<title>Maximum achievable traffic load balancing in cellular radio networks</title>

Abstract

In a cellular wireless communication system, channel bandwidth is a scarce resource. Even if the network design takes into account the average traffic pattern in a geographical area, time-dependent variation of traffic often creates load imbalance (commonly known as hot spots) in different parts of the network. Some attempts have been made to alleviate the time-varying network congestion in cellular networks. However, because of co-channel interference problem associated with the concept of frequency re-use in a cellular system, maximum possible channel capacity gain cannot be achieved through these conventional load balancing schemes. If somehow the co-channel interference problem could be avoided while balancing the traffic load in different cells, the maximum achievable capacity gain could be attained. In this paper, we provide an analytical framework to show the maximum possible capacity gain in a cellular system. Through an analogy of fluid flow among the connected reservoirs, we study the load balancing dynamics. An example of 3-tier cellular structure is used to demonstrate that the maximum achievable capacity gain could be as much as 69%. In an identical scenario, the best known technique such as load balancing with selective borrowing achieves a maximum capacity gain of only up to 18%.