Virtual cell in mobile computer communications

Abstract

In this paper, we design and develop a virtual cell approach for the transmission of IP datagrams in mobile computer communications. A virtual cell consists of a group of physical cells whose base stations are implemented by remote bridges and interconnected via high-speed datagram packet-switched networks. Host mobility is supported at the data link layer by virtual cell protocol (VCP) using the distributed hierarchical location information of mobile hosts. As far as the IP layer is concerned, it appears within a virtual cell as if the communication between two mobile hosts in different physical cells were taking place directly as in the same physical cell. Between virtual cells, a one-hop forwarding pointer from a mobile host's native virtual cell to its current virtual cell is maintained at the VCP layer. This means that the combination of the existing routing protocols of the IP layer and the forwarding pointer maintained at the VCP layer between virtual cells gives the same effect of having a fully duplicated location information among virtual cells for the global mobile network. Thus, the virtual cell approach eliminates the necessity of IP-level mobile host protocols that may interfere with the conventional IP protocol in a practical sense. In addition, given mobility and communication patterns among physical cells, it achieves a logically flexible coverage area of a virtual cell so as to minimize the total communication cost for the global mobile network where inter-virtual cell communication is more expensive than intra-virtual cell communication (K. Lim and Y.-H. Lee, IEEE Personal, Indoor and Mobile Radio Communications PIMRC'94, pp. 1237-1241, Sep. 1994; K. Lim, Y.-H. Lim and Y.-H. Lee, IEEE ICC'95, pp. 1839-1843, June 1995). To demonstrate the correct operations of VCP and measure data which are used as parameters to a performance model for the virtual cell system, we implement VCP on a simulated environment. The performance analysis of the virtual cell system is out of scope in this paper and one is referred to K. Lim, Y.-H. Lim and Y.-H. Lee, Proc. 10th Int. Conf. Information Networking ICOIN-10, pp. 551-560, Jan. 1996. © 1997 Elsevier Science B.V.