SLM localised SC‐FDMA performance evaluation based on 30 GHz channel measurement for 5G
2016; Institution of Engineering and Technology; Volume: 52; Issue: 18 Linguagem: Inglês
10.1049/el.2016.1501
ISSN1350-911X
AutoresAbdellatif Khelil, D. Slimani, Larbi Talbi, J. LeBel,
Tópico(s)Advanced MIMO Systems Optimization
ResumoElectronics LettersVolume 52, Issue 18 p. 1573-1574 Wireless communicationsFree Access SLM localised SC-FDMA performance evaluation based on 30 GHz channel measurement for 5G A. Khelil, A. Khelil Electronic Department, University of Setif 1, Setif, 19000 AlgeriaSearch for more papers by this authorD. Slimani, D. Slimani Electronic Department, University of Setif 1, Setif, 19000 AlgeriaSearch for more papers by this authorL. Talbi, Corresponding Author L. Talbi talbi@uqo.ca Computer Science and Engineering, University of UQO, Gatineau, QC, Canada, J8X 3X7Search for more papers by this authorJ. LeBel, J. LeBel Computer Science and Engineering, University of UQO, Gatineau, QC, Canada, J8X 3X7Search for more papers by this author A. Khelil, A. Khelil Electronic Department, University of Setif 1, Setif, 19000 AlgeriaSearch for more papers by this authorD. Slimani, D. Slimani Electronic Department, University of Setif 1, Setif, 19000 AlgeriaSearch for more papers by this authorL. Talbi, Corresponding Author L. Talbi talbi@uqo.ca Computer Science and Engineering, University of UQO, Gatineau, QC, Canada, J8X 3X7Search for more papers by this authorJ. LeBel, J. LeBel Computer Science and Engineering, University of UQO, Gatineau, QC, Canada, J8X 3X7Search for more papers by this author First published: 01 September 2016 https://doi.org/10.1049/el.2016.1501Citations: 5AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract A performance evaluation of selective mapping localised single carrier frequency division multiple access technique (SLM LSC-FDMA) is presented over channel measured at 30 GHz. These measurements were taken between three buildings under non-line-of-sight (NLOS) for a propagation path length of 183 m. Simulation results present a peak-to-average power ratio gain of 3.78 dB for the proposed scheme over localised orthogonal frequency division multiple access system and an acceptable bit error rate with and without high power amplifier compared with LSC-FDMA. These results show an improvement of the transmission efficiency under NLOS outdoor scenario at 30 GHz. Hence, these results suggest the use of SLM LSC-FDMA wave form for fifth generation mobile communication at 30 GHz. Introduction Many wireless communications [1-3] have used millimetre (mm)-wave bands to offer a traffic rate in the order of gigabits. The radio link used is non-line-of-sight (NLOS) for short range or line-of-sight (LOS) for point to point communication. Fifth generation (5G) mobile communications is aiming to satisfy the demand of higher throughput by providing data rates in order of gigabits with zero latency [4]. The use of wider bandwidth compared with 4G technologies and higher carrier frequency above 30 GHz are considered excellent candidate for the definition of some components of future 5G systems [5, 6]. However, the propagation at high frequency and the limited power at the transmitter present a great challenge for 5G systems. Indeed, the propagation is characterised by severe limitations in the transmission range due to the path loss that increases with square of the frequency. In addition, most objects cannot be penetrated by the signal and the reflection is very limited depending on the materials and the angle of arrival. The characterisation of the propagation channel is actually a challenge by itself due to the number of different parameters that can influence the signal and the diversity of physical scenarios that can be considered [7]. In the 3G partnership project long term evolution standard for 4G, localised single carrier frequency division multiple access (LSC-FDMA) has been selected for uplink since it performs best in the presence of multiple access interference [8]. However, this system presents a performance degradation caused by the non-linear distortions due by the high power amplifier (HPA). So, taking into consideration the non-linear distortions in the performance evaluation is indispensable for a good design of such system. This problem can be mitigated by using peak-to-average power ratio (PAPR) reduction techniques, such as selective mapping (SLM) scrambling technique as discussed in this Letter. First, measurements in NLOS outdoor environment for 1 GHz signal bandwidth centred at 29.5 GHz, were collected for a propagation path length of 183 m. Second, by using these measurements, a performance evaluation of the SLM LSC-FDMA technique with and without HPA are performed, where the complementary cumulative distribution function (CCDF) and the BER are used as metrics. SLM LSC-FDMA model In this system, modulated symbol are grouped into blocks of length M, a serial/parallel (S/P) converter is used to generate a complex vector that can be given as . The discrete fourier transform (DFT) pre-coded is performed to obtain Xn. This resulting signal is then mapped to N orthogonal subcarriers and we get . Then, generate U different scrambling sequences to modified , , , , v = 0, 1, …, N − 1 and u = 0, 1, …, U. The new vector is multiplied by all the U scrambling sequences , resulting U different LSC-FDMA blocks, . Inverse discrete Fourier transform (IDFT) is performed to obtain the time domain of each . The vector u is chosen so that the PAPR can be minimised which is given as . Finally, the signal with the lowest PAPR is amplified and selected for transmission. A minimum side information (SI) of must be transmitted to the receiver to allow it know the scrambling vector used in the transmitter in order to recover the original data. Measurement setup and procedure A schematic diagram of the experimental setup is presented in Fig. 1. The transmitter (TX) and the receiver (RX) are placed in two different building at 79 and 104 m, respectively, from the third building used as a reflector. Hence, the propagation path length is of 183 m. The transmitter and the receiver are equipped by directional lens antennas characterised by a gain of 35.6 dB and an effective circular aperture of 26.6 cm. Measurements were taken every 100 KHz over 1 GHz band centred at 29.5 GHz with vertical polarisation of antennas. Fig 1Open in figure viewerPowerPoint Schematic diagram of experimental setup Fig. 2 shows the impulse response of the measured channel. Magnitudes are normalised by that of the first path with respect that the LOS path loss is 39.65 dB. Many contributions caused by the channel itself and the building reflector are shown. These results approve the feasibility and the viability of mm-waves propagation under NLOS outdoor 30 GHz scenario for a path length of 183 m. Fig 2Open in figure viewerPowerPoint Impulse response of 30 GHz NLOS channel measurement outdoor scenario Simulation and results In this section, we use the measured impulse response over a bandwidth of 1 GHz centred at 29.5 GHz to evaluate the performance of SLM LSC-FDMA system. A complete transmission chain with both transmitter and receiver sides are considered in our simulation configuration. The simulation parameters are listed in Table 1. Table 1. Simulation parameters Parameters Values Channel bandwidth 1 GHz Carrier frequency 29.5 GHz Input subcarrier number (M) 128 Total subcarrier number (N) 256 Modulation 16QAM, QPSK Subcarrier mapping LFDMA Cyclic prefix (CP) 20 Channel equalisation MMSE Channel estimation Perfect CCDF analysis The PAPR performance is evaluated in this section. Both LSC-FDMA and localised OFDMA techniques are simulated and their respective performances are compared. To evaluate the PAPR performance, we used CCDF as an informative metric. Fig. 3 shows the PAPR performance of SLM LSC-FDMA with U = 4, 8 and 16 compared with the traditional LSC-FDMA and localised OFDMA using 16QAM modulation. It is clear that the SLM LSC-FDMA system has the lowest PAPR compared with the other systems. Further, the proposed 16SLM LSC-FDMA system completely outperforms the 8SLM and 4SLM. For a probability of 10−3, the 16SLM LSC-FDMA system has a PAPR0 of about 7.3 dB, whereas for LSC-FDMA and localised OFDMA is about 10.1 and 11.08 dB, respectively. Therefore, the PAPR gain of SLM LSC-FDMA system outperforms that of localised OFDMA by 3.78 dB. Fig 3Open in figure viewerPowerPoint CCDF of PAPR of SLM LSC-FDMA compared with LSC-FDMA and localised OFDMA BER analysis BER performances with and without HPA for SLM LSC-FDMA (U = 4 and 8) scheme compared with LSC-FDMA are evaluated, where measured response channel at 30 GHz is considered. The HPA used in simulation is meddled by the solid state power amplifier with input back off of 3 dB and smoothness factor of 2. We assume that the SI is detected correctly by the receiver. In Fig. 4, we can see that the BER without HPA is the same for all schemes because we assumed that the SI is detected correctly by the receiver. With HPA, the BER degraded for all schemes because of the non-linear characteristic of the HPA. Furthermore, the BER of LSC-FDMA is better than of SLM LSC-FDMA but this later is acceptable when we look to the gain of PAPR reduction provided by SLM scheme. Fig 4Open in figure viewerPowerPoint BER of SLM LSC-FDMA compared with LSC-FDMA with and without HPA for QPSK Conclusion In this Letter, first, we presented the propagation characteristics of NLOS outdoor mm-waves (30 GHz) for a path length of 183 m. The measured channel response is used to evaluate the performance of SLM LSC-FDMA wave form. Simulations results show an improved transmission over a distance of 183 m using higher gain antennas. These results are very encouraging and motivate the use of SLM LSC-FDMA as wave form for 5G mobile communications. Experimental measurements and simulation system operating in single input multiple output (SIMO) configuration at 30 GHz under NLOS outdoor scenario will be the main perspective of our future works. Acknowledgments The authors express their very special gratitude to A.M. 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