The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We propose and experimentally demonstrate a radio-over-fiber (RoF) system employing subcarrier-index modulation (SIM) orthogonal-frequency-division multiplexing (OFDM) signal. Thanks to the introduction of a new freedom in terms of SIM, a robust and energy-effective transmission solution is achieved for the RoF system. In the experiments, the 8-GHz QPSK-SIM-OFDM and conventional QPSK-OFDM signals...
We examine possibilities for transmit power reduction both from the relay station (R) and the base station (S − Source) on downlink in dual-hop OFDM decode-and-forward (DF) relay system. Two solutions, known for capacity enhancement in OFDM based relay systems, are applied for improving energy efficiency, while keeping end-user capacity on the same level. In the first analyzed solution, it is assumed...
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...
The perfect Gaussian integer sequences have been recently used in orthogonal frequency division multiplexing (OFDM) systems and code division multiple access (CDMA) systems. This paper proposes a new construction method, called monomial o-polynomials, to generate the perfect Gaussian integer sequences. The resulting sequences have odd periods and high energy efficiency. Furthermore, the number of...
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...
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...
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...
Newest achievements in underwater acoustic communications (UAC) open fresh possibilities for designing of more and more complex and larger scale underwater acoustics networks (UAN), which consist of bottom, moored and surface stations; autonomous underwater and surface vehicles (AUV and ASV); remotely controlled and manned vehicles. The process of UAN designing goes through stages of i) UAC physical...
Spectral efficiency and energy efficiency are important design criteria for green communications. In this paper, spectral efficiency and energy efficiency are addressed for transmission over channels that are orthogonal in frequency. The maximum sum rate is used in measuring the spectral- and energy-efficiency. The combined spectral- and energy-efficiency of particular total bandwidth and total transmit...
In this paper, we analyze the energy efficiency (EE) and outage performance in buffer-aided orthogonal frequency division multiplexing (OFDM) relay systems. All the relays adopt the amplify-and-forward (AF) protocol and the transmission from the source to destination on orthogonal subcarriers. We propose the max-sum relay selection scheme, which fully exploits the flexibility offered by both OFDM...
In this paper we study a dense small cell network employing multi-antenna Base Station (BS)s and analyse the two performance metrics, the Energy Efficiency (EE) and the Area Spectral Efficiency (ASE). In this network each BS utilizes the Frequency Reuse (FR) to mitigate the interference of the other BSs. Although the two network parameters, the BS density and the number of its antennas change the...
In this paper, the energy efficiency (EE) of an adaptive OFDM (Orthogonal Frequency-Division Multiplexing) system is analyzed taking not just the transmit power, but also the transceiver computation-power consumption into account. Such an energy-efficiency optimization problem belongs to a broader class of problems called convex-concave fractional programs, which in the case of the adaptive modulation...
In this paper, we presented a fairness-aware scheduling scheme in OFDM-based cognitive radio networks. Our objective is to maximize the systems energy efficiency while maintain the fairness among secondary users. In addition, many factors will be considered such as the channel quality, the interferences taken to the primary system and the total transmission power of the cognitive radio system. The...
The energy efficiency of underwater acoustic carrier aggregation in Orthogonal Frequency Division Multiplexing (OFDM) systems is studied and an energy-efficient aggregation bandwidth selection method is proposed. Via simulations it is found that (i) the aggregation bandwidth has an optimal value maximizing the energy efficiency, (ii) this optimal aggregation bandwidth decreases with increasing distance,...
Energy Efficiency in wireless communication is very important due to the slow progress in battery technology with improvement in technology. In this paper, we applied energy efficient link adaptation using Machine learning techniques in Orthogonal Frequency Division Multiplexing (OFDM). We sounding the channel condition periodically and observing the channel parameters. Our aim is to select the optimal...
Future wireless systems must be designed to meet high data rates and a variety of services such as voice, video, etc. which consume more energy. Therefore, designing energy-efficient systems in recent years has become an inevitable trend. In this paper energy efficient resource allocation in orthogonal frequency division multiple access (OFDMA) systems is discussed. After formulating the resource...
In this article, a potential architecture for 5G wireless networks and some new technologies which are enhanced for this architecture are described and analyzed. The technical infrastructure of developing technologies is expressed and compared with traditional RF communication protocols in terms of spectral efficiency and signal overhead on network. The objectives of these novel technologies are discussed...
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 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...
In today's world energy efficiency in wireless communication becomes vital topic in Telecommunication industry and also to create eco-friendly atmosphere we want green communication. Additionally, the data traffic is also a lot among users. Thus, we are considering energy efficient and QoS together for users. In our scheme, energy efficient radio and resource allocation for long term Evolution (LTE)...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.