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In the previous TD-LTE systems, the semi-static TDD DL/UL configuration can not work effectively under the instantaneous varied DL/UL traffic. Dynamic TDD DL/UL reconfiguration was proposed and discussed as one of the key features in LTE-A to increase the radio resource utilization. However, the freely reconfiguration of each cell TDD DL/UL configuration may result in significant co-channel co-subframe...
We propose a novel scheduler for an LTE-A network, which dynamically coordinates inter-cell interference for vulnerable users while limiting the effort of coordination. Vulnerable users are identified first, and then protected by assigning resources exclusively to them. Inter-cell interference coordination (ICIC) messages are transmitted to neighboring base stations (eNodeBs) via the X2 interface...
We investigate the problem of throughput-guaranteed energy saving for base stations in small-cell networks with universal frequency reuse. The objective function is to minimize the time average of total power expenditure in each slot over infinite horizon, while the data arrival rate is constrained in the mean rate stable region. We take advantage of both queue state information and channel state...
Allowing Secondary Users (SUs) to access the licensed spectrum without causing harmful interference to the Primary Users (PUs) is crucial in enabling the Cognitive Radio (CR) technology. In order to increase the utilization of the spectrum bands, we propose a Dynamic Spectrum Allocation (DSA) algorithm that integrates both interweave and underlay spectrum access schemes. The proposed algorithm will...
The millimeter wave (mmWave) bands are likely to play a significant role in next generation cellular systems due to the possibility of very high throughput thanks to the availability of massive bandwidth and high-dimensional antennas. Especially in Non-Line-of-Sight conditions, significant variations in the received RF power can occur as a result of the scattering from nearby building and terrain...
Currently, wireless video distribution cannot be provided in crowded venues due to resource limitations. In our recent papers we proposed AMuSe, a scalable system for WiFi multicast video delivery. The system includes a scheme for dynamic selection of a subset of the receivers as feedback nodes and a rate adaptation algorithm MuDRA that maximizes the channel utilization while meeting QoS requirements...
In this paper, an efficient multicast routing protocol was proposed for device to device (D2D) communication which helps in increasing the transmission power efficiency, quality of service (QoS) and also reduces the blocking probability and latency. In our algorithm, the packet transmission sequence is decided by the users need i.e. data demand. Base station (BS) selects one as the cluster head (CH)...
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...
Cognitive Radio Networks (CRNs) are considered as a promising solution to the spectrum shortage problem in wireless communication. We model the network of secondary users (SUs) as an undirected potential graph PG = (V (PG),E(PG)), where v ∈ V (PG) correspond to a secondary user and each edge (u, v) ∈ E(PG) represents link between nodes u and v (nodes are in within the transmission range). Two nodes...
In this paper, we present a new adaptive handover algorithm for LTE-Advanced system. This algorithm ensures the User Equipment (UE) requirements and the Quality of Service (QoS) expectations. The proposed algorithm relies on the dynamic adjustment of the handover parameters settings based on the velocity of the UE. In order to reduce the conflict between mobility robustness optimization and load balancing...
Heterogeneous network (HetNet) is one of the key architectures in 3rd Generation Partnership Projects (3GPP), in which lower-power but more flexible Pico base station (PBS) is appended. The original homogeneous base station stays the same and is called Macro base station (MBS) in HetNet. The traditional network admission and handover is performed by the reference signal received power (RSRP), which...
Task allocation is one of the main issues to be addressed in the domain of multi-robot systems, in which it is determined which robot(s) should execute which task(s) so that overall system goal is achieved. Such collective decision making process is of great significance during complex task execution by swarm of simple robots with heterogeneous capabilities. This work targets the issue of coalition...
Teaching-learning-based optimization (TLBO) algorithm is a new intelligence algorithm. It takes evaluation scheme which updates learners' grade totally in solving multi-dimensional function optimization problems, thus decreases the convergence speed. Moreover, the interference phenomena among dimensions would influence the quality of solutions. While all existing improvement strategies on TLBO introduce...
In this paper, we design a heuristic interference-graph-based time division multiple access (IG-TDMA) protocol for underwater acoustic sensor networks (UW-ASNs) to improve the network performance. A general underwater communication scenario is considered for the protocol design, where the communication network topology is modeled as a three-dimensional (3D) scenario and the mobility of sensor nodes...
Aiming the problem that it is difficult for the stationary spectrum allocation method of existing HF access network to meet the requirement of intelligent frequency hopping technology, the communication requirement of intelligent frequency hopping HF access network is analyzed in this paper, to come up with the dynamic frequency spectrum allocation strategy and algorithm of maximum handling capacity...
In this paper we compare three novel schemes for dynamic frequency allocation and transmission power assignment for cognitive radio networks. These spectrum allocation schemes are based on reinforcement learning and power optimization procedures. We propose the so-called RL+Power and RL+Power Coupled schemes and compare them with an existing constant power scheme. Simulation results show that the...
The focus of this paper is targeted towards multicell networks, when dense frequency reutilization is used in a given operating area by evolved Nodes B (eNodeB). The ensuing Inter-Cell Interference (ICI) harms the radio transmissions and degrades the performances. Thus, a certain degree of ICI coordination (ICIC) between the eNodeBs is required to manage the resources and minimize the interference...
Dynamic channel assignment algorithms allow wire- less nodes to select their communication channels based on the state of the network to reduce interference between the nodes and improve the overall network performance. They have been shown to outperform static channel assignment policies and thus are playing a critical role in Software Defined Networks (SDNs). In this paper, we examine the security...
In this paper we study the channel selection problem with dynamic users in distributed opportunistic spectrum access systems. Different with the ordinary assumption that users have data to transmit all the time, we assume that users transmit data randomly in each slot. The dynamical transmitting model makes the active number of users time-varying and channel interference levels dynamic. It makes a...
This paper considers the dynamic downlink spectrum resource allocation problem in dense small cell networks. To address the problem, we propose a distributed downlink resource allocation (DDRA) algorithm, which allows each base station to perform resource allocation for its users in a distributed manner. To support the DDRA algorithm, each base station needs to maintain a couple of interference tables,...
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