The Low Rate Wireless Personal Network (LR-WPAN) is a new standard uniquely designed for low data rates and low energy consumption. LR-WPAN researchers are focusing extensively on the wireless technology and energy consumption, but many papers do not cover channel characterization and link quality assessment in LR-WPANs, even though we could reasonably surmise that the network performance will be optimized only when the channel and link information are provided. In this paper, we will suggest a new mechanism for performance enhancement in the presence of a time-varying channel response. First, we will regard the Link Quality Indicator (LQI) as a channel state indicator. Second, we will modify the pure CSMA-CA procedure by reflecting the LQI measurement. Finally, we roughly observe the time-varying channel, and then we assign a weight to the L2 scheduling parameter known as the Backoff Exponent (BE). This mechanism upgrades the network performance when there is a time-varying channel. This paper addresses the problem by creating an efficient scheduling scheme that is based on the channel memory. The result of an NS-2 simulation indicates an overall improvement in the effective throughput, energy consumption, and end-to-end delay.