Energy and Delay Efficient Intelligent Release Assistant Indication Scheme for NB-IoT

3rd Generation Partnership Project (3GPP) has standardized Narrowband Internet of Things (NB-IoT) to support low power devices deployed in locations that mandate deep coverage and long battery life requirements. NB-IoT has its inheritance from LTE, however, the NB-IoT stack is further optimized in terms of hardware and software. Further, various power saving features like eDRX, PSM, and Release Assistance Indication (RAI) are standardized to enhance the coverage and battery life. In RAI, the eNB releases the connection to allow the UE to go into the idle state when it receives the indication from the upper layers that there are no further uplink/downlink packets. This way, RAI reduces the battery power consumption by IoT devices. However, switching to deep sleep state instead of idle state can help in a significant amount of battery power conservation in IoT devices with predominant downlink transmissions. Motivated by these facts, we propose a novel IRAI scheme that addresses both of these issues. Through simulations, we present various trade-offs achievable with the proposed IRAI scheme. We show that the proposed IRAI achieves significant improvements in the battery life of the NB-IoT devices.