The advancing MAC/PHY technique and architecture in the mobile network allows the DownLink (DL) capacity in radio access network (RAN) to vary from Kilo-Byte per-second level up to Giga-byte per-second level in a glimpse. The existing TCP congestion control algorithms (CCA) were not designed for such dramatic variability. In this paper, we proposed an improvement for end-to-end congestion control, called Client Driven Bandwidth Estimation (CDBE), which allows TCP clients to cooperate with its CDBE. The cooperation can enhance the down-stream (DS) performance of the connections, even in the mobile network. The CDBE client can measure the available bandwidth (BW) on the bottleneck and inform the server of the BW estimation (BWE) result. Unlike existing mobile cross-layer congestion control proposals, the proposed algorithm on TCP client does not directly invoke information from UE MAC/PHY layer module but implicitly reflect the varying cellular BW when the mobile last hop is the bottleneck of the network. The CDBE TCP server uses the received BWE value to calculate its pacing rate and congestion window, and it further calibrates the result according to the variation of down-stream delay (DSDL). The state transition in the server can react rapidly to eNB BW and queue variation. Sets of NS3 system simulation in a LTE network is conducted with BBR and CQIC as the baseline. The result shows that the proposed algorithm can improve the end-to-end throughput and good-put while keeping the DS delay at a low level.