Multiservice capacity and interference statistics of the uplink of high altitude platforms (HAPs) for asynchronous and synchronous WCDMA system

In this work, the capacity and the interference statistics of the uplink of high-altitude platforms (HAPs) for asynchronous and synchronous WCDMA system assuming finite transmission power and imperfect power control are studied. Propagation loss used to calculate the received signal power is due to the distance, shadowing, and wall insertion loss. The uplink capacity for 3- and 3.75-G services is given for different cell radius assuming outdoor and indoor voice users only, data users only and a combination of the two services. For 37 macrocells HAP, the total uplink capacity is 3,034 outdoor voice users or 444 outdoor data users. When one or more than one user is an indoor user, the uplink capacity is 2,923 voice users or 444 data users when the walls entry loss is 10 dB. It is shown that the effect of the adjacent channels interference is very small

Adaptive handover management for multiservice NGSO satellite systems

In this paper we propose a handover method for multiservice non-geo satellite systems. The proposed algorithm can be used for satellite handover as well as for cell handover when a fixed amount of resources is allocated to each cell. Specifically, we consider the case in which the satellite system provides services to users of different QoS requirements. The first type of users require the minimization and, if possible, the elimination of the probability of forcing a connection in progress to termination during a handover. On the other hand, the users of the second category do not have any specific handover requirements. The new method is evaluated through extensive simulations and is proved to meet the requirements of the first type of users while at the same time maximizes the system utilization for both types of users

Proposal of a reliable multicast protocol in a HAP-satellite architecture

Terrestrial and satellite networks have dominated the telecommunications arena for years. In parallel with these two well-established technologies, a new alternative based on platforms located in the stratosphere, termed High Altitude Platforms (HAP's), has gained considerable interest in the past few years. In this paper, we consider an integrated HAP-satellite architecture and propose a reliable multicast protocol that capitalizes upon the HAP-layer to perform local retransmissions. Our protocol relies on a progressive packet-level Forward Error Correction (FEC) scheme. The performance of this multicast protocol has been supported thorough the comparison with a theoretical bound in the literature

Responsible Editor: E. Ekici

Notwithstanding the limited commercial success of the first narrowband low earth orbit (LEO) satellite systems, the interest of the scientific community in this type of systems has been revived on the basis of the current trend toward the migration to all IP-based services. LEO systems can play a pivotal role in providing services to areas where there is no substantial terrestrial infrastructure. Above all, LEO satellite systems can be used as backbone networks to interconnect autonomous systems worldwide. Such an approach provides flexibility in managing the resulting integrated network infrastructure and supporting innovative applications. In this context, routing data from the source all the way to the destination constitutes a daunting challenge. In this paper, a location-assisted on-demand routing (LAOR) protocol is proposed and evaluated. The proposed protocol introduces for the first time in satellite systems the concept of on-demand routing. However, its implementation is tailored to the requirements imposed by the characteristics of the topology of LEO satellite systems. The performance of the LAOR protocol is assessed for different link-cost metrics and compared to the one of centralized routing protocols proposed in the literature so far. Simulation studies further document and confirm the positive characteristics of the proposed protocol