OFDM Simulation in MATLAB Simulink

At first, we define the expansion of OFDM as orthogonal frequency-division multiplexing. It is nothing but one of the emerging communication modes in digital transmissions. This technique is intended to encode the digital information on the multi-carrier spectrum. Further, it supports parallel data transmission which encloses overlying spectra and multi- closely spaced orthogonal subcarrier signals. Here, the demodulation process occurs based on the FFT algorithm.

From this page, we can learn about the advanced OFDM Simulation in MATLAB with the latest technologies and research ideas!!!

Generally, the multipath propagation will affect the performance of OFDM in transmission by introducing the guard interval. Further, it uses a traditional modulation scheme on every subcarrier signal which results in a low symbol rate. And, it manages the overall data transfer rate which relates to the traditional modulation scheme with the same bandwidth. 

Major Properties of OFDM

• Resilience to Interference
  • Constrained bandwidth is the one of the main interference in channels but it cause heavy data loss
• Resilient to Narrow-Band Impacts
  • In order to recover the lost symbols, one can use adequate channel coding and interleaving
• Immunity to Selective Fading
  • Main OFDM benefit is high resistance to frequency selective fading  (compare to single carrier)
  • Since, it splits the whole channels into numerous narrowband signals where it is affected independently as flat fading sub-channels
• Spectrum Efficiency
  • Effectively use the existing spectrum due to the closed-spaced overlying sub-carriers (i.e., OFDM)
• Equalization of Channel
  • In existing CDMA model, the equalization of channel is the tough task to be carried out. Since, it will be applied in whole channel
  • But in OFDM, the channel equalization is applied on the multiple sub-channels
• Resilient to ISI
  • Robust to interference of inter-frame and inter-symbol
  • So, it causes minimum data transfer rate on every sub-channel
  • Since, the symbols are lost based on the channel frequency selection and narrow band interference

As mentioned earlier, OFDM is the modulation type for digital transmission. In this, it transmits the signal over several frequencies bands. Further, it also supports different wireless communication technologies such as LTE Toolbox, 4G, Wi-Fi, 5G, etc. Also, it overcomes the drawbacks of the existing technologies. MATLAB is one of the best tools to support OFDM technology. Here, we have specified some main objectives of OFDM simulation in MATLAB. 

• To build, develop, test and simulate OFDM systems
• To overcome the error transmission by improving BER performance
• To accomplish the goal of reaching error free transmission in wireless communication

In the upcoming section, we will deliver useful information about wireless communication technologies and MATLAB to develop OFDM systems. Further, we also provide you with emerging ideas, techniques, supporting tools to make the OFDM system more efficient and reliable. Here, we have given you the significant uses of MATLAB over OFDM simulation. This presents you the reasons behind the preference of MATLAB.

What are the uses of Matlab for OFDM simulation?

• MATLAB is supported with several in-built wireless communication libraries, functions and toolboxes to support OFDM
• Support HDL  coder and wireless HDL toolbox specifically to apply OFDM algorithms on top of ASIC’s and FPGA’s
• Allow to visualize the data in execution of every process
• Enable to performs processes like modulation / demodulation, channel estimation, encode / decode, equalization, matching / de-matching, model designing, synchronization, and etc.

Now, we can see the different varieties of OFDM. Each type of OFDM has special benefits and necessities. Our researchers are skillful in handling all these technologies to support you in every aspect of the OFDM variant. Also, we are good to prefer the suitable OFDM variant for your project based on your application needs. Here, we have listed only a few main OFDM variants for your information. 

Variants of OFDM

• NOFDM
• COFDM
• FLASH OFDM
• BST-OFDM
• Multi-band OFDM
• Wavelet OFDM

For instance, we have selected the coded orthogonal frequency-division multiplexing (COFDM) from the above list. It is specifically used to implement frequency/time interleaving and forward error correction (convolutional coding) over the signal before transmission. And, it helps to tackle the transmission error caused due to the Doppler Effect and multipath propagation. For your reference, here we have given you the simple ways to perform the OFDM processes using MATLAB.

• Encode the modulation
• Perform IFFT
• Implement Cyclic prefix
• Design pilot symbols

Basically, the OFDM systems can be developed in two ways. One is direct real-world implementation and the other is simulation. For the real-world implementation, it needs sufficient antenna and hardware support. In the simulation, we can virtually design and develop all necessary network entities without any physical entities. 

What are the steps to develop OFDM Simulation in matlab simulink?

Here, we have given you the sample demonstration on OFDM simulation in transmitter and receiver sides. At this time, the signal is transferred from transmitter to receiver through the PUSCH baseband signal (channel).

Transmitter Phase

• Collect data from higher layer
• Produce CRC and attach them
• Encode the turbo
• Relate and match with rate
• Implement modulation and scrambling
• Perform DFT
• Map the resource by generated DMRS
• Insert CP and IFFT

Receiver Phase

• Perform FFT and eliminate CP
• De-map the resources
• Estimate the channel by generated DMRS
• Perform equalization and iDFT
• Implement demodulation and descrambling
• Rate de-matching
• Decode the turbo
• Verify CRC and deattach them

Next, we are going to primarily focus on the techniques used to improve the efficiency of the OFDM system in real-time simulation. Beyond this list of techniques, we also support you with other advanced techniques. In the case of a complex issue, our developer creates their algorithms to crack the issues. Further, we are also good at developing hybrid techniques to provide very efficient solutions. Let’s have a look at the current emerging techniques of OFDM simulation.

What are the emerging techniques for OFDM simulation?

• Artificial Noise-oriented
  • Depends on the receiver’s channel, the transmitter design the artificial noise and include them with transmitted signals
  • If the eavesdropper tries to overhear the data, then the original message cannot be recovered
• Feature Suppression of OFDM Signal
  • Cover-up the significant features within the OFDM signal
• Adaptive Transmission-oriented
  • Modify the transmission metrics based on the QoS needs (intended receiver)
  • Further, these schemes comprises sub-carrier deactivation (fading-oriented) methods, power distribution and pre-equalization
• Secret Key-oriented
  • Allow legal users to acquire the pseudo-random sequence in the channel
  • Make use of collected sequence for constellation rotation, runtime coordinate interleaving and data encryption

In fact, our experienced technical legends are very passionate about working in the different directions of the OFDM simulation field. They are always intended to identify the new dimension of OFDM simulation in MATLAB to create an incredible contribution to the research society. Here, we have given you the newly budding research ideas in OFDM. Further, if you looking for other ideas in your interested area then communicate with us.        

What are the emerging ideas in OFDM?

• Reference signal in Wireless Communication
• Efficient and Fast Generation of OFDM Signal
• Efficient Transform Precoding and Layer Mapping
• Design of Physical Resource and Frame Structure
• Resource and Modulation mapping (QPSK, BPSK, etc.)
• Estimation of Channel based on Physical Random-Access
• Advance Signal Modulation, Up-conversion and Scrambling
• Physical Channel Sharing in Uplink/Downlink Transmission
• Signal Assessment with Primary and Secondary Synchronization
• Estimation of Physical Channel in Uplink and Downlink Transmission

Now, we can see some simulation parameters of the OFDM system. Since these input and output parameters are more important in OFDM implementation. It is necessary to consider the following input parameters in designing the OFDM Simulation in Matlab. It creates a major impact on system performance and output parameters. Further, we have also given you some output parameters for your references. The below parameters will vary based on the proposed technique and research idea. 

OFDM Simulation Parameters

Input Parameters

• cyclicDuration
  • Calculate time taken to complete one cycle 
• Fs
  • Address the samples of frequency
• Input
  • Collect binary pattern of PRBS for modulation purposes
• IFFTsize
  • Measure the sum of total subcarriers
• samplesPerSymbol
  • Compute total count of samples or subcarriers / symbol
• modType
  • Specify phase / amplitude modulation type (16QAM, QPSK, 64QAM, BPSK)

Output Parameters

• modSignal
  • Represent the modulated signals of amplitude and phase prior to OFDM modulation
• sendedSignal
  • Represent the OFDM analog signal which will be further converted to optical signal

OFDM for 5G network

In the advanced wireless 5G communication, OFDM acquired a significant position due to its high usage. Since this modulation type combines the advantages of both FDM and QAM to achieve the high data rate. Here, the QAM addresses other major types of modulations such as QPSK, 64QAM, BPSK, 16QAM, 5g Qos and many more.

• Frequency Division Multiplexing (FDM)
• Quadrature Amplitude Modulation (QAM)
• Quadrature Phase Shift Keying (QPSK)
• 64-state QAM (64QAM)
• Binary Phase Shift Keying (BPSK)
• 16-state QAM (16QAM)

What are the Uses of OFDM for 5G Network?

In fact, the first and foremost wireless LAN protocol that uses OFDM Simulation in matlab is IEEE 802.11a. This protocol uses 64 subcarriers (312 kHz space) which modulate with different QAM variants. For instance: 16QAM, BPSK, 64 QAM and QPSK. 

By using OFDM in mobile communication, we can accomplish high bandwidth channels. In the existing approaches, OFDM is incorporated with the LTE systems. In this, it supports only downlink transmission with a fixed space of 15 kHz. And, the subcarriers support modulation types such as 16QAM, 64QAM, and QPSK.

Currently, OFDM is employed in 5G New Radio (NR) which supports both downlink and uplink transmission. The specialty of NR is flexibility to support nearly 33300 subcarriers for various kinds of applications. And, the supported carrier spacing is 30 kHz, 15 kHz, 240 kHz, 480 kHz, 60 kHz, and 120 kHz. 

Matlab for OFDM-5G

Next, we can see about the well-equipped toolbox and functions that support 5G-based OFDM in MATLAB. Here, we have given the characteristics and purpose of the 5G toolbox. In addition, we have also given examples for handling the OFDM model in 5G New Radio (NR) communications systems. 

Matlab 5G Toolbox supports

• Production of waveform (downlink)
• Enable to generate CP-OFDM waveform along with cyclic prefix
• Characteristics of produced waveforms
  • Multiple
    • PDSCHs
    • CORESETS
    • Search Spaces (SS)
    • Bandwidth Fragments
  • Varied Frame Numerology
  • Completely Parameterizable SS Bursts

Features of 5G Toolbox for OFDM

• Probable control channel locations in terms of frequency and time for selected numerology
• Fill the slot by assigning OFDM symbols
• Allocate the slot within the time period
• Periodically perform the allocation
• Set CORESET time in OFDM symbols (1 or 2 or 3)

Reasons to Choose OFDM in 5G

• Minimum Power Usage
  • Proficiently perform the uplink transmission using Single-carrier OFDM
• Spectral Adeptness
  • Support MIMO spatial multiplexing to design effective infrastructure
• Incidence Localization
  • Reduce out-band and in-band discharge on using windowing
• Asynchronous Multiplexing
  • Co-occurrence of multi-access and enhanced waveform for IoT
• Little Complication
  • Even for extended large-scale bandwidth, the receiver can experience low complexity

Matlab functions for 5G Uplink OFDM Modulation

The basic requirements of 5G uplink OFDM modulation are dimension details, OFDM demodulator, and modulator. Here, the OFDM modulation is used in the time of 5G new radio transmissions (uplink). Further, one can create the DFT-s-OFDM or SC-FDMA on integrating OFDM modulation with transform precoding. Below, we have mentioned the major functions of MATLAB that are more specific for 5G-based OFDM simulation.

Functions

• nrOFDMInfo
  • Read the data about OFDM
• nrTransformPrecode
  • Produce precoded symbols for transform
• nrOFDMModulate
  • Produce modulated waveform of OFDM
• nrTransformDeprecode
  • Improve deprecoded symbols for transform
• nrPRACHOFDMInfo
  • Read the data about PRACH OFDM
• nrOFDMDemodulate
  • Perform demodulation on OFDM waveform
• nrResourceGrid
  • Produce resource grid of empty carrier slot
• nrPRACHOFDMModulate
  • Produce modulated waveform of PRACH OFDM

The cyclic prefix time scale and OFDM symbol time are computed based on the selected numerology. Further, we have given some important parameters used to improve the frequencies range and bandwidth capacity of the OFDM system.

Subcarrier spacing

• 60 kHz (4 x 15kHz)
  • Slot time – 152 µs / 250 µs
  • OFDM symbol time – 16.67 µs
  • OFDM symbol (with CP) – 17.84 µs
  • Cyclic prefix time – 1.17 µs
  • Count of OFDM/slot – 7 or 14
• 30kHz (2 x 15kHz)
  • Slot time – 250 µs / 500 µs
  • OFDM symbol time – 33.33 µs
  • OFDM symbol (with CP) – 35.68 µs
  • Cyclic prefix time – 2.34 µs
  • Count of OFDM/slot – 7 or 14

In order to select the appropriate numerology, it uses frequency band and cell size. Usually, the larger cells have a high duration for distribution at the receiver/destination end. To count that larger time dispersion, the large cyclic prefix will be required. On the whole, it prefers greater frequencies such as larger subcarrier which has low vulnerability to phase noise. 

Further, if you want to know more research ideas/topics on OFDM simulation in MATLAB then communicate with us. We assure you that our research notions are purely based on technological advancements to fulfill your requirements in digital data transmission. So, reach us before someone pick your pearl of the idea.