BER and SIR Based Hybrid Link Algorithms Performance in Mobile Radio Channel

In the next generation of mobile communication networks (B3G) the using of effective handling of radio resources is supposed (channels, power and transmission rate) with simultaneous delivery of required services, in which the quality of service (QoS) is guaranteed. In this article we have described and simulated new BER based, SIR-frame based and SIR-slot based link adaptation algorithms. Algorithms were designed to increase efficiency of data transmission among user equipment and base stations (uplink) expressed by throughput and the outage probability for each link. Simulation results of hybrid adaptation (power and modulation BPSK, QPSK, 16-QAM, 64-QAM) are compared and expressed as data throughput and outage probability for different simulation environments (pedestrian channel with mobile subscriber speed 10 km/s and vehicular channel with speed 120 km/h)

The Comet Interceptor Mission

Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ΔV capability of 600 ms−1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule

Performance of Advanced Hybrid Link Adaptation Algorithms in Mobile Radio Channel

The fast power adaptation is essential for WCDMA based mobile radio networks, as 3G UMTS. Although the first version of UMTS has been released in 1999 (Release 99) evolution was not finished yet. Quality of Service (QoS) and user data rate (e. g. HSDPA and HSUPA) are continuously increasing from release to release. Even though link adaptation frequency (1500 times per second) seems to be enough to span accidental fadings of mobile radio channel, used link adaptation algorithm is based on non-actual information about mobile radio channel state, which causes transmitter reaction delay to the actual channel state. Usage of appropriate prediction method to estimate near future channel state seems to be a valuable step to improve hybrid link adaptation algorithm. In this article we have described and simulated the new SIR-slot based advanced link adaptation algorithms. Algorithms were designed to increase efficiency of data transmission among a user equipment and base stations (uplink) for different simulation environments (pedestrian channel with mobile subscriber speed 5 km/h, 15 km/h and vehicular channel with speed 45 km/h)

High Speed Downlink Packet Access in UMTS Network

High speed downlink packet access added to UMTS network provides to users data speed up to 10 Mbit/s. The achievement of high data speed is possible due to new link management and link control, and also due to change from power adaptation to modulation and coding adaptation. The most important benefit is an accessing of data services, which request big downlink data flow

Qos Enhancement in Manet by Directional Power Control

In this paper, the 4-Way Directional Power Control with Recoil Loop (4WDPCRL) protocol for power control of directional antennas is presented. We propose the scheme with using of control packets (RTS/CTS/DATA/ACK) for exchanging information about node's transmitted energy. Whenever the frame is received, the appropriate power for transmitted frame is computed. This information is stored together with updated information about position of node to the table. If a new transmission occurs, the node sends packet with updated information about position and appropriate power. The simulation results show that the throughput and energy consumption of the proposed protocol was improved compared to IEEE 802.11 MAC protocol with omni-directional antenna and DMAC protocol with directional antenna

Radio Resource Allocation in Mobile Communication Systems

In the article we deal with two types of Call Admission Control Schemes (Reservation-based CAC scheme and Probability-based CAC scheme) and we made simulations in Matlab environment. Both types of these transmission schemes belong to homogeneous type of radio resource management applications. Only voice application belongs here (traditional wireless networks) and each call demands the same amount of bandwidth (channel, frequency or time slots). Both schemes are compared and evaluated at the end of the article

Structural Health Monitoring of Helicopter Fuselage

The helicopter design is a challenging experience for fatigue concern as it is subjected to a very wide range of low- and high-frequency load cycles per flight, much more than a fixed wing aircraft. Structural Health Monitoring (SHM) seems to have capability in helping to reduce the maintenance and operational costs, which are about 25 percent of the direct operating cost of the helicopter, thus playing an important role especially in the case of the ageing helicopters. In fact, the damage tolerant design approach makes the fatigue resistance evaluation not only a safety issue but also a maintenance related concern. The work presented in this paper is a part of an international research project HECTOR (HElicopter fuselage Crack moniToring and prognosis through On-board sensoR network), founded by the European Defense Agency (EDA) and supported by 10 EDA Member States: Cyprus, France, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia and Spain