A Survey on Device-to-Device Communication in Cellular Networks (1310.0720v6)

Abstract: Device-to-Device (D2D) communication was initially proposed in cellular networks as a new paradigm to enhance network performance. The emergence of new applications such as content distribution and location-aware advertisement introduced new use-cases for D2D communications in cellular networks. The initial studies showed that D2D communication has advantages such as increased spectral efficiency and reduced communication delay. However, this communication mode introduces complications in terms of interference control overhead and protocols that are still open research problems. The feasibility of D2D communications in LTE-A is being studied by academia, industry, and the standardization bodies. To date, there are more than 100 papers available on D2D communications in cellular networks and, there is no survey on this field. In this article, we provide a taxonomy based on the D2D communicating spectrum and review the available literature extensively under the proposed taxonomy. Moreover, we provide new insights to the over-explored and under-explored areas which lead us to identify open research problems of D2D communication in cellular networks.

• The paper presents a detailed taxonomy of D2D communications by categorizing them into Inband (Underlay and Overlay) and Outband (Controlled and Autonomous) modes.
• The paper demonstrates significant efficiency improvements, with metrics showing up to 374% spectral gains and enhanced energy efficiency through optimized resource allocation.
• The paper outlines future research directions including real-world testbeds, advanced interference management with machine learning, and SDN-based D2D integration.

A Comprehensive Survey on Device-to-Device Communication in Cellular Networks

The paper "A Survey on Device-to-Device Communication in Cellular Networks" by Asadi, Wang, and Mancuso delivers an exhaustive review of Device-to-Device (D2D) communication within cellular networks. As mobile data demands continue to surge, traditional cellular architectures struggle to keep pace. D2D communication, facilitating direct interaction between mobile devices bypassing base stations (BS), positions itself as a prime candidate to augment the efficiency of next-generation cellular networks.

Core Contributions

1. Taxonomy of D2D Communications: The authors systematically categorize existing literature into two major sections: Inband and Outband D2D communication. Inband communication is further split into Underlay and Overlay categories, while Outband communication is divided into Controlled and Autonomous subsets. This classification aids in comprehensively understanding the different approaches, advantages, and challenges associated with D2D communication.
2. Inband D2D Communication: Much of the literature centers on Inband communication where D2D interactions share the cellular spectrum.

- Underlay Inband D2D: Underlay D2D reuses cellular spectrum, enhancing spectral efficiency. However, it introduces significant complexities in managing interference. Techniques such as power control and resource allocation are pivotal. For instance, Kaufman et al. propose uplink resource reuse where D2D devices adjust transmission power to mitigate interference with the BS. Numerical results across various studies show potential spectral efficiency improvements ranging from 16% to 374%.

- Overlay Inband D2D: Here, dedicated resources are allocated for D2D communication, eliminating interference concerns but potentially reducing available resources for conventional cellular transmissions. Fodor et al. illustrate how network-assisted scheduling can increase energy efficiency from 0.8 bps/Hz/mW to 20 bps/Hz/mW.

1. Outband D2D Communication: In Outband D2D, communications occur on an unlicensed spectrum, such as WiFi Direct or Bluetooth, separating it physically from cellular links to avoid interference.

- Controlled Outband D2D: Cellular networks manage these D2D communications. For instance, Asadi et al. propose clusters of devices wherein a cluster head with the highest channel quality communicates with the BS, improving throughput by 50% and energy efficiency by 30% compared to Round Robin schedulers.

- Autonomous Outband D2D: This category does not require changes at the BS. Wang et al. present a downlink dispatching policy where users balance traffic load among themselves, achieving up to 50% reduction in file transfer delays.

Analytical Methods and Practical Insights

The review highlights that most works employ numerical simulations or heuristic methods due to the NP-hard nature of many optimization problems in D2D communications, such as interference management and resource allocation. Techniques like game theory, convex optimization, and auction algorithms appear frequently but are often simplified for tractability.

Implications and Open Research Directions

Though the extensive literature provides insights into the potential of D2D communications, it also underscores significant gaps and challenges:

• Interference and Power Control: Effective management in Underlay Inband D2D remains unresolved. Future work could leverage advanced machine learning methods for real-time interference prediction and power control optimization.
• Practical Implementations and Standards: While protocols like those introduced by 3GPP (e.g., Proximity Services, ProSe) outline necessary architectural changes, actual deployment needs detailed exploration. Integration of Software-Defined Networking (SDN) principles could offer flexible and programmable D2D management frameworks.
• Experimental Validation: The majority of studies rely on simulations. Real-world testbeds could provide deeper insights into the practical efficacy and unforeseen challenges of D2D communications under various network conditions and user behaviors.

In conclusion, this survey by Asadi, Wang, and Mancuso thoroughly navigates the prevailing research on D2D communications in cellular networks, elucidating the nuanced advantages, tackling unresolved challenges, and paving avenues for future exploration. As D2D moves closer to real-world implementation, tackling these challenges will be crucial for the evolution of next-generation cellular networks.