Convex Hull Inspired Distributed Controller Placement for Assisting D2D Transfers in LTE-A Networks

摘要

With the exponential growth in mobile data traffic, the number of content access requests is increasing and hence, the load on the LTE eNodeB (eNB) is also increasing. In such a scenario, transferring data files using Device- to-Device (D2D) communication helps in offloading cellular data traffic. In order to reduce the load on eNB, Centralized Area Controller (CAC) has been proposed earlier to take content aware decisions for content access requests. CAC uses long range LTE communication for uplink transmission thereby leading to more energy consumption. Additionally, it relies on eNBs for spectral resource allocation thereby increasing the load on the eNBs. In this paper, a Distributed D2D Controller (DDC) deployment for arbitrating and scheduling D2D transfers is proposed. Every content access request from a User Equipment (UE) is first served by a neighboring DDC. In case the content is not available in the region, the request is sent to the eNB. A complete DDC working protocol that explains the above procedure is proposed. The service rate requirement for the DDC to achieve the same expected response time as that of the CAC is calculated. In order to reduce the overall cost of placement of DDCs, a DDC placement algorithm that uses convex hull to determine the locations for placing DDCs is proposed. The performance of DDCs is compared with CAC in terms of the number of content access requests that are serviced using D2D. In addition, we compare the total power consumed in uplink transmission in the case of DDC and CAC. Extensive simulations demonstrate that our proposed distributed controller is more energy efficient from users perspective than that of the centralized controller.