IEEE 802.22-based WRAN system for disaster-resistant network systems

In this letter, we investigate the spectral efficiency of IEEE 802.22 wireless regional area network (WRAN) spectrum overlay when it is used in TV white space. Since 2004, when the FCC published the notice of proposed rule making 04-186 to make use of unused TV spectrum, the IEEE 802.22 working group has been standardizing specifications for WRAN operations. There have been a few papers investigating the spectral efficiency of this, but their analyses were limited to the cases for various guard distances between WRAN base stations. Since WRAN base station (BS) power for WRAN service may differ from country to country, it is important to analyze the spectral efficiency for various WRAN BS powers. In this letter, we analyze the spectral efficiency of WRAN spectrum overlay as a function of the power of WRAN BSs. The simulation results show that spectral efficiency decreases as the power of WRAN BSs and guard distances increase.

Cognitive Radio systems have been studied to be deployed especially in the so-called TV White Spaces (TVWS) which are defined as the TV free channels left unused in specific territorial area as direct consequence of the digital switchover plans. The IEEE 802.22 Wireless Regional Area Network (WRAN) standard has been developed to exploit the TVWS bands to assure broadband access for remote and rural areas. WRAN devices are designed to operate in the frequency range 54–862MHz alongside Digital Terrestrial Television (DTT) transmissions. This paper studies the influence of adjacent channel interference of DTT signals on IEEE 802.22 WRAN transmission. The performance of IEEE 802.22 WRAN devices in the presence of with DVB-T2 broadcasting systems is evaluated.

IEEE 802.22 is the cognitive radio-based first worldwide standard for wireless regional area network (WRAN). The primary objective of this standard is to provide broadband access to remote and rural areas. In these remote areas, a large number of vacant TV channels are available, known as white spaces. This standard allows broadband access to the users using these TV white spaces (TVWS). Also, much analog transmission has been moved towards digital transmission in UHF band so this situation has created a digital divide. In this paper, we proposed a novel scheme of simulation for the physical layer of IEEE 802.22 Wireless Regional Area Network (WRAN) with another cyclic prefix. In this paper, we have also demonstrated the effect of length of cyclic prefix in OFDM symbol on the BER performance of the physical layer of WRAN. We simulated the physical layer of WRAN with cyclic prefix 1/4 and 1/32 between successive OFDM symbols. We used convolution code with code rate 1/2 as FEC and evaluated the performance with BPSK, QPSK, and QAM-19 digital modulation schemes in Rayleigh fading condition in MATLAB. We concluded that the effect of ISI can be mitigated with cyclic prefix 1/32 for all three proposed modulation schemes and found that better BER performance in limited SNR. Also, the performance of BPSK with CP 1/32 is superior to QPSK and QAM-16 for CP of 1/4 as well as 1/32.

SummaryThe wireless regional area networks (WRANs) operates in the very high frequency and ultra high frequency television white space bands regulated by the IEEE 802.22 standard. The IEEE 802.22 standard supports Extensible Authentication Protocol (EAP)‐based authentication scheme. Due to the participation of a server and the information exchanged between a customer primes equipment and the secondary user base station, it takes around 50 ms to complete a complete EAP authentication that cannot be accepted in a handover procedure in WRANs. In this paper, we propose an EAP‐based proxy signature (EPS) handover authentication scheme for WRANs. The customer primes equipment and secondary user base station accomplish a handover authentication without entailing the server by using the proxy signature. Approved by the logic derivation by Burrows, Abadi, and Needham logic and formal verification by Automated Validation of Internet Security Protocols and Applications, we can conclude that the proposed EPS scheme can obtain mutual authentication and hold the key secrecy with a strong antiattack ability. Additionally, the performance of the EPS scheme in terms of the authentication delay has been investigated by simulation experiments with the results showing that the EPS scheme is much more efficient in terms of low computation delay and less communication resources required than the security scheme regulated in IEEE 802.22 standard.

IEEE 802.22 is a standardized WRAN (Wireless Regional Area Network) system that operates in TVWS (TV White Spaces) and aims to achieve an effective spectrum utilization. Since IEEE 802.22 offers excellent propagation characteristics in the UHF (Ultra High Frequency) band, it is expected to support a cost-effective wireless communication system in rural areas. To provide a long-distance wireless communication, it is important for the receiver design to compensate a multipath fading attributed to large differences in path lengths, while existing multipath fading channel profiles applicable to IEEE 802.22 has generalization and statistical limitations. To generally and stochastically reproduce the multipath propagation characteristics in an actual wide area environment, an algorithm to obtain a statistical channel model extracted from the field experiment data is required. In this study, we develop a novel channel modeling algorithm based on the conventional S-V (Saleh-Valenzuela) modeling algorithm that offers an approach to model and reproduce the multipath characteristics in an actual environment. The proposed channel modeling algorithm applies a dynamic GEV (Generalized Extreme Value) distribution fitting for the amplitude fluctuation of individual arrival cluster. We also evaluate the channel reproduction performance of the proposed algorithm by computer simulation using channel modeling factors calculated from the experiment result with a FE (Fading Emulator). As a result, by applying the proposed algorithm, the multipath fading characteristics measured in the experiment can be modeled, and its reproducibility is confirmed with regard to relative path power distribution, rms delay spread distribution, and BER characteristics.

A two-hop wireless regional area network (WRAN) providing monitoring services using Television White Space (TVWS), i.e., IEEE p802.22b, is now under development. A great number of subscriber customer-premises equipments (S-CPEs) may be connected to a base station with relaying of a relay CPE (R-CPE)

High demand for water is driving potentially unsustainable practices and competition for water resources between various sectors in developing areas. As a result of improved quality of life and population growth, increase in demand for fresh water is anticipated in all African countries in all sectors, over the next 10 years. This study examines the effects of dry season irrigation farming (fadama) on the physical and chemical quality of the River Osin which receives both surface and subsurface flow from irrigated areas in the Upper Osin Catchment, Kwara State, Nigeria. A total of 90 samples were obtained from Upstream (UPS), Irrigated area (IRG) and Downstream (DNS) segments of the river in the dry and rainy seasons. Water samples were analysed for pH, conductivity, total dissolved solids (TDS), suspended solids, dissolved organic matter (DOM), pesticides (ionic basic type), Na+, K+, Mg2+,Cl-, NO3-, PO43-, Ca2+ and HCO3-. The results indicate that values of agricultural pollutants such as pesticides (CuSO4), NO3- and PO43- were significantly higher at IRG than at UPS, and decreased slightly at DNS, while all other anions and cations except DOM reached peak values at DNS. Agricultural pollutants (NO3-, PO43- and pesticides) contributed significantly to poor water quality observed at IRG and DNS segments but the values are within acceptable tolerance range at UPS. The findings further indicate that irrigation practice degrades the quality of water at IRG and DNS segments. As a result, a holistic approach to agriculture and water resource management is recommended to ensure sustainable water resources development in the catchment.

COVID-19 pandemic has had such drastic effects on every sector in the world that technology has become a very significant part of our daily lives. Information Communication Technology (ICT) is a broader term that refers to computers, the internet, software, wireless networks, cell phones, social networks, video conferencing, and all other communication technologies. It has the capacity to represent an appropriate method for the teaching process of this age where students prepare for life through ICT. ICT skills equip students with the qualifications needed to face future challenges. They help students develop their skills and knowledge, and increase their motivation. English Language Teaching (ELT) is another area that has changed over the years, moving from very teacher-centered approaches to learner-centered ones. The pandemic has led to school closures and a reevaluation of teaching methods in all countries. Among the many changes, digital technologies have become a mandatory tool for all education. Given their dynamic and interactive nature, ICTs are able to meet the needs of individual students by allowing them to direct their individual learning. This study aims to investigate, through a literature review, whether ICTs have the potential to guide educational methods in the language classroom. It concludes that ICT has become an important tool for change and reform in education. However, it is too early to abandon the advantages of traditional teaching methods. There is a need for further studies that examine the advantages and disadvantages of using ICT in language teaching.

The study was carried out to assess the implication of the use of selected Information and Communication Technologies (ICTs) for extension service delivery in Nigeria. The simple random technique was used to select fifty percent of the total extension agents which equivalent to forty-two respondents as sample size for the study. Frequency counts, percentages, mean and standard deviation were used as descriptive statistic. Also, Chi-Square test and Spearman’s rho correlation were employed as inferential statistic to test for the hypotheses. Findings indicated that access to various ICTs tools especially Radio and Mobile phone and were found to be relevant to farming operations. The result of Chi square test revealed that significant relationship exist between sex, age, level of education, years of working experience of the extension agents and level of use of ICTs. Furthermore, the result of Spearman rho Correlation showed that there was no significant relationship between ICT training of extension workers and the level of use of ICTs. The study recommended among others that, there should be a periodic review of the use of current ICTs in extension service delivery to facilitate effectiveness in the use of ICTs for extension service and adequate funding of extension service should also be ensured to enhance the maintenance of ICTs made available to extension personnel.

TV White Space (TVWS) spectrum utilization is totally a new idea in wireless communication technology. It refers to some portion of TV spectrum that is not used by TV channels and available for other applications. This unused spectrum has been opened up for the free and unlicensed users. This spectrum can be utilized greatly if a noninterference environment is created between the users of this spectrum. Therefore, a coexistence of multiple networks requires interference management. In this paper, an interference management algorithm is developed. It ensures that a network can access the TVWS spectrum without causing interference to other networks. This is done by using three stages. The first stage is for finding the group of networks that will not cause interference to one another. For this graph coloring algorithm is used. The second stage is for assigning different channels to each group of networks. Here, channel assignment gives priority to the user requirement of each group. If any bandwidth is left after second stage, then the third stage is performed where performance of each network will be increased. This is done by considering the number of networks in a group. Simulation results show that the proposed scheme provides better channel assignment along with bandwidth utilization.

During the system providers of mobile communication investing much money to deploy 3G mobile communication networks, computer industry proposes another wireless communication technology: WiMAX (Worldwide Interoperability for Microwave Access) technique, which is also called as IEEE 802.16 communication technology. It is a strong wireless communication technology to provide users being able to quickly and arbitrarily use wireless data communication services, and this technique also has the potential to be a last mile solution of broadband home network connecting to Internet in future. In the example of 802.16a using instead of DSL technique, the theoretical value of transmission range is about 50km and the transmission rate can be up to 75Mbps. In the example of 802.16e using for mobile equipments, the theoretical value of transmission range is about 2-5km and the transmission rate can be up to 15Mbps. Owing to the cost of wireless network infrastructure is lower than that of wire network infrastructure, WiMAX can be regarded as a cheap substitutive scheme of DSL and other broadband wire networks. On the other hand, although the data transmission rate of 3G mobile communication network is faster than the currently mobile telecom network, it is still slower 30 times than that of WiMAX network, and its radio range is also smaller 10 times than that of WiMAX. Therefore, the required number of base station of WiMAX network is fewer than that of 3G mobile communication network, moreover, some parts of frequency bands defined in WiMAX are license-exempt. Present there are 67 member companies of WiMAX Forum in the world using the name of WiMAX to push the standard. The semiconductor giant-Intel corp. fully supports the technique, and the mobile phone and network provider-Nokia corp. also supports this technique standard. Intel corp. begins to include WiMAX technique in its chip platform, and plans to sell the WiMAX chip in the next half year. The analysts of MIC predict that there will be 25% notebooks installed this sort of wireless technique till 2008. Nemcek believes that consumers will get the convenience brought from WiMAX in 3 or 4 years, and the market of WiMAX will grow in 2007 or 2008. In this thesis” Analysis and Implementation of IEEE 802.16 WiMAX System Software Architecture on Linux Operating System” is to analyze and implement WiMAX wireless system on Linux operating system. For system analyzing, study the standard speciation of IEEE 802.16 series at first, then start to design software architecture for Linux system. For system implementation, use standard PC for software implementation, and then for others to follow the system architecture to implement Linux Device Driver for WiMAX. The system architecture will also consider the efficiency of porting and development of the embedded system. Also implement Software Emulate Physical Layer to verity the Linux Device Driver for WiMAX.

We investigate the power budget of a fully coherent reflective passive optical network, based on self-coherent upstream (US) and self-homodyne downstream (DS) detection schemes. We consider, for US, both binary phase-shift keyed (BPSK) and quadrature phase-shift keyed (QPSK) at 1 GBd generated by direct modulation of a low-cost reflective semiconductor optical amplifier having 1-GHz electrical bandwidth and using simplified digital signal processing (DSP). We find that the penalty of increasing the order of US modulation format from BPSK to QPSK for higher capacity can be reduced to 1 dB by means of DS digital spectral shifting and US static postequalization.

TV White Space (TVWS) refers to frequency band reserved only for licensed terrestrial TV broadcasting and is opened to unlicensed use under regulatory conditions. While regulations protect licensed systems from interference, interference among unlicensed systems is left mainly to manufacturers. Consequently, there is a need to develop new coexistence approaches between TVWS networks. Busy tone broadcasting is a coexistence method, which can be used by TVWS networks to announce the selected frequency band is occupied. In this paper, a busy tone based coexistence algorithm is proposed for IEEE 802.11af and IEEE 802.22 networks and analyzed by considering different client distributions experiencing log-normal shadowing, where the exact interfering packet rate and successful packet transmission rate expressions are obtained and validated by simulations for different scenarios. The results show that with the proposed coexistence approach, a WLAN can reliably detect the busy tone signal to change its frequency band and can reduce interference to WRAN. Even if there is no available frequency band for the WLAN, the WRAN still maintains its enhanced successful packet transmission performance. The deployment of the proposed algorithm is important for successful coexistence between cognitive wireless networks, where interference is not regulated, such as in TVWS bands.

The interconnection of all things and industrial integration is the current trend of the times. Among them, the interconnection of all things is the demand of informationization of the times, and the industrial integration is the demand of industrial development. The interconnection of all things is realized based on wireless communication technology. It is necessary to combine the development of the tourist area and the surrounding culture. The relationship between tourist attractions and culture needs to be fully and effectively developed. In order to fully explore the advantages of the cooperation between the two, it is necessary to combine modern technology to package the tour process of each characteristic culture of the scenic spot. Virtual reality is a modern technology that can combine culture and tourism. Wireless communication and VR technology are applied to the development of integration of culture and tourism. The process of tourism will promote profound changes in the tourism model. Under the demand for informatization in various industries, the tourism industry is gradually developing in this direction. The integration of culture and tourism will also be driven by informatization and technology. This paper analyzes the current situation of culture and tourism, summarizes the problems existing in the current process of integration of culture and tourism, and finally puts forward targeted solutions. Mainly in the process of the integration and development of tourism and cultural industries, the traditional culture and scenic spots are the basic factors, combined with wireless communication and virtual reality technology, to develop a tourism industry with technological characteristics of the new era.

This research investigates the role of ICTs (mobile phones) in economic development particularly in the Papua New Guinean coffee and fresh produce value chains. It aims to interrogate the promises and unwavering optimism attached to the 'ICT revolution' by examining the effects of ICTs on economic practices and the extent to which communication and network integration will be a driver of development. Following the deregulation of the telecommunications sector in 2007, considerable attention has been paid to the digital transformation in Papua New Guinea and the Pacific Islands and the unprecedented growth of mobile phone and social media use. PNG's mobile phone penetration has increased exponentially from approximately 2% to over 48.6% in just over ten years (from 2005 to 2016 - World Bank 2017). Media commentators have noted with delight that there are now more Pacific Islanders with mobile phones than bank accounts and that in PNG alone, internet access from mobile phones is forecast to increase to about 50 per cent of the population in the near future (UNESCAP 2006, Beschorner 2008, SPC 2012). Much expectancy and promise has already been attached to the future impacts of such increased connectivity as World Bank Economists postulate that a 10% improvement in Internet penetration leads to an increase in GDP of up to of 1.5%; while 10% increase in mobile penetration can translate into a 0.81% increase in growth (Qiang et al. 2009). These projections are mainly premised on the assumption that increased connectivity will facilitate better access to current information about market prices and reduce price dispersion; producing savings in time, transport and search costs. Furthermore, ICTs could directly link small scale producers to buyer's markets by weeding out 'rent seeking' brokers and middlemen in the value chain through a process referred to as 'disintermediation'. Using case studies from key regional economic sectors, this thesis interrogates if such claims are borne out on the ground and tests if information infrastructure is necessarily going to lead to more openness, equality and an all-encompassing 'digital provide' (Jensen 2007).