The potential of using millimeter-wave (mmWave) to encounter the current bandwidth shortage has motivated packing more antenna elements in the same physical size which permits the advent of massive multiple-input-multiple-output (MIMO) for mmWave communication. However, with increasing number of antenna elements, the ability of allocating a single RF-chain per antenna becomes infeasible and unaffordable. As a cost-effective alternative, the design of hybrid precoding has been considered where the limited-scattering signals are captured by a high-dimensional RF precoder realized by an analog phase-shifter network followed by a low-dimensional digital precoder at baseband. In this paper, the max-min fair problem is considered to design a low-complexity hybrid precoder for multi-group multicasting systems in mmWave channels. The problem is non-trivial due to two main reasons: the original max-min problem for multi-group multicasting for a fully-digital precoder is non-convex, and the analog precoder places constant modules constraint which restricts the feasible set of the precoders in the design problem. Therefore, we consider a low complexity hybrid precoder design to tackle and benefit from the mmWave channel structure. Each analog beamformer was designed to maximize the minimum matching component for users within a given group. Once obtained, the digital precoder was attained by solving the max-min problem of the equivalent channel.
翻译:使用毫米波(mmWave)来应对当前带宽短缺的潜能,促使使用毫米波(mmWave)来应对当前带宽短缺,使更多的天线元素被包装成相同体积,从而能够出现大型多投入-多输出(MIMO)的毫米Wave通信。然而,随着天线元素数量的增加,每天线分配单一RF链的能力变得不可行和负担不起。作为一个具有成本效益的替代办法,混合预译设计被考虑,当一个高维的RF预编码信号被一个高维的RF预编码器捕获时,一个模拟阶段变变换网络随后在基带出现一个低维的数码变换式数字预译器(MIMODR),在本文中,最大问题在于设计一个低兼容性混合组合组合的混合编码预译码预译码(MLOF), 将一个最易变异式的混合组合的组合(ILOFDR) 设计工具(ILO),将一个最易变式的组合中,将一个最易变式的混合的混合的组合(RO化的系统),将一个最易变的组合视为最易变的组合。