A NOVEL LOAD BALANCING SCHEME FOR THE TELE-TRAFFIC HOT-SPOT PROBLEM IN CELLULAR NETWORKS

We propose a dynamic load balancing scheme for the tele-traffic hot sp ot problem in cellular networks. A tele-traffic hot spot is a region o f adjacent hot cells where the channel demand has exceeded a certain t hreshold. A hot spot is depicted as a stack of hexagonal 'Rings' of ce lls and is classified as complete if all cells within it are hot. Othe rwise it is termed incomplete. The rings containing all cold cells out side the hot spot are called 'Peripheral Rings'. Our load balancing sc heme migrates channels through a structured borrowing mechanism from t he cold cells within the 'Rings' or 'Peripheral Rings' to the hot cell s constituting the hot spot. A hot cell in 'Ring i' can only borrow a certain fixed number of channels from adjacent cells in 'Ring i + 1'. We first propose a load balancing algorithm for a complete hot spot, w hich is then extended to the more general case of an incomplete hot sp ot. In the latter case, by further classifying a cell as cold safe, co ld semi-safe or cold unsafe, a demand graph is constructed which descr ibes the channel demand of each cell within the hot spot or its 'Perip heral Rings' from its adjacent cells in the next outer ring. The chann el borrowing algorithm works on the demand graph in a bottom up fashio n, satisfying the demands of the cells in each subsequent inner ring u ntil 'Ring 0' is reached. A Markov chain model is first developed for a cell within a hot spot, the results of which are used to develop a s imilar model which captures the evolution of the entire hot spot regio n. Detailed simulation experiments are conducted to evaluate the perfo rmance of our load balancing scheme. Comparison with another well know n load balancing strategy, known as CBWL, shows that under moderate an d heavy tele-traffic conditions, a performance improvement as high as 12% in terms of call blockade is acheived by our load balancing scheme .