Chip for wireless sensor network node and on-chip digital baseband system

Abstract

The invention provides a digital baseband system used for a wireless sensor network node chip. The digital baseband system comprises a baseband modulation unit, a baseband demodulation unit, an automatic gain control unit and a cyclic code checker, wherein the cyclic code checker transmits checked data to be sent to the baseband modulation unit; the baseband modulation unit performs modulation processing such as direct sequence spread spectrum, delay, digital signal shaping modulation and analog-to-digital conversion on the data and then sends the processed data out; the baseband demodulationunit performs demodulation processing such as analog-to-digital conversion, spectrum despreading, optimal coherent demodulation, bit synchronization sampling determination on the received data and then transmits the processed data to the cyclic code checker for data check; and the automatic gain control unit adjusts a gain determination threshold according to received signal strength indication (RSSI) and link quality indication (LQI) in the process of sending or receiving the data so as to control the transmitting gain and receiving gain.

Description

technical field [0001] The invention relates to the field of wireless transmission, in particular to a chip used for wireless sensor network nodes and a digital baseband system on the chip. Background technique [0002] Wireless Sensor Network (WSN) is a self-organizing network application system composed of a large number of autonomous nodes densely deployed in the monitoring area. It has broad application prospects and can be widely used in military, environmental monitoring, medical health, traffic management, and commercial applications. Although wireless sensor network nodes have various applications, these applications have some common requirements for wireless sensor network nodes. The most challenging requirement is how to make wireless sensor network nodes have stronger computing power and a better application environment. wide, lower power consumption, smaller size, lower cost, and better communication quality. [0003] Most of the current wireless sensor network...

AI Technical Summary

Problems solved by technology

[0008] 1. The digital baseband system of these chips can do automatic gain control, and the gain range can be configured by software, but the decision threshold involved in the automatic gain control process adopts a fixed threshold value, which does not have the feature of adaptive adjustment

Moreover, the signal strength RSSI is generally used as the feedback value for control, and the signal is amplified to saturation, and the receiving link quality LQI is rarely considered comprehensively.

Narrowband interference in the channel will increase the RSSI, but will reduce the link quality LQI, so it is not accurate to use a single RSSI as feedback to adjust the acceptance gain

Considering the fact that wireless sensor network nodes have a wide range of application environments, in the actual application process, they will face problems such as complex and changeable channel conditions, uncertain transmission power, and real-time changes in communication distances, which will affect the node packet loss rate and energy consumption. The existing digital baseband system uses a fixed threshold judgment method, which will lead to a decrease in the environmental adaptability of the node

[0009] 2. The digital baseband system of these chips does not use the adaptive threshold Schmitt trigger method for signal phase judgment, but uses the traditional zero-crossing trigger method for signal phase judgment, so it cannot be avoided due to frequent jumps in the input phase. Demodulation bit error rate increased due to the change

[0010] 3. The digital baseband system of these chips uses a fixed generator polynomial instead of software configurable when doing cyclic code verification, resulting in poor flexibility and versatility of the baseband

[0011] 4. The digital baseband system of these chips does not have the function of suppressing carrier leakage, so the quality requirements of RF chips are very high, which increases the node cost

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