VOLUME: 09, Issue 06, Paper id-IJIERM-IX-VI, December 2022
12 FILTERED OFDM AS CANDIDATE FOR 5G COMMUNICATION SYSTEMSSanskriti Thakur M. Tech Scholar, BTIRT Sagar
Mr. Vikash Panthi Faculty, EC deptt, BTIRT, Sagar
Abstract - The upcoming fifth generation of cellular communication system is most likely to be deployed by the year 2020. The new generation of mobile network is expected to have high data rates, low latency and support a huge number of devices. Aside from this, some advanced technologies are expected to be handled by 5G system in a better and efficient way. For this reason, a number of waveform candidates have been proposed. Filtered orthogonal frequency division multiplexing (F-OFDM) is one of the proposed candidates for 5G systems, which highly resembles to its predecessor that is orthogonal frequency division multiplexing (OFDM). The crucial difference between the two multicarrier waveforms is the use of a well-designed filter. F-OFDM in comparison with OFDM thus provides reduced out of band emission, which enables it to utilize the allocated spectrum efficiently. This research work provides a brief review of F-OFDM performance and OFDM performance.
Using MATLAB, F-OFDM and OFDM has been tested with different digital modulation schemes including 16- QAM, 64-QAM and 256-QAM. The proposed work is tested in terms of PSD (Power spectral density) and Normalized frequency. It is seen that F-OFDM shows better performance in comparison with OFDM. It is concluded that F-OFDM can be a better candidate for 5G communication system.
1 INTRODUCTION
The article is about the upcoming 5th generation of mobile networks that how it is going to provide bulky data rates, low latency and a reliable interface for massive MTC and IoT. Although the current trend of mobile technology, which is long-term evolution (LTE), is being used for device-to-device communication however, it was not designed for that purpose. Where millimeter wave is expected to deliver high data rates reaching hundreds of Gbps, the lower frequency bands currently being utilized by LTE will continue to provide reliable radio access. The currently used multicarrier waveform, OFDM, has been working well so far but in order to meet the upcoming requirements of wireless technology, it has to be modified. As mentioned earlier, the OFDM has been able to provide good reliability and robustness against interferences but its structural design needs to be upgraded in order to support high data rates and diverse connectivity among devices.
Filtered-OFDM, a waveform candidate among many others, provides good solution to these problems and can thus be considered suitable for the fifth- generation networks. The architecture of F-OFDM highly resembles OFDM except for the fact that it has a well-designed filter added to it. F-OFDM is able to
overcome the limitations of OFDM by sub- bandbased filtering, which keeps the subcarriers within the allocated spectrum. This waveform candidate could accomplish both of the vital requirements of fifth generation networks that were mentioned previously. The per sub-band filtering enables it to maintain relaxed synchronization between different devices and a well-designed and suitable filter makes sure that the out of band emission is suppressed in such a way that the spectral consumption of the guard band is reduced. Aside from this, resemblance of F-OFDM with its predecessor would rule out the need for designing a new system from scratch for the future network. In order to increase the spectral efficiency even more and to increase the link reliability, this paper introduces multiple input multiple output (MIMO) system with F-OFDM. The fading suffered by a wireless signal while propagating through the channel caused by destructive interference among multiple copies of the signal (multipath effect) can attenuate the signal. MIMO systems provide diversity, which enables the receiver to entertain several multiple copies of the same signal that are ideally independent [4, 6]. There are several types of diversities used in MIMO system including time diversity and frequency
VOLUME: 09, Issue 06, Paper id-IJIERM-IX-VI, December 2022
13 diversity. However, this paper usesanother common form known as spatial diversity that involves increasing the number of transmit and receive antennas.
Furthermore, the transmit diversity or MISO system transmits multiple copies of the same signal with equal power and receive diversity SIMO system receives different copies of the same signal. In this paper, we have implemented all of these different diversity modes and have implemented it using different modulation schemes such as QPSK, 16-QAM etc.
Since the ultimate objective of the research was to enhance the system efficiency, these diversity modes and digital modulation schemes enable us to observe how system efficiency can be enhanced and suitable configuration for different circumstances.
2 OFDM
In broadcast communications, OFDM is a kind of advanced modulation, a strategy for encoding computerized information on various transporter frequencies. OFDM
has formed into a well-known plan for wideband advanced communication, utilized in applications, for example, computerized TV and sound telecom, DSL web access, wireless systems, power line systems, and 4G portable interchanges.
OFDM is a frequency division multiplexing (FDM) conspire utilized as a computerized multi-carrier modulation method. In OFDM, various firmly divided orthogonal subcarrier signals with overlapping spectra are transmitted to convey information in parallel.
Demodulation depends on Fast Fourier Transform algorithms. The presence of a gatekeeper interval gives better orthogonality in transmission channels influenced by multipath propagation.
Each subcarrier (signal) is modulated with a regular adjustment plot, (for example, quadrature adequacy balance or stage move scratching) at a low symbol rate.
This keeps up complete information rates like customary single-transporter regulation plans in a similar transfer speed.
Fig.1 Block Diagram for architecture of OFDM 3 F-OFDM
Filtered OFDM is capable of retaining the advantages of OFDM while avoiding its limitations. First, filtering is applied to every single sub-band to suppress OOB emissions. Thus the guard band can be reduced with a better-localized spectrum.
Second, numerology can be optimized independently for a certain type of service within each sub-band; thus services with different technical requirements are flexibly supported. Third, thanks to the
filtering, the synchronization requirement is also relaxed due to the reduced side- lobe, making interference from asynchronous transmissions more tolerable. Many aspects of f-OFDM, such as general framework and methodology, design and implementation, and field trials, has been reported in literature.
However, much of the research up to now has studied the advantages and there is a lack of mathematical analysis on the negative consequences brought by
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14 filtering operations, for instance, in-bandinterference and filter frequency response (FFR) selectivity. The limitation of this method is that it can neither differentiate the interference induced by channel or filtering nor the inter-carrier interference
from other sub-bands or its own band. To better suppress OOB emissions, the filters employed in f-OFDM systems are usually very long, which inevitably leaves the systems prone to in-band interference.
Fig. 2 Block Diagram for architecture of F-OFDM The existing works in the literature
indicate that it has a trivial influence on system performance for medium to wide sub-bands and few studies have investigated the performance degradation in narrow sub-band systems. FFR selectivity refers to non-uniform filter frequency response in a transition band, which reduces the power of signals on the corresponding subcarriers and makes them undesirable for carrying data. As a result, the system bandwidth efficiency can be compromised significantly, especially in the case of narrower sub- bands. Although existing works have discussed the FFR selectivity in a single- antenna case, to the best of our knowledge, no studies have investigated the issue in the multi-antenna scenario.
4 SIMULATION RESULTS
This section describes the simulation results for proposed work. A MATLAB program has been developed for F-OFDM and OFDM. OFDM is best candidate for 4G but it has some drawbacks. Here comparison has been done between performances of F-OFDM (proposed 5G candidate) and OFDM (existing 4G candidate). Simulation results have been obtained in the form of plots in terms of power spectral density and normalized frequency.
In this article performance of OFDM and F-OFDM is compared to prove that F-OFDM is better than OFDM and thus it can be a better candidate for 5G communication. Figure 1, 3 and 5 shows the performance of F-OFDM in terms of power spectral density. Figure 2, 4 and 6 shows the performance of OFDM in terms of power spectral density.
On comparing the results of OFDM and F-OFDM, it is very clear that the amplitude of PSD is more in F-OFDM than OFDM for same technique (i.e.
16QAM, 64QAM and 256QAM). The more important factor is OOBE. OOBE is more in OFDM and hence it is not suitable for 5G candidate. It can be seen in simulation results that OOBE is very less in F-OFDM when comparing with OFDM. These two factors make F-OFDM better in performance and hence it can be a better option for 5G communication system.
Fig. 3 Power spectral density of F- OFDM (16QAM)
VOLUME: 09, Issue 06, Paper id-IJIERM-IX-VI, December 2022
15 Fig. 4 Power spectral density for OFDM(16QAM)
Fig. 5 Power spectral density of F- OFDM (64QAM)
Fig. 6 Power spectral density for OFDM (64QAM)
Fig. 7 Power spectral density for F- OFDM (256QAM)
Fig. 8 Power spectral density for OFDM (256QAM)
5 CONCLUSION
Conclusions for this article have been made on the basis of simulated results obtained from MATLAB simulator. It is concluded from the simulation results that the PSD amplitude is greater in F- OFDM than OFDM. It is well known that greater the PSD better will be the performance of the network. The need of 5G network is high speed and uninterrupted service. The 5G requirements cannot be fulfill with lesser PSD and hence it is stated that F-OFDM can be a better option for 5G.
It is concluded after the simulation results that OOB emission is lesser in F-OFDM; this may lead to the better utilization of frequency band. In OFDM OOBE is higher, due to this reason a great frequency band is wasted.
For 5G communication a large frequency is required. Proper and efficient frequency utilization is required in 5G networks and hence OFDM cannot be suitable for 5G.
Due to less OOBE F-OFDM is the better candidate for 5G.
VOLUME: 09, Issue 06, Paper id-IJIERM-IX-VI, December 2022
16 REFERENCES1. Syam Chandran K. and C. K. Ali, “Filtered- OFDM with Index Modulation for Mixed Numerology Transmissions”, 6th International Conference on Advanced Computing & Communication Systems (ICACCS), 2020.
2. Asia Hazareena, B. Aziz Musthafa,
“Performance of Filtered OFDM over different fading channels”, International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958 (Online), Volume-9 Issue-4, April 2020.
3. Lei Zhang, Ayesha Ijaz, Pei Xiao, Mehdi Molu and Rahim Tafazolli, “Filtered OFDM Systems, Algorithms and Performance Analysis for 5G and Beyond”, IEEE Transactions on Communications · October 2017.
4. Selahattin Gokceli, Ertugrul Basar, Gunes Karabulut Kurt, “Universal Filtered OFDM with Filter Shift Keying”, IEEE 2018.
5. Md. Hasan Mahmud, MD. Maruf Hossain, Abid Anjum Khan, Shanjid Ahmed, Mirza Abir Mahmud, Md. Hafizul Islam,
“Performance Analysis of OFDM, W-OFDM and FOFDM Under Rayleigh Fading Channel for 5G Wireless Communication”, Proceedings of the Third International Conference on Intelligent Sustainable Systems [ICISS 2020]
IEEE Xplore Part Number: CFP20M19-ART;
ISBN: 978-1-7281-7089-3.
6. Yoga Prastiya Wibawa, Iskandar, Irma Zakia,
“Filtered-OFDM for High-speed Railway Communications”,978-1-7281-7596-
6/20/$31.00 ©2020 IEEE.
7. Bowen Yang, Lei Zhang, Oluwakayode Onireti, Pei Xiao, Muhammad Ali Imran, Rahim Tafazolli, “Mixed-Numerology Signals Transmission and Interference Cancellation for Radio Access Network Slicing”, IEEE transactions on wireless communications, VOL. 19, NO. 8, AUGUST 2020.
8. Juquan Mao, lei zhang, pei xiao, konstantinos nikitopoulos, “Filtered OFDM: An Insight Into Intrinsic In-Band Interference and Filter Frequency Response Selectivity”, IEEE Access, vol. 08, 2020.
9. Toni Levanen, Zexian Li, Jukka Talvitie, Markku Renfors, and Mikko Valkama,
“Filtered OFDM Based URLLC in 5G New Radio: Principles and Performance”, 2019 Enabling Ultra Reliability and Low Latency Communications for 5G and Beyond (EURCOMM), IEEE 2019.
10. Ramraj Dangi, Praveen Lalwani, Gaurav Choudhary, Ilsun You, Giovanni Pau, “Study and Investigation on 5G Technology: A Systematic Review”, Sensors 2022.
11. Shyamal Dhua , Arjun R , Kumar Appaiah , and Vikram M. Gadre, “Low complexity FBMC with Filtered OFDM for 5G wireless systems”, IEEE explore 2020.
12. M. Selvakumar, B. Sudhakar, “PAPR and BER Reduction on Improving Performance for Filtered-OFDM using MSM and PSO”, International Journal of Recent Technology and Engineering (IJRTE) ISSN: 2277-3878, Volume-8 Issue-6, March 2020.
13. Lizhang Yang, Yaohua Xu, “Filtered-OFDM System Performance Research Based on Nuttall’s Blackman-Harris Window”, 17th IEEE International Conference on Communication Technology, 2017.
14. Sukhpal Singh, Harmanjot Singh, “Review Paper on OFDM-Concepts and Applications”, Volume 3, Issue 3 ISSN: 2321-9939, IJEDR 2015.
15. G. Wunder, P. Jung, M. Kasparick, T. Wild, F.
Schaich, Y. Chen, S. Brink, I. Gaspar, N.
Michailow, A. Festag, L. Mendes, N. Cassiau, D. Ktenas, M. Dryjanski, S. Pietrzyk, B. Eged, P. Vago, and F. Wiedmann, “5G NOW:
nonorthogonal, asynchronous waveforms for future mobile applications, Communications Magazine,” IEEE, Vol. 52, No. 2, pp. 97105, Feb.2014.
16. V. Vakilian, T. Wild, F. Schaich, S. ten Brink, and J.-F. Frigon, “Universal filtered multi- carrier technique for wireless systems beyond LTE,” in Proc. IEEE Globecom Workshops (GC Wkshps), pp. 223228, Dec 2013.
17. J.-B. Dore, V. Berg, and D. Ktenas, “Channel estimation techniques for 5G cellular networks: FBMC and multiuser asynchronous fragmented spectrum scenario,” Transactions on Emerging Telecommunications Technologies, Vol. 26, No. 1, pp. 1530, 2015.
18. J.-B. Dore, R. Gerzaguet, and D. Ktenas, “5G Cellular Networks with Relaxed Synchronization: Waveform Comparison and New Results,” in Proc. VTC Spring Workshop on 5G air interface, 2016.
19. M. Matthe, D. Zhang, F. Schaich, T. Wild, R.
Ahmed, and G. Fettweis, “A reduced complexity time-domain transmitter for UF- OFDM,” in Proc. IEEE 83rd Vehicular Technology Conference (VTC), pp. 15, May 2016.
