Напиши небольшой текст выступления по introduction...
Tạo vào: 9 tháng 12, 2025
Trả lời bằng GPT-5.1 Thinking bởi Chat01
Tạo vào: 9 tháng 12, 2025
Trả lời bằng GPT-5.1 Thinking bởi Chat01
Напиши небольшой текст выступления по introduction части для этой презентации (первый файл). В качестве базы можешь еще использовать второй файл-статью. Текст на английском
Good afternoon, and thank you for attending this pre-defense. Today we will talk about Trainable FFT for beamspace selection in massive MIMO systems. Modern 5G and future 6G networks use base stations with up to 64 antennas and beyond, which means that the received signal in the frequency domain can be represented as a large matrix of size , where is the number of allocated subcarriers and is the number of receive antennas. Processing such a high-dimensional signal directly in the antenna domain leads to very high complexity in channel estimation and MIMO detection, as well as high fronthaul bandwidth requirements. (TFFT PreDefense slide.pdf)
Fortunately, in practice the wireless channel is sparse in the beamspace domain: most of the energy arrives only from a few dominant directions. This allows us to transform the received signal from the antenna domain to beamspace and keep only the strongest beams. Mathematically, we multiply by a beamspace transformation matrix and obtain a lower-dimensional matrix , whose columns correspond to the selected beams. As illustrated by the receiver diagram on the slide and in the reference article, this transformation is performed at the remote radio head, and all further operations—channel estimation, interpolation, MIMO detection and decoding—are done in the beam domain, which significantly reduces complexity. (TrainableFFT.pdf)
However, the standard way to construct this matrix is based on the Discrete Fourier Transform implemented via FFT. These FFT beams are fixed and are mainly tailored to uniform linear arrays, so in realistic antenna layouts they are not perfectly aligned with the true angles of arrival. This mismatch leads to a noticeable performance loss compared to more accurate but much more expensive methods such as SVD-based beamspace selection. Our goal in this work is to keep the low complexity of FFT-based processing, while making the transform trainable, so that its beams can adapt to the actual propagation environment and antenna geometry. In the rest of the presentation, we will first review existing beamspace selection methods and then introduce our proposed trainable FFT approach and its performance.