Abstract—L-band Digital Aeronautical Communication Sys- tem (LDACS) is an emerging standard that aims at enhancing air traffic management by transitioning the traditional analog aeronautical communication systems to the superior and highly efficient digital domain. The standard places stringent require- ments on the communication channels to allow them to coexist with critical L-band systems, requiring complex processing and filters in baseband. Approaches based on cognitive radio are also proposed since this allows tremendous increase in communication capacity and spectral efficiency. This requires high computational capability in airborne vehicles that can perform the complex filtering and masking, along with tasks associated with cognitive radio systems like spectrum sensing and baseband adaptation, while consuming very less power. This paper proposes a radioarchitecture based on new generation FPGAs that offers ad- vanced capabilities like partial reconfiguration. The proposed architecture allows non-concurrent baseband modules to be dynamically loaded only when they are required, resulting in improved energy efficiency, without sacrificing performance. We evaluate the case of non-concurrent spectrum sensing logic and transmission filters on our cognitive radio platform based on Xilinx Zynq, and show that our approach results in 28.3% reduction in DSP utilisation leading to lower energy consumption at run-time.
because there is a lack of methods to optimize the energy consumption of these types of equipment. The focus of this paper is reduction of energy consumption of wireless equipment. Energy reduction is performed by proposing a system which is able to switch off the radio frequency interface during the inactive period and to switch it on only if a communication demand occurs. The application of such an energy reduction strategy is numerous in the WSN. In this paper, the targeted scenario is the home multimedia network. As in the case of WSNs, in home multimedia networks, equipment, such as gateways, TV sets, PCs, and video game consoles, are used very sporad- ically and waste a large amount of energy even in standby mode. In order to solve this problem, a solution using a quasi-passive wake-up radio is proposed and thoroughly studied. The wake-up signal is sent by using an 802.11g- compliant emitter, commonly used in home multimedia equipment. Thus, there is no need of supplementary hard- ware.
Channel abstraction layer. Each PUMA node runs a number of multi-channel wireless radio devices (interfaces). Typically, the first interface operates on the common control channel (CCC), which is reserved for routing and channel se- lection protocol messages. A spectrum sensing 1 component is able to detect channels available for each interface by period- ically scanning a wide range of spectrum. The set of available channel information is then made available to the channel manager through the channel abstraction layer , which interacts with multiple radios and presents upper layers with a multi-channel communication interface. In order for packets to be routed to neighbors using appropriate interface/channel, the output of the channel manager is then used to initialize the channel assignment table at the channel abstraction layer. Forwarding agent. Finally, the output of declarative routing is a forwarding table (next-hop for each destination) used by the forwarding agent. Given a destination, the forwarding agent queries the channel abstraction layer to determine the corresponding interface/channel for the next-hop, and forwards the packet accordingly.
SDR is the technique of getting code as close to the antenna as possible. It turns radio hardware problems into software problems. The fundamental characteristic of software radio is that software defines the transmitted waveforms, and software demodulates the received waveforms. This is in contrast to most radios in which the processing is done with either analog circuitry or analog circuitry combined with digital chips. Software radio is a revolution in radio design due to its ability to create radios that change on the fly, creating new choices for users. At the baseline, software radios can do pretty much anything a traditional radio can do. The exciting part is the flexibility that software provides us with,. The block diagram for a Software Defined RadioArchitecture (SDR) is shown in Fig. 2.
Fig. 1. MT N (Nigeria) 4 X 3 Frequency Reuse Pattern. There are two possible radio architectures that could be adopted to realize the capacity enhancements, the ETSI GSM standards and functional requirements of NBS. These architectures are hardware radioarchitecture and software radioarchitecture. As communications technology continues its rapid transition from analog to digital, more functions of contemporary radio systems are implemented in software, leading towards the software radioarchitecture ,. Because of its flexibility, compactness, scalability, cost, portability and several other advantages over the hardware architecture counterpart, Software Defined Radio (SDR) architecture was adopted for the architectural design of NBS.
That problem of image with direct conversion can be overcome using superheterodyne receiver. This is the traditional radio receiver architecture for wireless communication. The solution is to place a filter before the mixer to remove the image. A very high quality band pass filter is needed, to provide the desired performance. To achieve good selectivity by down-converting the received RF signal in multiple steps. In multi-band heterodyne radioarchitecture, there will be higher power consumption, and a higher overall cost for the system, translation. Also at the end, the received signal information, though of high quality, is usually weak.
The CR is equipped with SW implementations of all the building blocks of a modern transceiver; including different source coding algorithms, channel coding, modulation techniques, and encryption/decryption blocks. The AE provides the glue logic that connects these different building blocks together to form a certain transceiver configuration. In this work, the AE is considered to be a subset, yet a fundamental component of the Cognitive Radio Engine (CRE), which includes addition blocks pertaining to Perception, Learning, Co-operation States in addition to in addition to some underlying technologies that aids in the internal decision making process through reasoning, like deduction, induction, explanation, abstraction, learning, creation, and planning.Instead of basing the engine architecture design on a particular meta-heuristic algorithm, and optimize its parameters for a particular utility function for a particular application or goal; the architecture design choice envisioned is set as generic as possible, to allow for the future engine development, scalability, and usage in multiple applications and scenarios. Generic design is achieved by introducing an architecture that employs a library containing multiple meta-heuristic algorithms, in addition to a mechanism for their selection and initialization according to
The main drawback of the energy detector is its inability to discriminate between sources of received energy (the primary signal and noise), making it susceptible to uncertainties in background noise power, especially at low signal-to-noise ratio (SNR). If some features of the primary signal such as its carrier frequency or modulation type are known, more sophisticated feature detectors may be employed to address this issue at the cost of increased complexity. These detectors rely on the fact that, unlike stationary noise, most communication signals exhibit spectral correlation due to their built-in periodicities (features) such as carrier frequency, bit rate, and cyclic prefixes. Since the spectral correlation properties of different signals are usually unique, feature detection allows a cognitive radio to detect a specific primary signal buried in noise and interference. However, Energy detection is considered to be optimal if the cognitive devices have no prior information about the features of the primary signals except local noise statistics .
General line-of-sight system design will strive to ensure that transmit and receive antennas are in the clear, and no obstructions lie between, hence providing a direct signal o f suitable strength. However, in some situations this is not possible, as will often be the case where transmitters are located in villages distributed around a non flat region, and paths may be required between them all, regardless of terrain. If the terrain between the transmitter and receiver is rough, possibly with obstructions, propagation is still possible as a result of diffraction. Diffraction is the bending o f waves around objects. The bending decreases with increasing thickness o f the obstruction and frequency of the radio wave. Thus, particularly in the VHF region, usable signal levels may be present at a receiver despite an obstruction in a path, such as a low hill. Additionally, it enables propagation beyond normal line-of-sight, allowing for the curvature of the earth, by diffraction around the horizon, albeit with a certain degree o f signal attenuation. The two extreme cases o f diffraction are those o f diffraction over a smooth sphere and over a knife-edge. For a given obstruction height, the loss due to knife-edge diffraction will be considerably lower than that due to smooth sphere diffraction. The above two diffraction situations are shown in figs 2.1 and 2.2.
All nations’ governments agencies small and medium enterprises have realized the need and importance for efficiency not only on the energy domain but also in the spectral domain, because better spectral usage implies less strain on other energy intensive systems which support the ICT. As foretold by the Mitola a cognitive radio is a promising radio network technology to improve better utilization spectrums of wireless communication systems. A cognitive radio is final evolution of software defined the Radio (SDR) framework architectures. A fully re-conﬁgurable radio system that changes its communication capability and functionality, depending on network conditions and user demands. Mitola’s Abstract: This paper proposes an integrated cognitive radio conceptual archicteture designed that qualified the radio to be called as an intellegent radio, the radio is classified and defined as promising technology leverage the services of other radio networks and management. The architeture were designed with capabilities to enables and support dynamic spectrum sensing network access systems which cover the operational cycle management. The research work enhance the concept radio architectre of wireless innovative communications forum cognitive radio concepts architectres designe in January 2013. An analysis of radio cognition information processe and functionality of each layer to compliments others in services delivered, also higlighted various stages and evalutions of technical operations parameters in industries standards and regulations policies from differents groups of reserchers in wireless communications. Challeneges and security imlemenatations amongst manfacturers, enteprises and vendors domain. Further more additional processes were added in the exiting and general widely used of cognitive radio definition cycle by Inernational Telecommunication Union (ITU) in respect to the three stages operations process learn, make decision and adjust within its presents environments. A regulations and standards policies on wireless communications concepts with speeds range from 2.3GHz to 2.4GHz for better utilize the radio spectrum standards teachniques IEEE 1900.1to P 1900.7 mobile operations MAC sub layer and PHY layer.
Timing Signals can be generated using standard timer IPP triggering pulse. It will be used as reference to generate different timing and control signal. Considering beneficial of implementation and flexibleness for particular application, Timing and control Signal Generator (TCSG) is a module supported on Unified Timing and control Signal Generator are used to switch different RF switches. In both transmitting and receiving. The TCSG is application particular timing signal generator that meets timing requirements of pulsed RADAR (Radio Detection and Ranging). Each of the 133 TR modules in the out-door field consists of a Xilinx Spartan-3E based TCSG card for control, communication and monitoring purposes. Communicate radar controller and TR module through Ethernet. Electrical Ethernet is to communicate with in-door sub systems and optical Ethernet is to communicate with out -door TR modules.
Security. DRONEE requires cluster members to cipher their tra ffi c according to LTE specifications. In LTE, ciphering is done in the Packet Data Convergence Protocol (PDCP) layer before the Radio Link Control (RLC) and MAC layers. As shown in Figure 9, we extend the ciphering requirement to the tra ffi c that has to be relayed, although that tra ffi c has to go through the WiFi protocol stack. Therefore, in DRONEE, clus- ter members use ciphered PDCP PDUs as payload of the WiFi frames that have to be sent to the cluster head for relay. Al- though the cluster head cannot read the ciphered data, it can process and forward each PDCP PDU through RLC, MAC and PHY layers, thus relaying it to the eNB. However, the relayed tra ffi c has to carry the MAC identifier of the original sender, so that the eNB can identify the source of the data and thus deci- pher it with the correct key. Since the deciphering key is only known to the eNB, the integrity of the relayed tra ffi c will be pro- tected and any data manipulation can be detected by the eNB. Note that, with the described procedure, all PDUs are transmit- ted exactly as in a legacy LTE system, with no extra protocol overhead being caused by DRONEE. Thanks to this mecha- nism, DRONEE does not introduce any new security risks to the current LTE architecture.
In this article we propose a novel clustering SDN-based cellular network architecture that does not only depend on a single controller, rather it divides the whole cellular area into clusters, and each cluster is controlled by a separate controller. A number of applications or services are kept available on top of the controller that maintains all the controlling functions of the network. The controllers communicate and share information between them through a controller service. Basically, a controlling function is dependent on a number of services. In this way, much of the traffic and single-controller overwhelming could be minimized. To our knowledge, this will be the ﬁrst work for cellular network that would utilize controller services efficiently by sharing their information rather than depending on only a central controller. The rest of the paper is organized as follows: section 2 briefly describes about the architecture of a generic cellular system, an overview of today’s LTE/EPC cellular network architecture is demonstrated in section 3 and the ONF SDN reference model architecture is described in section 4. Related work and background study have been discussed in section 5. We have described our proposed architecture in section 6 and finally section 7 concludes our proposal.
The SO network ((a) in figure 1(b)) communicates with the Information infrastructure via a gateway node (b). In the implementation, the gateway node serializes the SO events and transmits them to a Network Translator (c), whose role is to convert those messages into HTTP client requests to a Java Servlet server that acts as the gateway to the Information Infrastructure. The Information Infrastructure implementation architecture is more complex than the SO network since it involves many starting roles. XML-based Web Services (WS) were chosen due to their ability to provide cross-platform and cross-language communications over a network. Figure 1(b) details the software components and transport protocols that were used in the implementation of the information infrastructure. All the software was written in Java. XML and XSD were used to encode the events and event data. WSDL was used to describe the capture (d) and query interfaces (e). SOAP and HTTP were used as messaging protocols to transfer the XML-encoded events between the different architecture components. A PostgresSQL database was used as a repository (f) in order to store the structure of the Smart Object networks. Due to the flexible and interoperable nature of the XML-based WS, infrastructure clients could use a variety of methods for encoding requests sent to the Capture and Query Interfaces. In our implementation architecture, both Web Browser (h) and Java based clients (g) were built.
This paper has demonstrated that a re-configurable low-cost and low-power consumption OFDM wireless node is possible using general-purpose processors. Our findings indicate that pilot symbols using relatively few sub-carriers is suitable for start of frame detection thus greatly reducing the processing time overhead. The experimental results from an actual implementation also show that a highly optimized software realization of an OFDM transceiver is capable of meeting real- time operation objectives. The ADC/DAC rates effectively set the possible channel bandwidth so for reliable wideband OFDM signal reception and generation, it is vital to attain very high rate devices. Pass-band sampling demands extremely high ADC rates hence the need to convert the intercepted signal to a lower intermediate frequency but the ADC/DAC rates must have a sufficient rate to reliably sample/output the entire OFDM channel bandwidth. The next stage of this work is to combine a flexible architecture OFDM transmitter capable of being dynamically modified based on channel information from the receiver to maximize channel capacity usage and minimize power consumption. Further work is also being carried out on optimized waveform generation techniques and the incorporation of modulation scheme recognition techniques into the OFDM system with the aim of developing an adaptive modulation system.
Next, vehicular networks have to depend on some type of communication mechanism to exchange information. Moreover, while adopting the means of communication for vehicular networks features such as the ability to adapt to rapidly changing environments should be considered. Since, the communication in wireless systems is carried out by radio technology, it is considered more suitable for dynamic environments due to the lack of physical connections  . With that knowledge, Federal Communications Commission (FCC) dedicated IEEE 802.11p Wireless Access in Vehicular Environment (WAVE) standard for vehicular communications. IEEE 802.11 p standard is shown in the Figure 1.3 comprises of 7 channels with equal bandwidth of 10 MHz. In the Figure 1.3, the channel 178 located between 5885 GHz and 5895 GHz is regarded as the control channel. The channels 172 and 184 are allocated for life safety and public safety applications while, the remaining channels are used as service channels  .
The QoS requirements of users will be largely dependent on the service they require. Speech users may require some form of circuit-switched emulation, which pro- vides very tight bounds on the treatment of the flow to match latency and jitter requirements. Users requiring web access of file transfer facilities may be satisfied with a moderate QoS bounds whereby throughput and delay are within specified bounds. Other users may be satisfied with wide QoS bounds similar to ATM’s available bit- rate service whereby bandwidth is allocated to users when available, this type of service may be suitable for background download of emails etc. The QoS require- ments of these services could be specified statistically. Web applications could be offered, say, an average throughput of 64kbps over a given period of time as op- posed to a guaranteed constant throughput of 64kbps. Advanced MAC techniques may allow speech to be transported over the air-interface in packet form to take advantage of statistical multiplexing of users onto chan- nels which recognises that on average speech users are inactive more than 50% of the time. This would allow the QoS offered to speech traffic to be described statisti- cally, i.e. the delay perceived by the user will be within tight statistical bounds. This gives rise to assigning a statistical parameter to the QoS specification of network bearers. Therefore this architecture also introduces the concept of a commitment level. The commitment level is defined as the probability that the network will be able to meet the flow's specified QoS requirements on an ongo- ing basis without the need for re-negotiation. For exam- ple, for a speech flow it may be sufficient to state that the latency encountered by speech packets will be within prescribed bounds, say, 90% of the time. In this case a 90% commitment level is assigned to the flow – along with the associated bounds. Similarly for web traffic it may be sufficient to offer 64kbps over a given time pe- riod for only 80% of the time, i.e. an 80% commitment level is assigned to this type of flow.
In this paper, the drawbacks of the semi-active RFID tag and the previously proposed solutions have been reviewed. Based on the findings, an ultra-low power HIEH system with three input ambient sources from RF, TEG and PZT has been proposed as a solution. The main objective is to solve the semi-active UHF RFID tag limited lifespan issues due to the need for batteries to power their circuitries and to achieve maximum PCE with minimal power losses obtain from the HIEH system. To achieve the target, the proposed architecture will use rectifiers, matching network, a self-start-up circuit, DC-DC boost converter with MPPT, a control loop, an adaptive control circuit, energy storage and a voltage regulator. Each designed topology will be evaluated and characterized to get a maximum PCE. PSpice software and Verilog based on Mentor Graphics will be used for design simulation and code writing respectively. Then, the circuits design will be downloaded to the FPGA board for verification and the final layout will be implemented in a standard 0.13 µm CMOS process. The simulation result from this ultra-low power HIEH architecture is expected to deliver a total of 3.3 V of output voltage from low input ambient sources which is enough to recharge the battery and activate the semi-active RFID tag. Moreover, 6.5 mW of output power and 90% efficiency are expected when three input sources are simultaneously harvested.
Routing infrastructure, including handsets, utilize intelligent routing capabilities to determine the best path for each transmission. Routing for the best path must be defined for least power. That is, network nodes must be able to calculate and update routing tables to send data packets through the paths with minimal power requirements . This is different than network nodes associating with the physically closest available infrastructure. The 4G mobile system based on open wireless platform architecture will become the next wave in wireless
Abstract—Paving the way for future 5G technologies requires a need to overcome the spectrum crunch, which is one of the major challenges impeding the growth of wireless technology. The issue at hand becomes more pronounced when we consider Internet- of-Things (IoT), where billions of devices require connectivity. This article motivates the need for exploring new spectrum opportunities with reference to the requirements of IoT networks. Millimeter wave (mmWave) spectrum is considered as a panacea for overcoming the spectrum crunch, providing the much needed breathing space for introducing new applications that require higher rates. A network based on control/data separation ar- chitecture (CDSA) could further improve the performance by utilizing the mmWave-based data base stations (DBSs). The control base station (CBS) operates on the sub-6 GHz single band, while the DBS possesses a dual-band capability. This article presents a new dimension to spectrum heterogeneity by utilizing a dual-band approach at the DBS. One of the unique aspects of this work includes the analysis of a joint radio resource allocation algorithm based on Lagrangian Dual Decomposition (LDD) and we compare the proposed algorithm with the maximal-rate (maxRx), Dynamic sub-carrier allocation (DSA) and Joint power and rate adaptation (JPRA) algorithms. The analysis is further expanded by showing an interplay between the utilization of licensed and unlicensed mmWave resources and how the dynamic spectrum management could help in their efficient utilization.