Energy‐efficient opportunistic forwarding in multi‐hop cellular networks using device‐to‐device communications

Abstract

Cellular networks face significant capacity, efficiency and quality challenges because of the exponential growth of cellular data traffic. Multi-hop cellular networks (MCNs) have been proposed to address these challenges through the integration of cellular and device-to-device communications. This work investigates how the adoption and design of opportunistic store, carry and forward mechanisms in MCNs can help importantly decrease the energy consumption for delay tolerant traffic. To this aim, the study first derives an analytical framework to identify in two-hop scenarios the optimum mobile relay location and the location from which the mobile relay should start forwarding the information to the cellular base station in order to minimise the overall energy consumption. The derived optimum configuration is then used as a benchmark for the proposal and design of a novel context-based opportunistic MCN forwarding scheme that exploits context information provided at low cost by the cellular network. Numerical and simulation results demonstrate that the proposed contextbased opportunistic forwarding can achieve a performance close to that obtain with the optimum configuration and reduce the energy consumption by more than 90% compared with traditional single-hop cellular communications.

Energy benefits of opportunistic device-centric wireless networks

“…single-hop cellular communication or multi-hop cellular communication). In this context, this paper builds from the authors' previous results in [6][7], and proposes an integration of opportunistic networking and MCNs that takes into account the probabilistic availability of cellular radio resources.…”

“…The first study that analyzed the integration of opportunistic networking and MCNs was presented in [5], where the authors use information about the mobility of relays to derive routing policies that reduce the energy consumption and increase the spatial capacity. The authors presented in [6] an analytical optimization framework for two-hop opportunistic MCN communications where a Source Node (SN) transmits information to a Base Station (BS) using a Mobile Relay (MR). The framework derived the optimum locations at which the D2D (SN to MR) and cellular (MR to BS) transmissions should take place in order to reduce the energy consumption while satisfying the service QoS requirements.…”

“…Deriving these time values is actually equivalent to fInding the MR location at which the D2D transmission should start (Opt _ X,), and the MR location at which the cellular transmission should start (Opt_Y,). Further details about the optimization framework can be found in [6].…”

“…The scenario under evaluation considers that MR moves towards the BS. The opportunistic MCN transmission from SN to the BS needs to be completed before T. The time available to complete the end-to-end transmission (T) has to take into account: 1) the time needed for the D2D transmission from SN to MR (tD2D), 2) the time the MR stores and carr ies the information (tsc), and 3) the time needed by MR to upload the information to the BS (tCELL)' This study uses the optimization framework proposed in [6] to fInd the times tD2D, tsc, tCELL so that the end-to-end opportunistic MCN transmission satisfIes the QoS while minimizing the energy consumption:…”

“…NpRS has been set to 6 where pic is referred to as the utilization factor, and p is (7) equal to J-t·A. The distribution function of the time a cellular connection request waits in the system before being served can be estimated as [13]:…”