Algorithm 1 Encoding strategy at the source node

1: Destination nodes obtain the value of current signal strength $V$. 2: Destination nodes send packets pkg1 to the source node $S$. 3: $S$ receives some packets pkg1 from the destination nodes.

4: $S$ obtains the value of $V$ from pkg1. 5: $S$ works out the mean value Avg of V. 6: If $\mathit{Avg}\ge -\mathit{60}$

7:  Set the redundancy value $\mathit{r}$ to 0. 8: Else 9:  Set the redundancy value $\mathit{r}$ to (−60−Avg)/20.

10: Endif

11: $\mathit{S}$ divides a data frame $\mathit{F}$ into $\mathit{K}$ slices.

12: $\mathit{S}$ generates a $\left(\mathit{K}+\mathit{r}\right)$–by-$\mathit{K}$ random matrix $\mathit{M}$. 13: $\mathit{S}$ generates encoded data $\mathit{Y}$ with $\mathit{M}$ and $\mathit{F}$. 14: The encoded packets consisting of row vectors of $\mathit{M}$ and $\mathit{Y}$ will be generated. 15: $\mathit{S}$ sends encoded packets to the network.