Design and analysis of channel adaptive wireless cache invalidation strategies with downlink traffic

In this paper, we study the performance of the IR+UIR wireless data cache invalidation approach under a realistic system model: the quality of the wireless channel is time-varying; and there are other downlink traffics in the system. Our analysis and simulation results show that query delay significantly increases as a result of broadcast error and the additional downlink traffics experience longer delay due to extended broadcast period. Exploiting link adaptation (i.e., transmission rate is adjusted dynamically according to channel quality), we then propose three schemes to tackle these two problems. Our results indicate that the proposed scheme outperform IR+UIR under a wide range of system parameters.