A structured channel borrowing scheme for dynamic load balancing in cellular networks

Abstract

We propose an efficient dynamic load balancing scheme in cellular networks for managing a teletraffic hot spot in which channel demand exceeds a certain threshold. A hot spot, depicted as a stack of hexagonal 'ring' of cells, is classified as complete if all cells within it are hot. The rings containing only cold cells outside the hot spot are called 'peripheral rings'. Our load balancing scheme migrates channels through a structured borrowing mechanism from the cold cells within the 'rings' or 'peripheral rings' to the hot cells in the hot spot. For the more general case of an incomplete hot spot, a cold cell is further classified as cold safe, cold semi-safe or cold unsafe, and a demand graph is constructed from the channel demand of each hot cell from its adjacent cells in the next outer ring. The channel borrowing algorithm works on the demand graph in a bottom up fashion, satisfying the demands of the cells in each subsequent inner ring. Markov chain models are developed for a hot cell and detailed simulation experiments are conducted to evaluate the performance of our load balancing scheme. Comparison with an existing load balancing strategy under moderate and heavy teletraffic conditions, shows a performance improvement of 12% in terms of call blockade by our load balancing scheme.