Hardware Implementation And Calibration Verification Of Pre-Stored Channel Modeling Based On Measurement

Wireless channel measurement and modeling simulation has been regarded as an important part of the wireless communication system design, and is the base of channel simulation software, channel simulation instrument and network planning tool. The pre-stored channel hardware simulation realizes the replay of real-time measurement data on the hardware and has the characteristics of high reliability, short operation time and reproducibility, which is quite valuable for the evaluation of industrial products. With the development and evolution of communication technology, multiple-input and multiple-output (MIMO)technology has greatly increased the capacity of the channel, but also increases the difficulty of the performance testing and evaluation of system. Channel measurement technology and extraction of channel impulse response (CIR) technology, as well as the upgrade of hardware capacity and computing speed, make the pre-stored channel modeling hardware Simulation to be universal. This paper will focus on the measurement, modeling and hardware implementation of pre-stored wireless channel. According to the theoretical analysis and the experimental simulation, this paper studies the extraction of the propagation characteristics from wireless channel and the modeling by reconstruct of channel, which can be divided into three aspects:(1)Extraction of CIR without antenna response. A significant drawback of existing MIMO channel parameter acquisition simulation systems is that when the measurement of the channel parameters reflects the channel characteristics, the extraction of the channel characteristics inevitably will also record the response of the transmitting and receiving antennas used to measure the channel characteristics. The antenna response will be difficult to be removed from the measured CIR. Such channel measurement and extraction results are not the most realistic reflections of real wireless channel characteristics. So both for the verification of principle or for system testing, this kind results will bring greater errors and limitations. In addition, the existing pre-stored channel modeling and simulation system can not support MIMO-OTA test scheme.The channel characteristics used in the current MIMO-OTA test are modeled by the standardized channel model, so that the deviation between the generated channel and the actual channel can not be avoided at present. In this paper, we propose a set of channel parameter extraction scheme based on measurement to remove the antenna response. The method will directly reconstruct the equivalent real channel between the transmit and filter the measured CIR, remove the antenna gain, preserving the characteristics of the MIMO channel intact.(2)The hardware realization of pre-stored channel simulation.At present, there are channel simulation methods based on the software platform of MATLAB, C ++ simulation, but also hardware simulation.Considering the compromise between simulation complexity and accuracy, this paper presents a hardware simulation scheme. Firstly, the GBSM is modeled and sampled by C ++, then the reconstructed channel data is framed to high precision Of the DSP chip complex channel impulse response of the calculation; the final CIR and RF signal convolution output. The part of the program on the modeling part of C ++ is that it has good compatibility and flexibility, you can achieve complex channel modeling scene selection, network layout and other issues; DSP is playing its high-precision computing power and multi-core processing This paper presents an efficient DSP inter-core communication scheme, which can reduce the computing time to the order of ten microseconds for the reasonable deployment of DSP resources.(3) Calibration and verification of hardware simulation program.Based on the above-mentioned hardware realization of channel modeling and MIMO channel characteristics, this paper presents a calibration scheme for channel simulation. The scheme is divided into two steps,which are the calibration of channel software modeling phase and hardware simulation phase. The main considerations are channel mean square delay extension and angle extension.The above work is the main content and innovation of this paper.The channel measurement and parameter extraction scheme proposed in this paper has some reference significance for future channel measurement modeling and system conformance testing, MIMO-OTA test, DSP system The multi-core communication mechanism can be extended in practical application, and the calibration verification scheme also provides valuable theoretical reference for related fields, which will help to promote the standardization of related fields.