In this paper, the new scheme using a Combined Cache(CC) that combing the Paging and Routing Cache(PRC) and an alternative handoff method according to the type of data transmission for achieving the efficient realtime communication. The PRC and quasi-soft handoff method reduce the path duplication. But they increase the network traffic load because of the handoff state packet of Mobile Host(MH). Moreover the use the same handoff method without differentiating the type of transmission data. Those problems are solved by operating U with a semi-soft handoff method for realtime data transmission and with a hard handoff method for non-realtime data transmission. As a result or simulation a better performance is obtained because of the reduction of the number of control packet in case that the number of cells are below 20. And the packet arrival time and loss of packet decreased significantly for realtime data transmission.