8 - Data transmission in Mobile Communication Systems

Location-based service (LBS) is a kind of mobile valueadded services in mobile communication systems. The development of mobile positioning techniques promotes application of LBS. This paper presents a type of architecture of LBS. In this architecture, TDOA positioning modules are appended into the mobile basestations in order to implement LBS. LBS gateway and application platform are two vital parts in this architecture. LBS gateway modules are added into MSC of the mobile communication networks. LBS application platform is similar to a mobile location server. TDOA positioning modules deal with rough location testing and simple data computing. LBS gateway is a comprehensive management device which processes location information related to the mobile users. LBS application platform incepts location information processed in LBS gateway, cooperates with the mobile terminal and sends location information to the mobile users by proper data format. LBS application platform is developed based on ArcIMS map server which provides a lot of APIs. The application programming flowchart for LBS is implemented in detail in this paper. The real testing in the mobile communication systems shows that the proposed LBS can provide exact location services for mobile users.

In this paper, we propose a novel location-information-based multiple-landmark multicast protocol (MLMP). This protocol is an implicit, flexible hierarchical routing scheme following the traditional hierarchical method for handling scalability in large scale Ad hoc networks. MLMP features dynamic distributed election of multiple landmarks with scope constraints and multicast packet forwarding using location-information-based protocol. The protocol is very suit for large scale Ad hoc networks. The simulation results showed the better performance properties of MLMP in general Ad hoc networks infrastructures.

The subject of research in this article is the process of building a mobile communication system that operates under electronic countermeasures. The aim is to develop recommendations for building a wireless mobile communication system that operates effectively in a complex interfering electromagnetic environment. The strategy for building a mobile wireless communication system is based on the use of a grouping of low-altitude UAVs with ultra-wideband signal technology circulating in control and communication channels, with the integration of artificial intelligence elements into its structure. The objective of this study is to ensure the stable and secure operation of a wireless mobile communication system despite electronic countermeasures. The methods of analytical, temporal positional pulse coding, and fuzzy logical inference were used to make decisions on the transfer of service in the network. The following results were obtained. A strategy for building a wireless mobile communication system despite electronic countermeasures has been developed. It is shown that in order to obtain high noise immunity of control and communication channels and to protect information from interception, wireless ultra-wideband communication technology should be used. This will provide large volumes and speeds of information transmission. A technical solution for the design of an ultra-wideband transceiver antenna system is proposed. Moreover, it is recommended to use the results of data processing in a fuzzy decision-making system for the transfer of service between mobile network nodes in conditions of interference. Conclusions. The scientific novelty of the obtained results is as follows. The use of ultra-wideband channels makes it possible to increase the number of control and communication channels in a wireless mobile system almost unlimitedly. The preliminary distribution of orthogonal codes between the channels realizes the process of control and communication without the interception of information and mutual interference. The use of the time-position-pulse coding method prevents the occurrence of intercharacter distortions of the encoding ultrashort pulses. This also reduces the level of distortion of information signals caused by multipath propagation, which guarantees the security of information in the system. The use of a fuzzy decision-making system for the transfer of services between mobile network nodes allows dynamically changing the network topology in real time and maintaining high quality of service under electronic countermeasures.

IntroductionThe popularity of mobile communication systems has increased remarkably during the last decade and the market demand still continues to increase.As a fundamental part of these systems, antenna is one of the most important design issues in modern mobile communication units.Although there are several similar definitions, an antenna can be mainly described as a device, which transforms the electromagnetic waves in an antenna to radiating waves in an unbounded medium such as air in transmitting mode and vice versa in receiving mode.Because antennas are dependent on frequency, they are designed to operate for certain frequency bands.The rapid growth of mobile communication systems has forced to the use of novel antennas for base and mobile station applications (mobile phone, notebook computer, personal digital assistants (PDA), etc.).Earlier, mobile systems were designed to operate for one of the frequency bands of 2G (second generation) systems, which are Digital Cellular System (DCS), Personal Communications Service (PCS) and Global System for Mobile Communications (GSM) networks.Currently, many mobile communication systems use several frequency bands such as GSM 900/1800/1900 bands (890-960 MHz and 1710-1990 MHz); Universal Mobile Telecommunication Systems (UMTS) and UMTS 3G expansion bands (1900-2200 MHz and 2500-2700 MHz); and Wi-Fi (Wireless Fidelity)/Wireless Local Area Networks (WLAN) bands (2400-2500 MHz and 5100-5800 MHz) where the list of frequently used frequency bands is given in Table 1 ( Best, 2008).Conventionally, because a single antenna can not operate at all of these frequency bands of mobile communication, multiple different antennas covering these bands separately should be used.However, usage of many antennas is usually limited by the volume and cost constraints of the applications.Therefore, multiband and wideband antennas are essential to provide multifunctional operations for mobile communication.A multiband antenna in a mobile communication system can be defined as the antenna operating at distinct frequency bands, but not at the intermediate frequencies between bands.For example, a triple band antenna for GSM 900/1800/1900 bands can cover the frequency bands 890-960 MHz and 1710-1990 MHz (Ali et al., 2003); however, it does not operate properly at the frequencies such as 1200 MHz or 2500 MHz.On the other hand, a wideband antenna operates at every frequency points within a given frequency band.For example, a wideband antenna covering UMTS, extended UMTS and WLAN 2400 bands functions at every frequency points www.intechopen.com

Wide-band digital indoor and future mobile communication systems are being developed in the quasi-millimeter and millimeter wave frequency bands. In such high-speed systems, the degradation of transmission quality by multipath fading constitutes a limiting barrier. Multipath fading, which results from reflection, refraction and scattering of radio waves by buildings and other structures, gives rise to more than one path reaching the receiver and produces a distorted version of the transmitted signal. In mobile and indoor communication systems it cannot be eliminated, therefore the multipath channel must be well characterized in order to reduce its effect in the design of such systems. The objective of this research is to study the multipath fading and delay spread effects due to buildings in an urban propagation channel. In particular, the effects of the building materials, shapes and number of buildings on multipath fading are being studied.

Mobile traffic, which has increased significantly with the emergence of Fourth generation longterm evolution (4G-LTE) communications and advances in video streaming services, is still currently increasing at an incredible pace. Fifth-generation (5G) mobile communication systems, which were developed to deal with such a drastic increase in mobile traffic, aim to achieve ultra-high-speed data transmission, low latency, and the accommodation of many more connected devices compared to 4G-LTE systems. 5G communication uses high-frequency bandwidth to implement these features, which leads to an inevitable drawback of a high path loss. In order to overcome this disadvantage, small cell technology was developed, and is defined as small, low-power base stations that can extend the network coverage and solve the shadow area problem. Although small cell technology has these advantages, different problems, such as the effects of interference due to the deployment of a large number of small cells and the differences in devices accessing the network, need to be solved. To do so, it is necessary to develop an algorithm for a service method. However, general algorithms have difficulties in responding to the diverse environment of mobile communication systems, such as sudden increase in traffic in certain areas or sudden changes in the mobile population, and machine learning technology has been applied to solve this problem. This study employs a machine learning algorithm to determine small cell connections. In addition, a 5G macro system, the application of small cells, and the application of machine learning algorithms are compared to determine the performance improvement in the machine learning algorithm. Moreover, Support Vector Machine (SVM), Logistic Regression and Decision Tree algorithm are employed to show a training method that uses basic training data and a small cell on-off method, and the performance enhancement is verified based on this method.

Perform ability modelling and evaluation of wireless and mobile systems have been of interest for recent research work. Especially, because of the complexity of the next generation wireless and mobile systems, modelling and performance evaluation is essential to improve the architecture according to the quality of service. (QoS ) requirements and performance characteristics. A considerable amount of the existing work in literature focuses on handover phenomena using analytical modelling and/or simulation of mobile communication systems. This paper presents a perform ability evaluation framework of mobile communication systems with different handover strategies using analytical modelling approaches. The availability and mobility issues are also considered in the proposed models. Well-known approximate Markov reward model solution and the exact Spectral expansion solution approaches are considered. Perform ability measures of proposed models, such as blocking probability and mean queue length are presented.

Within a decade a 1000-fold increase in wireless communication traffic volume is expected, requiring increased throughput and data rates. Although the Terahertz (THz) band offers new possibilities it remains largely unexplored. Spectrum frequencies over 300 GHz are as yet unallocated but could fulfill the demand for wireless data transmission, e.g. in terms of available bandwidth. The fabrication of new cutting edge technology and the development of novel THz mobile communication systems are key to explore the spectrum at these frequencies and in order to achieve connectivity requirements of future mobile systems beyond 5G. This paper will report on novel coherent radio over fiber (CRoF) technologies for Terahertz transmission systems. World record experimental results for Terahertz transmission will be reported.

The key technical elements in designing digital mobile satellite communication systems are identified, and tradeoff studies on the transmission parameters of the satellite link, which were based on experience with an experimental system and the results of field trials, on digital maritime and aeronautical satellite communication systems, are described. The future evolution of the various new communication services to be offered in the digital mobile communication systems are discussed. In the digital mobile satellite communication systems which will be operated under the condition of low C/N and with a signal-level fluctuation due to multipath fading etc., it has been found that the most important requirement is to establish the frame synchronization quickly and maintain it stably in addition to the stable carrier/clock tracking, under this severe link condition. >

The commercial proliferation of cellular voice and data service has placed a new challenge for mobile communication systems. Next-generation wireless systems are envisioned to have an all-IP-based infrastructure with the support of heterogeneous access technologies (Akyildiz et al., 2004). Under the circumstance, the Internet Protocol (IP) is selected as the common interconnection protocol to integrate disparate wireless systems, so that mobile users can roam among multiple wireless networks, regardless of the underlying different radio access technologies (Akyildiz et al., 2005; Makaya & Pierre, 2008; Mohanty & Xie, 2007). However, with the advent of new value-added services (video-conference, multimedia streaming, etc.) and novel concepts introduced into Long Term Evolution (LTE) architecture of the 4th Generation (4G) networks, provisioning efficient mobilitymanagement with quality of service guarantees and seamless handoff feature become even more important for next-generation wireless network design. Generally, mobility management allows mobile communication systems to locate roaming terminals for voice/data delivery as well as maintaining network connectivity when the terminal moves into a new service area (Akyildiz et al., 1999). Typically, such process contains two aspects: location management and handoff management (Quintero et al., 2004; Zhang et al., 2010). Location management enables telecommunication systems to find out the network attachment points of roaming nodes for call/data delivery. It usually contains two components: location update and call delivery (or data delivery). The former requires mobile nodes to provide the system with their location information, while the latter indicates that the system is queried for the location information of specific mobile nodes, and then services are delivered to them while they are away from their home network (Zhang et al., 2010). Handoff management aims to maintain network connectivity when mobile nodes change their network attachment points or access points. Obviously, handoff protocols need to preservemobile users’ network connectivity as they move from one network to another, while simultaneously reducing disruption to the ongoing call/data sessions. Therefore, reducing handoff delay and maximizing session continuity are always the primary goals of handoff management (Dimopoulou et al., 2005). Generally, handoff seamlessness means lower packet Performance Analysis of Seamless Handover in Mobile IPv6-based Cellular Networks 13

Most work on cooperative diversity has assumed that the cooperating group (source and partners) and the associated average channel conditions between terminals (source, partners, and destination) are predetermined. In practical situations, however, it is important to develop the efficient algorithms for assigning the terminals with good inter-user channels for cooperating groups. In this paper, we propose the partner assignment algorithm for cooperative diversity in mobile communication systems. The proposed partner assignment algorithm is investigated by using the path loss model for mobile communication systems. Numerical results show that the proposed partner assignment algorithm provides the comparable probability of cooperative transmission to the partner assignment algorithm using exhaustive search. The probability of cooperative transmission increases with the number of users, which gives potential benefits of practical implementation to user cooperation in mobile communication systems. The proposed partner assignment algorithm also provides the tradeoff between probability of cooperative transmission, cooperative diversity gain, and the amount of average SNR information of inter-user channels.

A highly innovative global broadband mobile communication system concept

A mobile ad hoc network is a network consisting of a set of mobile hosts capable of communicating with each other without the assistance of base stations. One prospective direction to assist routing in such an environment is to use location information provided by positioning devices such as global positioning system. The grid routing protocol uses hierarchical approach in geographic forwarding. The protocol tries to exploit location information in router discover, packet relay, and maintenance. But there is no efficient location service in the protocol, which restrains the protocol from being scalable. In this paper, we improved gateway election method based on group decision, integrate the distributed location service with grid routing protocol, and propose an efficient location service. With this location service, one node can query for the locations of other nodes quickly through depth first searching method. Furthermore, we demonstrate the improved grid protocol through analysis and simulations.

5G mobile communication networks are emerging in order to cover the extreme needs for high data rates for delivering multimedia data to mobile communication users. The required bandwidth may be found if millimeter wave bands are fully employed for the establishment of such cellular systems. In this Book Chapter the propagation issues for 5G mobile communication systems are rigorously analyzed and presented. Firstly, the most popular scenarios and architectures of the next generation mobile systems are described and the channel models utilized for the evaluation of physical layer techniques (air interface are given. Secondly, the channel effects are described, i.e. effects due to local environment of the transceivers, atmospheric effects and their combination and the state of the art on the modeling of these effects is analytically presented. Finally, future directions for the propagation and channel model prediction for the next generation mobile communication systems -5G millimeter wave cellular systems are analyzed. Open issues and technical challenges of millimeter wave (mmWave) 5G cellular systems are finally described.

The Network layer adjacency information in ad-hoc networks can be used for a coarse estimation of the location of mobile sensor nodes in such networks. This method may be particularly useful for collecting approximate location information for a situational awareness system without taking too much bandwidth. However, past research has shown that the accuracy of this method is limited. In this paper, we explore the use of predictive filtering methods for improving the accuracy of adjacency-based coarse localization in MANETs. Using the fact that a mobile node would have a continuous path with smooth physical transitions, we treat abrupt turns and irregular jumps in estimated nodal speeds as noise, and explore the possibility of minimizing this noise by applying predictive filtering techniques. We examine and compare moving average, Kalman filtering and finally a hybrid method, and use simulations to show that a hybrid predictive filtering method could improve the accuracy of coarse localizations significantly.