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The limitation of bandwidth resource in a wireless network has driven a large amount of work in resource scheduling to better utilize the available bandwidth. Most of these work aim to maximize the throughput by considering a uniform user distribution across the cellular network. In reality, users may be distributed non-uniformly. This work studies the effects of nonuniform user distribution on throughput...
The emergence of 5G wireless communication calls for new paradigms to satisfy the individuation and diversification of users' demands. In this paper, we construct the multicast groups under the guidance of user interest and then allocate the subcarriers and power to these groups in orthogonal frequency division multiple (OFDM) networks. Specifically, in order to maximize the social utility related...
In recent years, a new communication technology emerged by taking advantage of the high-speed switching capabilities of LED known as VLC (Visible Light Communication) has been getting more attention. On the other hand, OFDM is one of the technology that can efficiently utilize a frequency band. In this paper, our goal is to develop a VLC OFDM system, that is easily operable, and capable of high speed...
In this paper, we present an ant colony optimization (ACO) based Bayesian learning which optimizes the transmission energy efficiency for a multi-user multi-carrier communication system. The ACO algorithm is inspired by the swarm behavior of ants — sharing out the work and helping one another, which is a kind of Bayesian learning. The resource allocation problem in a multi-user multi-carrier system...
Management of Interference Is the solution designing for LTE network to reduce inter symbol interference (ISI) and intercell interference (ICI) using the frequency reuse schemes which has the objective to maximize the coverage area and provide more capacity in cells, especially in cell edge. Based on those propositions, this paper analyzes the process of optimizing subcarrier and power allocation...
In this paper, we investigate the problem of cross-layer design of the link scheduling, frequency assignment and flow control in hybrid terrestrial-satellite wireless backhauling networks. Considering network limitations and requirements, the target is to maximize the traffic that can be delivered by the network in a given period of time by deciding the active backhauling links that can transmit simultaneously...
In most Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems, channel estimation is required for equalization and symbol detection. It often exploits the specified pilot symbols consuming not only a large part of the throughput but also significant power resources. This paper quantifies the theoretical maximum power reduction of the transmitted pilots when...
The radio access technology for railway communications is expected to migrate from GSM for Railways (GSM-R) to a more suitable generation of communication systems for the services offered nowadays, like the fourth generation (4G) or the fifth generation (5G). Recently, considerable attention has been devoted to high-speed trains since this particular environment poses challenging problems in terms...
In this paper, we investigate the physical layer (PHY) performance of generalized frequency division multiplexing (GFDM) for high throughput wireless communication. For comparison purposes, orthogonal frequency division multiplexing (OFDM)-based IEEE 802.11ac PHY is used as a benchmark. Harnessing the flexibility of GFDM, we propose a novel configuration, being compliant to the IEEE 802.11ac PHY for...
Adaptive DD-OFDM transmission is proposed for low-cost deployment of homogenous MCF links where ICXT can cause outage probabilities. Experimental demonstration shows a throughput gain relative to the static modulation of 13% and high ICXT tolerance with a reduction of the average throughput of only 9% relative to the situation measured without ICXT.
This paper presents field trial results of innovative air interface technologies: sparse code multiple access (SCMA), filtered orthogonal frequency division multiplexing (f-OFDM), and massive multiple-input multiple-output (MIMO). To confirm the improvement of the promising technologies, the counterparts in long term evolution (LTE) are selected as the comparison baseline. For each technology, detailed...
Recent works on the future 5G cellular communication proposed that the enormous raw bandwidth availability of the millimeter-wave (mmWave) frequencies is an excellent opportunity to increase data capacity and channel capacity. However, mmWave transmission requires beamforming to overcome the high path loss, as well as other losses due to rain and oxygen absorption and higher noise floor associated...
Coordinated Multi-Point (CoMP) is considered as one of the most important techniques in 3GPP LTE/LTE-A. In CoMP, several base stations can be grouped together to form the cooperating set, where the cooperating set is used to improve the system throughput as well as the throughput of cell edge users. Most of the studies discussed how to relieve the overload condition or maximize the system throughput...
This paper presents a field experimental trial on frequency-domain multiplexing of a mixture of multiple numerologies. The goal is to support diverse applications and services in the fifth generation mobile communications (5G) system. Frequency-domain multiplexing of mixed numerology has been discussed for 5G in order to flexibly support the variety of requirements introduced by future applications...
The directional nature of communication in millimeter-wave bands suggests that the frequency selectivity of the channel may be limited due to the absence of reflected paths. However, our measurement studies show that reflections often cause significant frequency selectivity in practical scenarios, which we can exploit to increase the otherwise limited range of 60 GHz networks. Specifically, we measure...
In this paper, we investigate the energy efficiency (EE) and spectral efficiency (SE) tradeoff in multi-cell heterogeneous networks (HetNets). Our objective is to maximize both EE and SE of the network while satisfying the rate requirement of users. We use multi-objective optimization techniques to define the objective function. We propose a three-stage algorithm in this paper. First, we select the...
The 5G physical layer will support applications with different requirements, such as high data rate, ultra low power consumption and low latency. Recently, there is significant interest in the design and performance of new waveforms for 5G. One of the most important candidates is the Generalised Frequency Division Multiplexing (GFDM) waveform. The new waveform must support a smooth transition from...
In this paper, we investigate the energy-efficient resource allocation problem in the downlink of an Orthogonal Frequency Division Multiple Access (OFDMA) system with multiple users. A iterative algorithm is developed to maximize the overall energy efficiency of the downlink transmission by allocating the resource blocks (RBs) and the transmit power, which is constant for all RBs assigned to a given...
4G/LTE (Long Term Evolution) is the state of the art wireless mobile broadband technology. It makes use of the OFDM technology to offer high speed and provides the system resources both in time and frequency domain. A scheduling algorithm running on the base station holds the allocation of these resources. In this paper, the performance of existing downlink scheduling algorithms has been investigated...
In this paper, we investigate the performances of schedulers, which basically allocate the resources to multiple users based on different algorithms, in multiple-input multiple-output (MIMO) and orthogonal frequency division multiple access (OFDMA) based cellular wireless networks. In addition to conventional OFDMA resources which are time and frequency, antennas are also considered as resource during...
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