The use of Bluetooth Low Energy (BLE) has been steadily increased since Bluetooth Special Interest Group (SIG) standardized BLE in 2010, and BLE performance has been improved owing to various studies. Bluetooth specification 4.2 defined only one data rate, i.e., 1 Mb/s. However, the specification 5 released in 2016 specifies 2 Mb/s and coded PHYs for higher throughput and more stable transmission, respectively. This version also allows the transmission power to be varied from -20 dBm to 20 dBm. Therefore we are enabled to use various data rates and transmission powers in BLE. However, no research has studied how to adapt these yet. In this paper, we propose an algorithm, termed $AdaptaBLE$, that selects data rate and transmission power of BLE by considering link stability and energy consumption. We implement $AdaptaBLE$ on real devices and measure its performance. As a result, we confirm that $AdaptaBLE$ successfully selects an appropriate TX power and data rate while keeping the BLE link stable.

The use of Bluetooth Low Energy (BLE) has steadily increased since 2010. Bluetooth specification 4.2 defined only one data rate, 1 Mb/s. However, Bluetooth specification 5 released in 2016 specifies 2 Mb/s and coded PHY for higher throughput and for more stable transmission, respectively. In addition, this version of specification defines transmission power from -20 dBm to 20 dBm. In this paper, we propose AdaptaBLE, an algorithm that selects the data rate and transmission power of BLE by considering link stability and energy consumption. We implement AdaptaBLE on real devices and measure its performance. As a result, we confirm that AdaptaBLE successfully lowers energy consumption while keeping the link stable.

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.

In this paper, we consider a protocol architecture that enables IPv6 routing protocol for low power and lossy networks (RPL) to run on top of Bluetooth Low Energy (BLE), aiming to provide a BLE-based multi-hop IoT network. In our approach to RPL over BLE, we propose to use both of advertising and data channels of BLE to create synergistic effects between RPL and BLE to jointly achieve high energy efficiency and reliable multi-hop routing. We design an adaptation layer between BLE and RPL (ALBER) which tightly couples RPL and BLE operations together. Specifically, ALBER provides RPL control message broadcast through BLE, RPL routing metric calculation that reflects BLE link quality, and routing table update that incorporates BLE connection management. We implement ALBER in a Linux kernel to realize RPL over BLE and compare its performance with that of RPL over IEEE 802.15.4 on a multi-hop testbed network. The performance results show that our architecture is not only feasible but also provides almost perfect packet delivery performance (↑100%) and reduces dutycycle up to 32% compared to RPL over IEEE 802.15.4 under varying link dynamics. Our research shows that RPL over BLE is a promising approach which can increase the utility and impactof BLE across different application domains.

In low-power wireless networks, maintaining multihop connectivity is considered effective in constructing communication routes between individual nodes to a gateway. Since sensor networks are typically used for data collection, multihop routing protocols are designed to find routes optimal in upward directions. As sensor networks become widely applied to diverse applications, efficient downward traffic delivery also becomes important. To achieve this, we consider an asymmetric transmission power-based network (APN), where a power-supplied gateway uses high-power radios to cover the entire network via single-hop transmission, whereas common nodes use low-power transmissions. For effective APN operations, we propose a single-hop downlink protocol (SHDP) that consists of direct downlink transmission, local acknowledgment, neighbor forwarding, and contention resolution among the destination’s neighbors. We evaluate SHDP through mathematical analysis, simulations, and testbed experiments. Our proposal outperforms other competitive multihop routing protocols. Specifically, SHDP shows high packet delivery performance and lowers the duty cycle greatly while reducing the packet transmission overhead by >50%.

Updating price tags in a large-scale market is a recurrent task, still performed manually in most markets. Given that human-errors can easily lead to customer complaints and accounting inaccuracies, the ability to autonomously reconfigure price tags can be of significant benefit. With the introduction of low-power display techniques such as electronic ink, applications of enabling electronic, wirelessly reconfigurable price tags show potential for future deployment. In this work, we examine networking architectures that can be applied in such scenarios. Through a series of preliminary pilot studies in an actual supermarket, we show that the performance of existing protocols are not ready to overcome the unique challenges of busy market environments. We identify underlying technical challenges and propose MarketNet, an asymmetric transmission power-based system designed for densely populated, obstacle-rich, downwards traffic-oriented environments. We evaluate MarketNet in a large indoor mar- ket visited by 5000+ customers per day. Our results show that MarketNet addresses the challenges of the target application and environment, while achieving higher packet delivery performance with noticeably lower radio duty-cycles than existing protocols such as RPL and SHDP.

In this demo, we present interoperability between Bluetooth Low Energy (BLE) and IPv6 routing protocol for low power and lossy networks (RPL). To make the operation of RPL over BLE feasible, we design an adaptation layer between BLE and RPL, termed ALBER. Specifically, we develop three technical features in ALBER which enable BLE to be combined with RPL. First, it broadcasts RPL control messages through BLE using advertising channels with low energy consumption. Second, it updates RPL routing table considering connection management of BLE. Lastly, it estimates link quality based on round trip time of link layer ping packets to provide routing metric for RPL. We implement our ALBER on Linux kernel. This demo will present an operation example of RPL over BLE using ALBER in a small scale multi-hop topology, where each node comprises a Raspberry Pi platform and a BLE dongle.