Starting from first principles of wave propagation, we consider a multiple-input multiple-output (MIMO) representation of a communication system between two spatially-continuous volumes. This is the concept of holographic MIMO communications. The analysis takes into account the electromagnetic interference, generated by external sources, and the constraint on the physical radiated power. The electromagnetic MIMO model is particularized for a pair of parallel line segments in line-of-sight conditions. Inspired by orthogonal-frequency division-multiplexing, we assume that the spatially-continuous transmit currents and received fields are represented using the Fourier basis functions. In doing so, a wavenumber-division multiplexing (WDM) scheme is obtained, which is not optimal but can be efficiently implemented. The interplay among the different system parameters (e.g., transmission range, wavelength, and sizes of source and receiver) in terms of number of communication modes and level of interference among them is studied with conventional tools of linear systems theory. Due to the non-finite support (in the spatial domain) of the electromagnetic channel, WDM cannot provide non-interfering communication modes. The interference decreases as the receiver size grows, and goes to zero only asymptotically. Different digital processing architectures, operating in the wavenumber domain, are thus used to deal with the interference. The simplest implementation provides the same spectral efficiency of a singular-value decomposition architecture with water-filling when the receiver size is comparable to the transmission range. The developed framework is also used to represent a classical MIMO system and to make comparisons. It turns out that the latter achieves better performance only when a higher number of radio-frequency chains is used.
翻译:从波波传播的第一条原则开始,我们考虑在两个空间连续的音量之间对通信系统进行多输出多重输出(MIMO)的表示。这是全息式MIMO通信的概念。 分析考虑到外部源产生的电磁干扰, 以及物理辐射功率的限制。 电磁MIMO模型是视线条件下一组平行线段的特异化。 由正方- 频率分解( 多重翻转) 所启发的, 我们假设空间连续传输流和接收字段是使用 Fourier 基函数代表的。 这样做, 获得了波数多路传输( WDM) 系统的概念, 这个系统不是最佳的, 但是可以高效地执行。 电磁电磁频道的不精确传输支持( 在空间域域域域内), WDMDM( ) 也代表着一个非精确的传输功能, 将一个稳定的电磁波结构转换到一个非交互的操作范围。 当使用时, 电磁电路路路路流结构的运行将一个不进行更精确的运行, 将一个更精确的功能变成一个比, 。 当使用时, 当使用时, 将一个数字的电路流结构变成一个更低的频率结构时, 将一个更精确的操作一个更精确的操作一个不进行一个不同的操作,,,, 将一个正常的频率的操作一个比,, 向一个正常的操作一个比, 向一个比, 向一个比, 向一个正常结构 将一个不同的 将 将一个 向一个, 向一个正常的 向一个正常的, 向一个正常的 将 向一个正常的, 向一个正常的 向一个正常的, 向一个正常的 向一个正常的操作结构 向一个 向一个 的 的 向 一个 的 的 的 的 向 一个, 的 将 向一个正常结构向一个 向一个 向一个正常结构 向一个 向一个 向一个 向一个 向一个 的 的 的 的 的 的 向一个 向一个 向一个 向一个 向一个 向一个 向一个 的 向一个 向一个 向一个