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Rapid development of wireless communications in recent years has imposed great chal-lenges for network support. As most current networking protocols were designed mainly for wired networks, many assumptions that make these protocols efficient in wired net-works are no longer true and cause severe performance degradation in wireless environ-ment. An urgent task for today’s networking research is to identify such deficiencies and to enhance these protocols. This dissertation contains four major enhancement results. The first result is a wireless TCP enhancement scheme called Congestion Coherence. Through a statistical analysis, we find the leading contributor of wireless TCP performance degradation is the timeout resulting from frequent packet losses. This scheme uses ECN to reduce number of time-outs, and based on the observation that congestion neither happens nor disappears suddenly, uses the sequential coherence of packet marking to determine cause of packet losses. Sim-ulations show this scheme works better than existing enhancements and produces good performance