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Vastly increasing capacity and coverage demand in communication networks accompanied by energy efficiency challenge is getting attraction in research topics. Phantom cells based heterogeneous networks (HetNets) is a new idea which proposed to fulfil these requirements in the next generation cellular networks. In this paper, the resource allocation problem in an orthogonal frequency-division multiple...
Heterogeneous network is a novel network architecture proposed in Long-Term-Evolution (LTE) which can highly increase the capacity and coverage compared with the conventional networks. However, in order to provide the best possible services, appropriate resource management must be applied. In this paper, we consider the joint optimization of subcarrier and power allocation for downlink transmission...
Fractional frequency reuse (FFR) is an efficient management technique to eliminate inter-cell interference (ICI) in multi-cell orthogonal frequency division multiple access (OFDMA) networks through inter-cell coordination. Generally, the derivations of throughput and coverage probability are treated as separate problems or investigated in different ways. In this paper, we derive average cell throughput...
In LTE networks, even if two communicating UEs are closed enough, the traffic must go around core network. If Device-to-Device (D2D) communications used, two nearby UEs can directly exchange data, rather than passing core network to reduce loading of core network. However, D2D communications are not always gaining benefit. This paper proposes two mechanisms, namely Capacity-based scheme and Delay-based...
The mechanisms of allocating the resources in Long Term Evolution (LTE) cellular networks are very critical issues, because scheduling algorithms have the main responsibility for determining how to allocate radio resources for different users. In this work a dynamically adopted Proportional Fair (PF) scheduling strategy for capacity enhancement of LTE system is proposed. Performance comparison with...
We formulate the resource allocation in the downlink of heterogeneous orthogonal frequency division multiple access (OFDMA) networks. Our primary objective is to maximize the system sum throughput subject to service and system constraints, including maximum transmit power, quality of service and per-user subchannel allocation. Due to the intercell interference, the corresponding optimization problem...
Inter-Cell Interference (ICI) is always a key problem in Fractional Frequency Reuse (FFR) system to be focused on, which should be well resolved to pursue higher throughput and better power efficiency. In this paper, we investigate throughput and power efficiency of RR scheduling in FFR system by both closed-form expression and Monte Carlo trials method. We improve a previous throughput model by applying...
LTE is designed to support user velocities of up to 500 km/h where experiments are expensive, time-consuming and dangerous. Fortunately, such experiments can be emulated at lower velocities by time-stretching the transmit signals. This method preserves the spatial properties of the mobile radio channel but performs a spectral compression. In this paper, we propose a new set of methods that preserve...
Multiuser Orthogonal Frequency Division Multiple Access (OFDMA) networks, such as Long Term Evolution networks, use the frequency reuse-1 model to face the tremendous increase of mobile traffic demands, and to increase network capacity. However, inter-cell interference problems are generated, and they have a negative impact on cell-edge users performance. Resource and power allocation should be managed...
In this paper, we address the energy efficient resource allocation problem for a secure orthogonal frequency division multiple access (OFDMA) relay system. In particular, we consider there is a eavesdropper near the base station (BS) which tries to overtake the information sent by BS. We formulate the joint optimization problem with the objective to optimize the energy efficiency of the considered...
In rate-adaptive orthogonal frequency division multiplexing (OFDM) systems, limited feedback schemes are essential to reduce the number of subchannels for which the channel state information is fed back by the users. For the practically important best-M scheme, in which each user feeds back only its M strongest subchannels and their indices to the base station (BS), we derive a throughput-optimal...
It is envisaged that there will be heterogeneous deployment of ultra-dense femtocells overlaying the existing macrocells in an ad-hoc manner to provide enhanced coverage and capacity for the indoor users in the fifth generation (5G) wireless networks. However, this will lead to serious interference between macrocells and femtocells (cross-tier interference) and interference between neighbouring femtocells...
In order to cope with the phenomenal growth of mobile data traffic, unlicensed spectrum can be utilized by the Long Term Evolution (LTE) cellular systems. However, ensuring fair coexistence with WiFi is a mandatory requirement. In one approach, periodically configurable transmission gaps can be used to facilitate a coexistence between WiFi and LTE. In this paper, a Multi-Armed Bandit (MAB) based dynamic...
This paper considers an orthogonal frequency division multiplexing (OFDM) based two-way cognitive radio (CR) multiuser multiple relay network. The target is to jointly solve the problem of power allocation, subcarrier assignment, selection of best relay/s, and the sub-carrier pairing at the relay nodes. The aim of the optimization is to maximize the end-to-end sum rate of the network under exclusive...
Due to Orthogonal Frequency Division Multiple Access (OFDMA) mechanism adopted in LTE cellular networks, intra-cell interference is nearly absent. Yet, as these networks are designed for a frequency reuse factor of 1 to maximize the utilization of the licensed bandwidth, inter-cell interference coordination remains an important challenge. In both homogeneous and heterogeneous cellular networks, there...
In this study, a Long Term Evolution Advanced (LTEa) — based multi-user Orthogonal Frequency Division Multiple Access (OFDMA) heterogeneous network has been simulated and a resource allocation strategy has been proposed. The strategy under consideration can inherently mitigate electromagnetic interference, hence increases the mean number of terminals, and requires no channel state information (CSI)...
In this contribution, we present the Bit Error Rate characteristics for an indoor, wideband body-to-body channel between two firefighters when using IEEE 802.11 ac, which is proven a very suitable standard for future, wideband public safety networks. Moreover, the BER and throughput characteristics, when applying both transmission blocking, fixed and adaptive, subcarrier modulation are presented....
We consider a novel way by which DL dynamic MAC scheduling can be augmented based on cross-layer inputs to provide desired performance enhancements. We describe ODDS, an automated design process for the data-driven refinement of downlink resource scheduling algorithms. ODDS extracts insights from the behavior of a simulated LTE cellular system under randomized traffic patterns and propagation conditions...
The ever increasing number of mobile broadband users requires the availability of enhanced data services. Long Term Evolution or LTE is the evolution of High Speed Packet Access (HSPA), which was standardized by third generation partnership project (3GPP) Release 8 in order to meet the increasing demand of faster and more efficient mobile internet access today by supporting the larger bandwidth. This...
Due to the exploding evolution of wireless communication systems, energy efficiency (EE) becomes the concern of many researches. In this context, we examine this metric into multiband orthogonal frequency division multiplexing ultra wideband (MB-OFDM UWB) systems. Indeed, the focus is about investigating a cross-layer design based on the joint combination between data link layer through the hybrid...
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