Adaptive Resource Allocation Scheme Research Articles

Joint Interference Coordination and Load Balancing for OFDMA Multihop Cellular Networks

Multihop cellular networks (MCNs) have drawn tremendous attention due to its high throughput and extensive coverage. However, there are still three issues not well addressed. With the existence of relay stations (RSs), how to efficiently allocate frequency resource to relay links becomes a challenging design issue. For mobile stations (MSs) near the cell edge, cochannel interference (CCI) become severe, which significantly affects the network performance. Furthermore, the unbalanced user distribution will result in traffic congestion and inability to guarantee quality of service (QoS). To address these problems, we propose a quantitative study on adaptive resource allocation schemes by jointly considering interference coordination (IC) and load balancing (LB) in MCNs. In this paper, we focus on the downlink of OFDMA-based MCNs with time division duplex (TDD) mode, and analyze the characteristics of resource allocation according to IEEE 802.16j/m specification. We also design a novel frequency reuse scheme to mitigate interference and maintain high spectral efficiency, and provide practical LB-based handover mechanisms which can evenly distribute the traffic and guarantee users' QoS. Our study shows that our scheme not only meets the requirement on coverage, but also improves the throughput while accommodating more users in MCNs.

Adaptive resource allocation and decoding strategy for underlay multi‐carrier cooperative cognitive radio systems

ABSTRACTThis paper proposes a resource allocation and decoding strategy at the secondary system for underlay and interweave multi‐carrier cooperative cognitive radio. The objective is to maximise the sum rate of both primary and secondary systems, taking into account the interference threshold constraint and the fact that the primary receiver always considers interference as noise. The decoding method at the secondary receivers is either Successive Interference Cancellation or treating interference as noise, depending on their channel gains. The rationale for this strategy is the extension of the Han–Kobayashi capacity‐achieving strategy on the Gaussian interference channel to the studied cognitive scenario. The proposed resource allocation algorithm is composed of a subcarrier allocation procedure to avoid intercell interference between secondary cells and of an iterative power allocation algorithm that maximises the sum rate on the primary and secondary cells, respectively. The proposed algorithm achieves high data rate improvements for the secondary systems while maintaining a low degradation on the primary system's rate. It also benefits from multi‐user diversity and is robust to the distance variations. Copyright © 2013 John Wiley & Sons, Ltd.

Adaptive radio resource allocation strategy based on density of femtocell

Serious interference and low radio resource utilization exist in femtocell that is also known as Home Node B(HNB) and Home Enhanced Node B(HeNB).To solve these problems,an adaptive radio resource allocation strategy based on the density of femtocell was proposed.The interference between the macrocell and femtocell was suppressed by frequency division,and interference between the femtocell was also suppressed by the reuse of resources and power control,and the Femtocell Access Point(FAP) was configured automatically based on self-organized network.The simulation and performance analysis show that the proposed strategy can maximize the utilization of radio resource,the interference is close to zero and the overall system throughput is increased by 20%.This strategy is especially suitable for intensive femtocell or occasions with radio resource constraints.

A multi‐cell adaptive resource allocation scheme based on potential game for ICIC in LTE‐A

SUMMARYIntercell interference coordination in Third Generation Partnership Project long‐term evolution‐advanced system has received much attention both from the academia and the standardization communities. Moreover, the network architecture of long‐term evolution‐advanced system is modified to take into account coordinated transmission. In this article, we study the dynamic resource allocation problem and potential game theory and propose a multicell adaptive distributed resource allocation algorithm based on potential game. The allocation process is divided into two steps; subchannel is allocated first, and then, transmitted power is optimized dynamically according to a novel pricing factor. Besides, existence and uniqueness of Nash equilibrium of the proposed game model are assured. As a result, intercell interference is well coordinated. Simulation results show that transmitted power is saved efficiently and system fairness is improved to a large extent, accompanied with good performance gain of total and cell‐edge throughputs. Copyright © 2013 John Wiley & Sons, Ltd.

Traffic-Adaptive and Link-Quality-Aware Communication in Wireless Sensor Networks

This paper is a summary of the main contributions of the PhD thesis published in [1]. The main research contributions of the thesis are driven by the research question how to design simple, yet efficient and robust run-time adaptive resource allocation schemes within the communication stack of Wireless Sensor Network (WSN) nodes. The thesis addresses several problem domains with contributions on different layers of the WSN communication stack.

An Adaptive Distance-based Resource Allocation Scheme for Interdependent Tasks in Mobile Ad Hoc Computational Grids

Two key components contribute to task completion time: execution cost and communication cost. The communication cost is induced by data transfers between tasks residing on separate nodes. The communication is always expensive and unreliable in mobile ad hoc Grids and therefore plays a critical role in application performance. To reduce communication cost, interdependent tasks are allocated to nodes located close to one another. However, once the tasks have been allocated, nodes can move within a Grid. The movement of nodes within a Grid may result in multi-hop communication between nodes executing dependent tasks. In order to deal with node mobility within a Grid, an effective resource allocation scheme is required, but the design of such a scheme for mobile ad hoc computational Grids is challenging due to the constrained communication environment, node mobility, and infrastructure-less network environment. In this paper, we have developed an adaptive and distance-based resource allocation scheme which takes into account the characteristics of an application and nodes and applies migration heuristics to address the local node mobility problem. The scheme is validated in a simulated environment using various workloads and parameters. DOI: http://dx.doi.org/10.5755/j01.itc.41.4.877

Resource Allocation for Interweave and Underlay CRs Under Probability-of-Interference Constraints

Efficient design of cognitive radios (CRs) calls for secondary users implementing adaptive resource allocation schemes that exploit knowledge of the channel state information (CSI), while at the same time limiting interference to the primary system. This paper introduces stochastic resource allocation algorithms for both interweave (also known as overlay) and underlay cognitive radio paradigms. The algorithms are designed to maximize the weighted sum-rate of orthogonally transmitting secondary users under average-power and probabilistic interference constraints. The latter are formulated either as short- or as long-term constraints, and guarantee that the probability of secondary transmissions interfering with primary receivers stays below a certain pre-specified level. When the resultant optimization problem is non-convex, it exhibits zero-duality gap and thus, due to a favorable structure in the dual domain, it can be solved efficiently. The optimal schemes leverage CSI of the primary and secondary networks, as well as the Lagrange multipliers associated with the constraints. Analysis and simulated tests confirm the merits of the novel algorithms in: i) accommodating time-varying settings through stochastic approximation iterations; and ii) coping with imperfect CSI.

Adaptive resource allocation for cognitive radio networks with multiple primary networks

Abstract In this article, adaptive resource allocation (ARA) is investigated for multiple primary networks based-cognitive radio networks under a more practical system model, where the bandwidth of each secondary user is assumed to be limited and the maximum allowable interference for each primary network is different. We first formulate the ARA as a constrained optimization problem with the objective function of maximizing the proportional fairness-based ergodic sum capacity. The multiple constraints optimization problem is NP-hard and therefore, we propose a scheme to decompose the optimization problem into two unconstrained optimization problems by designing alternative objective functions and penalty functions. Then, a suboptimal heuristic solution framework based on particle swarm optimization is proposed to solve the unconstrained optimization problems. Computation simulations are carried out and the results show that the proposed scheme outperforms traditional ARA schemes.

FFR 기반의 Femtocell 네트워크를 위한 적응 주파수 자원 할당 방법

According to distribute of resource of macro cell and reduce distance between transmitter and receiver, Femto cell system is promising to provide costeffective strategy for high data traffic and high spectral efficient services in future wireless cellular system environment. However, the co-channel operation with existing Macro networks occurs some severe interference between Macro and Femto cells. Hence, the interference cancellation or management schemes are imperative between Macro and Femto cells in order to avoid the decrease of total cell throughput. First, we briefly investigate the conventional resource allocation and interference cancellation scheme between Macro and Femto cells. So we found that cell throughput and frequency reuse ware decreased Then, we propose an adaptive resource allocation scheme based on the distribution of Femtocell traffic in order to increase the cell throughput and also maximize the spectral efficiency over the FFR (Fractional Frequency Reuse) based conventional resource allocation schemes. Simulation Results show that the proposed scheme attains a bit similar SINR (Signal to Interference Noise Ratio) distribution but achieves much higher total cell throughput performance distribution over the conventional resource allocation schemes for FFR and future IEEE 802.16m based Femtocell network environment.

COARSE: a cluster-based quality-oriented adaptive radio resource allocation scheme

There is an increasing demand by an ever-growing number of mobile customers for transfer of rich media content. This requires very high bandwidth which either cannot be provided by the current cellular systems or puts pressure on the wireless networks, affecting customer service quality. This study introduces COARSE - a novel cluster-based quality-oriented adaptive radio resource allocation scheme, which dynamically and adaptively manages the radio resources in a cluster-based two-hop multi-cellular network, having a frequency reuse of one. COARSE is a cross-layer approach across physical layer, link layer and the application layer. COARSE gathers data delivery-related information from both physical and link layers and uses it to adjust bandwidth resources among the video streaming end-users. Extensive analysis and simulations show that COARSE enables a controlled trade-off between the physical layer data rate per user and the number of users communicating using a given resource. Significantly, COARSE provides 25-75% improvement in the computed user-perceived video quality compared with that obtained from an equivalent single-hop network.

Proportional Data Rate Fairness Resource Allocation for MIMO-OFDM Multiple Access Channel by Considering the Correlation Effect of Line of Sight and Non Line of Sight Channel Conditions

In the MIMO-OFDM multiple access channel (MIMO-OFDM-MAC) uplink scenario, the base station decides the uplink parameters for multiple users based on channel state information (CSI) from each user in the system. The performance of MIMO-OFDM-MAC systems can be significantly improved by using an adaptive transmission and resource allocation schemes which consider the correlation effect of line of sight (LOS) and non line of sight (NLOS) channel conditions for different users in the system. A lot of papers have been published on resource allocation schemes for MIMO-OFDM systems. However, most of these resource allocation schemes have been considered for MIMO-OFDMA systems, where users are separated in the frequency domain and each user uses the same uplink and downlink channels in the same channel conditions. On the other hand, in the mulituser MIMO-OFDM systems, more than one user can be assigned the same frequency and channel conditions for the MIMO-OFDM broadcast channel (downlink) and MIMO-OFDM-MAC channel (uplink) are not the same. Therefore, the same resource allocation schemes for the conventional MIMO-OFDM systems can not be applied to multiuser MIMO-OFDM systems with different uplink and downlink channel conditions. Until now, most of the resource allocation schemes have been considered only for downlink MIMO-OFDM broadcast (MIMO-OFDM-BC) channel and very few papers tackle the fairness among users. Moreover, no paper considers a scheme to realize proportional data rate fairness among users in the MIMO-OFDM-MAC condition. In this paper, we propose a proportional data rate fairness resource allocation scheme with adaptive bit loading for MIMO-ODFM-MAC systems by considering the correlation effects of LOS and NLOS channel conditions in both spatial and frequency domains. Computer simulation results show that the proposed scheme can give larger system capacity while maintaining the proportional data rate fairness requirements among users in the system under the constraint of total transmit power and predetermined target BER.

A novel radio resource allocation scheme for IEEE 802.16e multicell networks

In this paper, we propose a new media access control (MAC) protocol, which is compatible with the IEEE 802.16e-2005 Orthogonal Frequency Division Multiple Access (OFDMA) wireless interface. In this protocol, the same radio resource can be shared by neighboring cells in the wireless mesh network (WMN) and collisions can be reduced in the overlapping areas. This protocol consists of two schemes: a downlink transmission and an uplink transmission. For downlink transmission we use a cross layer adaptive radio resource allocation (CL-ARRA) scheme, which consists of two steps: a dynamic subcarrier allocation (DSA) and a dynamic power allocation (DPA). For uplink transmission we propose a new subcarrier backoff scheme and use the Markov chain model to analyze this scheme. With this protocol, we analyze the performance of the downlink and the uplink operation in the OFDMA mode. The analytical results are well matched to the simulation results. We then extend our model to a star-mesh topology with multiple overlapped regions. Simulation results show that the performance can be improved with the application of the superior capability of our proposed MAC protocol to deal with collisions in the overlapped regions.

Mobile Agent Based Network Defense System in Enterprise Network

Security has become the Achilles’ heel of many organizations in today’s computer-dominated society. In this paper, a configurable intrusion detection and response framework named Mobile Agents based Distributed (MAD) security system was proposed for enterprise network consisting of a large number of mobile and handheld devices. The key idea of MAD is to use autonomous mobile agents as lightweight entities to provide unified interfaces for intrusion detection, intrusion response, information fusion, and dynamic reconfiguration. These lightweight agents can be easily installed and managed on mobile and handheld devices. The MAD framework includes a family of autonomous agents, servers and software modules. An Object-based intrusion modeling language (mLanguage) is proposed to allow easy data sharing and system control. A data fusion engine (mEngine) is used to provide fused results for traffic classification and intrusion identification. To ensure Quality-of-Service (QoS) requirements for end users, adaptive resource allocation scheme is also presented. It is hoped that this project will advance the understanding of complex, interactive, and collaborative distributed systems.

Cross-layer interactions in multihop wireless sensor networks

In this article, we propose a constrained queueing model to investigate the performance of multihop wireless sensor networks. Specifically, the cross-layer interactions of rate admission control, traffic engineering, dynamic routing, and adaptive link scheduling are studied jointly with the proposed queueing model. In addition, the stochastic network utility maximization problem in wireless sensor networks is addressed within this framework. We propose an adaptive network resource allocation scheme, called the ANRA algorithm, which provides a joint solution to the multiple-layer components of the stochastic network utility maximization problem. We show that the proposed ANRA algorithm achieves a near-optimal solution, that is, (1-ϵ) of the global optimum network utility where ϵ can be arbitrarily small, with a trade-off with the average delay experienced in the network. The proposed ANRA algorithm enjoys the merit of self-adaptability through its online nature and thus is of particular interest for time-varying scenarios such as multihop wireless sensor networks.

Adaptive Self-Learning Resource Allocation Scheme for Unlicensed Users in High-Rate UWB Systems

In this paper, we investigate a dynamic sub-band allocation for spectrum sharing in the multiuser OFDM-UWB systems while respecting the system constraints and the distributed MAC architecture. The contribution of this work is twofold: first we propose a dynamic spectrum allocation scheme based on an analytical study by deriving a multiuser optimization problem to find the optimal allocation solution. Based on an adaptive and low-complexity approach, the proposed scheme shares the available resources among unlicensed UWB users while taking into consideration the QoS requirements and the channel conditions. Then we extend the proposed scheme to allow the coexistence of a maximum number of secondary users in one channel while maintaining all the constraints support. This leads to a time-frequency allocation approach that exploits information laying in different layers, allowing a cross-layer design. This new approach improves the system performance compared to WiMedia solution and offers a considerable gain for users that have strict QoS requirements.

Performance Evaluation of Resource Allocation Scheme Based on Hierarchical Constellation in Cellular Networks

Hierarchical constellations offer a different property of robustness to the multiple bits that construct a symbol according to channel errors. We apply the characteristics of hierarchical constellations to a multi-user cellular system that has limited modulation levels, in order to improve cell capacity. We propose an adaptive resource allocation scheme based on the hierarchical constellation in which a symbol is shared by multiple users and each bit in a symbol is allocated adaptively according to the channel condition of each user. The numerical results show that the proposed resource allocation scheme provides mobile users with higher modulation levels so that the cell capacity is improved.

Adaptive multi-component service model for Wideband Code Division Multiple Access systems

In this paper, we propose and evaluate an adaptive resource allocation scheme for Wideband Code Division Multiple Access multimedia systems. We give a discussion on the inherently multi-component nature of multimedia applications for wireless communication systems, and describe our multi-component model. Subsequently, we introduce our adaptive resource allocation scheme based on the described teleservice model. The multimedia traffic and the adaptive scheme are modelled and analysed next, using queuing theory. The scheme is evaluated and compared against the conventional schemes, namely, the Non-Priority scheme and the Guard Channel scheme, using performance results for blocking and dropping probability. We demonstrate that the proposed scheme is more flexible and efficient in guaranteeing Quality of Service than the conventional schemes.

Adaptive rate scheduling for 3G networks with shared resources using the generalized processor sharing performance model

In current and next 3G and beyond wideband code-division with multiple access (WCDMA) cellular networks, sharing the radio access network has become an important issue for 3G mobile operators. 3G and beyond network rollout is a very costly and time consuming process. Therefore, sharing of network infrastructure among operators offers an alternative solution to reducing the investment in the coverage phase of WCDMA. In radio access network (RAN) sharing method, which is our focus in this study, each operator has its own core network and only the RAN is shared. It implies that multiple operators fully share the same RAN. Without an efficient RRM, one operator can exhausts the capacity of others. This study tackles an efficient scheduling to provide maximum system throughput and proportional fairness in accordance with operator capacity share through adaptive resource allocation scheme. We refer to this new scheme as Multi-operators Code Division Generalized Processor sharing scheme (M-CDGPS). It employs both adaptive rate allocation to maximize the resource utilization and GPS techniques to provide fair services for each operator. The performance analysis in terms of bounded delay and queue size are obtained.

An Adaptive Frame Resource Allocation Strategy for TDMA-Based Cooperative Transmission

Cooperative relaying transmission is addressed as an effective way to offer better channel capacity and larger coverage for B3G wireless system. In this letter, an explicit adaptive frame resource allocation (AFRA) strategy for adaptive TDD-TDMA frame structure is deduced in terms of slot allocation for cooperative relaying transmission, and through the analysis and numerical simulations, the proposed scheme can contribute to obtain the superior performances for the future cooperative wireless system

Simulation and Modeling Bandwidth Control in Wireless Healthcare Information Systems

Next generation wireless networks have been designed to provide support for multimedia services, with different traffic characteristics and different Quality of Service (QoS) guarantees. Medical broadband applications have attracted increased attention in recent years and furthermore, the tremendous growth of wireless technologies has introduced the potential of continuous healthcare monitoring for mobile patients. The bandwidth requirements and the emergency nature of medical applications introduce the need for QoS provisioning in wireless broadband medical networks. Wireless networks may support a number of e-health applications with different traffic requirements and characteristics, providing at the same time QoS guarantees. Resource allocation in e-health application is inherently different in many aspects including the offered services, traffic requirements, propagation characteristics, and network structure. In this paper, an adaptive resource allocation scheme for QoS provisioning in wireless healthcare information systems is proposed.