Pilar Andres-Maldonado

Latency evaluation of a virtualized MME

Network Virtualization is one of the key technologies for developing the future mobile networks. In this paper we propose an LTE virtualized Mobility Management Entity queue model to evaluate its service time for a given signaling workload. Additionally, we provide a compound data traffic model for the future mobile applications, and we predict theoretically the control workload that it will generate. Finally, we evaluate the virtualized Mobility Management Entity overall mean delay by simulation, providing insights for selecting the number of processing instances for a given number of users.

Optimized LTE data transmission procedures for IoT: Device side energy consumption analysis

The efficient deployment of Internet of Things (IoT) over cellular networks, such as Long Term Evolution (LTE) or the next generation 5G, entails several challenges. For massive IoT, reducing the energy consumption on the device side becomes essential. One of the main characteristics of massive IoT is small data transmissions. To improve the support of them, the 3GPP has included two novel optimizations in LTE: one of them based on the Control Plane (CP), and the other on the User Plane (UP). In this paper, we analyze the average energy consumption per data packet using these two optimizations compared to conventional LTE Service Request procedure. We propose an analytical model to calculate the energy consumption for each procedure based on a Markov chain. In the considered scenario, for large and small Inter-Arrival Times (IATs), the results of the three procedures are similar. While for medium IATs CP reduces the energy consumption per packet up to 87% due to its connection release optimization.

Handover implementation in a 5G SDN-based mobile network architecture

Requirements for 5G mobile networks includes a higher flexibility, scalability, cost effectiveness and energy efficiency. Towards these goals, Software Defined Networking (SDN) and Network Functions Virtualization have been adopted in recent proposals for future mobile networks architectures because they are considered critical technologies for 5G. In this paper, we propose an X2-based handover implementation in an SDN-based and partially virtualized LTE architecture. Moreover, the architecture considered operates at link level, which provides lower latency and higher scalability. In our implementation, we use MPLS tunnels for user plane instead of GTP-U protocol, which introduces a significant overhead. To verify the correct operation of our system, we developed a simulator. It implements the messages exchange and processing of the primary network entities. Using this tool we measured the handover preparation and completion times, whose estimated values were roughly 6.94 ms and 8.31 ms, respectively, according to our experimental setup. These latencies meet the expected requirements concerning control plane delay budgets for 5G networks.

Virtualized MME Design for IoT Support in 5G Systems

Cellular systems are recently being considered an option to provide support to the Internet of Things (IoT). To enable this support, the 3rd Generation Partnership Project (3GPP) has introduced new procedures specifically targeted for cellular IoT. With one of these procedures, the transmissions of small and infrequent data packets from/to the devices are encapsulated in signaling messages and sent through the control plane. However, these transmissions from/to a massive number of devices may imply a major increase of the processing load on the control plane entities of the network and in particular on the Mobility Management Entity (MME). In this paper, we propose two designs of an MME based on Network Function Virtualization (NFV) that aim at facilitating the IoT support. The first proposed design partially separates the processing resources dedicated to each traffic class. The second design includes traffic shaping to control the traffic of each class. We consider three classes: Mobile Broadband (MBB), low latency Machine to Machine communications (lM2M) and delay-tolerant M2M communications. Our proposals enable reducing the processing resources and, therefore, the cost. Additionally, results show that the proposed designs lessen the impact between classes, so they ease the compliance of the delay requirements of MBB and lM2M communications.

Narrowband IoT Data Transmission Procedures for Massive Machine-Type Communications

Large-scale deployments of massive machine type communications involve several challenges on cellular networks. To address the challenges of massive machine-type communications, or more generally, the Internet of Things (IoT), the 3GPP has developed Narrowband IoT (NB-IoT) as part of Release 13. NB-IoT is designed to provide better indoor coverage, support of a massive number of low-throughput devices, with relaxed delay requirements, and lower energy consumption. NB-IoT reuses Long Term Evolution functionality with simplifications and optimizations. Particularly for small data transmissions, NB-IoT specifies two procedures to reduce the required signaling: one of them based on the control plane and the other on the user plane (UP). In this work, we provide an overview of these procedures as well as an evaluation of their performance. The results of the energy consumption show both optimizations achieve a battery lifetime extension of more than two years for a large range in the considered cases, and up to eight years for CP with good coverage. In terms of cell capacity relative to Service Request, CP achieves gains from 26 to 224 percent, and UP ranges from 36 to 165 percent. The comparison of CP and UP optimizations yields similar results, except for some specific configurations.

Reduced M2M signaling communications in 3GPP LTE and future 5G cellular networks

The increase of machine-to-machine (M2M) communications over cellular networks imposes new requirements and challenges that current networks have to handle with. Many M2M UEs (User Equipment) may send small infrequent data, which suppose a challenge for cellular networks not optimized for such traffic, where signaling load could increase significantly and cause congestion over the network. This paper evaluates current proposals to manage small transmissions over the Long Term Evolution (LTE) cellular network. We also propose a new Random Access-based Small IP packet Transmission (RASIPT) procedure for M2M UEs small data transmissions. Its main feature is data transfer without establishment of Radio Resource Control (RRC) connection to reduce signaling overhead. In our design, we assume a Software Defined Networking-based architecture for 5G system. When compared with current LTE scheme, our procedure reduces significantly the signaling load generated by M2M UEs small transmissions.

Analytical modeling for Virtualized Network Functions

Network Function Virtualization (NFV) is considered one of the key technologies for the 5G mobile networks. In NFV, network functions are implemented in software components denominated Virtual Network Functions (VNFs) running on commodity hardware. In this paper, we propose an analytical model based on an open queuing network of G/G/m queues to model VNFs with several components, and chains of VNFs. Our model is flexible and generic enough to capture the behavior of such systems. We validate our model by simulation. Specifically, we validate it for an LTE virtualized Mobility Management Entity with a three-tiered architecture use case. We also compare our model with the estate of the art, in terms of computational complexity and estimation error. The results show that our model has a computational complexity similar to the method for analyzing Jacksons networks. Additionally, our model exhibits an estimation error, measured as the relative error for the estimation of the mean response time, approximately equal to 10%, whereas for the considered baseline systems it ranges roughly from 60% to 90%.