Mobile Cellular Environment Research Articles

Next-cell and mobility prediction in new generation cellular systems based on convolutional neural networks and encoding mobility data as images

Mobility prediction has been a popular research topic for many decades. With the advent of new generation technologies (5G and beyond) and smaller coverage cells, hand-over operations have become more frequent. Cellular system companies are therefore taking increasing interest in using the available predictive information on node movements to optimize and manage their bandwidth resources. In particular, the main challenging scope of our contribution consists in solving the issue of reliable next-cell prediction, aimed to call dropping probability minimization. In addition, our proposal is based on the innovative concept of mobility data to image encoding. The scheme is able to a-priori determine the next visited cells during host movements by applying a convolutional neural approach to mobility images. The power of machine learning is used to advantage, and highly accurate image classification is achieved for mobility prediction. We performed numerous simulation campaigns related to next-cell prediction in mobile cellular environments, obtaining very satisfactory results by the application of convolutional neural networks, which have an impressive history of effectiveness with image classification problems. The trained network has been associated to each coverage cell and the prediction accuracy has been evaluated.

A Comprehensive Study of the Behavior of Different TCP Variants using Multistate Error Model in Cellular Mobile Environment

The widespread use of internet services over the wireless links is expeditiously grown in recent years. The reinforcement of portable computing platform and technological elevation of wireless communication evokes substantial prosperity in the design and development of integrated environment such as cellular mobile environments. The repercussion of packet losses due to corruption and mobility is the radical circumstances of deteriorating TCP performance in the wireless ambience. Uniform and Multistate error model are both used in wireless environment; Uniform error model provides packet losses at a constant rate which consequence an imprecise results during simulation as in wireless environment packet losses are arbitrary, bursty and time diversify in nature. However Multistate error model imitates the behavior of the wireless packet loss in real environment and produce infallible outcome. In this paper we constitute a realistic Cellular Mobile Environment by considering multistage error model in the design of wireless packet losses. Mobility in structure is also conceived to estimate the actual performance of TCP. Moreover the behavior of TCP Tahoe, Reno, New Reno, Sack and Vegas in Cellular Mobile network is simulated to perceive the impact of wireless link on the behavior of these TCP variants. Finally from the result of our simulation we conclude the best TCP variants for different circumstances.

A survey on the channel assignment problem in wireless networks

AbstractEfficient allocation of channels for wireless communication in different network scenarios has become an extremely important topic of recent research. The main challenge lies in the fact that the channel allocation problem is NP‐complete. Because of a maximum allowable time limit imposed in practical situations for allocation of channels, sometimes we may need to be satisfied with a near‐optimal solution. In this correspondence, we present a discussion on the various challenges and approaches that have been used by different researchers to solve the problem of channel allocation taking into account different interference issues and efficient utilization of available communication channels for cellular mobile (including multimedia communication) environment and cognitive radio based networks. Copyright © 2010 John Wiley & Sons, Ltd.

Efficient Adaptive Algorithms for DOA Estimation in Wireless Communications

The problem of direction-of-arrival (DOA) estimation in mobile communication systems requires efficient algorithms with a high spatial resolution and a low computational complexity when moving sources are considered. MUSIC is known as a high resolution algorithm for DOA estimation but, this method demands high computational complexity to compute the signal subspace of the time-varying data of the correlation matrix. This paper focuses on MUSIC using subspace tracking methods, such as Bi-SVD and PAST, to carry out iterative DOA estimation. Accuracy and the processing time of both methods are evaluated and compared with the results of MUSIC. These results show the potential of Bi-SVD and PAST to reduce the processing time and to improve the accuracy when the number of snapshots and the source angular variation increases, assessing the source location for a dynamic mobile cellular environment.

Analysis of IPv6 handovers in IEEE 802.16 environment

The second generation of WiMAX solutions, based on IEEE 802.16-2005 standard, offers limited mobility support. Unfortunately, after quickly changing the point of attachment on the WiMAX data link layer (DLL), very slow and inefficient IPv6 reconfiguration takes place. Delays introduced by automatic configuration (DHCPv6 and IPv6 protocols) and Mobile IPv6 can easily diminish or even render useless all benefits gained using the efficient handover performed on DLL. As handover is a crucial process in mobile cellular environments, reasons behind delays introduced by IPv6 layer mechanisms have to be analyzed and appropriate countermeasures applied. In order to analyse influence of different factors on the handover delay a simulation environment modelling the full handover procedure in a WiMAX environment has been developed. It allows simulation and analysis of various mobility related issues, offering support for multiple base stations with groups of subscribers, both fixed and mobile, with various mobility models. Also support for tight integration with higher layers (IPv6, DHCPv6, and Mobile IPv6) is fully implemented. All stages of full IPv6 handover in IEEE 802.16 environment, focusing on major reasons of reconfiguration delays are described. The paper presents components, functional requirements and architecture of the simulation environment, together with example simulation results. The obtained results clearly show that most significant delays are caused by the IPv6 layer. The areas of improvement in several autoconfiguration mechanisms are identified. Proposals include novel use of DHCPv6 relays for remote configuration, solving DAD delays, limiting Binding Update procedure in Mobile IPv6, and configuring routing through DHCPv6 communication. A universal metric for assessing impact of every stage on handover efficiency is also defined. Several proposed improvements to the IPv6 handover process are evaluated. Discussion regarding possible generalization of best improvement proposals and remarks on further research areas conclude this paper.

QoS provision in wireless access networks: a routing perspective considering mobility

AbstractFuture wireless communications are expected to provide mobile users access to the desired service with the appropriate quality at any place. The essential elements for assembling such a vision are mobility, quality of service (QoS) provision and scalability, which are expected to be merged into the design process of wireless access networks. Internet mobility support is currently entering a mature phase in which scalable solutions provide low loss or even seamless handovers in cellular and heterogeneous mobile environments. Wireless and mobile QoS architectures extend the equivalent Internet approaches in order to accommodate the requirements associated with the presence of wireless links and mobility. Nevertheless, none of the popular mobility proposals combined with wireless and mobile QoS architectures encounter QoS in the routing function, leaving the QoS provision underutilized. QoS routing (QoSR) complements existing QoS architectures, enhancing application performance especially in the case of congestion, while providing efficient resource management. However, QoSR was originally designed for fixed IP networks without taking mobility into account. This paper investigates the interaction of QoSR in wireless access networks, identifying key points for the efficient cooperation with mobility and existing QoS architectures. Copyright © 2009 John Wiley & Sons, Ltd.

SOME PROPOSAL FOR IMPROVING CHANNEL ALLOCATION SCHEMES IN CELLULAR MOBILE NETWORK

In this paper, we propose two reformation of channel frequency allocation in Dynamic Load Balancing Strategy for Channel Assignment Using Selective Borrowing in Cellular Mobile Environment (LBSB) [2]. First, a proposal to classify cellular in three difference classes, then we determine the co-channel cell which have to lock channel frequency, the number of co-channel cell have to lock. Exprimentaions have showed the proposal methob has lower blocking probability with LBSB.

Discrete Simulation Framework for Wireless Cellular Networks

The aim of the discrete simulation framework is to deal with issues of the next generation of wireless cellular networks (e.g., multimedia traffic, radio resource management and mobility... etc) and to provide a platform for current and future investigations involving wireless cellular networks. The simulator is built from the scratch to enable customization requirements of any research and to provide the freedom to understand, configure protocol modules, draw desired topologies and specifies the movement paths of the mobile users and to plot the necessary performance graphs. In order to evaluate and validate the performance of the designed simulator, a simulation model for the wireless cellular network and mobile environment deployed. The performance of the developed simulator compared with the performance characteristics of existing algorithms. Simulation results verify the developed simulator is able to recapture the results of both the numerical result and simulation results of the comparative system utilizing an idealistic platform. In addition the simulator incorporates detail algorithms for the correlated components between the entities of the cellular networks and the development of the discrete simulator.

Superposition of Broadcast and Unicast in Wireless Cellular Systems

Practical application of superposition coding in multiplexing broadcast and unicast for OFDM-based mobile cellular systems is discussed. Superposition coding, whose gain is increased as the superposed signals have larger difference in signal-to interference-plus-noise ratio, is well matched for unicast and broadcast in a single-frequency network configuration. Combined with interference cancellation technique, broadcast signals from multiple base stations can be cancelled in a single step, minimizing the interference from broadcast to unicast. Issues related with scheduling and strategy for time, frequency and power resource sharing between broadcast and unicast are discussed. The application of superposed broadcast and unicast is then extended to MIMO systems. Simulation results in a practical mobile cellular environment are also provided, showing significant throughput gain of superposed broadcast and unicast.

A DOA-Based Adaptive Smart Antenna Processor for Cellular Mobile Systems

In this letter we propose an adaptive beamforming algorithm that efficiently suppresses interferences using a structured interference covariance matrix. The proposed algorithm provides high performance by exploiting angle diversity, especially in cellular mobile environments where the angular spread of a received signal is relatively small. We verify the superiority of the proposed algorithm to the well known linearly constrained minimum variance (LCMV) and reference signal-based algorithms.

A Low-Power Multicarrier-CDMA Downlink Baseband Receiver for Future Cellular Communication Systems

In this paper, design and implementation of a baseband receiver integrated circuit (IC) for a downlink multi-carrier code-division multiple access (MC-CDMA) system are presented. This MC-CDMA system aims to provide higher data transmission capacity than the current wide-band CDMA systems in mobile cellular communication environments. The proposed chip provides a robust tracking mechanism for synchronization errors and an accurate channel estimation strategy to overcome the challenge of outdoor fast-fading channels. Besides, low-power and low-complexity architecture design techniques are adopted to satisfy mobile receiver needs. Experimental results of the designed baseband receiver integrated circuit demonstrate its superior system performance and great reduction in power consumption. The chip was fabricated in a 0.18-mum CMOS technology with a core area of 2.6 mm times 2.6 mm. It can support up to 21.7-Mbps uncoded data rate in a 5-MHz bandwidth. When running at 5.76 MHz, its power consumption is as low as 9.9 mW from a supply voltage of 1.1 V.

Effective Radio Resource Management for MBMS in UMTS Networks

Broadcast and multicast offer a significant improvement of spectrum utilization, and becomes particularly important where information channels are shared among several users. Mobile cellular environments are expected to evolve with the technological approaches necessary to facilitate the deployment of multimedia services, such as streaming, file download and carousel services. The perspective that video streaming in wireless networks services is an attractive service to end-users has spurred the research in this area. To provide for a video delivery platform in UMTS, the Third Generation Partnership Project (3GPP) addressed this problem with the introduction of the Multimedia Broadcast and Multicast Services (MBMS) in 3GPP Release 6. In this document we analyse several effective radio resource management techniques to provide MBMS, namely, use of non-uniform QAM constellations, multi-code and macro-diversity to guarantee the optimal distribution of QoS depending on the location of mobiles.

Effective Radio Resource Management for Multimedia Broadcast/Multicast Services in UMTS Networks

Broadcast and multicast offer a significant improvement of spectrum utilization, and become particularly important where information channels are shared among several users. Mobile cellular environments are expected to evolve with the technological approaches necessary to facilitate the deployment of multimedia services, such as streaming, file download, and carousel services. The perspective that video streaming in wireless networks services is an attractive service to end-users has spurred the research in this area. To provide for a video delivery platform in UMTS, the third generation partnership project (3GPP) addressed this problem with the introduction of the multimedia broadcast and multicast services (MBMS) in 3GPP Release 6. In this document we analyse several effective radio resource management techniques to provide MBMS, namely, use of nonuniform QAM constellations, multicode, and macrodiversity to guarantee the optimal distribution of QoS depending on the location of mobiles.

Comparisons of link-adaptation-based scheduling algorithms for the WCDMA system with high-speed downlink packet access

The wideband code division multiple access (WCDMA) system with high-speed downlink packet access (HSDPA) is an important next-generation wireless system. By adopting adaptive modulation, efficient scheduling, and hybrid automatic repeat request technologies, it can support data rates of up to 10 Mb/s in the mobile cellular environment. Among these techniques, the scheduling algorithm plays a key role in realizing the HSDPA concept. A good scheduling algorithm should consider all the important factors, including channel impact, delay issues, and fairness. In this paper, a fairness index is adopted to examine the fairness performance of current link-adaptation-based scheduling algorithms, including the maximum carrier-to-interference (C/I), round-robin, proportional fair, and exponential rule schedulers. It is found that when multi-type services are supported, the fairness performance of current scheduling algorithms, including the round-robin scheduler, can be further improved even though the round-robin scheduler is viewed as the scheduler of the greatest fairness. Thus, a new scheduling algorithm, namely the queue-based exponential rule scheduler, is developed. Through simulations, it is shown that in the context of multi-type services the fairness performance of the queue-based exponential rule scheduler can surpass that of all the other schedulers in the time-multiplexing fashion, while maintaining good throughput and delay performance.

Challenges of computing in mobile cellular environment—a survey

Advances in cellular mobile technology have engendered a new paradigm of computing, called mobile computing. The frequency spectrum allocated to this service is not sufficient with respect to enormous growth of mobile communication users. Tracking down a mobile user in a cellular network which is a collection of geometric areas called cells each serviced by a base station is the other concern to the designer. This service also needs another problem to be solved, that is the access of common information by mobile users. Other than the issues in existing technology, many other issues on developing technology need to be addressed. The survey is done in two phases. In the first phase a survey of three fundamental problems in mobile computing on existing technology is done. The issues discussed arise from three essential requirements: the efficient management and sharing of the spectrum among the users; to locate a mobile user in the cellular mobile environments; and processing of queries on location dependent data. The second phase highlights on research on different issues such as security, routing etc. in third generation wireless network in developing technology.

Multimedia call admission control in mobile networks: a dynamical reservation-pool approach

The effective delivery of Multimedia traffic in next generation mobile cellular communication environment will become an increasingly important issue as cell sizes shrink to accommodate continuously large demand for high capacity. To provide the guaranteed mobile QoS for arriving multi-class calls, we should not only consider the regular latency requirement, but also minimize the dropping rate of handoff calls while at the same time controlling the blocking rate of new calls. In this paper, a new multi-class call admission control mechanism is proposed that is based on dynamically forming a reservation-pool for handoff requests. The prerequisite of this scheme is that wireless components can estimate future trajectory of mobile hosts with high degree of accuracy, which is possible in today’s increasingly improved position location techniques such as GPS. In this work, we first develop the notion of servicing various multi-class connections based on priority determined using the combined analysis of mobile movement information and the desired QoS requirements of multimedia traffic. We also provide a practical framework for determining the occurrence time of handoff request reservations. For our simulation experiments, three kinds of timers are introduced for controlling the progress of discrete events. The simulation results show that the individual QoS criteria of multi-class traffic such as the handoff call dropping probability can be achieved within a targeted objective and the new call blocking probability is constrained to be below a given level. The proposed scheme is applicable to channel allocation of multi-class calls over high-speed multimedia wireless ATM networks.

Performance of 1xEV-DO third-generation wireless high-speed data systems

Wireless high-speed data systems based on 1xEV-DO have recently been deployed commercially and in field trials. In this paper, the emphasis is placed on the validation of the simulated forward link system-level performance through comparison with field data. High spectrum efficiency observed both in simulations and in the field is explained by the salient features of 1xEV-DO that make it suitable for data communications in a cellular mobile environment. These features include, among others, the long-range channel estimation and rate prediction, incremental redundancy hybrid automatic request control (ARQ), turbo coding, and scheduling that exploits multi-user diversity in a fast fading environment. The paper also addresses the reverse link performance and the practical system constraints imposed by the signaling overhead necessary to support high throughput on the forward link.

A LP-RR principle-based admission control for a mobile network

In mobile networks, the traffic fluctuation is unpredictable due to mobility and varying resource requirement of multimedia applications. Hence, it is essential to maintain traffic within the network capacity to provide service guarantees to running applications. This paper proposes an admission control (AC) scheme in a mobile cellular environment supporting hand-off and new application traffic. In the case of multimedia applications, each applications has its own distinct range of acceptable quality of service (QoS) requirements. The network provides the service by maintaining the application specified QoS range. We propose a linear programming resource reduction (LP-RR) principle for admission control by maintaining QoS guarantees to existing applications and to increase the percentage of admission to hand-off and new applications. Artificial neural networks are used to solve the linear programming problem, which facilitates in real time admission control decision in the practical systems. We present an analytical model and results for the proposed AC scheme with resource reduction principle and a simulation study of the AC for performance evaluation. The simulation results demonstrate that the proposed AC scheme performs well in terms of increasing the number of admitted applications and maintains higher percentage of resource utilization. The suggested principle also shown that it is appropriate for the fair resource allocation with improved resource utilization.

A LP-based Admission Control Using Artificial Neural Networks for Integrated Services in Mobile Networks

In mobile networks the traffic fluctuation is unpredictable due to mobility and varying resource requirements of multimedia applications. Hence it is essential to maintain the traffic within the network capacity to provide the service guarantees to running applications. This paper proposes an Admission Control (AC) scheme in a single mobile cellular environment supporting real-time and non-real-time application traffic. In the case of a real-time and non-real-time multimedia applications, each application has its own distinct range of acceptable Quality of Service (QoS) requirements (e.g., packet loss, delay, jitter, etc.). The network provides the service by maintaining the application specified QoS range. We propose a Linear Programming Resource Reduction (LP-RR) principle for admission control by maintaining QoS guarantees to existing applications and to increase the percentage of admission to real-time and non-real-time applications. Artificial Neural Networks (ANNs) are used to solve linear programming problem, which facilitates an on-line admission control decision in the practical systems. The simulation results demonstrate that the proposed AC scheme performs well in terms of admitted applications and maintains lower percentage of rejection to hand-off and new applications of different traffic classes. The suggested principle also shown that it is appropriate for the fair resource allocation with improved resource utilization.

Distributed protocols for networks with mobile users - the mobilizer approach

This paper introduces a novel approach, called Mobilizer, of operating synchronous communication protocols in cellular mobile environment. First, we present a distributed protocol, called Mobile Propagation of Information (MPI), for broadcasting information in mobile environment. Then, we present the Mobile Propagation of Information with Feedback (MPIF) protocol, which can be used to implement the Mobilizer approach, i.e., enable broadcast-based synchronous protocols run over distributed networks with mobile users. We prove the correctness of the protocols and show that the additional message complexity overhead, induced due to the Mobilizer, is linear with the number of users' movements.