Intelligent Future Wireless Networks for Energy Efficiency: Overall Analysis and Standardization Activities

In order to meet the growing mobile data demand, future wireless networks will be equipped with a multitude of access points (APs). Besides the important implications for the energy consumption, the trend towards densification requires the development of decentralized and sustainable radio resource management techniques. It is critically important to understand how the distribution of signal processing operations affects the energy efficiency of wireless networks. In this paper, we provide a cross-layer framework to evaluate and compare the energy efficiency of wireless networks under different levels of distribution of the signal processing load: (i) hybrid, where the signal processing operations are shared between nodes and APs, (ii) centralized, where signal processing is entirely implemented at the APs, and (iii) fully distributed, where all operations are performed by the nodes. We find that in practical wireless networks, hybrid signal processing exhibits a significant energy efficiency gain over both centralized and fully distributed approaches.

Ever increasing user of electronic devices and high-data-rate applications has lead to continuous growing data traffic and hence carbon dioxide emission. Economical and environmental concern needs improved energy efficient network. As an energy efficient solution needs to outperform under various dynamic situations like varying traffic load, mobility, interference conditions etc Keeping in view of energy efficiency in wireless networks this paper aims at providing an extensive survey of the various researches at network architecture level for minimizing energy consumption in wireless mobile networks. A brief overview of the ongoing projects has also been discussed.

The desire for faster data speeds and increased Energy Efficiency has prompted the development of femtocells, which are short-range, low-cost, customer cellular access points. However, in a situation of Distributed Denial of Service (DDoS) which is caused by inefficient energy, distributed attack sources could be employed to amplify the assault and increase the attack's impact. By flooding the network with packets and creating malicious traffic, Distributed Denial of Service (DDoS) attacks try to deplete the network's communication and processing capability. A DDoS assault must be identified and neutralized quickly before a valid user can reach the attacker's target for 5G network to have an effective Energy Efficient service. For the next Fifth Generation (5G) Wireless Network, there is a pressing need to build an effective Energy Efficient mobile network solution. Despite their evident promise in assisting the development and deployment of the complicated 5G environment. The physical product, the digital product, and the relationship between both the physical and virtual goods are said to make up Digital Twin (DT). On the other hand, DT allows real-time communication with both the physical twins. The synergy of energy efficiency and security improvements in this research contributes to a more holistic optimization of 5G networks. This approach seeks to minimize energy consumption while fortifying the network against evolving security threats. Integrating energy-efficient practices with robust security measures enhances the overall resilience and sustainability of 5G systems. This is crucial for ensuring continuous, reliable, and secure communication in the face of dynamic challenges.

Unmanned aerial vehicles that abbreviates (UAVs) are flying platforms, known as drones, which have features such as mobility, adaptive altitude and flexibility. UAVs admit numerous applications that can be used as aerial base stations to enhance coverage, capacity, and energy efficiency of wireless networks. On the other hand, UAVs can operate as flying mobile terminals within a cellular network. Such cellular-connected UAVs can enable several applications ranging from real-time video streaming to item delivery. A Software Defined Network (SDN) Controller is the application that acts as a strategic control point in a software-defined network. It is the ’brain’ of the network. Controller manages flow control to the routers/switches ‘under’ (via southbound APIs), the business logic and applications ’above’ (via northbound APIs) to deploy intelligent networks. Wireless networking with software defined (SDWN) is the use of SDN conceptions in wireless networks by using a controller in the control plane. SDWN facilitates the creation of new adaptive mechanisms according to various applications and user requirements, such as mobility, handover, security and quality of service (QoS). In this paper, simulation work has been conducted to compare and investigate four SDN controllers (Pox, Ryu, Floodlight and OpenDaylight) in order to see which one is suitable to be used. Mininet-Wifi has been selected as the simulation tool to do the experiments and Python script for programming. The results obtained reveals that Ryu controller is the best selection in terms of latency and packet loss.

Network throughout and energy efficiency are of paramount importance for network performance in an energy-constrained wireless network. However, it is difficult to achieve optimal network throughout and energy efficiency simultaneously. So it is very necessary to find a solution based on tradeoff between network throughput and energy efficiency, which have not yet been well studied in existing works. In this paper, we present a cooperative differential game model and find a time-consistency solution by Shapley value which determines a fair distribution of the total cooperative cost among players.

The advent of network coding promises to change many aspects of networking. Network coding moves away from the classical approach of networking, which treats networks as akin to physical transportation systems. We overview some of the main features of network coding that are most relevant to wireless networks. In particular, we discuss the fact that random distributed network coding is asymptotically optimal for wireless networks with and without packet erasures. These results are extremely general and allow packet loss correlation, such as may occur in fading wireless channels. The coded network lends itself, for multicast connections, to a cost optimization which not only outperforms traditional routing tree-based approaches, but also lends itself to a distributed implementation and to a dynamic implementation when changing conditions, such as mobility, arise. We illustrate the performance of such optimization methods for energy efficiency in wireless networks and propose some new directions for research in the area.

Recently, energy efficiency in wireless networks has become an important objective. Aside from the growing proliferation of smartphones and other high-end devices in conventional human-to-human (H2H) communication, the introduction of machine-to-machine (M2M) communication or machine-type communication into cellular networks is another contributing factor. In this paper, we investigate quality-of-service (QoS)-driven energy-efficient design for the uplink of long term evolution (LTE) networks in M2M/H2H co-existence scenarios. We formulate the resource allocation problem as a maximization of effective capacity-based bits-per-joule capacity under statistical QoS provisioning. The specific constraints of single carrier frequency division multiple access (uplink air interface in LTE networks) pertaining to power and resource block allocation not only complicate the resource allocation problem, but also render the standard Lagrangian duality techniques inapplicable. We overcome the analytical and computational intractability by first transforming the original problem into a mixed integer programming (MIP) problem and then formulating its dual problem using the canonical duality theory. The proposed energy-efficient design is compared with the spectral efficient design along with round robin (RR) and best channel quality indicator (BCQI) algorithms. Numerical results, which are obtained using the invasive weed optimization (IWO) algorithm, show that the proposed energy-efficient uplink design not only outperforms other algorithms in terms of energy efficiency while satisfying the QoS requirements, but also performs closer to the optimal design.

Opportunistic spectrum access and adaptive power management are effective techniques to improve throughput, delay performance, and energy efficiency for wireless networks. In this paper, we consider the joint design of opportunistic spectrum access and adaptive power management under the setting of multi-radio nodes and multi-channel wireless local area networks (WLANs) under the distributed coordination function (DCF) mode. This design problem is particularly challenging due to the conflicting nature of the multi-radio capability of a node, i.e., multiple radios improve throughput and delay performance at the cost of increased energy consumption. To address this problem, we propose a power-saving multi-channel MAC protocol (PSM-MMAC), which is capable of reducing the collision probability and the waiting time in the ‘awake’ state of a node, resulting in improved throughput, delay performance, and energy efficiency. The key ideas of PSM-MMAC are the following: we first estimate the number of active links; given this estimation as well as queue lengths and channel conditions, we appropriately select channels, radios, and power states (i.e., awake or doze state); then we optimize the medium access probability in p-persistent CSMA used in the data exchange. Another contribution of this paper is an analytical model that characterizes the throughput performance. Simulation results validate the accuracy of our analytical model and show that our proposed protocol is able to significantly improve both throughput and energy efficiency.

In this paper, we describe GREENET (an early stage training network in enabling technologies for green radio), which is a new project recently funded by the European Commission under the auspices of the 2010 Marie Curie People Programme. Through the recruitment and personalized training of 17 Early Stage Researchers (ESRs), in GREENET we are committed to the development of new disruptive technologies to address all aspects of energy efficiency in wireless networks, from the user devices to the core network infrastructure, along with the ways the devices and equipment interact with one another. Novel techniques at the physical, link, and network layers to reduce the energy consumption and carbon footprint of 4G devices will be investigated, such as Spatial Modulation (SM) for Multiple-Input-Multiple-Output (MIMO) systems, Cooperative Automatic Repeat reQuest (C-ARQ) protocols, and Network Coding (NC) for lossy networks. Furthermore, cooperation and cognition paradigms will be exploited as additional assets to improve the energy efficiency of wireless networks with the challenging but indispensable constraint of optimizing the system capacity without degrading the user's Quality-of-Service (QoS).

This paper presents an initial study on how to model user mobility in a wireless cellular network scenario. The model provides realistic patterns of movement between a number of locations. The aforementioned mobility model is built upon to introduce a base station (BS) energy efficient power state control algorithm (EESC) that is able to provide significant energy savings for the simulated scenario. Erratic subsequent on and off BS behavior is avoided by referring to an average loading curve, generated for each BS during a learning period, when making decisions. Moreover, BSs are turned off only when the users can be handed off to nearby cells with a predefined maximum allowed predicted loss in data rate. The resulting system is able to deliver an energy consumption reduction between 36% and 11% over an always on benchmark for the simulated scenarios. There is negligible loss in terms of achieved data rate per user.

In wireless networks with energy limited nodes, user cooperation is usually exploited to reduce the network energy consumption. In many practical scenarios, however, nodes' selfishness raises doubts on whether each node will be willing to spend its valuable energy in forwarding packets for other users. To analyze this problem, a non-cooperative game theoretic framework is adopted in our work. Using this framework, the critical role of altruistic nodes in encouraging cooperation is established, both for small and large scale networks. In a small network, where nodes utilize the Decode-Forward scheme to cooperate, we show that a relay node, with appropriate strategy and location, successfully turns the Nash Equilibrium from no- cooperation to full-cooperation. In the large scale network, we show that it is sufficient to have a vanishingly small fraction of the nodes to be altruistic, i.e., relay nodes, in order to ensure full cooperation from all the nodes in the network. This result hinges on using the appropriate forwarding policies by the altruistic nodes, as detailed in the sequel. Our work also establishes the sub-optimality of traditional relaying strategies, which ignore the game-theoretic aspect of the problem. An important aspect of our work is that only reward/punishment policies that can be realized on the physical layer are used, and hence, our results establish the achievability of full cooperation without requiring additional incentive mechanisms at the application layer.

With the continuous increase of user requirement, the Information and Communication Technology (ICT) has developed rapidly. As a result, both capacity and coverage performances have been improved, and at the same time, the communication networks have been more energy-intensive. In order to improve the energy efficiency of cellular networks, the green communication must be realized in the future networks. In this article, we present a short survey on energy-efficient technology of cellular networks. Moreover, we classify them into three categories based on theirapplication scenarios: energy-efficient architectures, energy-efficient resource management and energy-efficient radio technologies. For the first scenario, the applications of relay, Coordinated Multiple Points (CoMP) and heterogeneous network are discussed in detail. For the second scenario, the switching off scheme will be introduced as an emphasis of this part. And for the third scenario, the Multiple-Input Multiple-Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) will be introduced as the representatives of the Energy-Efficient Radio Technologies. Finally, based on the technologies introduced above, a prospect forecast of the energy-efficient wireless cellular network is presented.

Energy efficiency of wireless networks is becoming more and more important because of the steadily rising energy cost and environmental concerns. In a real network with unequal traffic load distributions among cells, by offloading some edge users in a heavily-loaded cell to neighboring lightly-loaded cell, load balance, aims to utilize the radio resource more efficiently and consequently can improve the end-user performance. In this paper an energy efficient load balancing algorithm is proposed. In the proposed algorithm, the target cell in load balance is selected based on the prediction of the possible performance. Furthermore, an energy efficiency scaling factor is introduced into the criteria when selecting the target cell in load balance to achieve the joint optimization of both load balance and energy saving. Simulation results show that the proposed algorithm can reduce the power consumption in the network and at the same time improve the cell throughput.

Wake-up radio technology is proving to be an effective strategy for bettering energy efficiency of wireless networks. Nodes can transmit wake-up signals via their wake-up radios (WuRs), thereby preventing the unnecessary power drain of their main radio. In this paper we propose a multi-hop wake-up relay for CTP-WuR, the Collection Tree Protocol modified to work with wake-up radios. We implement and evaluate the performance of our multi-hop relay solution in the GreenCastalia simulator, and we compare its performance to that of baseline CTP-WuR. We also implement and evaluate the protocols on a physical testbed. Our results show the advantage of multi-hop relaying over the baseline implementation with respect to key metrics. Particularly, multi-hop relaying decreases average energy consumption to 78% of the baseline and packet delivery time is reduced to an average of 71% of the baseline.

To enhance channel throughput, end to end delay and energy efficiency for wireless networks based on a single-hop topology, this paper proposes a distributed reservation multiple access scheme with adaptive switching requests (DRMA-ASR). The DRMA-ASR scheme uses a repeating frame structure with a reservation period and a data transmission period based on the principles of the ALOHA-reservation scheme. To improve performance, this scheme proposes an adaptive or skipped reservation period with the probability based on a hidden Markov model (HMM). In addition, request packets are transmitted based on a permission probability to increase the probability with which the reservation period can be reduced in duration or skipped, and energy saving is achieved by putting terminals into a low power sleep mode when they are not required to transmit during the data transmission period. The scheme applies a virtual carrier sensing mechanism and does not require physical sensing. Simulation results show that DRMA-ASR provides better performance in terms of channel throughput, end to end delay, and energy efficiency than CSMA/CA with both small and large interference ranges.