UBC Theses and Dissertations
A proxy architecture to enhance the performance of WAP 2.0 by data compression Yin, Zhanping
This thesis presents a novel architecture for the Wireless Application Protocol (WAP) 2.0, employing a proxy to isolate the wireless from the wired domain and an advanced data compression scheme. The advanced data compression scheme combines content compression with robust header compression (ROHC) and minimizes the transmitted air-interface traffic, thus significantly reducing the wireless access time (WAT). By using a proxy at the transport layer to form a TLS tunnel, this architecture also overcomes WAP 1.x end-to-end security problems without deploying a gateway at the server side. A wireless channel is implemented in Network Simulator (NS-2) to emulate the characteristics of both narrow-band IS-95 and wide-band CDMA 2000 lxRTT wireless channels. The performances of the proposed WAP 2.0 architecture and WAP 1.x protocol stack are tested on it. Emulation results show that while WAP 1.x is optimized for narrow-band wireless channels, WAP 2.0 utilizing TCP/IP gives better performance than WAP 1.x in wide-band channels, even without compression. Huge performance enhancements can be achieved by the proposed data compression scheme in WAP 2.0. The reply contents compression is a major contribution to the improvement, while ROHC can offer further enhancement. The request compression is useful for low-bandwidth networks like IS-95, but gives no benefit in high-speed wireless networks, such as CDMA2000 lxRTT. In IS-95 channels, the reply and request compression with ROHC reduces the WAT of WAP 2.0 by over 70% to give comparable performance to WAP 1.x. In CDMA2000 lxRTT, even the uncompressed WAP 2.0 outperforms WAP 1.x, and the proposed method results in over 46% reduction in WAT. Although a proxy is optional in WAP 2.0, it can optimize the communication process by isolating the wireless from the wired domain, which gives a performance benefit as well as feature service enhancement. The proxy not only prevents the error propagation between wired and wireless domains, but also eliminates the wireless session delays (WSD) due to a TCP connection establishment by long-live connections between the proxy and wireless terminals.
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