23 research outputs found
Reconfigurable Intelligent Surface MIMO Simulation using Quasi Deterministic Radio Channel Model
Reconfigurable Intelligent Surface (RIS) is a planar array that can control
reflection and thus can implement the concept of partially controllable
propagation environment. RIS received a lot of attention from industry and
academia, but the majority of the researchers who study RIS-assisted systems
use simple Rician model. Though it is suitable for theoretical analysis,
stochastic Non Line-of-Sight (NLoS) component in Rician model does not account
for the geometry of deployment. Furthermore, Rician model is not eligible to
evaluate 3GPP standardization proposals. In this article we adapt the popular
Quasi Deterministic Radio channel Generator (QuaDRiGa) for RIS-assisted systems
and compare it against Rician model. The comparison shows that
geometry-inconsistent NLoS Rician modeling results in higher estimated
achievable rate. Our method, in contrast, inherits the advantages of QuaDRiGa:
spatial consistency of Large Scale Fading, User Equipment mobility support as
well as consistency between Large Scale and Small Scale Fading. Moreover,
QuaDRiGa comes with calibrated scenario parameters that ensure 3GPP
compatibility. Finally, the proposed method can be applied to any model or
software originally designed for conventional MIMO, so every researcher can use
it to build a simulation platform for RIS-assisted systems.Comment: 5 pages, 3 figures, submitted to IEEE ANTS 202
A Wideband MIMO Channel Model for Aerial Intelligent Reflecting Surface-Assisted Wireless Communications
Compared to traditional intelligent reflecting surfaces(IRS), aerial IRS
(AIRS) has unique advantages, such as more flexible deployment and wider
service coverage. However, modeling AIRS in the channel presents new challenges
due to their mobility. In this paper, a three-dimensional (3D) wideband channel
model for AIRS and IRS joint-assisted multiple-input multiple-output (MIMO)
communication system is proposed, where considering the rotational degrees of
freedom in three directions and the motion angles of AIRS in space. Based on
the proposed model, the channel impulse response (CIR), correlation function,
and channel capacity are derived, and several feasible joint phase shifts
schemes for AIRS and IRS units are proposed. Simulation results show that the
proposed model can capture the channel characteristics accurately, and the
proposed phase shifts methods can effectively improve the channel statistical
characteristics and increase the system capacity. Additionally, we observe that
in certain scenarios, the paths involving the IRS and the line-of-sight (LoS)
paths exhibit similar characteristics. These findings provide valuable insights
for the future development of intelligent communication systems.Comment: 6 pages, 7 figure
BER Performance of Spatial Modulation Systems under a Non-Stationary Massive MIMO Channel Model
In this paper, the bit error rate (BER) performance of spatial modulation
(SM) systems is investigated both theoretically and by simulation in a
non-stationary Kronecker-based massive multiple-input-multiple-output (MIMO)
channel model in multi-user (MU) scenarios. Massive MIMO SM systems are
considered in this paper using both a time-division multiple access (TDMA)
scheme and a block diagonalization (BD) based precoding scheme, for different
system settings. Their performance is compared with a vertical Bell labs
layered space-time (V-BLAST) architecture based system and a conventional
channel inversion system. It is observed that a higher cluster evolution factor
can result in better BER performance of SM systems due to the low correlation
among sub-channels. Compared with the BD-SM system, the SM system using the
TDMA scheme obtains a better BER performance but with a much lower total system
data rate. The BD-MU-SM system achieves the best trade-off between the data
rate and the BER performance among all of the systems considered. When compared
with the V-BLAST system and the channel inversion system, SM approaches offer
advantages in performance for MU massive MIMO systems