Effect of Mobility on SINR in Long Term Evolution Systems

To meet the ongoing demands for high speed broadband communications, network providers are opting for the next generation of mobile technologies like LTE and LTE-Advanced. Standardized by 3GPP, these technologies aim to meet the requirements of higher data rates, low latency, and wider mobility, in varying environments without affecting the quality of service of a network. With higher mobility, the various network performance parameters like signal to interference to noise ratio, throughput, received signal strength indicator etc. get affected. This paper highlights the effect of mobility on signal to interference to noise ratio (SINR) characteristics of an IMT-A system in various test environments like In-house (INH), Urban Micro (UMi), Urban Macro (UMa), Rural Macro (RMa), and Suburban Macro (SMa). Simulations have been carried out to obtain spatial plots and SINR vs CDF plots in various test environments, at different user equipment speeds, emphasizing the effects of user equipment speed on the fast fading channel gainsand SINR of the system. By varying the UE speeds from 0 km/hr to 360 km/hr there was an increase in the minimum SINR value required for acceptable performance in a system. It was observed that for given system parameters, the minimum SINR required in RMa environment increased from -5dB to 1dB, in SMa environment it increased from -6dB to -2dB, and in case of UMa environment it increased from -4dB to 1dB, when the UE speed was increased from 0km/hr to 360km/hr. To address the problem of poor SINR in high mobility systems, 3GPP has introduced the technique of Moving Relays. It is used to improve the SINR and hence the channel quality for UEs moving at high speeds in LTE systems.