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Device-to-device (D2D) communication not only expected to leverage the energy efficiency in the devices side but also on the network side. The previous works usually only address the energy efficiency of device discovery, which is an important process in D2D, in device side. In this work, we addressed the energy-efficiency of a network element during D2D device discovery. First, we adapted energy...
Massive MIMO technology can increase capacity, data rate, and link reliability significantly without additional bandwidth or transmission power. Most of the previous study on Massive MIMO systems are using low frequency (2.6 GHz). This frequency is not suitable for future broadband technology, because IoT devices will use high frequency and possible cell coverage would be smaller. This work proposes...
Millimeter-wave (mm-Wave) Massive Multiple Input Multiple Output (MIMO) at 60 GHz is a candidate of advanced wireless communications for indoor environment. Mm-Wave massive MIMO antenna with lower frequency with sectoring technique has been proposed in previous research. Also dual polarized configuration for MIMO in lower frequency and lower number of antenna. Massive MIMO at 60 GHz mm-Wave is not...
In the uplink system, different carrier frequency offsets (CFO) of different users at the receiver resulting multiuser interference (MUI) and thus degrade the performance of Multicarrier Code Division Multiple Access (MC-CDMA) system. In the previous study, Modified Minimum Mean Square Error Frequency Domain Equalization (Modified MMSE-FDE) has been proposed by Agnihotri which results in a better...
In this paper, we propose the usage of Unmanned Aerial Vehicle (UAV) as a flying mobile base tower station for discovering Device-to-Device (D2D) devices in the disaster area. In a disaster area, energy consumption of both devices and network become an important constraint. Therefore, there is a need to establish wireless network communication in large area rapidly under the condition of infrastructure...
This paper presents finite-length performance analysis for wireless super-dense networks comprising two multiway relays (SDN-2MWR) to support full data-exchange among massive number of users/devices over Rayleigh fading channels. In practice, finite-length analysis is important since the networks should serve users/devices with low latency indicated by short number of time-slots. Due to the nature...
Multi Carrier Code Division Multiple Access (MC-CDMA) has become options for high data rate systems in high mobility without reducing the interference robustness. Discrete Fourier Transform (DFT) MC-CDMA still has usual problem of Multi Carrier Modulation (MCM) that is high Peak to Average Power Ratio (PAPR), but this problem can be reduced by replacing fourier transform with wavelet transform. This...
Transmission techniques with coherent receiver that is widely employed nowadays need good channel estimation to give good transmission performance. However, there are conditions where channel information practically cannot be acquired, for example, when the channel condition is rapidly changing. Non coherent scheme without channel information is considered as the most potential scheme to combat this...
Data consumption increased sharply, all triple play services such as Voice, Data-Internet & Video can be performed on one communication path, even fiber optic has also bandwidth limitations, previous studies tried to maintain the fairness among the users, but there is no fairness of service therefore the allocation of data transmission must be optimized as their needs. A Passive Optical Communication...
The transmission system with high data rate and high mobility is needed. However, the system is susceptible to frequency selective fading and fast fading. We propose MC - CDMA system with Rotated Modulation that be able to solve the problems. MC - CDMA is a combination of OFDM and CDMA system which offer high spectral efficiency. However, this system still requires high power, so in this study Rotated...
In this paper, utilizing user-order chunk allocation algorithm for OFDMA systems using carrier aggregation environment is proposed and evaluated. Chunk allocation algorithm is performed based on mean greedy algorithm which has low complexity. In order to adopt this algorithm to those system, all users are divided into a certain group in accordance with the number of available aggregated carriers....
Improvement of information technology especially in telecommunication system support wireless communication system must provide high data rate service. OFDM is the system that have high data rate and had been used as the method to overcome multiple channel effect But the weakness of OFDM system is PAPR. Large PAPR causes non linear distortion of signal and non orthogonal of sub carrier that caused...
LTE-Advanced and Femtocell are deployed by cellular operators to improve the coverage and capacity to respond the demand for higher data rates in wireless networks. Integration of femtocell into cellular network faced interference between femtocell and macrocell. Several scenarios based on Fractional Frequency Reuse (FFR) methods have been proposed to mitigate this interference, including integer...
The most up-to-date application and many numbers of users need higher access speeds and lower latency of wireless communication. As a result, mobile companies need more capacity and higher efficiency to give the high quality service to the customers. LTE has been designed to get broader channels up to 20MHz, with low latency and packet optimized radio access technology. The peak data rate envisaged...
Rapid development of Broadband Wireless Access (BWA) requires improvement of system capacity. MU-MIMO is considered as a benefit solution as its ability to enhance the system capacity without additional bandwidth. However, the implementation of MU-MIMO creates interference problem that is Multi User Interference (MUI). Thus in order to suppress the MUI, precoding technique is needed before the signal...
Alteration of user's speed and direction to the base station cause Carrier Frequency Offset (CFO). CFO is able to damage orthogonality among subcarriers and decrease system performance significantly. There are several researches already focused on ICI mitigation, however most of them only employed restricted inputs for CFO in order to generate Inter Carrier Interference (ICI). This research proposes...
OFDM technology in Broadband Wireless Access has some disadvantages, one of which is Intercarrier Interference (ICI) caused by carrier frequency offset (CFO). Moreover, in high-mobility communication, Doppler effect from user shift causes CFO that affects the impairment of orthogonality among subcarriers, and obviously degrades OFDM performance. This research used Extended Kalman Filter (EKF) as scheme...
PAPR is the ratio of peak power of the signal with average power. Large PAPR value causes difficulty in the implementation of power amplifier device and higher cost of implementation. Recently it has been developed a system as an alternative to multicarrier OFDM system called OWDM (Orthogonal wavelet division multiplex). Basic idea of OWDM is replaced Inverse Discrete Fourier Transform (IDFT) with...
The development of wireless communication systems is focusing to provide a link with a high capacity and good quality. The multi-hop communication system using relay's diversity with a reliable coding is designed to fulfil the above requirements. Using multi-user WCDMA system, this research applies the above multi-hop technique using a relay with Alamouti code which can be defined as Distributed-Space...
The problem that often occur in multi-antenna wireless communication is how to maximize the throughput. Precoding is a generalization of beamforming to support multi-layer transmission in multi-antenna wireless communications. Beamforming is a signal processing technique used in sensor arrays for directional signal transmission or reception. In conventional single-layer beamforming, the same signal...
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