Research On Technology For Multi-Beam System Components

With the information explosion era coming,modern mobile communication needs faster data transmission rate,more stable reliability,less interference and higher power efficiency.In the face of these challenges,the fifth generation mobile communication technology(5G)requires the integration of multiple technologies,realizing the integration of the network.The large scale MIMO technology adopts the method of space division multiplexing to realize the further division of space resources,and becomes one of the most potential wireless transmission technology of 5G.The key of large scale MIMO technology is the realization of multi-beam system.This paper is based on the 5G wireless communication prototype which the Keysight company proposes.The design of a 16 x 4Local oscillator source.The signal source is used to realize the phase shift of the local oscillator signal,which is the key component of the digital beamforming system based on the combination of the local oscillator signal phase shift and the baseband phase shift.First,various frequency synthesis techniques are compared and the direct digital frequency synthesis(DDS)scheme is selected,and the overall scheme of the local oscillator signal source has been introduced.At the same time,this paper proposes a simple and stable XOR gate circuit solution to synchronous multiple DDS chips.Then,the link structure of the local oscillator signal source channel circuit is verified by ADS link simulation.Then the structure of the DDS circuit,the control circuit and the structure of the RF signal processing circuit are introduced,and the test results are given.In the design process,the influence factors of phase noise are analyzedAfter calibration,the local oscillator source has many characteristics,such as multi-channel,low phase noise,high phase amplitude control accuracy and fast response.In this paper,the real-ization of the local oscillator signal source with 810MHz and 4.51 GHz dual frequency output are achieved.The output power of 810MHz signal exceeds OdBm,and the spurious suppression ex-ceeds 80dBc,and the measured phase noise are:-96.7dBc/Hz@1KHz?-126.04dBc/Hz@100KHz,and the control accuracy is within 1°.The output power of 4.51 GHz exceeds OdBm,and the spu-rious suppression exceeds 49dBc,and the measured phase noise are:-92.67dBc/Hz@1KHz?-113.8dBc/Hz@100KHz,and the control accuracy is withinl.2°.The test results show that the local oscillator source has good performance,which can provide hardware support for Multi-beam System with the new digital beamforming scheme.