Algorithm 2 Dynamic resource allocation PF algorithm with location and SFR

Require: Train location information, coverage area L and bandwidth B, the number of PRB N, TAU maximum transmit power $P_{CMAX}$, and large-scale fading factor $\alpha$ and small-scale fading model, train CBTC service minimum transmission rate $r_{min}$ and resource availability of adjacent cells. Ensure: Calculate the minimum number of PRBs for each train based on the required minimum transmission rate $r_{min}$. Then the total PRBs occupied by train $1···K$ are marked as PRB group: $RB{G}_1,RB{G}_2,···,RB{G}_K$ 1:if not all trains are allocated radio resources then 2:   According to the principle of PF, find the train $k\in \left\{1···K\right\}$ and avaiable PRB $i\in \left\{1···N\right\}$ that maximize the metric value $m_{k,i}=\frac{d_k\left(i,j\right)}{\overline{R_k}\left(j\right)}$; 3:   According to service rate requirements $r_{min}$, the cell allocates PRB to the train k 4:   Merge the selected PRB into the initially allocated PRB block; 7:   Refresh RBG information $RB{G}_k$; 6:end if 7:return RBG allocation information on all trains