Minimization of frequency assignment span in cellular networks

Channel assignment for cellular radio using extended dynamic programming

“…EDP can determine the optimum solutions with the correct value of b . In EDP algorithm the quality of the assignment depends on the choice of b that plays a key role in channel assignment quality, this is evident from (12), (13), (14), (17). We also note except the heuristic solution strategies all other available methods are b dependent.…”

“…The constraint function in EDP algorithm must be selected such that there is no interference. This function keeps the cost function in (13) not to violate the electromagnetic compatibility constraints in each stages of Fig. 1(b).…”

“…Mainly these features achieve the extension of DP to result in EDP. Moreover, the term m−1 j =1 ( i j ( ), n) causes all the electromagnetic compatibility constraints checked and if any one of them is violated the value of this term grows unbounded, consequently, in (13) i m+1 (i, n) results in paths that their interference value, the value inside the bracket in (13), are the smallest and this interference is also less than the values for the other paths. Therefore, , the frequency value at (i, ) coordinate of the path, that results in interference is ignored and the values of are considered that i m+1 (i, n) is smallest, and those are selected that attain the lowest values, and saved into i m+1 (n) and for these 's the sum in (13) is finite.…”

“…Other researchers applied an adaptive local search [12] for the same purpose where an exhaustive local search is used to cope with the computational intractability of NP-hard combinatorial optimization. Another procedure allows the minimum distance between the consecutive channels of the same cell to vary between different spectrum points and as subsequent channels are being assigned according to electromagnetic compatibility constraints the spectrum width between consecutive channels are reduced by means of a fast iterative method [13], Genetic algorithms [14,15] are also applied for meeting electromagnetic compatibility constraints, for some more discussions of the other successfully tested methods in channel assignment problem, see [7].…”

A Proposal of a Quasi-Solution State Evolution Algorithm for Channel Assignment Problems

“…Besides, the existing results on channel spans in literature are also summarized there. Note that only the best result among several versions of their algorithms in [5], [9], [10], and [11] is described to simplify comparisons and save the space. In Table 4, "> x" indicates that they cannot find a feasible assignment using x channels.…”