How to solve logrithmic constraint in convex program?

%convex optimization for optimizing allocated powers (P1 and P2)

cvx_begin quiet

cvx_solver mosek

variable P(2,1) %optimization variables

R_min = 1; % 1 bits/Hz (minimum transmission rate)

maximize(Mn-mu_n*(1+exp(-an*(gnx*(P(1)+P(2))-bn))))

subject to

R1 = log2(1+(P(1)*hix)/(P(2)*hix)+Ni);

R2 = log2(1+(P(2)*hjx)/Nj);

R3 = log2(1+(P(1)*hjx)/((P(2,1)*hjx)+Nj));

R1 >= R_min;

R2 >= R_min;

R3 >= R1+R2;

qmx*P(1,1)+P(2,1) <= Gamma_m;

mu_n >= 0;

cvx_end

P

Getting error like this

Error using .* (line 173)

Disciplined convex programming error:

Cannot perform the operation: {real affine} ./ {real affine}

Error in ./ (line 19)

z = times( x, y, './' );

Error in * (line 36)

z = feval( oper, x, y );

Error in / (line 15)

z = mtimes( x, y, 'rdivide' );

Error in nov22 (line 41)

R1 = log2(1+(P(1)*hix)/(P(2)*hix)+Ni);