Performance analysis of RTS/CTS protocol over Basic Access in wireless networks

The CSMS/CA protocol is employed in wireless networks in order to overcome issues such as the hidden node problem. This mechanism is expected to handle collisions better using the RTS/CTS mechanism. This method will allow a participating node to take part in communication only if it receives a "Clear to Send" message and thereby, theoretically "avoiding" collision. The objective of this paper is to analyse the improvement that the RTS/CTS mode brings over the Basic Access mode. The paper presents the study of wireless nodes within a specific area with increasing node concentration to verify the performance impact of a protocol in wireless networks, particularly when the node concentration increases

Evaluation of Signal Attenuation for Bluetooth, ZigBee and Sound in Foliage

Rural environments have been struggling to get connected due to various reasons, one of them being the fact that the signal attenuation is too high in foliage, drastically affecting range and power consumption. This study evaluates the effect of foliage in the attenuation of 2.4 GHz signals, namely Bluetooth and ZigBee. An alternate candidate signal, sound is also analyzed in a similar environment. In order to further the experiment, a simulation model using Omnet++ was created and the alpha value, which marks the environmental constant was noted. We have concluded from the study that the signal attenuation for the 2.4 GHz signals are very high in foliage. The high frequency sound signals also suffered drastic signal loss in foliage, but the low frequencies penetrated quite well. Therefore, high frequency signals are poor candidate carrier signals for such environments

Dynamic threshold and quality meter based routing for cooperative broadband wireless networks

One of the important aspects to deal with in ad hoc cooperative wireless network is the mobility nodes. In ad hoc wireless networks, the nodes themselves are responsible for the routing and forwarding of packets. Hence, nodes of these networks function as routers that discover and maintain routes to other nodes in the same network as well as regular hosts. Frequent changes in the network topology require huge communication overhead in order to establish new routes and thus slowing down the communication or causes packet losses. In this paper, we proposed Channel State Information (CSI) based routing scheme for ad hoc cooperative wireless networks. The proposed approach will apply dynamic threshold and quality meter to improve the wireless channel quality of all available ad hoc nodes over the cooperative network and making sure that the conventional TCP will still be effective. The proposed scheme takes into consideration of choosing the best route on the fly for successful packet delivery while minimizing errors over the network

Digital inclusion of the Orang Asli of Peninsular Malaysia: Remote virtual mechanism for usability of telecentres amongst indigenous peoples

Over the last decades, researchers and development practitioners have been experimenting with models, frameworks and devises to meet the needs of diverse users of information communication technologies. Turning to an ICT‐based community development known as the Telecentre Programme amongst Orang Asli, an indigenous people groups in Peninsular Malaysia, this paper describes why a remote virtual management devise was invented to encounter challenges related to rugged terrain constraints, which would have directly impacted the planning and the execution of programmes designed at the telecentres. This paper argues as a technological solution, the virtual remote management system has powered an ecosystem, which shored up the digital inclusion of the indigenous communities and in the process enabled the enhancement of local informational capabilities. To this end, it reduced their technological dependency on outsiders leading to the usability and sustainability of the telecentre for local capacity building and socioeconomic benefits for the disadvantage communities

The Performance Improvement of Long Range Inter-relay Wireless Cooperative Network using Three Time Slot TDMA based Protocol

Time division multiple access (TDMA) amplify and forward based protocols for cooperative wireless networks have been investigated previously by various researchers. However, the analysis for these protocols is not considered for long range cooperative wireless networks over Rician fading channel. Therefore, the aim of this paper was to propose three time slot TDMA based transmission protocol for inter-relay cooperative wireless network with longer distances between source to relays and destination as well as between relays to destination. It is concluded that the proposed protocol shows less BER performance for long range inter-relay cooperative network over Rician fading channel as compared to two time slot long range cooperative network. Moreover, the proposed protocol shows better performance in terms of less BER values when the inter-relay distance is minimum

Location-based Solar Energy Potential Prediction Algorithm for Mountainous Rural Landscapes

The world is facing critical energy crisis today. As a result the conventional grid energy supplies are not enough to meet the present demand. Many advance researches are in progress to overcome this energy predicament. Power generation and management in disconnected rural villages is challenging. The situation is even more challenging when landscape structure in such environment are irregular. Forces of diffusion, ground reflectance and sky view factor among others, affect the quality of final solar radiation incident on a solar panel. This paper describes the implementation of an algorithm that can be used to predict solar energy potential of irregular landscapes. Location-based Solar Energy Potential Prediction Algorithm (LOSEPPA) takes as input, the geographic latitude and longitude of the location of interest to compute the Solar Irradiance Factor (SIF). Geographic latitude plays an important role in the availability of sufficient solar radiation as well as the state of the atmosphere. Therefore, SIF value serves as a guide to the state of the atmosphere in terms of degree of cloud cover, temperature, humidity and landscape structure; which determines the feasibility of the solar energy implementation. The approach described in this paper can be used for rapidly computing the amount of solar radiation generated on a mountainous landscape surface and in the atmosphere as a function of height parameters. With SIF value known, solar panel can be mounted along specific angle of inclination to the sun. The algorithm design covers one year period and is based on the Digital Elevation Model (DEM) of the location under investigation. The proposed system was simulated using MATLAB1. Result show that the more irregular the landscape is, the lower the solar irradiance factor. SIF value of 400 and above predicts well enough sunshine for solar PV implementation in mountainous landscapes. Sample results show that solar radiation per kernel per day for a given landscape is highest between 12noon and 2.00PM local time; and the radiation per kernel per year for a given landscape have highest sunshine hours in January and December

TCP throughput efficiency enhancement in IEEE 802.11n network

The new opportunities opened up by wireless technologies are also accompanied with new technical challenges. Principal among the challenges is the fact that wireless medium has limited bandwidth resources when compared with wired equivalent. The convenience brought about by the IEEE 802.11n protocol is also followed by the technical challenge of near average performance of the widely used transport control protocol (TCP) due to limited bandwidth resources of the wireless medium. IEEE 802.11n specifies standard for physical (PHY) and MAC layers of wireless local area networks (WLANs) which is based on the IEEE 802.11-2007 networking reference standard. This work is meant to enhance the efficiency of TCP in IEEE 802.11n network in order to improve per user bandwidth. ACK suppression in both downstream and upstream TCP flow is used to improve bandwidth. The network bandwidth of an IEEE 802.11n LAN is simulated under two access methods; request-to-send/clear-to-send (RTS/CTS) access method and the basic method. Results showed an improvement in throughput efficiency over 10 nodes, which demonstrate performance improvement of TCP ACK suppression as 50% in comparison with receiver policy of acknowledging every TCP data segment and approximately 20% when compared with receiver's policy of acknowledging every TCP data segment in the network. Simulation was conducted in Matlab R2012a

Effective PRCs positioning for PAPR reduction using PRCs in OFDM systems

In this paper, the effective use of peak reduction carrier (PRC) for PAPR reduction is evaluated. By taking into account the number of PRCs, its position and PRC-to-Data ratio, the recommendation on how to effectively adopt PRC for PAPR reduction is carried out for OFDM systems with sub-carriers from 64 sub-carriers to 8192 sub-carriers. From our simulations, it has been shown that there are effective positions for PRC allocation as well as a balance needs to be strike for transmission efficiency versus PAPR reduction effectiveness evaluated via the PRC-to-Data ratio