Codebook Design for Air-to-Air Communication Systems Operating in the UAM Corridor

Urban air mobility (UAM) is a subset of advanced air mobility which is provisioned to reduce traffic congestion in and around urban areas. Unlike traditional transportation, UAM operates in the airspace, which brings safety issues. Thus, ensuring robust, high-rate data transmission is a prime concern to prevent collisions and share information among UAMs. With its wide bandwidth, millimeter wave communications are regarded as a promising solution for feasible air-to-air (A2A) communications for UAMs. To compensate for the large path loss at millimeter wave bands, the use of codebook based multiple-input multiple-output signal processing has been studied due to its quality performance with low complexity. Most of existing codebooks exploit codewords producing beam patterns with equal beamwidth. However, for better communication within the UAM corridor, it is essential to design a codebook which considers the unique topology of the UAM corridor. To deal with this issue, we have developed a codebook customized for A2A communications by exploiting the spatial characteristics of the UAM corridor. Furthermore, we propose a weighting-based beamwidth allocation method, which can enhance the efficiency of data transmission. Simulation results show that the proposed codebook exhibits lower outage probability and higher spectral efficiency than conventional codebooks.