Analytical Modeling of Mode Selection and Power Control for Underlay D2D Communication in Cellular Networks (1405.2017v2)

Abstract: Device-to-device (D2D) communication enables the user equipments (UEs) located in close proximity to bypass the cellular base stations (BSs) and directly connect to each other, and thereby, offload traffic from the cellular infrastructure. D2D communication can improve spatial frequency reuse and energy efficiency in cellular networks. This paper presents a comprehensive and tractable analytical framework for D2D-enabled uplink cellular networks with a flexible mode selection scheme along with truncated channel inversion power control. Different from the existing mode selection schemes where the decision on mode selection is made based only on the D2D link distance (i.e., distance between two UEs using D2D mode of communication), the proposed mode selection scheme for a UE accounts for both the D2D link distance and cellular link distance (i.e., distance between the UE and the BS). The developed framework is used to analyze and understand how the underlaying D2D communication affects the cellular network performance. Through comprehensive numerical analysis, we investigate the expected performance gains and provide guidelines for selecting the network parameters.

• The paper introduces a bias-based mode selection strategy considering both D2D and cellular link distances to optimize network performance.
• It employs a stochastic geometry analytical framework and truncated channel inversion power control to effectively manage interference.
• The approach reduces cellular SINR outage and D2D transmit power, enhancing network capacity for future 5G scenarios.

Analytical Modeling of Mode Selection and Power Control for Underlay D2D Communication in Cellular Networks

The paper by Hesham ElSawy and Ekram Hossain develops an analytical framework designed to analyze device-to-device (D2D) communication underlaying cellular networks. This framework evaluates dynamic mode selection for user equipment (UE) that accounts not only for D2D link quality, but also for the cellular link quality, a distinct departure from traditional approaches.

Major Contributions

The paper presents a new mode selection strategy for UEs in cellular networks integrating D2D communication. It proposes a biasing-based mode selection scheme that considers both D2D link distance and cellular link distance, introducing a flexible method to control the offloading of traffic from cellular infrastructure to D2D communication. The decision-making process is dictated by a parameter referred to as the D2D bias factor $T_d$. This mode selection scheme inherently offers interference protection to the cellular network by optimizing the use of the D2D mode based on simultaneous consideration of both link distances.

The authors demonstrate that their proposed mode selection scheme can effectively manage the interference trade-offs imposed by D2D communication and achieve superior performance compared to traditional distance-only based mode selection approaches. Specifically, their scheme results in significant reductions in cellular users' SINR outage probabilities and lower transmit power for D2D users for equivalent levels of link intensity.

Analytical Framework and Model Assumptions

A comprehensive analytical model using stochastic geometry is developed, making significant advancements in understanding the implication of joint mode selection and power control in D2D-enabled cellular networks. The framework utilizes Poisson point processes (PPPs) to model cellular network topology and UEs' spatial distribution. This is based on the finding that PPPs provide a sufficiently tight approximation to the actual system performance, offering both analytical tractability and generalized results across various network conditions.

The power control mechanism employed by UEs is based on truncated channel inversion. This mechanism attempts to maintain a certain signal power threshold at the receiver and considers both maximum power constraints and spatial proximity.

Numerical Results and Insights

The extensive numerical analysis confirms the effectiveness of the proposed framework. Results indicate that enforcing a balance between the energy efficiency of D2D communication and the SINR constraints at cellular network levels yields optimal network performance. Importantly, user densification and increasing bias towards D2D mode $(T_d > 1)$ can lead to increased network capacity, subject to control of cross-interference from D2D links.

Implications and Potential Future Research Directions

The implications of this research are multifold: First, it provides network operators with critical guidance on the parameter selection for traffic management in cellular environments with D2D support. Second, it sets a foundation for further exploration into flexible mode selection criteria that maximize network resource utilization while minimizing interference. Considering the potential scaling of D2D-enabled networks, there may be promising future avenues in enhancing interference management via cognitive network strategies.

The presented framework for single-tier networks can be adapted for multi-tier environments, which could offer useful insights into heterogeneous networking scenarios. An extension involving coordinated interference management could significantly enhance network throughput, confirming the potential of such integrated approaches in future 5G and beyond scenarios.

This work positions itself as a critical contribution to understanding and optimizing D2D communications' role within cellular networks, providing a baseline for more sophisticated future enhancements.