Power allocation in the energy harvesting full-duplex Gaussian relay channels (original) (raw)
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Communication and Information Theory (IWCIT), 2013 Iran Workshop on , 2013
Energy Harvesting (EH) is a novel technique to prolong the lifetime of the wireless networks such as wireless sensor networks or Ad-Hoc networks, by providing an unlimited source of energy for their nodes. In this sense, it has emerged as a promising technique for Green Communications, recently. On the other hand, cooperative communication with the help of relay nodes improves the performance of wireless communication networks by increasing the system throughput or the reliability as well as the range and efficient energy utilization. In order to investigate the cooperation in EH nodes, in this paper, we consider the problem of optimal power and rate allocation in the degraded full-duplex Gaussian relay channel in which source and relay can harvest energy from their environments. We consider the general stochastic energy arrivals at the source and the relay with known EH times and amounts at the transmitters before the start of transmission. This problem has a min-max optimization form that along with the constraints is not easy to solve. We propose a method based on a mathematical theorem proposed by Terkelsen [1] to transform it to a solvable convex optimization form. Also, we consider some special cases for the harvesting profile of the source and the relay nodes and find their solutions efficiently.
Optimal resource allocation for energy harvesting two-way relay systems with channel uncertainty
2013 IEEE Global Conference on Signal and Information Processing, 2013
In this paper, we consider two-way decodeand-forward (DF) multiple access and time division broadcasting relaying protocols with energy harvesting (EH) nodes. We propose optimal offline joint energy and transmission time allocation schemes for the considered relaying protocols taking into account channel state uncertainty. The proposed joint energy and transmission time allocation schemes are obtained based on convex optimization problems and maximize the aggregate system throughput over a finite number of transmission intervals. We compare the optimal throughputs obtained for the multiple access and time division broadcasting protocols via simulations. Our results reveal that the proposed schemes are robust to imperfect channel state information and that multiple access broadcasting is less affected by low harvesting rate at the relay than time division broadcasting.
Energy Minimization for the Half-Duplex Relay Channel with Decode-Forward Relaying
IEEE Transactions on Communications, 2013
We analyze coding for energy efficiency in relay channels at a fixed source rate. We first propose a half-duplex decode-forward coding scheme for the Gaussian relay channel. We then derive three optimal sets of power allocation, which respectively minimize the network, the relay and the source energy consumption. These optimal power allocations are given in closed-form, which have so far remained implicit for maximumrate schemes. Moreover, analysis shows that minimizing the network energy consumption at a given rate is not equivalent to maximizing the rate given energy, since it only covers part of all rates achievable by decode-forward. We thus combine the optimized schemes for network and relay energy consumptions into a generalized one, which then covers all achievable rates. This generalized scheme is not only energy-optimal for the desired source rate but also rate-optimal for the consumed energy. The results also give a detailed understanding of the power consumption regimes and allow a comprehensive description of the optimal message coding and resource allocation for each desired source rate and channel realization. Finally, we simulate the proposed schemes in a realistic environment, considering path-loss and shadowing as modelled in the 3GPP standard. Significant energy gain can be obtained over both direct and two-hop transmissions, particularly when the source is far from relay and destination.
Full-Duplex Energy-Harvesting Enabled Relay Networks in Generalized Fading Channels
—This paper analyzes the performance of a full-duplex decode-and-forward relaying network over the generalized κ-µ fading channel. The relay is energy-constrained and relies entirely on harvesting the power signal transmitted by the source based on the time-switching relaying protocol. A unified analytical expression for the ergodic outage probability is derived for the system under consideration. This is then used to derive closed-form analytical expressions for three special cases of the κ-µ fading model, namely, Nakagami-m, Rice and Rayleigh. Monte Carlo simulations are provided throughout to verify the correctness of our analysis.
Optimal Transmission Using a Self-Sustained Relay in a Full-Duplex MIMO System
IEEE Journal on Selected Areas in Communications
This paper 1 investigates wireless information and power transfer in a full-duplex MIMO relay channel where the self-sustained relay harvests energy from both source transmit signal and self-interference signal to decode and forward source information to a destination. We formulate a new problem to jointly optimize power splitting at the relay and precoding design for both the source and relay transmissions. Using duality theory, we establish closed-form optimal primal solutions in terms of the dual variables, based on which we then design a customized and efficient primal-dual algorithm to maximize the achievable throughput. Numerical results demonstrate the rate gains from using multiple transmit and receive antennas in both information decoding and energy harvesting, and the significant benefit of harvesting energy from self-interference signals. We also extend our analysis to the case when channel state information is only available at receiving nodes and show how our algorithm can optimize the power splitting at the relay for it to remain self-sustained. Through analysis and simulation, we demonstrate that an optimal combination of non-uniform power splitting, variable power allocation, and self-interference power harvesting can effectively exploit a full-duplex MIMO system to achieve significant performance gains over existing uniform power splitting and half-duplex transmissions.
Power management is significant criterion in Wireless Relay Networks (WRN) to increase the lifetime of the network. Energy harvesting is a recent emerging proficient method to attain the transmission power in a profuse level. So the use of energy harvesting is utilized for classic three node Gaussian relay channel with co-operative relaying of DecodeAmplify and Forward in order to achieve the superior energy levels thereby achieving the maximum throughput. In particular, two types of data traffic are compared to provide the best case which gives the maximum throughput. The source and relay nodes transmit with the power drawn from the EH source. Also the performance of co-operative relaying network is analyzed for both amplify- forward and decode- forward relaying.
IEEE Journal on Selected Areas in Communications, 2016
In this paper, we consider a multiuser multipleinput multiple-output (MIMO) decode-and-forward (DF) relay broadcasting channel (BC) with single source, multiple energy harvesting (EH) relays and multiple destinations. All the nodes are equipped with multiple antennas. The EH and information decoding (ID) tasks at the relays and destinations are separated over the time, which is termed as the time switching (TS) scheme. As optimal solutions for the sum-rate maximization problems of BC channels and the MIMO interference channels are hard to obtain, the end-to-end sum rate maximization problem of a multiuser MIMO DF relay BC channel is even harder. In this paper, we propose to tackle a simplified problem where we employ the block diagonalization (BD) procedure at the source, and we mitigate the interference between the relaydestination channels using an algorithm similar to the BD method. In order to show the relevance of our low complex proposed solution, we compare it to the minimum mean-square error (MMSE) solution that was shown in the literature to be equivalent to the solution of the sum-rate maximization in MIMO broadcasting interfering channels. We also investigate the time division multiple access (TDMA) solution which separates all the information transmissions from the source to the relays and from the relays to the destinations over time. We provide numerical results to show the relevance of our proposed solution, in comparison with the no co-channel interference (CCI) case, the TDMA based solution and the MMSE based solution.
Optimal Power Allocation Strategies in Two-Hop X-Duplex Relay Channel
IEEE Transactions on Communications, 2018
We consider a dual-hop, decode-and-forward network where the relay can operate in FD or HD mode (X-duplex relay). We model the residual self-interference as an additive Gaussian noise with variance proportional to the relay transmit power, and we assume a Gaussian input distribution at the source. Unlike previous work, we assume that the source is only aware of the transmit power distribution adopted by the relay, but not of the symbols that the relay is currently transmitting. This assumption better reflects the practical situation where the relay node forwards data traffic but modifies physical-layer or link-layer control information. We then identify the optimal power allocation strategy at the source and relay, which in some cases coincides with the HD transmission mode. We prove that such strategy implies either FD transmissions over an entire time frame, or FD/HD transmissions over a variable fraction of the frame. We determine the optimal transmit power level at the source and relay for each frame, or fraction thereof. We compare the performance of our scheme against reference FD and HD techniques, which assume that the source is aware of the symbols instantaneously transmitted by the relay, and show that our solution closely approaches such strategies.
Optimal Power Allocation Strategies in Full-duplex Relay Networks
ArXiv, 2017
In this work, we consider a dual-hop, decode-and-forward network where the relay can operate in full- duplex (FD) or half-duplex (HD) mode. We model the residual self-interference as an additive Gaussian noise with variance proportional to the relay transmit power, and we assume a Gaussian input distribution at the source. Unlike previous work, we assume that the source is only aware of the transmit power distribution adopted by the relay over a given time horizon, but not of the symbols that the relay is currently transmitting. This assumption better reflects the practical situation where the relay node also forwards signaling traffic, or data originated by other sources. Under these conditions, we identify the optimal power allocation strategy at the source and relay, which in some cases coincides with the half duplex transmission mode. In particular, we prove that such strategy implies either FD transmissions over an entire frame, or FD/HD transmissions over a variable fraction o...
IEEE Transactions on Wireless Communications, 2017
This paper is devoted to the end-to-end performance analysis, optimal power allocation (OPA), and energyefficiency (EE) optimization of decode-and-forward (DF)-based full-duplex relaying (FDR) and half-duplex relaying (HDR) systems. Unlike existing analyses and works that assume simplified transmission over symmetric fading channels, we consider the more realistic case of asymmetric multipath fading and shadowing conditions. To this end, exact and asymptotic analytic expressions are first derived for the end-to-end outage probabilities (OPs) of the considered DF-FDR set ups. Based on these expressions, we then formulate the OPA and EE optimization problems under given end-to-end target OP and maximum total transmit power constraints. It is shown that OP in FDR systems is highly dependent upon the different fading parameters and that OPA provides substantial performance gains, particularly, when the relay self-interference (SI) level is strong. Finally, the FDR is shown to be more energy-efficient than its HDR counterpart, as energy savings beyond 50% are feasible even for moderate values of the SI levels, especially at larger link distances, under given total transmit power constraints and OP requirements.