如何在Gnuradio中进行通道测量？-HowtodoChannelmeasurementsinGnuradio?

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If you trying to measure the impulse response of the channel, then one technique would be to transmit a known pseudo-random bit sequence (an m-sequence) using BPSK modulation at the carrier frequency of interest. The chip rate of the sequence determines the measurement system bandwidth, while the sequence length determines the 'dynamic range' of the measurement.

如果您试图测量信道的脉冲响应,则一种技术是在感兴趣的载波频率上使用BPSK调制发送已知的伪随机比特序列(m序列)。序列的码片速率决定了测量系统的带宽,而序列长度决定了测量的“动态范围”。

At the receiver set the LO to the same carrier frequency as that at the transmitter. Here you need to cross-correlate the equivalent low-pass received signal with the known m-sequence to give the (complex) impulse response of the channel. Any 'peaks' that exceed your definition of a threshold noise level would be your channel coefficients in the time domain.

在接收器处将LO设置为与发射器处的载波频率相同的载波频率。在这里,您需要将等效的低通接收信号与已知的m序列进行互相关,以给出通道的(复数)脉冲响应。任何超出阈值噪声水平定义的“峰值”都将是您在时域中的通道系数。

This is actually implemented in gr-sounder.

这实际上是在gr-sounder中实现的。

The channel sounder transmitter is sending the PRNG modulated BPSK at 32 Mchips/sec. You need to do the correlation at this speed; it's not possible to send that much data over the USB to the host.

通道发声器发射器以32 Mchips / sec发送PRNG调制BPSK。你需要以这种速度进行相关;无法通过USB将大量数据发送到主机。

A channel sounder in software would work for chip rates less than 4 Mchip/sec. But that limits the resolution of your impulse response to about 250 ns per bin, or 75 meters per bin in the spatial domain.

软件中的通道发声器可用于小于4 Mchip / sec的芯片速率。但这会将您的脉冲响应的分辨率限制为每箱约250 ns,或空间域中每箱75米。

Unfortunately, the cross-correlation done on the very limited space FPGA has no frequency offset compensation, so the resulting impulse response vectors "roll" in the time domain.

不幸的是,在非常有限的空间FPGA上完成的互相关没有频率偏移补偿,因此产生的脉冲响应矢量在时域中“滚动”。

-- answer (c) by Johnathan Corgan

- 由Johnathan Corgan回答(c)