Experimental Evaluation of Transmitted Signal Distortion Caused by Power Allocation in Inter-Cell Interference Coordination Techniques for LTE/LTE-A and 5G Systems

Abstract

Error vector magnitude (EVM) and out-of-band emissions are key metrics for evaluating in-band and out-band distortions introduced by all potential non-idealities in the transmitters of wireless systems. As EVM is a measure of the quality of the modulated signal/symbols, LTE/LTE-A and 5G systems specify mandatory EVM requirements in transmission for each modulation scheme. This paper analyzes the influence of the mandatory satisfaction of EVM requirements on the design of radio resource management strategies (RRM) (link adaptation, inter-cell interference coordination), specifically in the downlink (DL). EVM depends on the non-idealities of the transmitter implementations, on the allocated power variations between the subcarriers and on the selected modulations. In the DL of LTE, link adaptation is usually executed by adaptive modulation and coding (AMC) instead of power control, but some flexibility in power allocation remains being used. LTE specifies some limits in the power dynamic ranges depending on the allocated modulation, which ensures the satisfaction of EVM requirements. However, the required recommendations concerning the allowed power dynamic range when inter-cell interference coordination (ICIC) and enhanced ICIC (eICIC) mechanisms (through power coordination) are out of specification, even though the EVM performance should be known to obtain the maximum benefit of these strategies. We perform an experimental characterization of the EVM in the DL under real and widely known ICIC implementation schemes. These studies demonstrate that an accurate analysis of EVM is required. It allows a better adjustment of the design parameters of these strategies, and also allows the redefinition of the main criteria to be considered in the implementation of the scheduler/link adaptation concerning the allocable modulation coding scheme (MCS) in each resource block.

A Flexible mmWave Layer 2 Protocol Implementation for Integrated Access and Backhaul Architecture

“…Recent research and development in the area of wireless communications using software-defined radio (SDR) platforms have been primordial in testing novel algorithms and network architectures allowing a faster evolution and deployment of the proofs-of-concept in the 5G communication networks [32], [33]. Furthermore, our research team has demonstrated the viability of employing the SDR together with Matlab TM software in the cooperative 5G network implementation [34].…”

“…It is worthwhile to mention the amount of research involving theoretical aspects of the design of IAB architectures [24], [26], [27]. Besides, several works have studied the link-level simulation of the mmWave backhaul network and the hardware implementation still constitutes a significant challenge [28], [31], [32]. It should be highlighted that the theoretical implementations and link-level simulations are really an important way for studying algorithms and architectures.…”

Performance of Modified Fractional Frequency Reuse in Nakagami-m Fading Channel

“…In Reference [2], the signal distortion due to power allocation in various FFR schemes was studied. The joint optimization of FFR and the modern cellular technique, particularly Dynamic Time-Divison Duplex, was investigated [3].…”