Energy Cooperation in Cellular Networks with Renewable Powered Base Stations

Abstract

In this paper, we propose a model for energy cooperation between cellular base stations (BSs) with individual hybrid power supplies (including both the conventional grid and renewable energy sources), limited energy storages, and connected by resistive power lines for energy sharing. When the renewable energy profile and energy demand profile at all BSs are deterministic or known ahead of time, we show that the optimal energy cooperation policy for the BSs can be found by solving a linear program. We show the benefits of energy cooperation in this regime. When the renewable energy and demand profiles are stochastic and only causally known at the BSs, we propose an online energy cooperation algorithm and show the optimality properties of this algorithm under certain conditions. Furthermore, the energy-saving performances of the developed offline and online algorithms are compared by simulations, and the effect of the availability of energy state information (ESI) on the performance gains of the BSs' energy cooperation is investigated. Finally, we propose a hybrid algorithm that can incorporate offline information about the energy profiles, but operates in an online manner. .sg 2 sources. Examples where such a scenario occurs include the deployment of BSs with renewable energy sources by Ericsson in Africa [1] and Huawei in Bangladesh [2].Although renewable energy sources are attractive for the above reasons, they also suffer from significantly higher variability as compared to conventional energy sources. As a result, even in BSs that deploy renewable energy sources, conventional energy sources, such as diesel generators or the power grid, is still required to compensate for the variability of the renewable energy sources. One practical method of mitigating the variability of renewable energy sources is through energy storage means such as fuel cells and batteries. Energy storage, however, is very costly to deploy and therefore, the amount of storage available at BSs will usually be quite limited. A key consideration in deploying BSs with renewable energy sources is minimization of the amount of conventional energy consumed, because it is only then cost-effective to deploy renewable energy sources and storage. A survey of issues involved in deploying renewable energy sources in BSs is given in [3]. Related work on deploying renewable energy sources in smart grids, not necessarily constrained to a communications systems setup can be found in [4], [5] and the references therein. Other than work in smart grid, a closely related area of research is in the area of energy harvesting for wireless communications, where several authors have proposed the idea of energy cooperation between different nodes in a communications network; see e.g. [6], and [7]. More broadly, the area of "green communications" has attracted significant attention from the communications community in recent years. For an overview of the many significant research activities in this area, interested readers may refer to, e.g., [8], [9], [10], [11], [1...

Performance Analyses of Renewable and Fuel Power Supply Systems for Different Base Station Sites

“…Recent studies show that such systems can offer significant energy savings if a joint energy and communication cooperation approach will be implemented. Actually, in the [18] and [19] novel paradigm based on the transfer of energy between BSSs over the electrical grid is presented, where the grid can be considered as an energy reservoir with ideally infinite capacity which enables two-way energy transfer among distributed BSSs. Such a concept allows the one BSS that has excess of energy to compensate the other that has a deficit due to either lower generation of renewable energy or higher demand of the users connected to the BS.…”

Cooperative energy harvesting communications with relaying and energy sharing

“…Since the base levels are fixed within each iteration, a directional water-filling procedure [6] can be used to find the optimal power allocation. Finally, transmit powers can be calculated by finding the optimal transfer rates δ i and γ i using (14). We remark that v s,i = βv r,i for h sps,i < h rpr,i , and v s,i = v r,i /α for h sps,i ≥ h rpr,i , implying that water levels are linearly related based on which transmitter is generous in that time slot.…”

“…More recent developments in energy harvesting communications includes the possibility of energy transfer between nodes [3], [12], [13], [14]. Of particular relevance is reference [3] where the two-hop model with one source one relay is studied when both nodes are energy harvesting and the source can unidirectionally transfer energy to the relay.…”

Renewable energy distribution in cooperative cellular networks with energy harvesting

“…The game is guaranteed to have at least one Nash equilibrium. Energy cooperation in energy harvesting networks has been explored recently, for instance, in [8], [9], where harvesting modules share a portion of their harvested energy with other harvesting modules. In [8], the optimal energy cooperation among a source and a relay is found that maximizes the network throughput.…”

“…The energy cooperation between two cellular BSs equipped with harvesting and hybrid modules is studied in [9]. In [9], the harvested energy and the demanded energy are considered to be deterministic and the optimal energy cooperation policy of BSs is derived.…”