Algorithm 1 Caching algorithm at base station

Initialize:$first\_cached\_seq$=0, $seq\_acked$=0, $last\_cached\_seq$=0 1:Receive packet i 2:for Every packet i from wired network do 3:    if Destination address == vehicle’s ID then 4:        if $first\_cached\_seq$=0 then 5:           Cache the package. 6:           $first\_cached\_seq$=$se{q}_i$ 7:        else if $seq$<$first\_cached\_seq$ then 8:           $first\_cached\_seq$=$se{q}_i$ 9:           Cache the package. 10:        else 11:           Drop the package. 12:        end if 13:        if $last\_cached\_seq$=0 then 14:           $first\_cached\_seq$=$se{q}_i$ 15:        else if $last\_cached\_seq$<$se{q}_i$ then 16:           $last\_cached\_seq$=$se{q}_i$ 17:           Cache the package. 18:        else 19:           Drop the package. 20:        end if 21:    end if 22:    if Source address == vehicle’s ID then 23:        if $seq\_acked$=0 then 24:        else if $seq\_acked$ <$ac{k}_i$ then 25:           $seq\_acked$=$ac{k}_i$ 26:        end if 27:        if $first\_cached\_seq$<$seq\_acked$ then 28:           Release the caching package from $first\_cached\_seq$ to $seq\_acked$-1 29:           $first\_cached\_seq$ = $seq\_acked$ 30:        end if 31:    end if 32:end for