The Application Of The Link-Level To System-Level Interface In Broadband Mobile Communication System

Broadband mobile communication technique has become a hot topic in recent years in the communication technique market. It is commonly agreed that a system-level simulation is the most important way to evaluate a system's performance. This method is through a simulation of the actual user and the system's action to get some vivid result, such as throughput. However, it is difficult for us to endure the system-level simulation for the heavy computation cost of it with high resolution and long simulation time. Therefore, in pratice, a separate link-level and system-level simulators are used. Through a mapping function of the interface between the link-level to system-level(L2S) to predict and get the performance of the system. It can be seen that the mapping technique of the L2S interface is so important that it can affect the system's performance. Average Value Interface and Actual Value Interface have often been used in previous references. For the reason of their inaccuracy and complexity, those two techniques are inefficient, thus, we need a new mapping method to evaluate the system.Among many L2S interface techniques, the most common ones are the following two:Exponential Effective SINR Mapping (EESM) and Mutual Information Based Effective SINR Mapping (MI-ESM). EESM is a simple mapping method, in which all the sub-carriers for one mobile terminal have to use the same modulation and coding scheme (MCS). Compared to EESM, MI-ESM is more advanced, especially when adaptive modulation and coding (AMC) method is introduced, for the reason that it is not necessary to use the same MCS for all the sub-carriers of one mobile terminal for MI-ESM. That means that there is big freedom to design adaptive resource allocation algorithms for multi-carrier system.This paper focuses on the basic principles and processes and the implement procedures and results of the MI-ESM method, shows how to integrate the multi-state channes into a single state, and then compares the performance of MI-ESM with EESM to prove the advantage of MI-ESM technique. The paper mainly covers the MI-ESM application in OFDM, HARQ and MIMO system, including the effective SINR computing method and some corresponding simulation results and conclusion.