Brief Review on Wireless Communications and Networks. Dr. Frank Lee Computer Science Department California Lutheran University 10/26/2005. Outline. Cellular Wireless Networks Wireless Local (Subscriber) Loop Mobile Internet Protocol (IP) Wireless Application Protocol (WAP)
Dr. Frank Lee
Computer Science Department
California Lutheran University
1. Mobile unit initialization: selects the strongest setup control channel
2. Mobile-originated call: sends the number of the called unit on the pre-selected setup channel
3. Paging: The MTSO sends a paging message to certain BSs depending on the called mobile unit number
4. Call accepted: The called mobile unit recognizes its number on the setup channel being monitored and responds to that BS, which send the response to the MTSO
5. Ongoing call: The two mobile units exchange voice or data signals, going through their respective BSs and the MTSO
6. Handoff: If a mobile unit moves out of range of one cell and into the range of another during a connection, the traffic channel has to change (without either interrupting the call or alerting the user) to one assigned to the BS in the new cell
1. Server X transmits an IP datagram destined for mobile node A.
2. The home agent encapsulates the entire datagram inside a new IP datagram that has the A’s care-of address (foreign agent’s location) in the header, and retransmits the datagram to foreign agent. The use of an outer IP datagram with a different destination IP address is known as tunneling.
3. The foreign agent strips off the outer IP header, encapsulates the original IP datagram in a network-level PDU (protocol data unit, such as a LAN logic link control frame), and delivers the original datagram to node A across the foreign network.
4. Each IP datagram is sent from A to a router (the foreign agent) on the foreign network for routing to X.
5. The IP datagram from A to X travels directly across the Internet to X, using X’s IP address.
5. If the filter is separate from the proxy, HTTP/TCP/IP is used to deliver the WML to the proxy
6. The proxy converts the WML to a more compact form known as binary WML and delivers it to the mobile user over a wireless network using the WAP protocol stack
7. If the Web server is capable of directly generating WML content, then the WML is delivered using HTTP/TCP/IP to the proxy, which converts the WML to binary WML and then delivers it to the mobile node using WAP protocols