We propose an asynchronous acoustic chirp slope keying to map short bit sequences on single or multiple bands without preamble or error correction coding on the physical layer. We introduce a symbol detection scheme in the demodulator that uses the superposed matched filter results of up and down chirp references to estimate the symbol timing, which removes the requirement of a preamble for symbol synchronization. Details of the implementation are disclosed and discussed, and the performance is verified in a pool measurement on laboratory scale, as well as the simulation for a channel containing Rayleigh fading and Additive White Gaussian Noise. For time-bandwidth products (TB) of 50 in single band mode, a raw data rate of 100 bit/s is simulated to achieve bit error rates (BER) below 0.001 for signal-to-noise ratios above $-6$ dB. In dual-band mode, for TB of 25 and a data rate of 200 bit/s, the same bit error level was achieved for signal-to-noise ratios above 0 dB. The simulated packet error rates (PER) follow the general behavior of the BER, but with a higher error probability, which increases with the length of bits in each packet.

中文翻译：

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水下声通信的同步线性调频斜率键控

我们提出了一种异步声学线性调频斜率键控，以将短比特序列映射到单个或多个频带上，而无需在物理层上进行前同步码或纠错编码。我们在解调器中引入符号检测方案，该方案使用上下线性调频参考的叠加匹配滤波器结果估计符号时序，从而消除了符号同步的前同步码的要求。公开和讨论了实现的详细信息，并在实验室规模的池测量以及包含瑞利衰落和加性高斯白噪声的信道的仿真中验证了性能。对于单频带模式下的时间带宽乘积（TB）为50的情况，对于高于100的信噪比，将模拟原始数据速率为100 bit / s，以实现低于0.001的误码率（BER）。$-6$D b。在双频带模式下，对于25的TB和200 bit / s的数据速率，对于高于0 dB的信噪比，可以实现相同的误码级别。模拟的数据包错误率（PER）遵循BER的一般行为，但是具有较高的错误概率，该概率随每个数据包中比特长度的增加而增加。