CABLE: Connection Interval Adaptation for BLE in Dynamic Wireless Environments

Taeseop Lee, Jonghun Han, Myung-Sup Lee, Hyung-Sin Kim, Saewoong Bahk

Abstract: Bluetooth Low Energy (BLE) is one of the widely used low power wireless protocols due to its simplicity and low energy consumption. The BLE standard is being developed further to support a wide range of applications spanning smart homes, wearables, and myriad appliances as part of IoT (Internet of Things). These new applications bring forth an important challenge: connection maintenance with low energy consumption in dynamic channel environments. In this paper, we investigate effective solutions to this technical challenge. First, we show using experiments that the current design of using fixed connection intervals incurs significant performance degradation under dynamic link conditions. To overcome the problem, we mathematically find an optimal connection interval that minimizes energy consumption while maintaining connectivity for a given link condition. Then, we design a simple yet effective connection interval adaptation mechanism for BLE, named CABLE. We implement the proposed solution on real embedded devices, and using extensive testbed experiments and simulation verify that CABLE leads to significant performance improvement while providing resilient connectivity in dynamic link environments.