The application of multiple-input multiple-output (MIMO) over orthogonal time frequency space (OTFS) modulation is envisioned to provide high-data-rate wireless transmission in high-mobility environments. However, in these communication scenarios, the multiple-dimensional interference, which can generate from space, delay and Doppler domains, challenges the channel equalization and symbol detection at the MIMO-OTFS receiver. To tackle this issue, we propose a time-space domain channel equalizer, relying on the mathematical least squares minimum residual algorithm, to remove the channel distortion on data symbols. The proposed channel equalizer adopts a recursion method to achieve symbol estimates, which can realize fast convergence by leveraging the sparsity of MIMO-OTFS channel matrix. Instead of directly remapping the equalized OTFS symbols into data bits, we develop an enhanced data detection (EDD) scheme to iteratively demodulate the superposed multi-antenna signal. The EDD can not only realize the linear-complexity interference cancellation, but also efficiently reap the spatial and multi-path diversities of MIMO-OTFS channel. The simulations show the proposed channel equalization and EDD algorithms enable the MIMO-OTFS receiver to robustly demodulate multi-stream 256-ary quadrature amplitude modulation symbols, under a maximum velocity of 550 km/h at 5.9 GHz carrier frequency.

中文翻译：

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MIMO OTFS 系统的高效信道均衡和符号检测


预计在正交时频空间 (OTFS) 调制上应用多输入多输出 (MIMO)，可在高移动性环境中提供高数据速率无线传输。然而，在这些通信场景中，空间、延迟和多普勒域产生的多维干扰对 MIMO-OTFS 接收机的信道均衡和符号检测提出了挑战。为了解决这个问题，我们提出了一种时空域信道均衡器，依靠数学最小二乘最小残差算法来消除数据符号上的信道失真。所提出的信道均衡器采用递归方法来实现符号估计，可以利用MIMO-OTFS信道矩阵的稀疏性实现快速收敛。我们开发了一种增强型数据检测（EDD）方案来迭代解调叠加的多天线信号，而不是直接将均衡的 OTFS 符号重新映射为数据位。 EDD不仅可以实现线性复杂度的干扰消除，还可以有效地获得MIMO-OTFS信道的空间分集和多径分集。仿真表明，所提出的信道均衡和 EDD 算法使 MIMO-OTFS 接收器能够在 5.9 GHz 载波频率下的最大速度 550 km/h 下稳健地解调多流 256 进制正交幅度调制符号。