Offloading cellular hotspot regions to small-cells has been the main theme for the fifth generation of cellular network. One such hotspot is the public transport which carries a large number of cellular users who frequently receive low quality of service (QoS) due to vehicular penetration effect (VPE). Hence installation of mobile-cell (MC) within public transport is seen as a potential enabler to enhance QoS for commuting users. However, unlike fixed cells, MC requires wireless backhaul (BH) connectivity along with in- vehicle Access-Link (AL) communication. These additional wireless links for MC communication will pose an excessive burden on an already scarce frequency spectrum. Hence, in this research, we exploit VPE and line-of-sight (LOS) communication to allow the downlink backhaul (DL-BH) sub- channels to be shared by in-vehicle downlink access-link (DL-AL) transmission. Our analysis and simulations show that using the above-mentioned technique, both links maintain high success probability, especially in regions with low signal to interference ratios.