Tuning transmission power for TCP fairness in next generation wireless networks: An analytical paradigm

It is well known that TCP is unfair when connections with different round trip times (RTTs) share the same bottleneck. In the literature TCP fairness in wired networks has been widely studied but little effort has been devoted to this issue in wireless networks, where new problems arise. As known, in fact, due to the wireless medium characteristics, the frequent link errors and consequent losses are interpreted as congestion clue and the transmission rate is drastically reduced. The objective of this paper is to investigate the possibility of achieving TCP fairness through power management in next generation wireless networks which are expected to use CDMA-based MAC schemes. The basic idea is to allow long RTT connections, which are usually the most disadvantaged, to have higher signal-to-interference ratios. To this aim, an analytical framework is introduced to calculate the appropriate transmission power, giving fairness to each mobile terminal. The impact of this power management scheme on fairness and overall throughput performance is evaluated by means of both analysis and simulations.