CLB: a multilevel co-operative load balancing algorithm for C-RAN architecture

The Fifth-Generation (5G) cellular and wireless communication envisage to integrate multiple technologies to provide a wide range of applications. The rapid growth of Information and Communication Technology (ICT) needs a common cellular platform to increase the network's extensibility and adaptability. The Cloud Radio Access Network (C-RAN) offers a scalable and flexible Base Station (BS) architecture for the next-generation wireless and mobile networks, where the BS functionality is split into a distributed radio unit known as Remote Radio Head (RRH) and a Centralized BaseBand Unit (C-BBU). To further make the C-BBU scalable and flexible, the baseband signal processing is carried out over a virtualized platform. The load at the RRH and C-BBU can vary from under-loaded to overloaded conditions which increase the power consumption and degrade the Quality-of-Service (QoS) of the C-RAN. In this paper, we formulate under-loaded and overloaded conditions at the RRH and the C-BBU, and propose a Co-operative Load Balancing (CLB) algorithm for handling the cellular traffic in real-time under different load conditions. The proposed CLB aims to maximize the utilization of hardware resources at the RRH and C-BBU. The CLB algorithm is compared with CDI, CZ, NDLB, DLB in the first phase for the RF load balancing. In the second phase of simulation, CLB is compared with the FCFS, IWRR, OLB, GP and TLB algorithms for server (C-BBU) load balancing. The parameters considered for comparison are: User Entity (UE) waiting time, blocking probability and processing time at the RRH and the C-BBU. Simulation results show that the use of co-operative load balancing technique improves the QoS in the C-RAN by reducing the blocking probability and UE waiting time. The CLB algorithm is validated with LTE TU-Vienna and cloudSim simulators for the RRH and the C-BBU, respectively.