Borhanuddin Mohd Ali

A Review of 6LoWPAN Routing Protocols

Internet Engineering Task Force (IETF) working group has standardized the transmission of internet protocol version 6 (IPv6) packets over IEEE 802.15.4 low power wireless personal area network (LoWPAN) as 6LoWPAN protocol. It provides the wireless sensor network (WSN) node with IP communication capabilities by putting an adaptation layer above the 802.15.4 link layer. Different mechanisms performed by adaptation layer require the 6LoWPAN header encapsulation in the packet. Although routing is among the key issues of 6LoWPAN research, the way to encapsulate a new routing header in the 6LoWPAN packet has yet been investigated thoroughly. In this paper, different ways of routing header encapsulation in 6LoWPAN protocol stack is discussed. The simplified version Ad-Hoc On-Demand Distance Vector (AODV) such as On-Demand Distance Vector (LOAD) and Dynamic MANET On-demand for 6LoWPAN (DYMO-low) have currently been proposed in 6LoWPAN routing. Hierarchical routing (HiLow) is another routing protocol that is used in 6LoWPAN to increase the network scalability. Some comparisons of these routing protocols have been made in terms of their routing metric such as number of hops count. The used control messages for the route discovery in different routing protocols have also been investigated. These comparisons show that each routing protocol has its own advantage depends on the involved applications. There are some tradeoffs of respective routing protocols. The routing protocol that uses hello message may provide more reliable but results a higher delay in the packet routing.

Power Efficiency in Broadband Wireless Communications

Power Efficiency in Broadband Wireless Communications focuses on the improvement of power efficiency in wireless communication systems, especially of mobile devices. Reviewing cutting-edge techniques for conserving power and boosting power efficiency, the book examines various technologies and their impact on consumer devices. It considers each technology, first by introducing the main physical layer components in recent wireless communication systems along with their shortcomings, and then proposing solutions for overcoming these shortcomings.The book covers orthogonal frequency division multiplexing (OFDM) signal generation and formulation and examines the advantages and disadvantages of OFDM systems compared to alternative multiplexing. It introduces one of the main drawbacks of OFDM systems, peak-to-average power ratio (PAPR), and discusses several PAPR techniques. It also explains how to overcome the main drawbacks of real-world OFDM system applications. Considers power amplifier linearization for increasing power efficiency and reducing system costs and power dissipation Describes the implementation scenario of the most promising linearization technique, digital predistortion Presents some experimental demonstrations of digital predistortion when the device under test is in the loop Because the most costly device in a communication system that has a direct impact on power efficiency and power consumption is the power amplifier, the book details the behavior and characteristics of different classes of power amplifiers. Describing the evolution of the mobile cellular communication system, it details a cost-effective technique to help you increase power efficiency, reduce system costs, and prolong battery life in next generation mobile devices.

Hybrid AHP and TOPSIS methods based cell selection (HATCS) scheme for mobile WiMAX

In the past, the earlier cellular systems concentrated on voice calls as the main application that has to be considered to fulfil end-user requirements. However, nowadays with the variety of the user application and their requirements, the new 3G/4G systems have to consider many applications such as voice calls video streaming/conference, online gaming, peer-to-peer application and many other application and their different requirements as shown in Table 1 [1-2].

Data Storage as a new perspective of future IP networks

This paper propose a novel approach to utilize the network to store data in form of floating IP packets. Network could play the role of temporary storage in certain applications and packets could be retained in the network in a closed routing loop. This approach which is called Data Storage Technique on IP Networks (DSTN) could be considered as one of the new applications of future IP networks. With applying this technique, data could be accessed with least delay by intermediate forwarding nodes. This is a preliminary work to investigate the feasibility of the technique. Simulation results achieved by OpNet Modeller simulation tool and show that the generated traffic retained in the network for the complete simulation time. As the feasibility is tested, this technique can be implemented and tested on the real networks in the future.

Route Optimization Security in Mobile IPv6 Wireless Networks: A Test-Bed Experience

Route Optimization (RO) is standard in Mobile IPv6 (MIPv6) to route packets between Mobile Node (MN) and Correspondent Node (CN) using shortest possible path. It provides better bandwidth and faster transmission. RO greatly increases the security risk. In this paper, focus is given on enhanced security scheme in terms of RO based Test-bed evaluation experiment. An enhanced security algorithm is developed on top of MIPv6 RO to secure data. This algorithm is able to detect and prevent the attacker from modifying the data with using an encryption algorithm by cost of little bit increase but tolerable delay. The real-time network Test-bed is implemented to prove the efficiency of proposed method. The experimental results show that the proposed security scheme increases the security performance of the network. This gives advantage of safe communication that can significantly improve the data security of RO while maintaining the quality of other network performance.

Peak-to-Average Power Ratio Reduction in Orthogonal Frequency Division Multiplexing Systems

Broadband wireless is a technology that provides connection over the air at high speeds. Orthogonal frequency division multiplexing (OFDM) system has generally been adopted in recent mobile communication systems because of its high spectral efficiency and robustness against intersymbol interference (ISI). However, due to the nature of inverse fast Fourier transform (IFFT) in which the constructive and destructive behaviour could create high peak signal in constructive behaviour while the average can become zero at destructive behaviour, OFDM signals generally become prone to high peak-to-average power ratio (PAPR) problem. In this chapter, we focus on some of the techniques to overcome the PAPR problem (Krongold and Jones, 2003; Bauml, et al. 1996).

Dynamic Space-Code Multiple Access (DSCMA) System: A Double Interference Cancellation Multiple Access Scheme in Wireless Communications System

It is well known that cellular mobile phone systems have evolved from 1G and 2G that use frequency and time division multiple access (FDMA and TDMA) systems respectively, to code division multiple access (CDMA) of third generation (3G) systems (Chen et al., 2006). Furthermore, the exploitation of spatial diversity from the emergence of advance antenna technologies such as smart antenna and space time signal processing have given rise to induce another multiple access scheme called space division multiple access (SDMA) systems (Fang, 2002). Among these schemes, the system capacity and spectrum efficiency are the key factors to compare the performances of various mobile communication systems. Since radio frequency (RF) spectrum is a limited resource, these techniques have approached their fundamental limitations. Flexible utilization of such resources in space, time and code has led to great improvement in system capacity. For a given bandwidth, the system capacity for narrowband radio systems such as FDMA and TDMA is dimension or bandwidth limited. In contrast, the system capacity of CDMA and SDMA systems is interference limited. Any reduction in interference in CDMA and SDMA systems converts directly and linearly into increased capacity (Yu et al., 2004), (Chen et al., 2008). Multiple access schemes such as FDMA and TDMA increase their system capacity and spectrum efficiency by dividing the different network planning phases more clearly into individual parts to allow different frequencies to be used at different time moments (Castaeda & Lara, 2008). In CDMA systems, the same frequency is used simultaneously in adjacent cells and the interference level should be taken into account in the coverageplanning phase (Niemela & Lempiainen, 2003). Furthermore, cell splitting and sectorisation to form SDMA systems with use of directional antenna could also result in increase of system capacity and spectrum efficiency over the omnidirectional antenna system (Godara, 27