Dynamic link budget simulation

A new simulator named DLBS (Dynamic Link Budget Simulator) was written to simulate the time-varying communication link between a vehicle that re-enters the atmosphere from the outer space, and a ground station. During the vehicle descent trajectory, communications blackouts typically occur due to the effects of plasma that forms around the vehicle. A companion simulator, AIPT (Antenna In Plasma Tool), evaluates the electric field at the input of the ground station antenna, taking into consideration the vehicle structure, its antenna, the characteristics of plasma at some specified points along the vehicle trajectory, and the obtained values are stored in a file. DLBS processes the data read from the AIPT output file and evaluates the corresponding channel transfer functions. DLBS then allows to simulate the typical telemetry and telecommand links, using both CCSDS standardised and some non standard channel encoding schemes and modulations. For each generated frame, DLBS uses a channel transfer function obtained by adequately interpolating the two nearest transfer functions evaluated in the initial phase. DLBS includes realistic frame, frequency, phase and bit synchronisation, so that synchronisation errors are also included as source of performance degradation, and measures both the average bit and frame error rates, and the bit error rate at frame level, so that it is possible to appreciate the dynamic system behaviour. The paper will show the results obtained for a case stud

Dynamic link budget simulation

A new simulator named DLBS (Dynamic Link Budget Simulator) was written to simulate the time-varying communication link between a vehicle that re-enters the atmosphere from the outer space, and a ground station. During the vehicle descent trajectory, communications blackouts typically occur due to the effects of plasma that forms around the vehicle. A companion simulator, AIPT (Antenna In Plasma Tool), evaluates the electric field at the input of the ground station antenna, taking into consideration the vehicle structure, its antenna, the characteristics of plasma at some specified points along the vehicle trajectory, and the obtained values are stored in a file. DLBS processes the data read from the AIPT output file and evaluates the corresponding channel transfer functions. DLBS then allows to simulate the typical telemetry and telecommand links, using both CCSDS standardised and some non standard channel encoding schemes and modulations. For each generated frame, DLBS uses a channel transfer function obtained by adequately interpolating the two nearest transfer functions evaluated in the initial phase. DLBS includes realistic frame, frequency, phase and bit synchronisation, so that synchronisation errors are also included as source of performance degradation, and measures both the average bit and frame error rates, and the bit error rate at frame level, so that it is possible to appreciate the dynamic system behaviour. The paper will show the results obtained for a case study

Chap. 5. Lidar Link Budget

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Antenna Gain and Link Budget for Waves Carrying Orbital Angular Momentum (OAM)

This paper addresses the RF link budget of a communication system using unusual waves carrying an orbital angular momentum (OAM) in order to clearly analyse the fundamental changes for telecommunication applications. The study is based on a typical configuration using circular array antennas to transmit and receive OAM waves. For any value of the OAM mode order, an original asymptotic formulation of the link budget is proposed in which equivalent antenna gains and free-space losses appear. The formulations are then validated with the results of a commercial electromagnetic simulation software. By this way, we also show how our formula can help to design a system capable of superimposing several channels on the same bandwidth and the same polarisation, based on the orthogonality of the OAM. Additional losses due to the use of this degree of freedom are notably clearly calculated to quantify the benefit and drawback according to the case.Comment: 33 pages, 11 figure

PERHITUNGAN LINK BUDGET PADA KOMUNIKASI GSM DI DAERAH URBAN CLUSTER CENTRAL BUSINESS DISTRIC (CBD), RESIDENCES, DAN PERKANTORAN

Pada saat ini, kebutuhan terhadap komunikasi wireless sangat tinggi sehingga diperlukan suatu perencanaan jaringan komunikasi wireless. Dalam perencanaan sistem komunikasi wireless diperlukan perhitungan link budget yang merupakan perhitungan loss dari antena transmitter menuju receiver. Perhitungan link budget mempunyai peranan penting agar rancangan jaringan komunikasi dapat mencapai hasil yang optimum dan efisien baik dari segi kehandalan teknis maupun biaya. Oleh karena itu pada proyek akhir ini telah dibuat sebuah software visualisasi perhitungan link budget dari provider GSM di daerah urban cluster CBD, Residences, dan Perkantoran. Data yang digunakan dalam perhitungan link budget GSM adalah data hasil pengukuran dengan metode drive test. Dari data tersebut dihitung nilai pathloss dan coverage area-nya. Untuk menghitung besar pathloss di daerah urban menggunakan model Okumura Hata sedangkan untuk menentukan coverage area menggunakan Two Ray Model. Berdasarkan software perhitungan link budget yang telah dibuat, pada jarak 2 km; ht=30m; hr=1m; f=1875MHz diperoleh nilai pathloss pada cluster CBD sebesar 127.8dB, cluster residences sebesar 121.8dB, dan cluster perkantoran sebesar 119.9dB

A New Approach to the Link Budget Concept for an OAM Communication Link

Following on from the increasing interest for electromagnetic waves carrying Orbital Angular Momentum (OAM), different configurations of antenna systems able to generate such beams have been proposed. However, in our opinion, a traditional radiation pattern approach does not provide the right picture of an OAM-based communication link. For this reason we propose a new general concept, the "OAM-link pattern", which takes into account the peculiar phase structure characterizing these waves. Focusing on OAM transmissions between antenna arrays, we introduce a formula for the link budget evaluation which describes the whole communication link and directly leads to a "classically shaped" main lobe pattern for a proper rephased reception in the case of uniform circular arrays.Comment: 4 pages, 3 figure

Fade depth scaling with channel bandwidth

The dependence of small-scale fading on bandwidth is quantified experimentally in the 3.1–10.6 GHz band for indoor channels. The fade depth converges to 4 dB at 1 GHz bandwidth, with little reduction for further increase in bandwidth. A simple yet accurate empirical fade depth model is developed, enabling convenient evaluation of the link budget for a channel with given bandwidth

Power link budget for propagating Bessel beams

International audienceThe power link budget for a system that transmits and receives propagating Bessel beams is studied. The transmitter and receiver are separated by a distance D and consist of leaky radial waveguides. Full-wave simulations are used to compute the admittance-matrix representation of the system. The resonances of the coupled transmitter and receiver are then derived using classical network theory. For comparison purposes, a second configuration with its transmitter and receiver connected by a circular waveguide is considered. In contrast to the open system, such a configuration is closed and does not radiate. It is found that within the non-diffractive range of the Bessel beam, both closed and open systems exhibit the same resonances within an error of 0.6%. Calculations show that the power efficiency of the open system can exceed 85% within the non-diffractive range. The proposed system may find application in areas such as wireless power transfer, near-field communication and non-destructive evaluation

Comparison of the link budget with experimental performance of a WiMAX system

The performance of different modulation schemes of a broadband fixed wireless 802.16 (WiMAX) system in a sector is experimentally determined and compared to link budget calculations using different path loss models. A link budget based on path loss measurements of the actual WiMAX signal at 3.5GHz for a typical residential scenario in a suburban environment is determined. The link budget calculations show a reasonable agreement with actual performance measurements with certified WiMAX modems. Carefulness is advised when these models are used for the actual deployment of aWiMAX network in a specific area