Robust relay selection for large scale energy-harvesting io t networks
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The document discusses a new relay selection scheme for large-scale energy-harvesting IoT networks that aims to minimize outage probability and feedback costs by considering the residual energy of relays and channel distribution. It highlights the limitations of traditional methods that rely on perfect channel state information and introduces a stochastic geometry approach for efficient relay selection without adding complexity. The proposed method enhances network lifetime and energy efficiency, making it suitable for energy-limited IoT devices.
Robust relay selection for large scale energy-harvesting io t networks
- 1. #13/ 19, 1st Floor, Municipal Colony, Kangayanellore Road, Gandhi Nagar, Vellore – 6. Off: 0416-2247353 / 6066663 Mo: +91 9500218218 Website: www.shakastech.com, www.shakastech.weebly.com, Email - id: shakastech@gmail.com, info@shakastech.com ROBUST RELAY SELECTION FOR LARGE-SCALE ENERGY- HARVESTING IOT NETWORKS ABSTRACT Relay selection problem in large scale energy-harvesting (EH) networks is considered. It is known that if channel state information (CSI) is available at EH relays, a diversity order equal to the number of relays can be obtained, however at the penalty of a feedback overhead which is not suitable for energy-limited devices intended e:g: for internet- of-things (IoT) applications. Therefore a new EH relay selection scheme is proposed, which is based on the residual energy at each relay’s battery, and on information on the distribution of the channels between relays and the destination. The method thus minimizes both the outage probability and the feedback cost. Where previous work relay selection based on channel distribution information (CDI) consider only small-scale fading distribution, a stochastic geometry approach to consider jointly the geometrical distribution and small-scale fading yielding a simple relay selection criterion that furthermore utilizes only rough information on the relay’s location, i:e:, an ordinal number from the destination. The outage probability of the proposed relay selection scheme is analytically derived, and the achievable diversity order of the proposed approach is investigated. INTRODUCTION In 2011, Cisco Internet Business Solution Group (IBSG) predicted that there will be 50 billion devices connected to the internet by 2020. This vast network of devices, would enable us to gain information on virtually anything, creating enormous opportunities for new services and applications, for things such as logistics, transportation, health care, agriculture and so on. For such an internet-of-things (IoT) applications, the quality of wireless communications and low energy consumption are fundamental, since the former defines applicable areas, while the latter the readiness of energy-limited devices. Typical wireless channels, however, suffer from multipath fading and shadowing, which significantly reduce communication capacity for a given average transmission power and hinder reliable transmission. Although an effective option is to use multiple antennas to obtain spatial diversity gain, in practice, it is difficult equip small IoT devices with multiple
- 2. #13/ 19, 1st Floor, Municipal Colony, Kangayanellore Road, Gandhi Nagar, Vellore – 6. Off: 0416-2247353 / 6066663 Mo: +91 9500218218 Website: www.shakastech.com, www.shakastech.weebly.com, Email - id: shakastech@gmail.com, info@shakastech.com antennas due to their size, complexity, and cost. Hence, another concept has been proposed: when the source cannot reliably communicate directly with its destination, other nodes temporarily serve as relays in order to support the communication. This cooperative diversity approach allows devices to enjoy spatial diversity gain without the need to equip them with additional antennas, and it has been shown that if sufficiently many relays are available, opportunistic relying can attain a diversity order equal to the number of relays itself. In opportunistic relaying, the best relay among those available is chosen based on the perfect knowledge of the instantaneous channel state information (CSI), where best is defined in terms of the corresponding instantaneous signal-to-noise ratio (SNR) at the destination. However, in a cooperative diversity system, relays consume their own battery order to support other nodes’ communication, so that if multiple nodes drain their batteries at the same time, the network life-time or its topology may quickly deteriorate. A remedy for this crucial issue is the use of energy harvesting (EH) in combination with opportunistic relaying. Energy harvesting makes it possible to use solar, kinetic, wind, electromagnetic, or other types of energy sources to recharge the relay nodes’ batteries. The result of using EH in opportunistic relaying is that non-selected relays efficiently use their inactive time to recharge their batteries while the selected relay forwards the source’s information in order to obtain diversity. EXISTING SYSTEM Symbol error rate (SER) of a cooperative network with EH relays was derived theoretically, and the advantages of opportunistic relaying was shown for the case in which the selection is based on the current available energy and the CSI. Drawbacks If channel fluctuation is slow, there is a possibility that the same relay is selected repeatedly, so that its activity surpasses its ability to harvest energy to recharge, such that considering both the relays suitability and its energy state in the is necessary selection process. A scheme based on the relative throughput gain of each relay and its energy state information (ESI) was proposed. This method of relay selection was shown to
- 3. #13/ 19, 1st Floor, Municipal Colony, Kangayanellore Road, Gandhi Nagar, Vellore – 6. Off: 0416-2247353 / 6066663 Mo: +91 9500218218 Website: www.shakastech.com, www.shakastech.weebly.com, Email - id: shakastech@gmail.com, info@shakastech.com improve short-term performance, since the harvested energy can be efficiently utilized. Drawbacks Assumption of perfect CSI at relays, even if perfect channel reciprocity holds, this assumption implies the need that every relay accurately estimates its channel to every other relay, and forward the information to its peers. Assumption perfect CSI is virtually unfeasible in the context of IoT networks Opportunistic relaying methods avoiding the requirement for perfect CSI have been proposed. A scheme relying on the average channel gains only was presented. Drawbacks Leaves out the contribution of fading. PROPOSED SYSTEM Introduce a stochastic geometry to model large-scale networks with EH relays. This model captures both the topological and fading contributions to channel fluctuation that affect relay selection. Propose a new EH relay selection scheme based on residual batteries of relays and the CDI of both small-scale and large-scale fading. This requires neither extra communication nor does it result in increased computational complexity, and thus it is suitable for IoT devices. The closed form of the end-to-end outage probability is derived. Based on this result, we devise a simple relay selection rule that only requires approximate information about the relay’s location; specifically, it only requires the ordinal number of the relays. Advantages Energy efficient High network lifetime
- 4. #13/ 19, 1st Floor, Municipal Colony, Kangayanellore Road, Gandhi Nagar, Vellore – 6. Off: 0416-2247353 / 6066663 Mo: +91 9500218218 Website: www.shakastech.com, www.shakastech.weebly.com, Email - id: shakastech@gmail.com, info@shakastech.com SYSTEM SPECIFICATION HARDWARE REQUIREMENTS Processor : Any Processor above 500 MHz. Ram : 128Mb. Hard Disk : 10 Gb. Compact Disk : 650 Mb. Input device : Standard Keyboard and Mouse. Output device : VGA and High Resolution Monitor. SOFTWARE SPECIFICATION Operating System : Windows Family. Techniques : JDK 1.5 or higher Database : MySQL 5.0