A Network-Based Approach to Improve TCP Performance in Wireless Systems with Opportunistic Scheduling

Recent research on opportunistic schedulers for wireless data transmission has shown that link utilization is greatly improved by exploiting the independent variations in the wireless channels of users. The trade-off between spectral efficiency and fairness among users at the link level has been well studied in the literature. The focus of this paper is the impact of the variable rate and delay jitter induced by opportunistic scheduling on the congestion control and avoidance mechanisms of TCP. We use extensive simulations to expose the linkage between scheduling at the medium access (MAC) layer and TCP performance. The results in this paper underscore the need for careful design of opportunistic scheduling mechanisms in order to ensure that gains in MAC layer are also realized by TCP.