A Link-to-System Level Interface for B3G Scenarios Y. Nasser 1 , M. Helard 1 V. Monteiro 2 , J.Bastos 2 , J. Rodriguez 2 , H. El-Mokdad 3 1: Institute of Electronics and Telecommunications of Rennes, UMR CNRS 6164, Rennes, France. 2: Instituto de Telecommunicaçoes, University of Aveiro, Campus de Santiago, 3810-094 Aveiro, Portugal 3: Lebanese University, Hadath Campus, Beirut, lebanon Email: youssef.nasser@insa-rennes.fr ; vmonteiro@av.it.pt ABSTRACT— Advanced simulation tools have taken a lot of attention for development and analysis of new and existing protocols and technologies in wireless communications. The huge amount of information, protocols and techniques to be analysed make however their implementation difficult in one simulator. It is thus of paramount importance to define a common interface between the different layers in order to simplify the implementation task but guaranteeing also the confidence of the obtained results. This paper provides a complete specification of the system level simulation envisaged for Beyond 3 rd Generation (B3G) systems. The main idea of this paper is to explain how we could extract information from the link level simulation and to implement them in the system level simulation. Two particular cases are considered for the proof of concept in this work. The first one concerns the Spatial Division Multiple Access (SDMA) technique using positioning information. The second one concerns the use of the cooperative communications to improve the quality of service at the cell border. Index Terms- System-to-link level, Cooperation, Resource allocation, MAC protocol, Cross-layer. 1. INTRODUCTION Efficient use of radio resources requires Cooperative Radio Resource Management (CRRM), a module that carries out RRM on a global scale between systems of diverse technologies and operators. To solve the CRRM challenge, an experimental platform is required that models all environmental and system issues pertaining to a heterogeneous networking scenario, and that has desirable attributes which include: low complexity and simulation time and high modeling accuracy. A traditional system level simulator simulates a large number of mobile terminals in a wide environment with several base stations. In practice, the use of an efficient experimental platform dealing with all technologies, protocols, simulation scenarios and all mobile terminals is rather time consuming. Nevertheless, it is important to include the different transmission parameters (mobility, fading, interference, etc) in the system level simulator. In literature, some work has been done to implement and analyze the system performance with all these scenarios and parameters, in terms of the average of the Signal to Interference and Noise Ratio (SINR). The problem is that the average SINR does not fully reflect the Quality of Service (QoS) at the user terminal. It is therefore essential to express the QoS requirements in terms of Block Error Rate (BLER) (or Packet Error Rate, PER) which reflects better the actual quality of the signal received by the user terminal. This paper presents an experimental link-to-system level interface for B3G scenarios. The goal is to describe first the system level platform used for RRM algorithms in B3G scenarios, using wireless systems. Afterwards, we describe one of the most promising techniques used for link-to- system level interface called effective exponential SNR mapping (EESM) technique. This technique, proposed in 3GPP-LTE, is applied in this work in different transmission scenarios for the proof of concept targets. The latter will be considered in two cases: in SDMA technique and in cooperative communications networks. The rest of the paper is presented as follows. Section 2 presents the system level simulator architecture based on a layered structure of communications systems. Section 3 describes the EESM technique as the link-to-system level interface. In section 4, we show the proof-of-concept by considering two transmission cases: SDMA technique and cooperative communications technique. The conclusions are drawn in section 5. 2. SYSTEM LEVEL SIMULATOR ARCHITECTURE 2.1. Problem domain The high level objectives of the system level tool are to measure system coverage capacity and spectral efficiency, for which the evaluation criteria is given in [1][2][3]. Moreover, the design of the reference system level simulator must be sufficiently complete, so as to provide sufficient modeling accuracy, whilst still keeping simulation time and excess complexity to a minimum. In order to reflect a realistic system, the performance evaluation should consider the impact of the relevant layers of the communication protocol: physical layer, link-layer (L2 layer) and upper layers. The details regarding the Link Level Interface to the Physical layer can be found in [4]. The structure of a single Radio Access Technology (RAT) simulator, with some of the blocks representing the functions described above, is presented in Figure 1. The Medium Access Control (MAC) layer comprises two types of models: MAC protocols that include algorithms and procedures which affect system performance and optimization, such as Call Admission Control (CAC), 978-1-4244-7157-7/10/$26.00 ©2010 IEEE 233