Abstract
Abstract Femtocell is considered to be one of the most promising solutions for future indoor wireless communication. Due to the scarcity of spectrum resources, femtocells need to share the spectrum with other networks, which will inevitably bring in severe interference. Therefore, minimizing the cross-tier and co-tier interference while maintaining high system throughput or spectrum efficiency is one of main challenges before largely deploying femtocell networks. In order to effectively mitigate the interference, cognitive radio-enabled techniques can play a key role by providing more secondary spectrum access opportunities, especially in dense femtocells deployment scenarios. Supported by cognitive radio functionality, femtocell users can access and share these licensed spectra including the frequency bands of both macrocells and other licensed systems (e.g., TV white spaces) as long as not causing harmful interference to the coexisting licensed systems. In this paper, based on cognitive sensing, we propose a joint channel assignment and power allocation scheme, aiming to minimize the aggregate interference from multiple femtocells to the licensed users while satisfying the constraints of each femtocell’s capacity and power budget. It is believed that the cooperation among multiple femtocells is quite helpful in mitigating the interference considering the mobility of the licensed users. Specifically, Hungarian algorithm is involved in our scheme to address the co-tier femtocell interference issue. In order to illustrate our scheme more explicitly, we come up with the concepts of Physical Cluster and Virtual Cluster and synthetically apply the related algorithms to reduce the interference step by step. Finally, the performances of employed algorithms are evaluated and analyzed. Numerical results have validated that the proposed scheme is viable and effective in managing the femtocell interference.
Highlights
With the advent of big data era and the emergence of new hand-held devices such as tablet physical cluster (PC) and smart phones, data intensive applications like online video streaming and network gaming have inexorably occupied more and more users’ focus
Afterwards, the indoor femtocell user equipment (FUE) can be connected to the femtocell access point (FAP) instead of a macrocell base station to get high-quality voice and data services with much lower power consumption, and all the network traffic will be backhauled to the macrocell network and/or the internet via either wired broadband connections such as digital subscriber line, passive optical network, or a divided wireless backhaul channel [3]
We propose two independent algorithms including subcarrier power allocation algorithm for interference minimization in a single femtocell and virtual cluster-based power budget adjustment algorithm to be part of solutions for the femtocell interference management
Summary
With the advent of big data era and the emergence of new hand-held devices such as tablet PC and smart phones, data intensive applications like online video streaming and network gaming have inexorably occupied more and more users’ focus. In [14], the authors have studied the downlink cross-tier interference problem in macro-femto two-tier networks with shared spectrum, and a distributed power control scheme is proposed and analyzed. In [15], the authors have studied downlink spectrum sharing co-tier interference in an overlay mode in cognitive femtocell networks They employed dual decomposition method to solve the problem and proposed a joint channel allocation and fast power control scheme. A new interference mitigation scheme is presented to address both co-tier and cross-tier interference problem for future cognitive LTE-femtocell networks. We employ Hungarian algorithm, which is a typical solution to the linear task allocation problem, to minimize cross-tier interference from femtocells to the users of licensed systems including macrocell networks and TV broadcast systems while avoiding co-tier femtocell interference based on the physical cluster. Member femtocells operating on the same channel in a virtual cluster should be separated as far as possible to guarantee minimum interference
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: EURASIP Journal on Wireless Communications and Networking
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
