Electrical and Computer Engineering Department-College of Engineering-Sultan Qaboos University
Analysis of Uplink Power Control and SC-FDMA in LTE System
Mohammed Ahmed Aal Abdulsalaam
Abstract
Long term evolution (LTE) is the latest generation radio access system that supports today enduser requirements. The fundamental aim of LTE is to improve data rates, system capacity and
reducing latency. The thesis presents an analysis of two of the main factors that play an important
role in LTE uplink transmission, power control and single carrier – frequency division multiple
access (SC-FDMA).
In this thesis, it was noted that with a conventional power control scheme, the received power
spectral density (PSD) by evolved NodeB (eNodeB) is same from all users independent of their
path loss for a given SNR target. While with a fractional power control where path-loss is
partially compensated by the power control scheme, the higher is the path-loss, the smaller is the
received power at eNodeB and thus cell edge user equipments (UEs) are received with a weaker
signal. They however create less inter-cell interference because their transmitted power is also
reduced.
Bit error rate (BER) is the key parameter for indicating the system performance of any data link.
In this thesis, a proposed SC-FDMA system model was implemented and BER was analyzed for a
system in multipath fading environment and with and without an equalizer. It was found that an
equalizer is required to get an acceptable BER value - using ITU pedestrian A channel power
delay profile - as the coherent bandwidth (Bc) is less than the sampling bandwidth (Bs) of the
proposed frequency selective channel system. When multipath Rayleigh fading was introduced
along with AWGN to the channel without an equalizer, the BER was very high (4.75x10-1)
because the coherent bandwidth (Bc 90% = 0.44 MHz) is less than the sampling bandwidth of the
model (Bs = 1.92 MHz). However, when an equalizer was added to the model, BER reduced to
9x10-5.