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The demand for multimedia services in modern networks has experienced exponential growth in recent years and it is expected to dominate the mobile traffic in near future. On the other hand, the link capacity of mobile networks is limited due to the scarce wireless resources. Caching is a popular technique that uses available storage capability of the mobile devices to relieve this traffic tension...
In Dual Connectivity (DC), a User Equipment (UE) can be configured with two radio access nodes in order to aggregate the available resources at both nodes. As with dual connectivity each node has independent radio resource manage- ment, the maximum power allocation at the UE can be easily exceeded and the interference can be increased. Hence, the power distribution among the carriers needs to be optimized...
The ubiquity of WLAN networks bears inherently a risk of generating considerable interference level. Measurements have been obtained to demonstrate that densely, though randomly deployed Access Points cannot operate at maximum bit rates due to mutual interference. A simple non-collaborating algorithm has been proposed and verified under carefully controlled measurement conditions providing a proof...
Device-to-device (D2D) communication has been considered as a promising technique to meet the challenging requirements in the fifth generation (5G) cellular networks. Traditional power control schemes mainly focused on delay-unaware metrics, such as throughput and power consumption, thus being only efficient for delay-insensitive applications. To overcome this problem, we in this paper propose an...
Due to the dense deployment of low-cost small base stations (SBSs), the serious interference among small cells has become a great challenge, which will decrease the system throughput significantly. Most of traditional time-domain inter-cell interference coordination (ICIC) schemes use almost blank subframes (ABS) to completely avoid the inter-cell interference. We observe that users can suffer a certain...
In this paper, we study the performance of hybrid cognitive radio systems that combine the benefits of interweave and underlay systems by employing a spectrum sensing and a power control mechanism at the Secondary Transmitter (ST). Existing baseline models considered for performance analysis assume perfect knowledge of the involved channels at the ST, however, such situations hardly exist in practical...
Power control policies in the fading multiple-access channels (MAC) with quality of service (QoS) constraints and random arrivals are studied. Perfect channel side information (CSI) is assumed to be available at both the transmitters and the receiver. Two types of Markovian sources, namely discrete Markov source and Markov fluid source, are considered. The maximum average arrival rates that can be...
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 addition to providing high data rate, Device-to-Device (D2D) communication reduces the transmit power of users and improve spatial spectrum reuse significantly. In this paper, we formulate the joint power control and mode selection problem for D2D communications underlaying LTE-A network for minimizing the aggregate transmit power of users subject to a minimum target throughput for each cellular...
Device-to-device (D2D) communication is a promising method to reduce power consumption and improve the throughput of cellular networks. However, densely deployed D2D pairs could result in severe interference to cellular users without proper power control. Therefore, the discrete location-aware power control (DLPC) scheme is proposed in uplink D2D underlaid cellular networks. The entire cell area is...
In this paper, we focus on energy efficiency in cognitive radio networks (CRNs). This is formally stated as the problem of maximizing the energy efficiency (defined as the ratio of the total rate of secondary users (SUs) to total energy consumption), which is a nonlinear integer programming, and then a polynomial time heuristic algorithm is presented to address it. In contrast to existing schemes,...
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...
Most of the LTE (Long Term Evolution) network operators are deploying low power small cells in hotspots like airports, shopping malls and corporate offices to meet increasing data demands. Since users are not deemed to fixed locations in such places, the network experiences uneven distribution of traffic load across the cells which degrades the average user throughput. This problem is even more severe...
The well-known distributed power control algorithm with temporary removal and feasibility check (DFC) improves outage probability but it is not able to improve and maximize the system throughput simultaneously. In this paper, we have proposed a new algorithm which gives an improvement in DFC algorithm such that it optimizes the transmission sum rate and reduces the number of outage users at the same...
In this paper, we present a throughput optimized cross-layer design for multiple-input multiple-output (MIMO) wireless systems. The proposed design efficiently combines power control (PC), adaptive modulation and coding (AMC) and MIMO technology at the physical layer, with an automatic repeat request (ARQ) protocol at the data-link layer. Both basic ARQ and type-I hybrid ARQ are considered. More specifically,...
In the LTE system the fractional power control and the universal frequency reuse have been targeted. The fractional power control approach decreases the inter-cell interference but may impact the throughput. The universal frequency reuse improve the spectrum efficiently but may increase the inter-cell interference. In this paper, a novel approach power control will be proposed, to avoid such throughput...
In an energy-constrained underwater system environment, it is very important to find ways to improve the life expectancy of sensors. The basic power control scheme has been proposed in underwater MAC protocol design, of which the main idea is to use different power levels for RTS-CTS and DATA. Specifically, the maximum transmission power is used for RTS-CTS, and the minimum required transmission power...
Interference coordination in heterogeneous cellular networks is a major bottleneck. In LTE-A (release 10), enhanced inter cell interference coordination (eICIC) scheme is proposed as an effective solution. It notably involves the approach of almost blank subframes (ABS) consisting of muting the macro cell during a set of predefined subframes. This offers the opportunity to the overlay small cells...
The Device-to-Device (D2D) communication is a promising technique to empower local wireless communications. However, without proper management it may generate interference to the existing network and degrade the overall performance. By treating each multipath as a virtual antenna, time-reversal (TR) signal transmission in a rich-scattering environment produces a spatial-temporal resonance which efficiently...
Considering the uplink power control scheme worked effectively in compensating the path loss of intra-cell users, mitigating inter-cell interference and improving the cell coverage and system throughput in LTE-A system. An optimization physical uplink shared channel (PUSCH) closed loop power control algorithm based on power headroom report (PHR) is proposed in this paper for the existing ones with...
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