Abstract—In order to evaluate the performance of new mobile network technologies, system level simulations are crucial. They aim at determining whether, and at which level predicted link level gains impact network performance. In this paper we present a MATLAB computationally efficient LTE system level simulator. The simulator is offered for free under an academic, noncommercial use license, a first to the authors’ knowledge. The simulator is capable of evaluating the performance of the Down-link Shared Channel of LTE SISO and MIMO networks using Open Loop Spatial Multiplexing and Transmission Diversity transmit modes. The physical layer model is based on the post-equalization SINR and provides the simulation pre-calculated ”fading parameters” representing each of the individual interference terms. This structure allows the fading parameters to be pregenerated offline, vastly reducing computational complexity at run-time.
I. INTRODUCTION 介绍The Long Term Evolution (LTE) standard, specified by the 3rd Generation Partnership Project (3GPP) in Release 8, defines the next evolutionary step in 3G technology. LTE offers significant improvements over previous technologies such as Universal Mobile Telecommunications System (UMTS) and High-Speed Packet Access (HSPA) by introducing a novel physical layer and reforming the core network. The main reasons for these changes in the Radio Access Network (RAN) system design are the need to provide higher spectral efficiency, lower delay, and more multi-user flexibility than the currently deployed networks [2]. In the development and standardization of LTE, as well as the implementation process of equipment manufacturers, simulations are necessary to test and optimize algorithms and procedures. This has to be performed on both, the physical layer (link-level) and in the network (system-level) context. While link-level simulations allow for the investigation of issues such as Multiple-Input Multiple-Output (MIMO) gains, Adaptive Modulation and Coding (AMC) feedback, modeling of channel encoding and decoding [3] or physical layer modeling for system-level [4], system-level simulations focus more on network-related issues such as scheduling [5], mobility handling or interference management [6]. Along with the standardization process, commercially available LTE simulators have been developed. Equipment vendors, to this effect, have also implemented their own, proprietary solutions. Some universities and research centers have also developed such simulators, but to the authors’ knowledge none with publicly available source code. The LTE system-level simulator [1] supplements an already freely-available LTE link-level simulator [7]. This combination allows for detailed simulation of both the physical layer procedures to analyze link-level related issues and system-level simulations where the physical layer is abstracted from link level results and network performance is investigated. The license under which the simulators are published allows for academic research and a closer cooperation between different universities and research facilities. In addition, developed algorithms can be shared under the same license again, facilitating the comparison and cross validation of algorithms and results and making them more credible. The LTE system-level simulator implementation offers a high degree of flexibility. For the implementation, extensive use of the Object-oriented programming (OOP) capabilities of MATLAB, introduced with the 2008a Release have been made. Having a modular code with a clear structure based in objects results in a much more organized, understandable and maintainable simulator structure in which new functionalities and algorithms c
