A dynamic transmission strategy based on network slicing for cloud radio access networks

The Cloud Radio Access Network (C-RAN) has clearly emerged as a promising evolution of wireless networks. This architecture consists in decoupling the baseband units (BBUs) from the remote radio heads (RRHs). The BBUs are pooled in the same centralized BBU pool, while the RRHs are distributed through different distant sites. Typically, the one-to-one logical mapping consists in assigning one BBU to one RRH so that distinct frames are generated for each RRH. Also, a logical mapping of one BBU to many RRHs could be established in order to deliver the same frames of a single BBU to a cluster of RRHs. Motivated by the network slicing concept, we propose a hybrid transmission strategy where the resource units (RUs) of each frame are partitioned in two slices. The first one constitutes the unshared slice and is allocated to the cell center users (CCUs) according to the one-to-one logical mapping. The second slice is constituted by a quantity of RUs shared by a cluster of RRHs that belong to the same BBU. This last common slice is transmitted according to the one-to-many mapping in order to be allocated to the cell edge users (CEUs) and to the mobile users (MUs). We also present a flexible solution that dynamically adjusts the BBU-RRH mapping scheme (i.e., one-to-one, one-to-many or hybrid) based on the radio resource usage of BBUs. On the one hand, our proposed solution achieves close packet delay to the one-to-one configuration, while providing lower power consumption and handover frequency. On the other hand, in comparison with the one-to-many configuration, our technique provides lower packet delay and subsequently better Quality of Service (QoS).