Enhanced Random Access with Beamforming Techniques in 5G Networks

In cellular networks, User Equipments (UEs) must perform a Random Access (RA) process in which UEs are allocated resources for data transmission from the Base Station (BS). The 5G network using the high-frequency band adopts the beamforming technology in order to overcome the high path-loss. As the narrow coverage characteristic of the beam, the BS and UEs use the beam-sweeping and beam-switching methods at the RA process. In this paper, we propose an Enhanced Random Access (E-RA) process, in which the UE selects multiple preambles and transmits them through the beam-sweeping method, and transmits the Connection Request Message (Msg3) through the random beam-switching method. Furthermore, we also propose an improved re-access process that begins with Msg3 retransmission. Through the E-RA process, we can reduce the access delay of the network and the number of transmitted messages causing the energy consumption of the UE and increase the success probability of the RA process.