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Telecommunication problems Description
Further explanation of this example:
'Applications of optimization with Xpress-MP', Chapter 12: Telecommunication problems
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Data Files
g2dimens.mos (!****************************************************** Mosel Example Problems ====================== file g2dimens.mos ````````````````` Diminsioning of a mobile phone network Consider a network of 10 cells and a 5-node ring of hubs (simple hubs + one MTSO=Mobile Telephone Switching Office that controls the network) with defined capacity. The more links between a cell and the ring increases the reliability of the network. The traffic in this type of system is equivalent to bidirectional circuits. The capacity is the number of simultaneous calls during peak periods. The required number of connections, forecasted traffic, and the cost per connection is known. Which connections of cells to the ring minimize the connection costs while still meeting the traffic demand within the capacity limit? First, ensure that the ring capacity is sufficiently large to meet all the traffic requirements with an 'if-then' condition. If not, the function 'exit' is used to stop the execution. A simple MIP formulation follows. (c) 2008-2022 Fair Isaac Corporation author: S. Heipcke, Apr. 2002, rev. Mar. 2022 *******************************************************!) model "G-2 Mobile network dimensioning" uses "mmxprs" declarations HUBS = 1..4 MTSO = 5 ! Node number of MTSO NODES = HUBS+{MTSO} ! Set of nodes (simple hubs + MTSO) CELLS = 1..10 ! Cells to connect CAP: integer ! Capacity of ring segments COST: array(CELLS,NODES) of integer ! Connection cost TRAF: array(CELLS) of integer ! Traffic from every cell CNCT: array(CELLS) of integer ! Connections of a cell to the ring ifconnect: array(CELLS,NODES) of mpvar ! 1 if cell connected to node, ! 0 otherwise end-declarations initializations from 'g2dimens.dat' CAP COST TRAF CNCT end-initializations ! Check ring capacity if not (sum(c in CELLS) TRAF(c)*(1-1/CNCT(c)) <= 2*CAP) then writeln("Ring capacity not sufficient") exit(0) end-if ! Objective: total cost TotCost:= sum(c in CELLS, n in NODES) COST(c,n)*ifconnect(c,n) ! Number of connections per cell forall(c in CELLS) sum(n in NODES) ifconnect(c,n) = CNCT(c) ! Ring capacity sum(c in CELLS, n in HUBS) (TRAF(c)/CNCT(c))*ifconnect(c,n) <= 2*CAP forall(c in CELLS, n in NODES) ifconnect(c,n) is_binary ! Solve the problem minimize(TotCost) ! Solution printing writeln("Total cost: ", getobjval, " (total traffic in the ring: ", getsol(sum(c in CELLS, n in HUBS) (TRAF(c)/CNCT(c))*ifconnect(c,n)), ")") forall(c in CELLS) do write(c, " ->") forall(n in NODES | getsol(ifconnect(c,n))>0) write(" ", n) writeln end-do end-model | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

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