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The solar power satellite (SPS), Space Solar Power (SSP), or Space Based Solar Power (SBSP) attracts attention since they can send CO2 free clean energy 24 hours a day. However, SPS sends the energy by microwave. Frequency allocation is an important issue for SPS as well as WPT (wireless power transmission). ITU (international telecommunication union) activities on spectral management are an essential...
The advancements in cognitive radios coupled with the ever increasing demand for spectrum have propelled research into dynamic and adaptive spectrum management techniques. More specifically, the need to support a wide variety of network centric warfare(NCW) applications combined with the dearth in ‘available’ spectrum underscores the need for opportunistic spectrum use, whereby idle spectrum can be...
We investigate distributed frequency allocation problem in dynamic environment of cognitive radio (CR) networks with a stochastic game (SG) model. Traditional multi-agent reinforcement learning (MARL) algorithms, as the primary online strategy learning algorithms of SG game, are not suitable for the application of wireless communication. Hence, a new MARL algorithm, maximizing the average Q function...
Considering the latest development after introducing Relay Nodes (RNs) into the cellular networks and the effect of inter-cell interference coordination in the cellular networks, we propose a novel method of inter-cell interference coordination for relay enhanced cellular networks. Firstly, for each cell, all available frequency resource is divided into two parts. The first part is for the users connected...
This paper considers coordination of users in wireless ad-hoc networks. We define coordination as a scheme that tries to achieve the rate region given by Shannon's capacity by allowing users to exchange information and agree upon future actions, while still treating interference as noise. This differs from cooperative schemes which try to increase the achievable rate region by introducing and exploiting...
Carrier aggregation (CA) is one of the most distinct features for LTE-Advanced systems, which can support a much wider transmission bandwidth up to 100 MHz by aggregating two or more individual component carriers (CCs) belonging to the same (intra-band) or different (inter-band) frequency bands. With CA, it is possible to schedule a user equipment (UE) on multiple CCs simultaneously. From radio resource...
This paper proposes a generalized methodology for frequency reuse in future cellular networks. These networks are equipped with a mixture of access points (APs) in different sizes and power capabilities. Some (or all) of the APs are deployed autonomously which results in an irregular deployment pattern. We first generalize the concept of a frequency reuse cluster — originally proposed for traditional...
This paper investigates downlink frequency resource coordination for LTE network that comprises of macrocell and femtocell. Due to the requirement of high data rate for indoor coverage, femtocells have been considered as a potential solution recently. However, owing to their random and uncoordinated deployment, cross-tier interference exists and affects the system throughput seriously. A hybrid resource...
The radio spectrum is a highly value resource that call for efficient utilisation. This involves developing both good radio equipment able to operate under challenging conditions and cost-effective spectrum management regimes. The pressure on available suitable spectrum is getting high, in particular for mobile data services. The management at all levels need to address the new challenges. Some trust...
Wireless Technologies are being used extensively for telecommunication services, thus increasing the demand for frequency spectrum. Regulators are pushed to allocate spectrum efficiently resulting in increased possibility of interference. Interference management becomes a challenge if the same spectrum is allocated to different network operators in neighboring geographic areas. Operators generally...
Abstract-In this paper, we develop a downlink dynamic soft frequency reuse (SFR) scheme with inter-cell coordination in orthogonal frequency division multiple access (OFDMA) cellular networks. A clustered base station (BS) coordination strategy is employed to facilitate frequency resource allocation among coordinated sectors. Compared to the traditional static SFR scheme, the proposed scheme can exploit...
Spectrum allocation algorithms are able to improve the performance of wireless mesh networks by exploiting the frequency agility of modern radios, and several such algorithms have been proposed. However, their interference constraints are at a coarse-grained level, which results in a low spectrum efficiency. To achieve higher spectrum resource utilization, we use interference pairs as a finer granularity...
This paper proposes a novel load distribution aware soft frequency reuse (LDA-SFR) scheme for inter-cell interference mitigation and performance optimization in next generation wireless networks. Our proposed scheme aims to provide a solution to effectively achieve inter-cell interference mitigation while maintaining high spectrum efficiency to all users in the cell. The proposed scheme consists of...
This paper proposes an adaptive fractional frequency reuse (FFR) resource allocation scheme for downlink transmission of OFDMA cellular networks. Resource allocation is localized in the sense that in each region system resources are assigned based on local traffic demand. Furthermore, the allocated resources in each region adapt to changes in the environment (i.e. channel gains and number/mobility...
Cognitive radio (CR) is a novel approach to improving the spectral efficiency of licensed radio frequency bands by opportunistically accessing unused portions of the band without introducing interference to a licensed user. To reliably identify unused portions in a dynamic environment, a collaborative spectrum sensing (CSS) approach is known to be advantageous. In this article we will consider a weighted...
Spectrum Sensing and Spectrum Decision making are the main functions that cognitive radios have to perform in order to select the `best available band' for the establishment of a wireless communication. We model the Spectrum Decision making functionality with multiple attributes and we propose a novel use of the Analytic Hierarchy Process to optimally select available bands from a finite set of options...
Reducing interference induced by secondary users is one of the most challenging problems in spectrum sharing. In this paper, we derive the optimum transmission strategy that minimizes the average interference power created by cognitive radios at a given point of space i.e. the location of a primary receiver. Surprisingly, this is not given by the water-filling solution.
In cognitive multimedia mesh networks (CMMNs), unlicensed users (secondary users, SUs) can share the spectrum with licensed users (primary users, PUs) on a non-interfering basis. The main challenge in CMMN is how to implement an efficient optimal control policy that can allocate spectrum and transmission powers for the SUs efficiently and how to adapt these resources to the changing network conditions...
This paper propose an iterative inter-cell interference coordination strategy to meet the requirements of the next generation mobile communication systems, which are higher data rate, broader coverage, especially more stringent demand on cell edge spectral efficiency. Sector cooperation is introduced in MU-MIMO (multi-user multiple input multiple output) systems. In the aspect of user pairing, both...
Resource allocation is an important issue in multiuser cognitive OFDM systems. In this paper, the highest achievable rate of each OFDM subchannel for a cognitive radio user (also referred to as secondary user, SU) is calculated by jointly considering the channel gain and the interference level. A low complexity algorithm is presented to allocate radio resource to the SUs. Each subchannel is assigned...
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