Long Range Dependence of IEEE 802.15.4 Wireless Channels
Several works have attempted to determine whether the process that introduces errors into transmissions over a wireless channels is long range dependent (LRD). Most of these efforts were focused on IEEE 802.11b/g channels. Knowledge of LRD is of significant interest to designers of wireless network systems. This experiment-based study attempts to gain a better understanding of the standardized IEEE 802.15.4 low rate-wireless personal area network (LR-WPAN) specification. We determine whether the bit, symbol and packet level error processes are LRD or not. Is the memory length of the channel measurable and finite, or is it sufficiently long to qualify it as an LRD process? We record channel behavior by capturing all transmissions at the receiver including the ones that would under normal operation be dropped and use these to generate residual error traces. We perform statistical data analysis of these traces using various tools for scenarios with and without interference from 802.11b/g sources. For the bit and symbol level error process we conclude that channel memory remains fixed at 2 bits and 2 symbols respectively regardless of channel and environment. For the packet level error process we conclude that the perception of on and off LRD is actually due to interference from co-located 802.11b/g networks.