Conferences and supporting programme
Connecting Sub-1 GHz Low-Power IoT Nodes to the Internet Using 802.15.4
With Internet of Things (IoT) applications triggering large scale deployment of wirelessly connected sensors, cost-effective implementation will depend on keeping sensor costs low. The choice of wireless technology will affect whether gateways are required for internet access, how close an endpoint must be to a gateway, the choice of battery or power source, the data rate an endpoint can transmit at, and whether there are data transmission costs. Choosing an inappropriate wireless technology may result in higher deployment and operational costs. In many IoT applications, such as for farms, warehouses, or industrial plants, sensors will need to be placed over a wide area and in locations where metal or concrete may attenuate or obstruct the signal. This creates a challenge for the application developer: well-known technologies such as Wi-Fi have somewhat limited range and don’t easily adapt to radio environment that must turn corners while cellular is expensive as it incurs telco fees. In addition, both have relatively high power requirements. The Sub-1 GHz spectrum provides publically available bands that allow long-range communication and can better penetrate walls and bend over obstacles. It is the band used by Low Power Wide Area Network technologies like Sigfox and may also be used in proprietary solutions. Unfortunately, the Sub-1 GHz band has lacked a standard networking solution, limiting its use in the IoT market because developers needed implementation expertise in low-level RF communications. IEEE has now extended support to the Sub-1 GHz band in the ‘g’ amendment of the IEEE 802.15.4 specification, creating an opportunity for standards-based protocol implementations. We will begin with a summary of IoT sensor requirements that impact the selection of the wireless technology required. We will then overview the key attributes of the Sub-1 GHz spectrum, including longer range and penetration, data rates, and power consumption, as well as introducing the 802.15.4 standard, including the ‘g’ amendment. We next consider additional networking and protocol architectural choices that impact sensor power consumption and network complexity, such as IP at the node and mess versus star topology. This will also use benchmark data to demonstrate the relationship between power consumption and transmission range. We will continue with an implementation overview of a protocol stack based on the 802.15.4 MAC layer, including how security and message integrity is implemented, and the additional link layer protocols required for network management. We will then discuss a Linux-based stack and gateway implementation that bridges the packets to the internet using a serial port abstraction for the Sub-1 GHz radio device. We will conclude with benchmark data showing potential battery life for application usage scenarios with a Sub-1 GHz radio.
--- Date: 28.02.2018 Time: 10:30 AM - 11:00 AM Location: Conference Counter NCC Ost