Research On Wireless Signal Processing Methods Based On General-Purpose Processor

ABSTRACT:There is higher and higher real-time requirement for the wireless signal processing in wireless mobile communication systems. Conventional signal processing devices are based on a DSP or FPGA hardware platform. However, since a majority of signal processing modules of the existing DSP or FPGA development platform is non-open, it is difficult for engineers to implement hardware upgrade and system optimization. With the development of multi-core multi-threading and single instruction multiple data (SIMD) technologies, current general-purpose processors have been able to meet the requirements of high data load operation of digital signal processing. This paper mainly focuses on wireless signal processing algorithms based on general-purpose processors. The proposed algorithms can be applied to a novel wireless channel sounding system, and have a good performance in the actual channel measurement activities.For a start, we study the relevant knowledge of software defined radio and general-purpose processor, and analyze the requirements of real-time signal processing. Meanwhile, in order to verify the accuracy, reliability and applicability of the proposed wireless signal processing algorithms, a novel radio channel measurement system platform is built up. This platform is able to satisfy the actual measurement requirement, and it has the advantage of low cost and high efficiency.At the same time, we study two kinds of wireless signal real-time processing algorithms, involving the real-time processing algorithm for a received signal of channel sounding based on PN sequence and LTE downlink signal sequence. Some technologies, such as the autocorrelation characteristics of the PN sequence for sliding correlation calculation, the modular program design, parallel programming, multi-threaded programming and FFTW (the Faster Fourier Transform in the West) standard assemblies, are employed for implementation of the algorithms. The most important parameter for channel characterization, PDP (Power Delay Profile), can be extracted by the algorithms. It also can be plotted and displayed by the designed software interface. Besides, extensive experimental back to back calibrations in laboratory are performed to validate the proposed algorithms.Finally, we conduct the field channel measurement in indoor and outdoor scenarios, employing the established channel sounding system and corresponding processing algorithms. Multipath delay characteristics of the measured channel are analyzed based on the collected PDP data.The derived results are consistent with the expected results, which ensure the reliability and feasibility of the proposed algorithms further.Innovation of this paper is mainly reflected in the following points:â… . According to the characteristics and needs of the radio channel measurement, we set up a radio channel measurement system platform, and prove it feasible through field measurements.â…¡.The procedures of the real-time processing algorithm for a received signal of channel sounding based on PN sequence and LTE downlink signal sequence are developed. The real-time processing results of radio signals are displayed on PC interface. And the procedures are applied to the channel sounding system. Based on experiments and field measurements, the proposed algorithms are verified in terms of the correctness, reliability and applicability.â…¢.Using the channel measurement system and the designed wireless signal processing program, radio channel measurements are conducted in different propagation scenarios. According to analysis of the measurement results, some useful conclusions are obtained.