Small Cells Integration with the Macro‑Cell Under LTE Cellular Networks and Potential Extension for 5G

Mohammed H. Alsharif,Rosdiadee Nordin,Mohammed Mudhafer Shakir,Athirah Mohd Ramly 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.6

Heterogeneous Networks (HetNet) requires the deployment of small cell networks that can co-exist with the existing macrocell. To provide a high Quality of Service (QoS), a massive multiple-input-multiple-output (MIMO) must be equipped with a HetNet of a macro-cell base station to the multiple users. This paper highlights three important aspects of the emerging small cell wireless networks. First, the architectures of small cell networks in LTE wireless network is reviewed, with specifc references to the current wireless network standards. Second, the performance evaluation of overlay small cells integrated with the underlay macro-cell is investigated. The third part of this study focuses on the future trends of small cell deployment in 5G and the critical technical preparation needs to be done to allow integration with the existing 4G network. The results show that the proposed integration of 5G small cells into existing macro 4G networks has improved both of the data rate (91.46%) and energy efciency (98.66%).

Dynamic Fractional Frequency Reuse based on an Improved Water-Filling for Network MIMO

( Noor Shahida M. K ),( Rosdiadee Nordin ),( Mahamod Ismail ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.5

In Long Term Evolution-Advanced (LTE-A) systems, Inter-cell Interference (ICI) is a prominent limiting factor that affects the performance of the systems, especially at the cell edges. Based on the literature, Fractional Frequency Reuse (FFR) methods are known as efficient interference management techniques. In this report, the proposed Dynamic Fractional Frequency Reuse (DFFR) technique improved the capacity and cell edge coverage performance by 70% compared to the Fractional Frequency Reuse (FFR) technique. In this study, an improved power allocation method was adopted into the DFFR technique to reach the goal of not only reducing the ICI mitigation at the cell edges, but also improving the overall capacity of the LTE-A systems. Hence, an improved water-filling algorithm was proposed, and its performance was compared with that of other methods that were considered. Through the simulation results and comparisons with other frequency reuse techniques, it was shown that the proposed method significantly improved the performance of the cell edge throughput by 42%, the capacity by 75%, and the coverage by 80%. Based on the analysis and numerical expressions, it was concluded that the proposed DFFR method provides significant performance improvements, especially for cell edge users.

Fast Networks as a Candidate for LTE-Advanced Networks

Miyim, A.M.,Mahamod Ismail,Rosdiadee Nordin 한국산학기술학회 2013 SmartCR Vol.3 No.2

WiMAX, a technology that is based on the IEEE 802.16 standard air interface, is said to be a potential candidate for next generation (4G) wireless mobile systems. For the system to meet the requirements of LTE-Advanced/IMT-Advanced, it is expected to provide better cell coverage, improved performance and capacity, reduced latency, advanced mobility mechanisms, increasing peak data rates, and most of all to provide quality of service while integrating well with the complex nature of the entire network. This paper therefore, attempts to explain key parameters of the mobile WiMAX technology and developmental stages that make it the future 4G network structure. The focus is on the mobile WiMAX (IEEE 802.16m) specifications, salient features of layer 1 (PHY layer) and layer 2 (data link layer), with emphasis on the MAC sub-layer of the internet layer protocol stack, QoS and scheduler.

Resource Allocation in Multiuser Multi-Carrier Cognitive Radio Network via Game and Supermarket Game Theory: Survey, Tutorial, and Open Research Directions

( Omar B. Abdul-ghafoor ),( Mahamod Ismail ),( Rosdiadee Nordin ),( Musbah M. R. Shaat ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.11

In this tutorial, we integrate the concept of cognitive radio technology into game theory and supermarket game theory to address the problem of resource allocation in multiuser multicarrier cognitive radio networks. In addition, multiuser multicarrier transmission technique is chosen as a candidate to study the resource allocation problem via game and supermarket game theory. This tutorial also includes various definitions, scenarios and examples related to (i) game theory (including both non-cooperative and cooperative games), (ii) supermarket game theory (including pricing, auction theory and oligopoly markets), and (iii) resource allocation in multicarrier techniques. Thus, interested readers can better understand the main tools that allow them to model the resource allocation problem in multicarrier networks via game and supermarket game theory. In this tutorial article, we first review the most fundamental concepts and architectures of CRNs and subsequently introduce the concepts of game theory, supermarket game theory and common solution to game models such as the Nash equilibrium and the Nash bargaining solution. Finally, a list of related studies is highlighted and compared in this tutorial.

On the Performance of Cooperative Spectrum Sensing of Cognitive Radio Networks in AWGN and Rayleigh Fading Environments

( Wasan Kadhim Saad ),( Mahamod Ismail ),( Rosdiadee Nordin ),( Ayman A. El-saleh ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.8

For the purpose of enhancing the spectrum efficiency, cognitive radio (CR) technology has been recently proposed as a promising dynamic spectrum allocation paradigm. In CR, spectrum sensing is the key capability of secondary users in a cognitive radio network that aims for reducing the probability of harmful interference with primary users. However, the individual CRs might not be able to carry out reliable detection of the presence of a primary radio due to the impact of channel fading or shadowing. This paper studies the cooperative spectrum sensing scheme as means of optimizing the sensing performance in AWGN and Rayleigh channels. Results generated from simulation provide evidence of the impact of channel condition on the complementary receiver operating characteristic (ROC). Based on the results, it was found that with constant local SNRs at the secondary users, the probability of missed detection (P_m) of cooperative spectrum sensing in a cognitive radio network, calculated using a closed form expression, can be significantly minimized. Thus, the paper illustrates that improvement of the detection performance of the CR network can be achieved by establishing a centralized cooperation among neighboring cognitive radio users. Finally, verification of the validity of the fusion schemes utilized for combining the individual CR decisions is provided.

Resource Allocation in Spectrum Sharing ad-hoc Cognitive Radio Networks Based on Game Theory: An Overview

( Omar B. Abdul-ghafoor ),( Mahamod Ismail ),( Rosdiadee Nordin ),( Ayman Abd El-saleh ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.12

The traditional approach of fixed spectrum allocation to licensed networks has resulted in spectrum underutilisation. Cognitive radio technology is envisioned as a promising solution that can be used to resolve the ineffectiveness of the fixed spectrum allocation policy by accessing the underutilised spectrum of existing technologies opportunistically. The implementation of cognitive radio networks (CRNs) faces distinct challenges due to the fact that two systems (i.e., cognitive radio (CR) and primary users (PUs)) with conflicting interests interact with each other. Specially, in self-organised systems such as ad-hoc CRNs (AHCRNs), the coordination of spectrum access introduces challenges to researchers due to rapid utilisation changes in the available spectrum, as well as the multi-hop nature of ad-hoc networks, which creates additional challenges in the analysis of resource allocation (e.g., power control, channel and rate allocation). Instead, game theory has been adopted as a powerful mathematical tool in analysing and modelling the interaction processes of AHCRNs. In this survey, we first review the most fundamental concepts and architectures of CRNs and AHCRNs. We then introduce the concepts of game theory, utility function, Nash equilibrium and pricing techniques. Finally, we survey the recent literature on the game theoretic analysis of AHCRNs, highlighting its applicability to the physical layer PHY, the MAC layer and the network layer.

Efficient power allocation algorithm in downlink cognitive radio networks

Omar Abdulghafoor,Musbah Shaat,Ibraheem Shayea,Farhad E. Mahmood,Rosdiadee Nordin,Ali Khadim Lwas 한국전자통신연구원 2022 ETRI Journal Vol.44 No.3

In cognitive radio networks (CRNs), the computational complexity of resource allocation algorithms is a significant problem that must be addressed. However, the high computational complexity of the optimal solution for tackling resource allocation in CRNs makes it inappropriate for use in practical applications. Therefore, this study proposes a power-based pricing algorithm (PPA) primarily to reduce the computational complexity in downlink CRN scenarios while restricting the interference to primary users to permissible levels. A twostage approach reduces the computational complexity of the proposed mathematical model. Stage 1 assigns subcarriers to the CRN’s users, while the utility function in Stage 2 incorporates a pricing method to provide a power algorithm with enhanced reliability. The PPA’s performance is simulated and tested for orthogonal frequency-division multiplexing-based CRNs. The results confirm that the proposed algorithm’s performance is close to that of the optimal algorithm, albeit with lower computational complexity of O(Mlog(M)).