Simplified approach for symbol error rate analysis of SC-FDMA scheme over Rayleigh fading channel

Abstract

In this paper, we present a comprehensive analytical study of the symbol error rate (SER) of single-carrier frequency-division multiple access (SC-FDMA) with zero-forcing frequency domain equalization (ZF-FDE) over a Rayleigh fading channel. SC-FDMA is considered as a potential waveform candidate for fifth-generation (5G) radio access networks (RANs). First, the N C fold convolution of the noise distribution of an orthogonal frequency-division multiplexing (OFDM) system is computed for each value of the signal-to-noise ratio (SNR) in order to determine the noise distribution of the SC-FDMA system. N C is the number of subcarriers assigned to a user or the size of the discrete Fourier transform (DFT) precoding. Here, we present a simple alternative method of calculating the SER by simplifying the N C fold convolution using time and amplitude scaling properties. The effects of the N C fold convolution and SNR over the computation of the SER of the SC-FDMA system has been separated out. As a result, the proposed approach only requires the computation of the N C fold convolution once, and it is used for different values of SNR to calculate the SER of SC-FDMA systems. K E Y W O R D SBER, noise characterization, OFDMA, Rayleigh, SC-FDMA, SER, zero-forcing | INTRODUCTIONOrthogonal frequency-division multiplexing (OFDM) is used primarily to protect against the detrimental effects of wireless multipath channels. By sampling the received signal at an optimum time, the receiver can avoid the intersymbol interference (ISI) caused by fading environments up to the length of the cyclic prefix (CP) being used [1,2]. Moreover, for this reason, the CP is chosen to be slightly longer than the maximum delay spread of the fading channel. To summarize the advantages, OFDM systems transmit multiple low-data-rate subcarriers, resistant to multipath, spectrally efficient, and the frequency-domain representation further simplifies the error correction at the receivers and reduces the complexities involved in multiple-input multiple-output (MIMO) implementation. OFDM also supports multiple users or multiaccess scheduling. The primary design criteria for an OFDM-based communication system are the maximum delay spread, maximum Doppler frequency, and the targeted cell size.However, OFDM has two significant drawbacks. First, the high peak-to-average power ratio (PAPR) results in problems at the amplifiers. The other disadvantage is related to the tightly spaced subcarriers that are induced to compensate the loss of bandwidth due to CP insertion. The subcarriers start to lose orthogonality because of frequency errors [3]. Aside from the CP overhead and high sensitivity to frequency, the timing offset limits the performance of OFDM systems. The undesirable high PAPR of OFDM led the third generation partnership project (3GPP) to choose a different modulation format for the long-term evolution (LTE) uplink, namely the single-carrier frequency-division multiple access --

Trigonometric transforms and precoding strategies for OFDM‐based uplink hybrid multi‐carrier nonorthogonal multiple access

“…Two cases; one with full matrix compensation and another with BMI for JECC are presented as subfigures A and B, respectively. It can be checked from these figures that the performance of NOMA‐OFDMA acts as the lower bound for NOMA‐SC‐FDMA for low values of SNR . These precoding gains are furthermore prominently visible for interleaved mode.…”