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Recently, the YouTube service has been one of the most popular channels to upload and download many video clips. Even in the mobile networks, the user satisfaction on YouTube service becomes the key performance index to benchmark the system quality among various service providers. However, there are many parameters indicating Quality of Service (QoS) of YouTube service. This causes a lot of efforts...
In the past, the Quality Of Service (QOS) was the key performance of every network because it could be really measured and helped engineers to improve the network services. However, QOS parameters reflect only the network performances which do not directly indicate the satisfaction of users. Some users experience a bad service due to crowd accessibility even though the signal strength is still good...
It is the fact that the optimization of antenna tilt angle at base station is necessary for all cellular networks since 2G/3G to 4G/5G and beyond. This is because it is impossible to realize the true propagation fading with only simulation. After the installation of base station, there is a compulsory task to test the assumed performance using drive test. If it is not acceptable, the most common adjustment...
All users in Cognitive radio networks (CRN) try to occupy the vacant channels sharing with the primary users and other users in CRN under limited channel utilization. Each selfish user can independently choose his strategy to maximize his own payoff at the Nash equilibrium (NE) state. In this work, we analyze the channel allocation problem of multiple CR users in the presence of interference of Primary...
Direction of Arrival (DOA) estimation technique has been lately used to determine the location of mobile devices. Using array antennas with the help of signal processing makes it possible to effectively identify the location or direction of the user. Some well-known DOA estimation algorithms have been proposed such as delay and sum method, Capon's minimum variance method, subspace method with MUSIC...
The growth of customers in 3G network has forced the operators to always optimize their network performances. One of the most concerned parameters to indicate the quality of network is the interference area. Especially in 3G network, this parameter is directly influenced by the number of users. Hence, it would be better if the operators can predict the areas experiencing interference before getting...
A heterogeneous network that consists of various wireless networks is being developed to achieve high speed transmission. Integration of the networks should be error free to achieve the next generation networks and it needs seamless and efficient handoff between different access technologies known as vertical handoff (VHO) Several criteria for VHO decision have been proposed in the literature. There...
The main factor to degrade the orthogonality of OFDM subcarriers is the carrier frequency offset (CFO) linked to the intercarrier interference problem. Hence, it is necessary to precisely estimate and suitably compensate the CFO. In this study, two pilot tones where their pilot symbols are antipodal to each other are proposed in order to provide the same benefit as being null when they are combined...
The use of multiple antennas is another major element of any 5G cellular system because it will be possible to alter the beam direction to enable more direct communications and limit interference and increase overall cell capacity. Among techniques in the area of multiple antennas, MB-MIMO (Multi beam-Multiple Input Multiple Output) technique gains a lot of attention due to the performance improvement...
Mobile network is moving in the era of 5G (fifth generation) communications as a research and development from 3G and 4G. Due to the growth of new applications available on network development, the demand for access to the internet increases enormously which makes the data rate grow beyond expectation. This is an important reason to accelerate the development of more progressive 5G technology to allocate...
Mobile communication technology has been developed rapidly and extensively. For 5G technology, various applications used by one device have been integrated largely into the same approach. Vehicle-to-Vehicle (V2V) communication is one candidate technology which is developed along with other 5G techniques. Applications for the vehicle communication requirethe high accuracy, such as safety warning. In...
The developing fifth generation (5G) wireless networks are prepared to support the fundamental challenges, for example, very high data rate application, power control and high spectrum efficiency. To achieve these requirements, Multiuser Multiple-Input Multiple-Output (MU-MIMO) systems is the attractive option to increase both data rate and spectrum efficiency in uplink channel. In this paper, switching...
The benefit of a Full-Duplex Single-Channel (FDSC) system is the double throughput because it can transmit and receive simultaneously at the same time and on the same frequency. However, the expense of FDSC system is on the very strong self-interference signals due to the leakage of transmitting signals that interfere the receiving signals. Moreover, for MIMO systems, the problem of interferences...
Spectrum sensing is a key enabling cognitive radio networks, which increases the opportunity of spectrum access to cognitive radio users, by avoiding interference with the operation of the primary network (licensed network). In literature many research conducted cognitive radio networks with SISO systems. However, the trend of MIMO users should be taken into account. In fact, the use of spectrum sensing...
In this paper, the performance of wireless local area networks (WLANs) with Single-User MIMO (SU-MIMO) vs. Single-User Beamforming (SU-BFM) and Multi-User MIMO (MU-MIMO) vs. Multi-User Beamforming (MU-BFM) schemes in terms of data rate and average throughput has been investigated. The MIMO technique is the use of multiple antennas at both transmitter and receiver to improve data rate performance while...
IEEE 802.11ad standard, so called WiGig has been defined due to the increasing market demands for high data rate communications. The standard was approved at 60 GHz band employing a beam formation to mitigate interference signal. However, a signal loss is introduced at the intersection of two adjacent beams when employing original beamforming codebook, hence the systems provide low BER. Therefore,...
Multi-user multiple-input–multiple-output (MU-MIMO) systems are a promising technology for increasing spectral efficiency and diversity gain in the up-link channel. Space-time block coding (STBC) or the spatial-multiplexing (SM) scheme may selectively be used by each user. The simple techniques, zero-forcing (ZF), STBC and successive interference cancellation are jointly applied to separate and detect...
It is the fact that the bandwidth of wireless communication system is such a limited resource that several techniques are selectively applied to increase the bandwidth efficiency. The highest bandwidth efficiency can be taken by applying MU-MIMO technique. For this technique, the complexity of detection at receiving side is rapidly increased by increasing the number of users at transmitting side....
From literatures, path loss effect has not been taken into account when analyzing beamforming performance of distributed or cooperative beamforming networks such as Wireless Sensor Networks (WSNs). Therefore, this paper investigates into the mentioned effect on beamforming performance of WSNs through computer simulation. The obtained results indicate that the path loss occurring between the networks...
The cooperative MIMO communications is a new challenge to provide more reliable transmissions from the collaboration between users. Mostly, the MIMO employment is performed by using a simple diversity scheme. However, there are many MIMO schemes that can be implemented in practice. This paper proposes the modified STBC scheme for cooperative MIMO communications. Also the performance analysis of the...
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