Exact and Heuristic Solutions for Energy-Aware Multihop Cooperation over Wireless Networks

Abstract

This paper addresses the problem of energy-aware multihop cooperation among the mobile terminals that cooperatively download a common content from a wireless network. The base station unicasts or multicasts the content to selected mobile terminals that, in turn, either unicast or multicast it to other mobile terminals forming a multihop ad hoc network with a predefined maximum allowed number of hops. This work presents the optimization formulations whose solution gives the exact optimal set of receiving mobile terminals from the base station, the optimal multihop ad hoc network and the optimal unicasting and multicasting transmission bit rates that minimize the total energy consumption of the mobile terminals. Second, a simplified multicasting formulation is proposed that has a close-to-optimal performance with notably lower computational complexity. Third, interference avoidance among the transmitting mobile terminals is considered. For each presented formulation, the complexity is identified and results show that some formulations can be efficiently solved for medium network sizes while others are more computationally complex. Thus, polynomial time heuristic solutions are presented that have close-to-optimal performance. Results demonstrate remarkable energy consumption reduction gains and wireless resources savings in various network scenarios.

Energy-aware optimization and mechanism design for cellular device-to-device local area networks

“…Group communication is an application scenario of D2D LAN in which the BS receives a large number of requests for similar data. One class of this emerging mobile application is simultaneous multicasting of common real-time content to a group of MUs over the cellular band [2].…”

“…In D2D LAN, MUs actively transmit and receive data on two wireless links: one link to communicate with the BS over the cellular band, known as the long range (LR), and another link to communicate with other MUs in the D2D LAN, known as the short range (SR) link.Group communication is an application scenario of D2D LAN in which the BS receives a large number of requests for similar data. One class of this emerging mobile application is simultaneous multicasting of common real-time content to a group of MUs over the cellular band [2].Conventionally, when MUs request the same content, the BS can multicast it to all MUs. But in a D2D LAN, the BS only multicasts the content to a group of MUs, known as "the seeds" [2], who in turn forward it to the rest of MUs.…”

“…Several studies have proposed cellular offloading via D2D communication and the main goal of existing literature is reducing the energy consumption of MUs [2], [3] and [4]. The problem of finding the optimal energy-aware one-hop or multi-hop cooperation for all unicast/multicast combinations on LR and SR links is NP-hard as shown in [3].…”