Modeling and Performances Evaluation of HARQ Technique for MIMO Transmission in Downlink LTE Cellular Networks

Long Term Evolution (LTE) is designed for deployment in a variety of spectrum allocation ranging from 1.4 MHz to 20 MHz. The peak data rate envisaged for LTE is 100 Mbps in downlink and 50 Mbps in the uplink. Unfortunately, different constraints have a strong influence on system performance such as the velocity of user equipment and effect of multipath channel. To achieve data rate compliance with LTE standard, Different transmissions techniques are deployed such as MIMO transmission, Adaptive Modulation and Coding (AMC) and Hybrid Automatic Repeat request (HARQ) Technique. In this paper we simulate and discuss the performances of HARQ process for downlink LTE system using MIMO transmit diversity and spatial multiplexing. In first time, we study the effect of HARQ technique over AWGN channel then we perform different MIMO transmission schemes for downlink LTE system in multipath channel. Extended Vehicular-A tapped delay channel model are used to model high speed user equipment. Keywords—Hybrid Automatic Repeat reQuest; transmit diversity; Open loop spatial multiplexing; Mutiple input mutiple output