Separation Framework: An Enabler for Cooperative and D2D Communication for Future 5G Networks

Abstract

Soaring capacity and coverage demands dictate that future cellular networks need to migrate soon toward ultra-dense networks. However, network densification comes with a host of challenges that include compromised energy efficiency, complex interference management, cumbersome mobility management, burdensome signaling overheads, and higher backhaul costs. Interestingly, most of the problems that beleaguer network densification stem from legacy networks' one common feature, i.e., tight coupling between the control and data planes regardless of their degree of heterogeneity and cell density. Consequently, in wake of 5G, control and data planes separation architecture (SARC) has recently been conceived as a promising paradigm that has potential to address most of the aforementioned challenges. In this survey, we review various proposals that have been presented in the literature so far to enable SARC. More specifically, we analyze how and to what degree various SARC proposals address the four main challenges in network densification, namely: energy efficiency, system level capacity maximization, interference management, and mobility management. We then focus on two salient features of future cellular networks that have not yet been adapted in legacy networks at wide scale and thus remain a hallmark of 5G, i.e., coordinated multipoint (CoMP) and device-to-device (D2D) communications. After providing necessary background on CoMP and D2D, we analyze how SARC can particularly act as a major enabler for CoMP and D2D in context of 5G. This article thus serves as both a tutorial as well as an up-to-date survey on SARC, CoMP, and D2D. Most importantly, this survey provides an extensive outlook of challenges and opportunities that lie at the crossroads of these three mutually entangled emerging technologies

Joint Energy-Spectral-Efficiency Optimization of CoMP and BS Deployment in Dense Large-Scale Cellular Networks

“…It is widely recognized that a promising technique of increasing the network capacity is that of shrinking the coverage area of base stations (BSs) with the spectral resource spatially reused as densely as possible [2]- [5]. However, the tremendous increase in the number of BSs and mobile devices will inevitably lead to fast-rising energy cost and severe interference caused by the massive number of BSs deployed in self-organized patterns.…”

“…The term 'BS deployment' in this context refers to the positioning of the BSs and how the deployed BSs operate, i.e., switched on or off. Traditional BS deployment is designed for worstcase ubiquitous coverage scenarios, which often results in the under-utilization of the BSs whilst consuming considerable energy to maintain cellular coverage even under the scenario of only supposing few users [5]. Therefore, it is vital to conserve energy by exploiting both the temporal and geographic fluctuations of the users' behaviors, such as the network's mobile traffic intensity and the users' required service rates, in dense cellular networks.…”

A Novel Approach for Centralized 3D Radio Resource Allocation and Scheduling in Dense HetNets for 5G Control-/User-plane Separation Architectures

“…Because of allocating resources to all MUs and FUs at the central station, Unlike traditional decentralized CUSA [15][16], the main advantage of CrrAS is that there is no need for exchanging control signaling between C-plane and U-plane BSs for synchronization, FCBSs' transmit power switching on/off, and SC discovery and wake up mechanism required in CUSA. This results in reducing the control signaling overhead and increasing the user data traffic capacity in the backhaul.…”

“…Further, in contrast to traditional coupled control-plane and user plane (C-/U-plane) network, C-/Uplane separation architectures (CUSAs), also termed as device centric networks [13], have been considered as a potential solution for 5G, and an extensive research is ongoing on CUSA [14][15][16] either by considering routing control-plane (C-plane) traffic of a SC with the SCBS itself [14] or the macrocell BS (MCBS) [15][16]. Though the CUSA has been considered as one of the enabling technologies to address prospective features of 5G (e.g., a high indoor data rate, resource utilization, and energy efficiency), to our best knowledge, no existing works addressed the issue of a centralized allocation and scheduling of 3D radio resources, namely time, frequency, and power, in CUSA based 5G, which we aim to address in this paper.…”

Nyquist-SEFDM: Pulse shaped multicarrier communication with sub-carrier spacing below the symbol rate

“…In future 5G networks, a thousand-fold wireless traffic increase is predicted from 2020, originating from over 50 billion connected devices [2]. Such massive device connection and communication will be associated with the continuously emerging internet of things (IoT).…”