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

Abstract

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-toone 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-toone 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).

Dynamic Cell-Less Radio Access Network Meta-Scheduler for High System Capacity Increase

“…This makes them to need much more RUs than usual to end their transmission. As the resource allocation is performed TS per TS in this example, the red mobile takes advantage that others mobiles have ended their transmission to transmit on the sub-carriers they previously used (RUs : (3,12), (5,12), (3,13), (5,13), (2,14) and ends on the RU (3,14)). However, considering that the red mobile is likely to do not have a good SNR on these sub-carriers and interferes mobiles of the RRH j, it is not always efficient that the red uses these RUs.…”

“…Depending on the channel state of this mobile and the number of RUs available, it could be more profitable for the system that the red waits for transmitting on sub-carriers 1 and 4. Notice that users from the RRH j are not interfered on the RUs (4,14), (5,14) and (6,14) as well as on the TS 15 since users from the RRH i have ended their transmission.…”

“…In C-RAN, most of the computational tasks can be considered as moved to BBU pool such as the channel state information estimation, the centralized signal processing management of the RAN etc [13]. On the other hand, the RRHs include radio antennas with their associated amplifier and are dispatched among several remote sites [14]. Thus, It is possible to distinguish different C-RAN oriented approaches.…”

“…In [14], the Hybrid Static (HS) strategy is presented. It is based on the analyze that giving resources to mobiles from different cells, at the same time and on the same frequency is better than protected them when the magnitude of interferences received is not significant.…”

A Two-Timescale Approach for Network Slicing in C-RAN

“…Costanzo et al in[35] proposed a prototype for network slicing in C-RAN based on Open Air Interface platform and FlexRAN SDN controller to handle the creation and configuration of network slices. Ezzaouia et al in[36] focused on slicing the BBU pool to establish a logical mapping between the BBU pool and RRHs.…”