Mobility Effect on Different MIMO Modes and Scheduler Schemes under Different Network Layout in Downlink LTE-A

Abstract

Modern wireless communication systems have to meet the demand of very high data rates. Unlike conventional methods, LTE addresses the higher data rate by introducing several Multiple-Input and Multiple-Output (MIMO) transmission modes. Transmit diversity and Spatial multiplexing techniques are the most popular techniques that are used now- a -days. Open loop and closed loop spatial multiplexing techniques can both transmit multiple data streams in a single time interval. This significantly enhances the data rate and channel capacity. In addition, closed loop spatial multiplexing uses a Pre-coding matrix indicator which is fed back from the UE to the base station and this optimizes the data transmission. Resource scheduler type also has a significant impact on the system performance because the scheduler performance ranges from optimizing the UE fairness to maximizing the UE throughput. In practical, many User Equipments (UEs) can move at high velocities and which affects the overall performance of scheduler. Thus, UE mobility must be taken into account for a fair comparison between different schedulers and transmission modes. Therefore, thorough performance analysis with different combination of transmission modes, scheduling types and network layouts can be greatly helpful. The performance analysis can be done using computer simulations instead of real network to save the cost. The results of the analysis can be used for proper settings in the real network. In other words, for optimizing the network system and reducing the operational cost of the operator, performance analysis must be done for choosing the right scheduler and transmission modes for different network layout under mobility. In this work, a thorough performance analysis has been done for various LTE downlink performance parameters between several MIMO techniques to find which MIMO mode is best suited for mobile users and dense urban environment under different scheduling algorithms in different network Layouts.