Towards Energy-efficient Resourceallocation In Heterogeneous Networks

With the wide-spread development of wireless applications and wireless equipments, the demand for wireless services increases in a high speed that has never been met. At the same time, the energy consumption increases with the development of wireless communications, the increase of energy consumption not only increase the production of carbon dioxides which may pollute the environment, but also enhance the operation expense of the operators. Thus, the issue of enhancing the energy efficiency of wireless networks need to be investigated. To increase the network throughput, expand the network coverage, and reduce the energy consumption, 3GPP proposes a novel network structure: Heterogeneous Networks(Het Nets), which integrates a set of low power consumption wireless access nodes into the deployment of macro nodes. Since the transmission distance between is less than that in macro nodes, Het Nets can enhance the network energy e fficiency effectively, that is, the energy consumption of Het Nets reduce while the Qo S of users can be guaranteed. The multi-layer network structure can increase the reuse frequency of frequency resources, and enhance the network spectrum efficiency. However, the high density, varying, and flexible site deployment scheme brings a novel chanllenge to the optimization of the network. The goal of this paper is to use resource allocation techniques to increase the energy efficiency of Het Nets, the content of this paper is:To fully utilize the network resources in Het Nets, the problem of joint relay selection and resource allocation is investigated in long term evolution advanced(LTE-A) downlink network by maximizing energy efficiency under certain constraints of quality of service(Qo S) and transmit power. Two joint relay selection and resource allocation schemes: single relay selection(SRS) and multiple relay coordination(MRC), are proposed. In the SRS scheme, evolved node base-station(e NB) connects to each user equipment(UE) with the help of only one relay node(RN). In the MRC scheme, the signal emitted by e NB can be forwarded by multiple relays, whereby spatial diversity provided by multiple relay nodes(RNs) can be exploited. With the purpose of maximizing energy efficiency, two joint relay selection and resource allocation algorithms are developed for SRS and MRC schemes, respectively. Simulation results show the characteristics of the two proposed schemes and demonstrate the effectiveness of the propos ed schemes in terms of energy efficiency, spectral efficiency, and energy consumption.A new transmission paradigm for the deployment of Het Nets in LTE-Advanced system proposes, where the Donor evolved node B(De NB) is able to cooperate with multiple relay nodes(RNs) in a crowdsourcing way, i.e., the De NB first distributes the reward to the distributive RNs, and the RNs conduct cooperative communication with other participants. Since RNs usually belong to independent profit entities, the motivation of participating in cooperative transmission is essential. In order to stimulate these RNs, we propose an incentive mechanism by exploiting the Stackelberg Game, where the De NB plays the role of the leader, while all participating RNs work as the followers. To derive the unique Stackelberg Equilibrium, we further devise an algorithm by which the utility of the De NB is maximized, and the RNs also reach the unique Nash Equilibrium where no RN can improve its utility by unilaterally changing its own transmission power. Extensive numerical simulations are conducted, and the results demonstrate the effectiveness and efficiency of our proposed incentive mechanism.An incentive mechanism to simulate relay nodes(RNs) to participate in cooperative transmission in multi-hop cellular networks(MCN) is designed. Since RNs and Donor evolved Node B(De NB) belong to profit independent entities, RNs require enough motivation for retransmission. We consider two transmission interactions in the transmission process: the interaction between De NB and the first layer RNs, and the interaction between two adjacent layers of RNs. We model the two interactions using the Stackelberg Game, where the De NB and the upper layer RN is the leader, while the first layer RNs and the lower layer RNs are the followers. We show how to compute the unique Stackelberg Equilibriums, when the utility of the De NB or the upper layer RN is maximized, and none of the first layer or lower layer RNs’ utilities can be improved by unilaterally deviating from their derived schemes. After numerical analysis, we demonstrate the effectiveness and efficiency of our proposed scheme.