can someone help me regarding my code and error?

we have to find;

{Objective fuction:throughput maximisation in 5g networks

Constraints:using outer approximation algorithm to solve mixed integer non linear programming problem

Variables:No of users, base station, channels, macro and microcell(pico, femto, relay nodes) each of them are connected to each other. (Making a heterogeneous network)

In the output using SNR formulae for results}

here's my code containig error in line 31

% Define the problem parameters
numMacrocells = 4; % Number of macrocells
numMicrocells = 6; % Number of microcells
numBaseStations = numMacrocells + numMicrocells; % Total number of base stations

% Define the power budget and power limits
totalPowerBudget = 200; % Total power budget in watts
macrocellPowerLimit = 50; % Macrocell power limit in watts
microcellPowerLimit = 30; % Microcell power limit in watts

% Define the channels and bandwidths for each base station
channels = [12, 10, 8, 11, 13, 15, 14, 9, 7, 12]; % Channel gain for each base station
bandwidths = [20, 25, 15, 20, 15, 20, 15, 10, 25, 20]; % Bandwidth for each base station

% Define the optimization problem
problem = optimproblem('ObjectiveSense', 'maximize');

% Define the decision variables
powerAlloc = optimvar('powerAlloc', numBaseStations, 'LowerBound', 0, 'UpperBound', totalPowerBudget);
size(powerAlloc)

ans = 1×2

10 1

size(bandwidths)

ans = 1×2

1 10

size(channels)

ans = 1×2

1 10

throughput = optimvar('throughput');

% Define the objective function
problem.Objective = -throughput; % Minimize negative throughput

% Define the constraints
problem.Constraints.PowerBudget = sum(powerAlloc) <= totalPowerBudget;
problem.Constraints.MacrocellPower = powerAlloc(1:numMacrocells) <= macrocellPowerLimit;
problem.Constraints.MicrocellPower = powerAlloc(numMacrocells+1:end) <= microcellPowerLimit;

% Calculate the individual throughput values for each base station
baseStationThroughputs = channels .* log2(1 + (powerAlloc .* channels) ./ bandwidths.');

Error using optim.internal.problemdef.ElementwiseOperator/checkIsValid
Argument dimensions 10-by-1 and 1-by-10 must agree.

Error in optim.internal.problemdef.Times/checkIsValid

Error in optim.internal.problemdef.Times.getTimesOperator

Error in .*

% Define the total throughput constraint
problem.Constraints.Throughput = throughput == sum(baseStationThroughputs);

% Solve the optimization problem
[solution, fval] = solve(problem);

% Extract the optimal power allocation and throughput
optimalPowerAlloc = solution.powerAlloc;
optimalThroughput = solution.throughput;

% Display the results
disp("Optimal Power Allocation:");
disp(optimalPowerAlloc);
disp("Optimal Throughput:");
disp(optimalThroughput);

Error in the code;

Error in optim.internal.problemdef.Times.getTimesOperator

Error in .*

Error in Untitled786 (line 31)

baseStationThroughputs = channels .* log2(1 + (powerAlloc .* channels) ./ bandwidths.');

Answer 1

[Torsten]

Adjust the sizes of the arrays involved in the calculation of "baseStationThroughputs" (see above).

Further, use "fcn2optimexpr" to define "baseStationThroughputs" - log2 makes a problem to define it directly.

Answer 2

[Cris LaPierre]

It looks like you have a dimension misalignment. Create both your variables to be either row or column vectors. However, this does lead to a new error because log2 does not accept optimization variables as valid inputs.

% Define the problem parameters
numMacrocells = 4; % Number of macrocells
numMicrocells = 6; % Number of microcells
numBaseStations = numMacrocells + numMicrocells; % Total number of base stations

% Define the power budget and power limits
totalPowerBudget = 200; % Total power budget in watts
macrocellPowerLimit = 50; % Macrocell power limit in watts
microcellPowerLimit = 30; % Microcell power limit in watts

% Define the channels and bandwidths for each base station
channels = [12, 10, 8, 11, 13, 15, 14, 9, 7, 12].'; % Channel gain for each base station
bandwidths = [20, 25, 15, 20, 15, 20, 15, 10, 25, 20].'; % Bandwidth for each base station

% Define the optimization problem
problem = optimproblem('ObjectiveSense', 'maximize');

% Define the decision variables
powerAlloc = optimvar('powerAlloc', numBaseStations, 'LowerBound', 0, 'UpperBound', totalPowerBudget);
throughput = optimvar('throughput');

% Define the objective function
problem.Objective = -throughput; % Minimize negative throughput

% Define the constraints
problem.Constraints.PowerBudget = sum(powerAlloc) <= totalPowerBudget;
problem.Constraints.MacrocellPower = powerAlloc(1:numMacrocells) <= macrocellPowerLimit;
problem.Constraints.MicrocellPower = powerAlloc(numMacrocells+1:end) <= microcellPowerLimit;

% Calculate the individual throughput values for each base station
baseStationThroughputs = channels .* log2(1 + (powerAlloc .* channels) ./ bandwidths);

Incorrect number or types of inputs or outputs for function 'log2'.

% Define the total throughput constraint
problem.Constraints.Throughput = throughput == sum(baseStationThroughputs);

% Solve the optimization problem
[solution, fval] = solve(problem);

% Extract the optimal power allocation and throughput
optimalPowerAlloc = solution.powerAlloc;
optimalThroughput = solution.throughput;

% Display the results
disp("Optimal Power Allocation:");
disp(optimalPowerAlloc);
disp("Optimal Throughput:");
disp(optimalThroughput);