Throughput Gain of Fractional Frequency Reuse with Frequency Selective Scheduling in SC-FDMA Uplink Cellular System

Abstract

SC-FDMA is a multiple access technique adopted in LTE uplink transmission. SC-FDMA, as well as OFDMA, can improve system throughput by assigning different frequency portions of system bandwidth to different user equipments (UEs) adaptively based on their channel quality information. In SC-FDMA uplink cellular system, interference arising from UEs in neighboring cells degrades system performance, especially the performance of the cell-edge UE. To overcome this drawback, many papers propose the Fractional Frequency Reuse (FFR) technique and analyze its influence. However, these studies have different conclusions on the effectiveness of FFR, and the throughput gain of FFR depends on the evaluating conditions. In this paper, we reveal the conditions where FFR is effective by demonstrating the throughput gain of FFR in SC-FDMA uplink cellular system. In order to analyze the throughput gain of FFR, we focus on the performance relationship between FFR and frequency selective scheduling (FSS). From the analysis, the throughput gain of FFR is small because of the degradation of the FSS gain, and FFR is effective when the following conditions are met; (i) the number of UEs is small, (ii) the multipath delay spread is large or equal to 0.

Analytic estimation for uplink capacity reduction due to co-channel interference in LTE networks

“…We focus on the reference base station (denoted as BS 0 ) and examine its uplink performance. The primary co-channel signals come from the mobile users located at the coverage of BS 1 -BS 6 . The frequency reuse factor is set to three, which means the radio resources are divided into three partitions or channels denoted as f 1 , f 2 , and f 3 .…”

“…The LTE standard adopts orthogonal frequency division multiplexing (OFDM) technology as the downlink access technology that has many advantages, such as high spectral efficiency and the robustness for multipath fading [6]. On the other hand, for uplink transmission, LTE adopts singlecarrier frequency division multiple access (SC-FDMA) to avoid intra-cell interference.…”