Research and development of mobile communications systems require a detailed analysis and evaluation of novel technologies to further enhance spectral efficiency, connectivity and reliability. Due to the exponentially increasing demand of mobile broadband data rates and challenging requirements for latency and reliability, mobile communications specifications become increasingly complex to support ever more sophisticated techniques. For this reason, analytic analysis as well as measurement based investigations of link level methods soon encounter feasibility limitations. Therefore, computer aided numeric simulation is an important tool for investigation of wireless communications standards and is indispensable for analysis and developing future technologies. In this contribution, we introduce the Vienna 5G Link Level Simulator, a Matlab-based link level simulation tool to facilitate research and development of 5G and beyond mobile communications. Our simulator enables standard compliant setups according to 4G Long Term Evolution, 5G new radio and even beyond, making it a very flexible simulation tool. Offered under an academic use license to fellow researchers it considerably enhances reproducibility in wireless communications research. We give a brief overview of our simulation platform and introduce unique features of our link level simulator in more detail to outline its versatile functionality.
A well known tool for simulation of communications networks is the @cite_39 , which is the successor of the . Although this tool has to be understood as a set of open source modules forming a generic network simulator, there exists an LTE module @cite_56 that allows to simulate 4G networks. Further, there exists a module @cite_13 @cite_40 that covers MMW propagation aspects of 5G . Still, the main focus of the lies on network simulations. The mentioned LTE module models radio resources with a granularity of resource blocks and does not consider time signals on a sample basis, as our simulator does. Therefore, the does not provide the detailed level of PHY accuracy that distinguishes pure link level simulation tools from system and network level simulators, where a certain degree of physical layer abstraction is unavoidable to manage computational complexity.
@cite_40 @cite_56 @cite_13 @cite_39
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The rapid evolution of nowadays wireless communication systems constitutes a challenge for the versatile and flexible evaluation of transmissions under different scenarios. In order to evaluate the current fourth generation (4G) and future fifth generation (5G) communication techniques, a modular link-level simulator was developed at the GTEC group of the University of A Coruna. In this paper, the structure of the simulator as well as how to use it are presented in detail. The simulator allows for performing link layer simulations both for Orthogonal Frequency-Division Multiplexing (OFDM) and Filter Bank Multicarrier (FBMC) signals. It includes fully-functional transmitter and receiver implementations, as well as different channel models and functions for processing the obtained results. Moreover, we show also that the simulator is fully integrated with the GTEC testbed, enabling not only for performing simulation-based evaluations, but also considering over-the-air measurements. Hence, the GTEC 5G Simulator constitutes a valuable tool for evaluating new communication systems in a versatile and flexible way. Some exemplary results obtained both by simulations and through measurements are included. Communication systems in practice are subject to many technical technological constraints and restrictions. Multiple input, multiple output (MIMO) processing in current wireless communications, as an example, mostly employs codebook-based pre-coding to save computational complexity at the transmitters and receivers. In such cases, closed form expressions for capacity or bit-error probability are often unattainable; effects of realistic signal processing algorithms on the performance of practical communication systems rather have to be studied in simulation environments. The Vienna LTE-A Uplink Simulator is a 3GPP LTE-A standard compliant MATLAB-based link level simulator that is publicly available under an academic use license, facilitating reproducible evaluations of signal processing algorithms and transceiver designs in wireless communications. This paper reviews research results that have been obtained by means of the Vienna LTE-A Uplink Simulator, highlights the effects of single-carrier frequency-division multiplexing (as the distinguishing feature to LTE-A downlink), extends known link adaptation concepts to uplink transmission, shows the implications of the uplink pilot pattern for gathering channel state information at the receiver and completes with possible future research directions. The forthcoming 5G cellular network is expected to overlay millimeter-wave (mmW) transmissions with the incumbent micro-wave ( @math ) architecture. The overall mm- @math resource management should, therefore, harmonize with each other. This paper aims at maximizing the overall downlink (DL) rate with a minimum uplink (UL) rate constraint, and concludes: mmW tends to focus more on DL transmissions while @math has high priority for complementing UL, under time-division duplex (TDD) mmW operations. Such UL dedication of @math results from the limited use of mmW UL bandwidth due to excessive power consumption and or high peak-to-average power ratio (PAPR) at mobile users. To further relieve this UL bottleneck, we propose mmW UL decoupling that allows each legacy @math base station (BS) to receive mmW signals. Its impact on mm- @math resource management is provided in a tractable way by virtue of a novel closed-form mm- @math spectral efficiency (SE) derivation. In an ultra-dense cellular network (UDN), our derivation verifies mmW (or @math ) SE is a logarithmic function of BS-to-user density ratio. This strikingly simple yet practically valid analysis is enabled by exploiting stochastic geometry in conjunction with real three-dimensional (3-D) building blockage statistics in Seoul, South Korea. The increasing demand of data, along with the spectrum scarcity, are motivating a urgent shift towards exploiting new bands. This is the main reason behind identifying mmWaves as the key disruptive enabling technology for 5G cellular networks. Indeed, utilizing new bands means facing new challenges; in this context, they are mainly related to the radio propagation, which is shorter in range and more sensitive to obstacles. The resulting key aspects that need to be taken into account when designing mmWave cellular systems are directionality and link intermittency. The lack of network level results motivated this work, which aims at providing the first of a kind open source mmWave framework, based on the network simulator ns-3. The main focus of this work is the modeling of customizable channel, physical (PHY) and medium access control (MAC) layers for mmWave systems. The overall design and architecture of the model are discussed in details. Finally, the validity of our proposed framework is corroborated through the simulation of a simple scenario.