Алгоритм выбора параметров передачи для апериодического URLLC-трафика в восходящем канале
Ultra-Reliable Low-Latency Communications (URLLC) is a key service for the fifth generation (5G) cellular systems. Typical requirements for this service are the transmission reliability above 99.999% and the latency below 1 ms. The paper considers a scenario with sporadic URLLC traffic in the uplink. To satisfy the strict latency requirements, User Equipments (UEs) use the grant-free channel access method. According to this method, the base station allocates time-frequency resources and selects transmission parameters (i.e., the modulation and coding scheme, number of transmission attempts) in advance for each UE. To provide high resource utilization in the case of sporadic traffic, the base station allocates shared channel resources to several UEs, which can lead to interference between transmissions of different UEs. The paper proposes an algorithm for transmission parameters selection for each UE that takes into account the channel conditions of each considered UE and the interference caused by transmissions of other UEs. Numerical results obtained with NS-3 show that the proposed algorithm up to six times increases the network capacity with respect to the algorithms presented in the literature.