Skip to main content

Single Carrier OFDM (SC‑OFDM): Benefits over OFDM in LTE/5G Uplink


Single Carrier Orthogonal Frequency Division Multiplexing (SC-OFDM) is used for uplink communication in LTE and 5G systems. Unlike traditional OFDM, which uses multiple subcarriers, SC-OFDM employs a single carrier for transmission. This method is particularly effective for communication between a single mobile station (MS) and the base station (BS).

The Discrete Fourier Transform (DFT) operation within SC-OFDM divides the original signal into different orthogonal frequency bands, enhancing its resilience to noise and distortion. After the DFT, the Inverse Fast Fourier Transform (IFFT) is applied to convert the signal from the frequency domain back to the time domain for transmission.

SC-OFDM (Single-Carrier Orthogonal Frequency Division Multiplexing) is a variation of the traditional OFDM (Orthogonal Frequency Division Multiplexing) technique. It is particularly useful in systems where a single carrier is preferred, such as in some 5G communication systems and LTE (Long-Term Evolution) systems. SC-OFDM is used to improve spectral efficiency and reduce peak-to-average power ratio (PAPR) when compared to regular OFDM.

Block Diagram of SC-OFDM:

Data → Modulation → DFT → IFFT → Add CP → Transmit


Received Signal → Remove CP → FFT → Demodulation → Data


Key Features of SC-OFDM:

  1. Single Carrier Modulation:

    • Unlike traditional OFDM, which uses multiple subcarriers to transmit data, SC-OFDM uses a single carrier for each block of data. This reduces the complexity and makes it more power-efficient in certain contexts.


    • In OFDM / OFDMA, the data bitstream is first converted from serial to parallel blocks, each block of symbols is modulated and directly assigned to distinct subcarriers, then those are passed through an IFFT (or IDFT) to produce a time-domain signal. After that, a cyclic prefix is appended before transmission.

      In contrast, SC‑FDMA (a.k.a. DFT-spread OFDM or SC-OFDM in uplink context) includes an extra DFT precoding stage applied to the modulated symbol stream (without serial-to-parallel conversion). This spreads each data symbol across multiple frequencies. But uses single wideband carrier.


  2. Reduced PAPR:

    • One of the advantages of SC-OFDM over standard OFDM is its lower peak-to-average power ratio (PAPR). This is crucial for power efficiency, especially in wireless communication where high PAPR can lead to more power consumption, higher interference, and reduced battery life in mobile devices.









    • You can observe that for a typical OFDM signal, the sample amplitudes fluctuate more than those of SC‑OFDM. Thus, the peak‑to‑average power ratio (PAPR) of OFDM is high, which makes it less efficient in terms of signal‑transmission power and amplifier usage.

  1. Spectral Efficiency:

    • SC-OFDM can offer improved spectral efficiency in certain conditions compared to OFDM due to its use of single-carrier transmission and frequency domain equalization.


  2. Applications:

    • SC-OFDM is used in 5G New Radio (NR) for uplink transmission. In particular, it is useful for low-latency communication, where minimizing the power consumption of the uplink signal is crucial.


    • It is also applied in systems with frequency-selective channels.


Advantages of SC-OFDM:

  1. Lower PAPR: This is a major advantage, especially in wireless communication systems where power consumption is a critical factor.

  2. Reduced Interference: By using a single carrier for transmission, SC-OFDM is less prone to out-of-band emissions and other forms of interference.

  3. Better for Uplink: In cellular systems like 5G, SC-OFDM is highly advantageous for uplink transmission, where power consumption and spectral efficiency are critical.


SC-OFDM in 5G:

SC-OFDM is used in 5G's uplink due to its lower PAPR and spectral efficiency. It enables faster data rates and more efficient power usage in devices like smartphones and IoT devices, especially when sending data in high-mobility environments.


Further Reading

📊 MATLAB & ONLINE SIMULATIONS (Web-Based)
🎓 GATE & UGC - NET SOLUTIONS
📡 WIRELESS & SIGNAL PROCESSING


Contact Us

Name

Email *

Message *

Popular Posts

CMOS Logic Gates: Inverter, NAND, and NOR

CMOS Logic Gates: Inverter, NAND, and NOR Complementary metal–oxide–semiconductor (CMOS) technology forms the backbone of modern digital IC design. Patented by Frank Wanlass in 1963 ( US patent 3,356,858 ), CMOS enables low-power, high-speed, and noise-immune logic circuits. CMOS gates, including inverters, NAND, and NOR, are widely used in both large-scale and small-scale integrated circuits due to their efficiency and versatility. CMOS Inverter A CMOS inverter consists of a complementary pair of PMOS and NMOS transistors. The PMOS transistor connects to the supply voltage V DD , while the NMOS connects to ground. The input voltage V IN controls both gates, and the output voltage V OUT is taken from the connected drains. CMOS inverters are highly energy-efficient and produce minimal heat due to their comple...
Read more

UGC NET Electronic Science Previous Year Question Papers with Solutions

Download Papers and Solutions Exam Pattern Preparation Tips FAQs More Home / Engineering & Other Exams / UGC NET 2026 PYQ 📊 Exam Highlights: Electronic Science (88) Feature Details Junior Research Fellowship (JRF) ₹37,000 + HRA per month Eligibility M.Sc/M.Tech in Electronics (55%) Validity of Certificate JRF (3 Years) | Lectureship (Lifetime) 📥 Download UGC NET Electronics PDFs Complete collection of previous year question papers, answer keys and explanations for Subject Code 88. Start Downloading 📂 View All Question Papers June 2026 - Question Paper Download PDF June 202...
Read more

OFDM Symbols and Subcarriers Explained

This article explains how OFDM (Orthogonal Frequency Division Multiplexing) symbols and subcarriers work. It covers modulation, mapping symbols to subcarriers, subcarrier frequency spacing, IFFT synthesis, cyclic prefix, and transmission. Step 1: Modulation First, modulate the input bitstream. For example, with 16-QAM , each group of 4 bits maps to one QAM symbol. Suppose we generate a sequence of QAM symbols: s0, s1, s2, s3, s4, s5, …, s63 Step 2: Mapping Symbols to Subcarriers Assume N sub = 8 subcarriers. Each OFDM symbol in the frequency domain contains 8 QAM symbols (one per subcarrier): Mapping (example) OFDM symbol 1 → s0, s1, s2, s3, s4, s5, s6, s7 OFDM symbol 2 → s8, s9, s10, s11, s12, s13, s14, s15 … OFDM sym...
Read more

IIR Filter Simulation

IIR Filter & Feedback Lab IIR Filter & Feedback Lab Exploring Recursive Systems: Where Output depends on Output 1 Input Signal $x[n]$ Signal Type Unit Impulse δ[n] Sine Wave Unit Step u[n] Frequency (for Sine) Notice: With an Impulse input, the output of an IIR filter can ring forever (Infinite response). 2 Feedback Coefficients Numerator $b$ (Feed-forward) Denominator $a$ (Feedback - $a_0$ is always 1) System Stable Try setting $a$ to 1.0, -1.1 to see an unstable system! ...
Read more

(Filters) Free MATLAB alternative for signal analysis

Advanced Signal Filters Upload CSV (1st Col) or Audio (WAV, MP3, etc.) Generate Messy Signal (20Hz + 50Hz + 150Hz) No Operation FFT (Spectrum) Amplitude Modulation (AM) Double Sideband Supressed Carrier (DSBSC) Pulse Amplitude Modulation (PAM) Flat Top PAM Filters - LPF, HPF, BPF, Notch Principal Component Analysis (PCA) Cross Spectrum Filter Type: Signal Cleaner ...
Read more

Online Simulator for Frequency Modulatiuon and Demodulation

FM Modulation Simulator Frequency Modulation (FM) In Frequency Modulation, the frequency of the carrier signal varies in accordance with the message signal's amplitude. s FM (t) = A c cos(ω c t + k f ∫m(t)dt) where ω = 2πf & k f = Frequency Sensitivity Modulation index, β = (k f * A m ) / f m Change the parameter values to see the effect. Message Freq (Hz) 1 Carrier Freq (Hz) Message Amplitude (Am) Kf (sensitivity): 50 Perform FM Demodulation 🧪 Experiment for Students: ...
Read more

Decision Feedback Equalizer (DFE) in MATLAB

  MATLAB Code M = 4; % QPSK numSymbols = 10000; numTrainingSymbols = 5000; chtaps = [1 0.5*exp(1i*pi/6) 0.1*exp(-1i*pi/8)]; % Generate QPSK symbols data = randi([0 M-1], numSymbols, 1); tx = pskmod(data, M, pi/4); % DFE setup eq = comm.DecisionFeedbackEqualizer; eq.ReferenceTap = 1; eq.NumForwardTaps = 5; eq.NumFeedbackTaps = 3; % SNR sweep snrVec = 0:5:25; % 0,5,10,...25 dB berBefore = zeros(size(snrVec)); berAfter = zeros(size(snrVec)); for k = 1:length(snrVec) % Apply channel and AWGN rx = awgn(filter(chtaps,1,tx), snrVec(k), 'measured' ); % BER before equalization rxDataNoEq = pskdemod(rx, M, pi/4); [~, berBefore(k)] = biterr(data, rxDataNoEq); % Equalize [y,~,~] = eq(rx, tx(1:numTrainingSymbols)); % Phase correction phaseOffset = angle(mean(conj(tx(1:numTrainingSymbols)) .* y(1:numTrainingSymbols))); yCorrected = y * exp(-1i*phaseOffset); % BER after equalization rxDataEq = pskdemod(yCorrected, M, pi/4); [...
Read more

The electric field of a monochromatic plane wave travelling in a lossless isotropic and homogenous medium is given by E(z, t) = ...

  Q. The electric field of a monochromatic plane wave travelling in a lossless isotropic and homogenous medium is given by E(z, t) = E₀ [x̂ cos(ωt − kz) + ŷ sin(ωt − kz)] in a right-handed orthogonal co-ordinate system. Which of the following is the correct polarization of the electromagnetic wave? (A) Right-handed circularly polarized Correct answer under the IEEE convention. (B) Left-handed circularly polarized (C) Linearly polarized (D) Linearly polarized at −45° to x̂ Solution 1. Identify the electric-field components Let ψ = ωt − kz. The components along the x and y directions are: Eₓ = E₀ cos ψ Eᵧ = E₀ sin ψ Both components have equal amplitudes, the same frequency, and a phase difference of 90°. These are the conditions for circular polarization. ...
Read more