Enhancing the Capabilities of Mobile Backhaul: A User Plane Perspective

Avoiding problems such as packet loss in the transport network is crucial for mobile network providers to offer high-quality services reliably and without interruptions. In this paper, we propose and compare three different transmission strategies, namely Caching, Network Coding (NC) and Repetition enabled transmission in the User Plane (UP) of mobile backhaul for network operators to prevent such performance degradation. In the proposed NC-enabled transmission method, NC provides robustness to transport network failures such that no further retransmission is required by the User Equipment (UE) compared to conventional approaches where UE applications perform retransmissions. The proposed scheme requires only a minor modification to the packet structure of the UP protocol, which requires a small development effort and no new extensions to the current UE standard features. We also discuss their placement in the O-RAN protocol stack and in the core network, and propose a new architecture that can utilize caching, repetition and NC features in the mobile network architecture. Our simulation results show that an exact 1% packet loss ratio in the backhaul link results in an additional total transmission time of 59.44% compared to the normal GPRS Tunneling Protocol-User Plane (GTP-U) transmission. Applying NC at a rate of 1% and 2% reduces this value to 52.99% and 56.26%, respectively, which is also better than the total transmission time of some previously studied dynamic replication schemes while keeping the bandwidth utilization at low rates. On the cache side, a reduction in latency of about 20% can be achieved with a cache size of 100 MB. At the end of the paper, we summarize some of the benefits and limitations of using these three strategies in UP of mobile backhaul networks.