Design And Implement Of The Digital Baseband System In SoC Chip Based On ZigBee Protocol

ZigBee, as the communication standard for wireless sensor networks with features of low powerconsumption, low cost and low data rate, has become a research and application hotspot currently. Sodesigning a ZigBee-based chip has great significance to the research and development of wirelesssensor network. The work of this thesis is to design the digital baseband system in a SoC chip basedon ZigBee and complete the functional simulation.Firstly, based on analysis of the system’s role in the SoC chip, this paper divides the digitalbaseband system into modules including data transmission module, frame control module, CSMA/CAmodule, system control module, bus control module, FIFO management module, registersmanagement module and clock management module. Then the paper gives the overall structure of thedesign. For the modulation technology of DSSS and O-QPSK in data transmission module, themodulation/demodulation scheme is provided. The Matlab simulation result, that the bit error rate isnearly10^-4 when the SNR is0dB, shows that it could satisfy the performance requirement of ZigBee.The CSMA/CA algorithm is studied and an improved method for the algorithm is proposed, aiming atthe disadvantages that the initial value of BE is fixed and the value of NB increase linearly. Thesimulation results in NS2show that when the network load is large, the new method improvesthroughtput and reduce energy consumption compared to the original one.The paper implements each module using Verilog HDL, and completes the RTL level structure ofthe digital baseband system. In order to verify the correctness of the design, the function simulationsto each module and entire system are completed by Modelsim. And the results prove that each moduleis correct and the functions of the system meet the design requirements. At the same time, the papergives the FPGA verification plan for the system as the basis for further verification.