M. K. Hasan

Inter-cell interference coordination in Heterogeneous Network: A qualitative and quantitative analysis

Heterogeneous Networks (HetNet) comprise networks with specially designed architecture. To cover large areas, established base stations (macro sites) are used; for coating buildings, microcells are employed; for covering individual levels or floors in a building, Pico-cells are utilized; and finally for providing wireless coverage to individual apartments, small offices, and home based businesses, femtocells (HeNodeBs) are exploited. The goal behind the implementation of HetNets involves incrementing the capacity, modifying spectrum use, lowering the capital and operating costs, as well as offering steady user-based experience of network architecture. Furthermore, HeNodeBs have been developed for voice, data, video services in home and offices and a certain outdoor scenario with a very limited geographical coverage. However, these random HeNodeB deployments raises co-tier and cross-tier inter-cell interference which results system performance degradation. The existing approaches have tried to solve Inter-cell Interference (ICI) issues. Yet, these techniques are become unsatisfactory for recent communications as aggressive frequency reuse is desired to maintain high data-rates. In this paper, we investigated and identified recent issues of inter-cell interference coordination problems. The related schemes and techniques are also analyzed in order to highlight the pros and cons of each of the schemes.

Traffic flow model for vehicular network

Intelligent Traffic Management (ITM) system promises to reduce the traffic congestion, intelligent intersection management as well as the smart dissemination of the informatics to control the traffic flow. Development of any Intelligent Transportation System (ITS) applications requires realistic road traffic model to analysis the performance. Service rate or service time is one of the most important components of any vehicular traffic model to analyze its properties. Traffic flow model which is based on any existing queuing methods have different properties to analyze such delay, queuing length, saturation flow (for fixed cycle of signaling period) etc. Depending on the on road traffic capacity and the intensity of the vehicle the service rate will determine and also the mentioned properties. In this paper, the model involves the analysis of the traffic parameters of an intersection with MM1 queuing system to optimize the service rate that is needed to develop the long term evaluation (LTE) based intersection management system (IMS).

Performance Analysis of Spectrum Sensing Methods: A Numerical Approach

Recent enhancement of Long Term Evolution / Advanced (LTE/LTE-A) is aimed to increase the throughput of the Orthogonal Frequency Division Multiplexing (OFDM) system. This is quite obvious where both frequency and time division are employed in order to augment the system capacity. In LTE/LTE-A heterogeneous Networks (Het Nets), femto cells (He Node Bs) are the optimal choice to extend the coverage within indoor environment. Nonetheless, the deployment of such base stations, somewhat to certain extent, does create cross-tier and co-tier interferences with the macro cell users (UEmacro-eNB) that ostensibly can become a critical challenge. It is implied that the unutilized / idle spectrums reallocation might be one of the solutions to mitigate such challenge. However, the errorless spectrum sensing does pose another issue. This paper outlines the investigation findings where spectrum sensing techniques is deployed to maximize the spectrum detection capacity with minimum error in OFDM based Het Nets. In addition, in the attempt to increase the efficiency of spectrum resources, this paper proposes a sensing technique which is imposed over advanced energy detection technique to detect the idle spectrums. The result of the proposed scheme is evaluated using Monte Carlo simulation.

Inter-cluster synchronization scheme for femtocell network

Femtocell is for indoor coverage, and cannot use a GPS antenna for time synchronization. High-precision crystal oscillators can solve the timing problem, but they are often too expensive for consumer grade devices. Since fBS and macrocell Base Station (mBS) network operate on the same frequency under a licensed spectrum fBS network can interfere with the macrocell network. In addition, fBSs can also interfere with each other if multiple units are in close proximity. In some cases, conflicting base stations may simultaneously raise transmit power in order to improve signal quality, thereby creating some interference. Furthermore, in a flat fBS structured network using IEEE 1588 synchronization algorithm and fBS-fBS synchronization scheme creates offset and frequency error which results inaccurate synchronization. However, in this paper an inter-cluster synchronization scheme is proposed in order to reduce offset and frequency error (skew) to achieve precise synchronization in fBS neighbor nodes. The analytical result shows that the proposed scheme is able to reduce the offset and skew significantly through inter-cluster synchronization ultimately increases synchronization accuracy. Therefore, achieved synchronization accuracy is 90% higher than the existing MS-assisted schemes.

An investigation of packet scheduling algorithms for Long Term Evolution-Advanced

Carrier Aggregation (CA) is a potential technique to increase the band width in LTE-Advanced system. However, the introduction of CA brings a number challenges to the traditional Radio Resource Management (RRM) mechanisms. This paper investigates the current algorithms of CA and packet scheduling forthe Long Term Evolution-Advanced (LTE-A). In the beginning, the evolution from third generation (3G) to fourth generation (4G) is illustrated in terms of featured performance requirements and the integration of current and future radio access technologies, is also highlighted. Additionally, this paper discusses the current technical trends and possible improvements of the packet scheduling algorithms with CA for LTE-A.

Lightweight inter-cluster synchronization scheme for femtocell network

Femtocell is a small sized indoor basestation to increase the coverage and capacity. Femtocell is connected through broadband backhual to the IEEE1588 to synchronize and manage the network. Due to limited/poor connectivity femtocell suffers by frequency misallignment and clock differencs. To overcome this problem MS-Assisted Receiver-Receiver Time Synchronization Strategy has been proposed. But this strategy is not fully covered in all situations if there has no Mobile Station for a long time in any of fBS network and make network overhead by generating the message flooding for a big adjacent network. However, in this paper, lightweight inter-cluster synchronization scheme is proposed which functions through intra-cluster and inter-cluster synchronization scheme and added between them as enhancement intermediate nodes selection if the Cluster Head cannot see neighbor CH and by using the Hybrid Wireless Mesh Protocol (HWMP) to select one intermediate node, and so we get the best path to access neighboring CH to update clocks and synchronize the clusters. The proposed scheme provides high scalability and works in a decentralized manner. The analytical results show that synchronization accuracy can be achieved up to 60% higher than MS-Assisted Receiver-Receiver time synchronization strategy for femtocells.