With smartphones and tablets, mobile wireless communications have revolutionized the way people work.
A wide area wireless connection can access Internet servers from anywhere, and the next step is to spread the power of wireless communications to machine type communications (MTC), which will set off a game of manufacturing, urban management, transportation and energy services across the industry change.
Sensors along the road convey traffic flow information to incoming vehicles and allow them to move freely. The same data can inform customers of the expected arrival time of goods. Other nearby sensors track moisture and air pollution levels to ensure that the air is fresh and healthy And plants get enough water and nutrients, all of these sensors will use wireless communication technology to stay in touch with the cloud server and they will track their location using other wireless services such as the Global Navigation Satellite System (GNSS) network.
Location identification is crucial not only for motion sensors such as those mounted on transport trucks, but also for environmental sensors that have a fixed position over the life cycle.Positioning identification can reduce sensor deployment costs and allow them to accurately report where they are Position without operator intervention, and signal unintentional or intentional movement.
Broadly distributed sensor and IoT nodes are necessary to support LPWAN applications.Many existing IoT applications are based on short-range protocols such as 6Lowpan, Bluetooth and Zigbee, which are exposed by hundreds The limited range of meters is not enough to support a new generation of large-scale MTC systems.
The protocol designed for LPWAN applications provides communications capabilities that can cover nodes between one kilometer or the nearest gateway and nodes, greatly reducing deployment costs, including equipment such as environmental sensors needed by agriculture, To monitor IoT nodes on highways, railways and rivers, and smart meters for home use. In addition, LPWAN's typical frequencies go directly to equipment buried in the ground or in the basement without the need for additional expensive gateways.
The MTC implementation has many options, including access to the unlicensed and licensed bands. LoRA labeling works in an unlicensed band with data rates up to 12.5 kbit / s. Unauthorized bands appear to provide lower operating costs, but In practice, users still need to deploy their own gateways or hire third-party devices.Relying on unlicensed bands can also lead to higher risk, interference from other users in the same band.In addition, LoRA technology licensing approach Will limit the number of chip suppliers to prevent it from being integrated into a custom low-cost single-chip IoT controller.
Cellular communication adds options
On the other hand, cellular communications, due to the use of licensed frequency bands, prevent much interference and provide chip integrators with more overall flexibility and freedom.3GPO defines a series of IoT-ready protocols, most recently defined as narrowband IoT (NB-IoT) .It can support penetration of underground signals, similar to the enhanced coverage of GSM.NB-IoT to data rates from 10kbit / s to 50kbit / s, enhanced functionality not only can improve system performance, but also Can save energy.
For example, in the NB-IoT standard Release 14, the 3GPP committee experts found that maintaining relatively high throughput during transmission was more than limiting the bit rate even more when the process of standardizing data throughput focused on energy efficiency and continuous improvement A good approach, which allows IoT nodes to complete transmissions faster and enter power-saving hibernation mode, consumes less power during transmission (it is primarily implemented by a power amplifier (PA).) Operators Is committed to deploying Release 14 as soon as possible to ensure that the device now under development supports the real-world network.
NB-IoT architecture
To complete the NB-IoT support, an efficient computing architecture is required to handle the signal processing, modem stack, and sensor application code required to achieve peak data rates on a unique processor. If these three Tasks can be done on the same processor subsystem, saving silicon cost and power consumption compared to dual-core processors.CCEVA analyzed the mobile Internet of Things standards and found that under strict power budget, dedicated instruction processing High data throughput pipeline than the hardware acceleration of the overall performance better.
If the chip implementation is running at 150MHz processor, half of the processor performance can run the application, at the same time, DSP core is NB-IoT channel to send or receive data.
Complete NB-IoT platform
Further, CEVA's Dragonfly NB platform includes software support from the CEVA-X1 processor and partner ASTRI, plus peripherals designed for IoT nodes for energy-efficient design because many LPWAN-compliant IoT node applications require location identification , The RF transceiver supports both cellular and GNSS signals, a low-IF architecture that converts RF-to-baseband data and integrates and directly connects a digital front-end unit (DFE). The transceiver provides an on-chip digital oscillator to avoid Use a more expensive off-chip pressure control temperature compensation device.
A complete software stack provides end-to-end support for NB-IoT and GNSS to manage data communications and user application tasks through the RTOS operating system, so this is a platform designed for a new generation of large-scale MTC systems that can support Rapid development of Internet of Things applications.