# On Analyzing Beamforming Implementation in O-RAN 5G
## 1 Introduction  
The past few decades have seen extraordinary growth in wireless communication structure due to the approach of massive Internet of Things (IoT) and advanced real-time applications such as high-resolution video streaming, online gaming, vehicle-to-everything, self-driving vehicles, and other applications that are under development. However, these applications require high traffic-streaming bitrates and high quality of service (QoS), as well as a versatile network and flexible management technology. Unfortunately, the traditional radio access network (RAN) lacks enough flexibility, and, at the same time, the cost of network implementation will be high for the operators of the new application in traditional RAN. To overcome these challenges, the operators demand to contribute to the configuration of the mobile network by re-shaping the RAN network regarding their needs in order to achieve a cell network and equipment operating in a more software-driven, virtualized, flexible, intelligent, and energy-efficient way [1, 2]. The O-RAN Alliance has introduced an Open RAN solution that allows the operators to manage the network implemented by components from multiple vendors. O-RAN has mainly been introduced to support the application of the 5G and NR. To achieve this goal, the O-RAN Alliance has made nine workgroups to cover the O-RAN architecture. Examples of these workgroups tasks are the Non-Real-Time RAN Intelligent Controller and AI Interface, The Open Front-Haul Interfaces, Operations & Management (OAM), etc. Moreover, the Alliance has created O-RAN Focus Groups such as the Standard Development Focus Group, the Test & Integration Focus Group, the Open Source Focus Group, and the Security Focus Group. O-RAN is based on intelligence and openness principles,such as improved performance and agility and pushing towards an ecosystem of innovative, multi-vendor, interoperable, and autonomous RAN. Furthermore, O-RAN suggests open interfaces such as a front-haul interface that adopted a Split Option 7-2x from 3 GPP specifications between the open distributed unit (O-DU) and open radio unit (O-RU) [3; 4]. Split Option 7-2x enables flexibility in the implementation of O-DU and O-RU, so that vendors' operational expenditures (OPEX) may leverage the wide range of network optimizations such as, for example, better beamforming configuration. Improving the capability of beamforming and beam handling is one of the hot topics of the O-RAN concept. Based on O-RAN classification, beamforming can be implemented between O-DU and O-RU based on the Category A O-RU scheme and the Category B O-RU scheme. Our focus in this paper is Category B, where the advantage is that the front-haul bandwidth requirement should be comparatively low since it carries fewer bits, allowing many antennas without requiring high transport bandwidth. The challenge is that the O-RU design is more complex compared with Category A. If each O-RU measures beamforming matrices separately, there will be inter-RU interferences. However, using channel-information-based beamforming and applying zero-forcing precoding in O-RU, the inter-RU interferences can be eliminated. This paper presents the definition, function, current research challenges, and evolution of O-RAN beamforming methods. We discuss the drawbacks of current implementations principles of O-RAN for achieving ultra-reliable low-latency communication in scenarios with noise and/or interferences by comparing the transferred packet size of C-Plane through the front-haul in different beamforming methods. The paper is organized as follows.