Self-organized Spectrum Chunk Selection Algorithm for Local Area LTE-Advanced Sanjay Kumar 1 , Yuanye Wang 2 , Nicola Marchetti 2 1 Birla Institute of Technology, Mesra, Ranchi, India, 2 Aalborg University, Denmark Email: skumar@bitmesra.ac.in Abstract: - This paper presents a self organized spectrum chunk selection algorithm in order to minimize the mutual inter- cell interference among Home Node Bs (HeNBs), aiming to improve the system throughput performance compared to the existing frequency reuse one scheme. The proposed algorithm is useful in Local Area (LA) deployment of the Long Term Evolution-Advanced (LTE-A) systems, where the HeNBs are expected to be deployed randomly and without coordination in distributed manner. The result shows that the proposed algorithm effectively improves the system throughput performance with very limited signaling exchange among the HeNBs, Keywords: - Frequency Reuse, Local Area, LTE-Advanced, self-organized. I. INTRODUCTION The LTE-A which is generally recognized as the evolved Long Term Evolution (LTE) system, aims to provide high capacity for improving user experience [1]. It is also expected to be flexible in terms of deployment. The Local Area deployment scenarios such as in home or office environment provide services to users in a limited geographical area [2]. This deployment scenario has been considered as an important research area in the latest International Mobile Telecommunications-Advanced (IMT-Advanced) workshop [3]. Keeping this in view it becomes important to investigate techniques to be suitable for such deployment scenarios in order to improve the throughput performance. Fixed frequency reuse schemes have been considered as effective means to improve throughput performance for many systems by reducing inter-cell interference [4, 5, 6]. In traditional Wide Area (WA) deployment scenarios, this is achieved by a proper network planning, including frequency reuse plans, base station location, controlling transmit power levels and antenna radiation characteristics. In contrast to such scenario the deployment of HeNBs for LA of LTE-A cannot be planned before hand by the operators, because of the random and uncoordinated deployment, since the owner of the each HeNB device will be responsible for the deployment. Hence, such network planning is absolutely not feasible. Therefore the network has to operate in random deployment scenario. It is also natural to envision the lack of coordination between operators providing services over the same geographical area in distributed manner. Moreover, it is also expected that such deployment scenario will lead to a possible environment where all HeNBs share the available radio spectrum based on certain physical layer mechanisms and higher layer policies. Keeping these aspects in view, a mechanism is required to assign spectrum in self organized manner to the HeNBs deployed in the local area. The algorithm should help HeNBs to adapt to the suitable set of the spectrum chunks in order to minimize the mutual interference and improve the system throughput performance. In the previous study [11] it has been outlined that the fixed frequency reuse scheme with reuse factor two helps to achieve the highest throughput performance compared to all other fixed frequency reuse schemes in the LA deployment scenario. However, the frequency reuse two, like other schemes requires beforehand network planning for spectrum assignment in order to minimize the mutual interference. As an example, fig. 1 shows an optimal frequency plan with reuse two in an indoor office environment with 4 cells, where different colors are used to represent different spectrum chunks. Here a chunk is defined as the part of the available spectrum band for allocation to a HeNB, following a frequency reuse scheme. In our example reuse two has been considered, hence only two spectrum chunks are shown here. In this figure the x and y dimensions have been indicated in meters. Fig. 1. Spectrum allocation for frequency reuse two with optimal plan. When we can plan a network beforehand, this configuration can be easily achieved. However in the assumed LA scenarios of LTE-A such planning is not feasible, because of random and uncoordinated deployment. Therefore a mechanism is required