Switch Strategy for Smart Utility Network Orthogonal Frequency-division Multiplexing Phy Based on Reinforcement Learning in Low-power and Lossy Networks

Content Provider	Semantic Scholar
Author	Wei, Ling Wu, Wenjia Li, Chuanwei
Copyright Year	2019
Abstract	Techniques are described herein for a switch strategy based on actor-critic reinforcement learning. This depends on not only the Received Signal Strength Indicator (RSSI) and packet loss rate but also on the distribution of error segments in a packet. The states, actions, and values for the actor-critic model may be defined to fit the switch strategy. The mechanism of dynamical adjustment may depend on the different PHY formats. DETAILED DESCRIPTION The IEEE 802.15.4g protocol is applied in connected grid mesh networks (CGMESH). This protocol supports multiple Smart Utility Network (SUN) Orthogonal Frequency-Division Multiplexing (OFDM) PHY formats to adapt the data rate on the basis of the wireless Channel State Information (CSI). In current CG-MESH systems, the switch strategy among these different formats depends on the Received Signal Strength Indicator (RSSI) and packet loss rate. However, packet collision may occur due to the "hidden node" problem. Packet collision may be misjudged due to channel fading in current switch strategies. Thus, the node may incorrectly decide to switch the SUN OFDM PHY to the lower data rate format, thereby degrading network performance and causing disruption in the system. Accordingly, a switch strategy is provided herein to avoid misjudgment between packet collision and channel fading. The switch strategy depends not only on the RSSI and packet loss rate, but also on the distribution of error segments in a packet. Furthermore, actor-critic reinforcement learning is applied to determine the switch strategy and improve performance in Low-power and Lossy Networks (LLNs). 2 Wei et al.: SWITCH STRATEGY FOR SMART UTILITY NETWORK ORTHOGONAL FREQUENCY-DI Published by Technical Disclosure Commons, 2019 2 5899 There are several SUN OFDM PHY formats in CG-MESH systems. When a wireless channel suffers from great attenuation or noise interference, which results in higher packet loss rate, the relevant nodes should switch to a lower data rate format to guarantee valid communication service. Conversely, nodes should improve the data rate when the channel improves. Therefore, the CSI may be accurately measured while packets are received. Due to the "hidden node" problem, packet collision may occur, increasing the packet loss rate. But the relevant nodes should not switch the PHY format because doing so cannot resolve packet collision. Thus, the system may determine the true reason for increasing packet loss rate: packet collision or channel error. Figure 1 below illustrates an example typical packet structure. Figure 1 RSSI and packet loss rate alone is not enough to distinguish the true reason for packet loss, because the results of packet collision and channel fading are nearly identical. Accordingly, a multi Cyclic Redundancy Check (CRC) segments packet structure is provided to offer more details regarding packet loss. Figure 2 below illustrates an example multi-CRC segments packet structure.
File Format	PDF HTM / HTML
Alternate Webpage(s)	https://www.tdcommons.org/cgi/viewcontent.cgi?article=3673&context=dpubs_series
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article