Network-Coded Macrocell Offloading in Femtocaching-Assisted Cellular Networks

Abstract

The femtocaching idea was proposed as a solution to compensate for the weak backhaul capacity, by deploying coverage-limited nodes with high storage capacity called femtocaches (FCs). In this paper, the macrocell offloading problem in femtocaching-assisted cellular networks is investigated. The objective is to minimize the number of transmissions by the macrocell base station (MBS) given that all requests should be served simultaneously to satisfy quality-of-experience (QoE) of the clients. We first formulate this MBS offloading problem as an optimization problem over a network coding graph, and show that it is NP-hard. Therefore, we propose an ONC-broadcast offloading scheme that exploits both broadcasting and opportunistic network coding (ONC) to minimize the number of required MBS transmissions. We utilize a random graph model to approximate the performance of the proposed ONC-broadcast scheme in terms of the resultant average number of transmissions by the MBS. Moreover, despite the complexity of finding the optimal solution for each and every case, we prove that this ONC-broadcast scheme is 2 asymptotically optimal, i.e., for large number of requests, the ONC-broadcast scheme achieves a similar macrocell offloading performance to that of the optimal solution. To implement the ONC-broadcast scheme, we devise a heuristic that employs a dual conflict graph or broadcasting at the FCs such that the remaining requests can be served using the minimum number of transmissions at the MBS.Simulations show that the dual graph scheme improves MBS offloading as compared to the traditional separate graph scheme. Furthermore, the simple heuristic proposed to implement the ONC-broadcast scheme achieves a very close performance to the optimal ONC-broadcast scheme.

Network Coding for Backhaul Offloading in D2D Cooperative Fog Data Networks

“…In this section, the simulation results are presented for the proposed algorithm in a cooperative D2D setting in comparison with a uncooperative decentralized conflict-free IDNC approach that was incorporated in [21]. The aim of both approaches is to reduce the number downloads from the servers.…”

“…This technique has recently gained much attention due to its instant decodability (as the name suggests) by using a simple XOR operation that results in reducing the computational complexity of the decoding at the end-users. It also provides a significant benefit to real-time communications, where studies in [4,14,20,21] show through heuristic algorithms utilizing IDNC results in significant performance improvements over uncoded transmissions in both centralized point-to-multipoint (PMP) and decentralized network settings.…”

Opportunistic Network Coding-Assisted Cloud Offloading in Heterogeneous Fog Radio Access Networks

“…In order to minimize the number of CBS orthogonal transmissions to the unserved clients in any one time epoch, a conventional ONC conflict graph, such as the one used in [7] is built. This graph is a special case of the above dual conflict graph with only the CBS as a transmitter, and only coding conflicts in generating edges (as there are no transmission conflicts here since the CBS is the only transmitter).…”

“…Such combined files can be decoded at the designated clients, thus simultaneously delivering a larger number of requested files compared to simple broadcast of uncoded source files. Our recent work [6], [7] has thoroughly studied the content delivery problem in an F-RAN like setting with homogeneous eRRHs (i.e., eRRHs that are all employing LTE technologies). However, this setting does not take into consideration the vast proliferation of smart phones, which have other embedded long and short range wireless technology cards such as WiFi, bluetooth, near-field communications (NFC), etc.…”

Implementation of Network-Coded Cooperation for Energy Efficient Content Distribution in 5G Mobile Small Cells

“…On the other hand, cooperative relaying leveraged the use of mobile clouds [27] to improve network performance in terms of throughput and resilience, and, as a result, it reduces the energy consumption of the system [28]. For example, Shnaiwer et al [29] proposed a NC broadcast offloading scheme in homogeneous cellular networks that offloads macrocell traffic into femtocells. The same authors expanded their work by adding ONC in the offloading scheme [20].…”