Intelligent Reflecting Surfaces Assisted Cellular V2X Based Open RAN Communications
Mohamad Abou Houran, Maimoona Asad, Gautam Srivastava, Jawad Mirza, Ali Ranjha, Muhammad Awais Javed, Xu Yang
Abstract
Open radio access networks (RAN) enhance the capabilities of traditional RAN by introducing features such as interoperability, open interfaces, software/hardware separation, and intelligence. Open RAN has several use cases in cellular vehicle-to-everything communications such as low-latency information exchange between vehicles and RAN intelligence controller (RIC). However, efficient data sharing between vehicles and RIC suffers from the challenges of signal loss due to mobility and dynamic channel conditions. In this regard, intelligent reflecting surfaces (IRS) have emerged as an intriguing concept of reconfigurable and smart environments to improve the performance of wireless communication systems. In the proposed research work, our main focus is on a multi-IRS aided single input single output system, where open RAN base stations (BS) convey information to a remote vehicular user. The transmitted signal is reflected by IRSs via multi-hop passive beamforming over pairwise line-of-sight links. To maximize the overall network sum-rate, we propose an IRS assignment method that allocates either a single IRS or multiple IRSs to each BS-user pair. In particular, the proposed algorithm consists of two stages, where in the first stage we perform <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$k$</tex-math></inline-formula> -means clustering to group the IRSs according to their location. In the next stage, for each group, we select the best IRS-assisted path (based on received signal strength) by transforming the original network into a trellis graph and using a trellis-search method. Simulation results show that the proposed technique outperforms existing IRS selection techniques in multiple IRS-enabled multi-hop communication systems.