, which isobtained from measurement inside Tokyo. As a result, propagation loss model and Ricean channel parameter for theSPF channel is reported in different scenarios. By using this result we then estimate the required transmitted power ofSPF to serve the mobile users in a several transmission rate that is used in IMT-2000 services. Finally, an evaluation ofBER of IMT-2000 link is performed in order to estimate the system level performance. From this evaluation, the maincontribution of this paper is to clearly show the critical limitations of both power requirement as well as system levelperformance of mobile communication IMT-2000 by using the concept of the SPF.Keywords: link performance, IMT-2000, high altitude platform, stratospheric platfor

Mobile and Wireless Communications

Mobile and Wireless Communications have been one of the major revolutions of the late twentieth century. We are witnessing a very fast growth in these technologies where mobile and wireless communications have become so ubiquitous in our society and indispensable for our daily lives. The relentless demand for higher data rates with better quality of services to comply with state-of-the art applications has revolutionized the wireless communication field and led to the emergence of new technologies such as Bluetooth, WiFi, Wimax, Ultra wideband, OFDMA. Moreover, the market tendency confirms that this revolution is not ready to stop in the foreseen future. Mobile and wireless communications applications cover diverse areas including entertainment, industrialist, biomedical, medicine, safety and security, and others, which definitely are improving our daily life. Wireless communication network is a multidisciplinary field addressing different aspects raging from theoretical analysis, system architecture design, and hardware and software implementations. While different new applications are requiring higher data rates and better quality of service and prolonging the mobile battery life, new development and advanced research studies and systems and circuits designs are necessary to keep pace with the market requirements. This book covers the most advanced research and development topics in mobile and wireless communication networks. It is divided into two parts with a total of thirty-four stand-alone chapters covering various areas of wireless communications of special topics including: physical layer and network layer, access methods and scheduling, techniques and technologies, antenna and amplifier design, integrated circuit design, applications and systems. These chapters present advanced novel and cutting-edge results and development related to wireless communication offering the readers the opportunity to enrich their knowledge in specific topics as well as to explore the whole field of rapidly emerging mobile and wireless networks. We hope that this book will be useful for students, researchers and practitioners in their research studies