The ability to perform device-to-device (D2D) communication in Long Term Evolution (LTE)-based cellular networks became possible with the introduction of Proximity Services (ProSe) functionalities in the 3rd Generation Partnership Program (3GPP) specifications. In this paper, we provide a description of the ProSe implementation that extends the LTE model already available in ns-3. Our model contains key features defined in LTE Release 12 and further enhanced in LTE Release 13 related to synchronization, discovery, and communication. We also provide validation of each feature by comparing simulation results with analytical models developed as part of our work on D2D communication.

/pdf/implementation-and-validation-of-an-lte-d2d-model-for-ns-3-21arkgqkbk.pdf

Implementation and Validation of an LTE D2D Model for ns-3

The 3rd Generation Partnership Project released the cellular vehicular-to-everything (C-V2X) specifications as part of the LTE framework in Release 14. C-V2X is the alternative to dedicated short range communications and both are specifically designed for V2X control signaling. C-V2X extends the device-to-de-vice specifications by adding two more modes of operation targeting the vehicular environment in coverage and out of coverage of LTE base stations. Vehicle-to-vehicle communications (V2V) is established with Mode 4, where the devices schedule their transmissions in a distributed way employing sensing-based semi-persis-tent scheduling (SPS). Research is needed to assess the performance of SPS, especially in congested radio environments. This paper presents the first open-source C-V2X simulator that enables such research. The simulator is implemented in ns-3. We analyze the effect of the Mode 4 resource pool configuration and some of the key SPS parameters on the scheduling performance and find that the resource reservation interval significantly influences packet data rate performance, whereas resource reselection probability has little effect in dense vehicular highway scenarios. Our results show that proper configuration of scheduling parameters can significantly improve performance. We conclude that research on congestion control mechanisms is needed to further enhance the SPS performance for many practical use cases.

Performance Analysis of Sensing-Based Semi-Persistent Scheduling in C-V2X Networks

To prevent economic losses, maintain social order, and protect the well-being of the populace during public safety and crisis recovery scenarios, such as man-made and natural disasters, the efficient and effective delivery of time-critical information to first responders and victims plays a key role. Nonetheless, too often, the communication infrastructures that enable time-critical information delivery become dysfunctional, due to traffic overloads or physical damage. Thus, the user-side solution [e.g., device-to-device (D2D) communications] and the network-side solution [e.g., dynamic wireless networks (DWNs)] are essential communication techniques that can enhance or restore communication for responders and victims in the harsh environment associated with public safety scenes. While D2D has been widely studied and investigated in legacy/commercial communication networks, as well as DWN, little work has been done toward adapting D2D and DWN from a public safety perspective. In this survey, we first design a layered structure, consisting of the public safety service layer, time-critical information delivery layer, and physical object layer, from which to consider the public safety system and its key components. We then extensively review research efforts on both D2D and DWN as complimentary user-side and network-side communication techniques toward effective public safety communications. Particularly, we investigate the approaches and standardization progress of D2D and DWN for public safety communications. Finally, we provide insights into challenges and potential solutions regarding D2D, DWN, security and resilience, and performance evaluation of public safety communication, as well as the integration of state-of-the-art communication and computing technologies to further improve time-critical information delivery in various public safety scenarios.

Survey of Public Safety Communications: User-Side and Network-Side Solutions and Future Directions

Autonomous vehicles, on the ground and in the air, are the next big evolution in human mobility. While autonomous driving in highway scenarios is already possible using only the vehicles sensors, the complex scenarios of big cities with all its different traffic participants is still a vision. Cellular Vehicle-to-Everything (C-V2X) communication is a necessary enabler of this vision and and an emerging field of interest in today's research. However, to the best of our knowledge open source simulators essential for open research do not exist yet. In this work we present our open source C-V2X mode 4 simulator based on the discrete-event network simulator ns-3. To analyze the performance of C-V2X mode 4 using our simulator, we created a worst case scenario and the 3GPP reference Manhattan grid scenario using the microscopic traffic simulator SUMO. We also added the WINNER+ B1 channel model to ns-3, as this is also used by 3GPP. Our results show, that C-V2X is scalable to 250 vehicles within a worst case scenario on a playground of 100 m x 100 m, with respect to the LTE rel. 14 V2X requirements. For the more realistic Manhattan grid scenario, the performance is better, as to be expected. We also analyzed the Packet Inter-Reception time with an outcome of max. 100 ms for more than 99 % of all transmissions. In addition, we investigated the impact of the Resource Reservation Period and the Resource Reselection Probability on the system's Packet Reception Ratio.

Performance Analysis of C-V2X Mode 4 Communication Introducing an Open-Source C-V2X Simulator

The Third Generation Partnership Project (3GPP) has recently published a new set of specifications to enable advanced driving applications in fifth generation (5G) vehicle-to-everything (V2X) scenarios, with particular effort dedicated to the sidelink resource allocation in the autonomous mode, named Mode 2. In this paper, we conduct a comprehensive analysis of Mode 2 performance via an open-source system-level simulator, which implements the 5G New Radio (NR) flexible numerology and physical layer aspects together with the newly specified sidelink resource allocation modes for V2X communications and different data traffic patterns. Results collected through extensive simulation campaigns, under a wide variety of vehicle density, data transmission settings and traffic patterns, showcase the effects of the new 5G-V2X features on the sidelink resource allocation performance and provide some insights into possible ways to further improve Mode 2 performance.

/pdf/performance-analysis-of-sidelink-5g-v2x-mode-2-through-an-36my5dvam7.pdf

Performance Analysis of Sidelink 5G-V2X Mode 2 Through an Open-Source Simulator

User Equipments (UEs) that send data must advertise the upcoming transmission by broadcasting signaling messages over the Physical Sidelink Control Channel (PSCCH). Thus, it is important for the network operator to define the PSCCH resource pool to maximize the probability that each UE will be able to successfully decode all of the control messages that appear on the PSCCH. For UEs operating in Mode 2 (i.e., outside the coverage area of an eNodeB), this is especially challenging because there is no base station present that can assign PSCCH resources. UEs must choose pool resources randomly, which can lead to collisions of transmitted messages. In addition, UEs are half-duplex and a poorly designed control channel resource pool can create a significant risk that a signaling message and its duplicate will be missed by a UE that transmits its own signaling message in the same pair of subframes. In this paper, we present an analytical model that allows us to develop closed form expressions for the distribution of the number of UEs that successfully receive a transmitted message on the PSCCH. This model can support PSCCH design by network operators, and can be used to investigate other aspects of D2D communications.

Physical Sidelink Control Channel (PSCCH) in Mode 2: Performance analysis

In this paper, we provide an overview of our ongoing implementation of a 3 rd Generation Partnership Program (3GPP) Proximity Services (ProSe) module in ns-3 to enable the performance evaluation of device-to-device (D2D) discovery and communication in Long Term Evolution (LTE) networks.

https://hal.archives-ouvertes.fr/hal-01501725/document

A Long Term Evolution (LTE) Device-to-Device module for ns-3

In many public safety scenarios, Device-to-Device (D2D) communication should be capable of handling out-of-coverage situations, ensuring that D2D devices can communicate directly without the aid of network infrastructure. In this paper, we investigate a set of distributed resource allocation schemes for out-of-coverage D2D group communication. Particularly, we first provide guidelines concerning how to allocate D2D resources based on Modulation and Coding Scheme (MCS), Physical Resource Block (PRB) size, and Time Resource Pattern (TRP) to meet the Quality of Service (QoS) requirements of applications. We then design three distributed resource allocation schemes that select PRBs in the resource pool and/or adjust the transmitting power based on the level of available information about the network. To evaluate the designed distributed resource allocation schemes, we conduct extensive performance evaluation, validating their effectiveness in a variety of deployment scenarios.

Distributed Resource Allocation Schemes for Out-of-Coverage D2D Communications

This paper examines the performance of the Long Term Evolution (LTE) Physical Sidelink Shared Channel (PSSCH) in out-of-coverage (OOC) device- to-device (D2D) communication scenarios. We develop a closed form expression for the distribution of the number of User Equipments (UEs) that successfully decode a message sent on the PSSCH, given the number of UEs that received the transmitter's Sidelink Control Information (SCI) message over the Physical Sidelink Control Channel (PSCCH). We validate our results using Monte Carlo simulations of the PSSCH and network simulations in ns-3, and discuss some of the effects of system parameters on performance.

Fernando J. Cintron

Papers

Implementation and Validation of an LTE D2D Model for ns-3

Physical Sidelink Control Channel (PSCCH) in Mode 2: Performance analysis

A Long Term Evolution (LTE) Device-to-Device module for ns-3

Distributed Resource Allocation Schemes for Out-of-Coverage D2D Communications

Modeling and Simulation Analysis of the Physical Sidelink Shared Channel (PSSCH)