Frequency Assignment for Cellular Mobile Systems Using Constraint Satisfaction Techniques

Abstract

The studies of a frequency assignment problem (also called a channel assignment problem) in cellular mobile systems have a long history [4], and various AI techniques have been applied to this problem [1,3]. A frequency assignment problem is formalized as follows. Frequencies are represented by positive integers 1,2,3, ....

Given:

• N: the number of cells

• d _i ,1 ≤ 1 ≤ N: the number of requested calls (demands) in cell i

• c _ij ,1 ≤ i,j ≤ N:the frequency separation required between a call in cell i and a call in cell j

Find:

• f _ik , 1 ≤ i ≤ N, 1 ≤ k ≤ d _i : the frequency assigned to the kth call in cell i.

• such that,

• subject to the separation constraints,

• | f _ik – f _jl | ≥ c _ij , for all i, j, k, l except for i = j and k = l,

• minimize

• maxf _ik for all i, k.