Millimeter-wave (mmWave) communications provide access to spectra with
bandwidths and in abundance. However, the high susceptibility of mmWave to
blockage imposes crucial challenges, especially to low-latency services. In
this paper, a novel intelligent reflecting surface (IRS) assisted mmWave scheme
is proposed to overcome the impact of blockage. New methods are developed to
minimize the user power for a multi-user mmWave system by jointly optimizing
individual device power, multi-user detection matrix and passive beamforming,
subject to delay requirements. An alternating optimization framework is
delivered so that the joint optimization problem can be decomposed into three
subproblems iteratively optimized till convergence. In particular, closed-form
expressions are devised for the update of the powers and multi-user detection
vectors. The configuration of the IRS is formulated as a sum-of-inverse
minimization (SIMin) fractional programming problem and solved by developing a
new solution based on the alternating direction method of multipliers (ADMM).
The configuration is also interpreted as a latency residual maximization
problem, and solved efficiently by designing a new complex circle manifold
optimization (CCMO) method. Numerical results corroborate the feasibility and
effectiveness of our algorithms in terms of power saving, as compared with an
existing semidefinite relaxation technique.

该论文提出了一种智能反射面辅助毫米波通信方案，通过联合优化个体设备功率，多用户检测矩阵和被动波束成形来实现多用户毫米波系统中用户功率的最小化。使用了交替优化框架来支持同步迭代优化三个子问题，其中采用闭合形式表达了功率和多用户检测向量的更新。提出了一种新的解决方案，基于交替方向乘子法（ADMM），将方案的配置形式化为分数规划（SIMin），并将配置解释为延迟残留最大化问题，并通过设计新的复杂圆曼德尔优化（CCMO）方法高效地解决。最后，数值结果证实了该算法在功率节约方面的可行性和有效性，与现有的半定松弛技术相比。

智能反射面辅助上行毫米波系统中的时延约束联合功率控制、用户检测和被动波束成形

Delay-Constrained Joint Power Control, User Detection and Passive  Beamforming in Intelligent Reflecting Surface Assisted Uplink mmWave System

Conventional spatial modulation (SM) is typically considered for transmission
in the downlink of small-scale MIMO systems, where a single one of a set of
antenna elements (AEs) is activated for implicitly conveying extra bits. By
contrast, inspired by the compelling benefits of large-scale MIMO (LS- MIMO)
systems, here we propose a LS-SM-MIMO scheme for the uplink (UL), where each
user having multiple AEs but only a single radio frequency (RF) chain invokes
SM for increasing the UL-throughput. At the same time, by relying on hundreds
of AEs but a small number of RF chains, the base station (BS) can
simultaneously serve multiple users whilst reducing the power consumption. Due
to the large number of AEs of the UL-users and the comparably small number of
RF chains at the BS, the UL multi-user signal detection becomes a challenging
large-scale under-determined problem. To solve this problem, we propose a joint
SM transmission scheme and a carefully designed structured compressive sensing
(SCS)-based multi-user detector (MUD) to be used at the users and BS,
respectively. Additionally, the cyclic- prefix single-carrier (CPSC) is used to
combat the multipath channels, and a simple receive AE selection is used for
the improved performance over correlated Rayleigh-fading MIMO channels. We
demonstrate that the aggregate SM signal consisting of SM signals of multiple
UL-users in one CPSC block appears the distributed sparsity. Moreover, due to
the joint SM transmission scheme, aggregate SM signals in the same transmission
group exhibit the group sparsity. By exploiting these intrinsically sparse
features, the proposed SCS-based MUD can reliably detect the resultant SM
signals with low complexity. Simulation results demonstrate that the proposed
SCS-based MUD achieves a better signal detection performance than its
counterparts even with higher UL-throughtput.

本文提出了一种 LS-SM-MIMO 方案用于上行通信，该方案通过聚合多个用户的 SM 信号以增加 UL 吞吐量，并使用压缩感知和多用户检测以实现效率高、低复杂度的检测性能。