Symbol Error Rate Analysis of M-QAM with Equal Gain Combining Over A Mobile Satellite Channel

Mobile Satellite Communications (MSC) have become an essential part of the world telecommunication infrastructure. However, the systems suffer from multipath propagation effects. In this paper, error analysis of M-ary quadrature amplitude modulation (M-QAM) with Equal Gain Combiner (EGC) over mobile satellite channel was carried out. The satellite channel was modelled as the product of Rayleigh and Ricians. This was then used to develop a system model for the received signal which was simulated and evaluated in terms of Average Symbol Error Rate (ASER) using the exact closed-form expression derived from moment generating function (MGF) and Padé Approximants (PA) theory. The results showed that at 16dB, Rician factor ‘k’=0, ASER obtained are 41.83%, 18.56% and 10.81% for paths ‘L’ = 2, 3, 4 respectively. ASER values reduced as ‘k’ increased. The results are in agreement with the simulation.DOI:http://dx.doi.org/10.11591/ijece.v3i6.434

GPON and V-band mmWave in green backhaul solution for 5G ultra-dense network

Ultra-dense network (UDN) is characterized by massive deployment of small cells which resulted into complex backhauling of the cells. This implies that for 5G UDN to be energy efficient, appropriate backhauling solutions must be provided. In this paper, we have evaluated the performance of giga passive optical network (GPON) and V-band millimetre wave (mmWave) in serving as green backhaul solution for 5G UDN. The approach was to first reproduce existing backhaul solutions in Very Dense Network (VDN) scenario which served as benchmark for the performance evaluation for the UDN scenario. The best two solutions, GPON and V-band solutions from the VDN were then deployed in 5G UDN scenario. The research was done by simulation in MATLAB. The performance metrics used were power consumption and energy efficiency against the normalized hourly traffic profile. The result revealed that GPON and V-band mmWave outperformed other solutions in VDN scenario. However, this performance significantly dropped in the UDN scenariodue to higher data traffic requirement of UDN compared to VDN. Thus, it can be concluded that GPON and V-band mmWave are not best suited to serve as green backhaul solution for 5G UDN necessitating further investigation of other available backhaul technologies

Intersymbol Interference Distortion Cancellation Using a Modified Maximal Ratio Combiner in Mobile Wireless Communication

This paper presents a modified maximum Ratio Combiner (MRC) for correcting inter symbol interference (ISI) distortion in mobile wireless channel. Mobile wireless system produces fast frequency selective fading channel which is due to the variation of the channel in such a way that the coherent time will be less than the symbol period of the modulation schemes considered and the delay be greater than the symbol period. This causes overlapping of successful symbols and resulted in intersymbol interference (ISI). The modified MRC performance investigated uses a single Radio Frequency (RF) chain and a single Matched Filter (MF). The two paths were considered and combined using MRC at the RF stage. Then the received signal was evaluated in term of Bit Error Rate (BER) and the results were compared with the conventional MRC which used many RF chains and MF depending on the number of paths. The results obtained showed that the modified MRC gave approximately the same BER performance when compared with the conventional MRC receiver indicating the same performance over this ISI distortion channel. Also, the modified MRC receiver at the RF stage gave relatively lower processing time which is an indication of a lower complexity. Therefore, the modified MRC receiver has been shown to be capable of reducing the hardware complexity and the implementation cost of the system over the ISI channel. Keywords: Maximum Ratio Combining, Matched Filter, RF chain, Multipath fading, GMS

Autocorrelation Based White Space Detection in Energy Harvesting Cognitive Radio Network

Accurate detection of White Space (WS) is of paramount importance in a Cognitive Radio Network (CRN) to prevent authorized users from harmful interference. However, channel impairment such as multipath fading and shadowing affects accurate detection of WS resulting in interference. The Existing Feature Detection (EFD) technique used to address the problem is faced with computational complexity and synchronization resulting in long sensing time, bandwidth inefficiency, energy constrain and poor detection rate. Hence, this paper proposes autocorrelation based multiple antenna with energy harvesting for WS detection in a CRN using Radio Frequency (RF) energy harvesting and autocorrelation of the received signal with a modified Equal Gain Combiner (mEGC). Antenna Switching (AS) RF energy harvesting with mEGC are used to harvest energy and information from the received PU signal in a multiple antenna configuration. Autocorrelation is then obtained and compared with the set threshold of zero to determine the presence or absence of WS. The proposed technique is evaluated using Spectral Efficiency (SE), Probability of Detection (PD) and Sensing Time (ST) by comparing with EFD technique. The results obtained revealed that the proposed technique shows better performance than EFD

Statistical analysis of rain height over Malaysia

Rain height is one of the key parameters in rain attenuation prediction. However, few studies on it had been carried out due to unavailability of data especially over tropics. Presented here is the result of eleven years zero degree isotherm height for eight locations over Malaysia. The studies had been carried out over two main seasons in the country (Northeast and Southwest Monsoon). The result shows that rain height is grossly under estimated by ITU-R P. 839-3

Performance of multiple antenna beamforming in higher constellation PSK signaling schemes

The quality of reception of radio signals at the destination is greatly influenced by the type of signaling schemes used and the use of multiple antennas at the output of transmitter and the input of receiver. However, this configuration usually causes InterCarrier Interference (ICI), which leads to distortions. In this paper, the performance of 6×6 multiple antenna beamforming in offset 16, 32 and 64-Phase Shift Keying (PSK) schemes is evaluated using the system model for the received signal developed to reduce distortions. The beamforming is performed on the offset signaling schemes by weighing the transmitted streams with the eigenvalues of the 6×6 antenna channel before the transmission through the 6 multiple antennas over the Rayleigh channel. The distorted signals received are demodulated and filtered by using the square root raised cosine receive filter. These signals are detected and compared with the transmitted bits to evaluate the performance using Bit Error Rate (BER). The results obtained show that as the constellation size of offset PSK schemes increases, the BER values increase and provide better performance than the corresponding conventional schemes

Improvement of Multiple Antenna Sensing Technique for Detecting the White Space in a Spectrum Sharing System

Exact detection of White Space (WS) is one of the actions in a Spectrum Sharing System (SSS) to determine unused spectrum for proper utilization. However, exact detection of WS is being affected by channel impairments, resulting in harmful interference. The Existing Multiple Antenna Spectrum Sensing (EMASS) technique used in addressing this effect is characterized with noise uncertainty leading to low detection rate due to setting of thresholds that is based on noise variance. Hence, this paper proposes an Improved Multiple Antenna Spectrum Sensing (IMASS) for detecting the WS in a SSS. Various copies of licensed user’s signals are received through the unlicensed user antennas over different antenna configuration. The received signals are combined using a modified equal gain combiner and energy of the combined signal is determined using Parseval’s relation for a discrete time signal. The received signal is used to form a square matrix which is converted to covariance matrix. Characteristic equation is obtained from covariance matrix to determine the minimum eigenvalue. The ratio of energy to minimum eigenvalue of the received signal is obtained and used as test statistics. The IMASS technique is evaluated using Probability of Detection (PD) and Total Error Probability (TEP) by comparing with EMASS. The proposed IMASS technique gives better performance with higher PD and lower TEP values than EMASS at all different antenna configurations

On the applicability of some existing tropospheric scintillation prediction models for Ikeja and Abuja, Nigeria

Tropospheric scintillation which causes rapid fluctuation of signal due to the turbulence in the atmosphere is of significance in satellite link budget design. Existing models that predict the intensity of scintillation such as Karasawa, International Telecommunication Union Radiocommunication (ITU-R) Sector, Otung, Van de Kamp and Ortgies are not appropriate for predicting scintillation intensity (SI) in Nigeria due to localization of the models to particular regions. The monthly average air temperature and relative humidity for Ikeja and Abuja, Nigeria, retrieved from the Nigerian Meteorological Centre data bank were used for the investigation. An elevation angle of 5° was used as look angle, antenna diameter of 0.3 m, 40 GHz and 45 GHz frequencies were considered in this study. The existing scintillation model values were then compared with the measured values for the two locations to determine the best performance model. The SI results at 40 GHz and 45 GHz were obtained for each of the existing models. It could be deduced from the results obtained that orgies model values were the most closet to the measured values. Therefore, Orgies-N model was the most appropriate for SI prediction in Ikeja and Abuja