Glaucio H. S. Carvalho

Technical Communication: Performance analysis of multi-service wireless network: An approach integrating CAC, scheduling, and buffer management

Traffic management (TM) mechanisms such as Call Admission Control (CAC), Scheduling, and Buffer Management (BM) play a key role in the design of multi-service wireless network by providing service differentiation from diverse applications and assigning the network resources (radio channels or buffer) according to the quality of service (QoS) requirements of each service class. We propose in this work two new models that integrate CAC, Scheduling, and BM in the design of multi-service wireless network. By presenting their Markovian models and their performance metrics, we investigate their respective design tradeoffs and compare their performance.

QoS-Aware Energy-Efficient Joint Radio Resource Management in Multi-RAT Heterogeneous Networks

A heterogeneous wireless network (HetNet), which combines multiple cooperating radio access technologies in an overlapping structure, is a communication system that has been recognized as an efficient way to meet the increasing traffic demand in broadband wireless networks. In this paper, we exploit the network cooperation in HetNets to propose two joint radio resource management (JRRM) schemes that improve energy savings while satisfying the system quality-of-service (QoS) performance requirements. First, we present an optimal QoS-aware energy-efficient JRRM scheme, which is formulated as a semi-Markov decision process model, and provide the optimal control policy for the HetNet under analysis. Second, we present an implementation-friendly QoS-aware energy-efficient JRRM scheme that utilizes a threshold on the macrocell radio resource occupancy to trigger the switching-on/off procedure of the base transceiver station resources, as well as a load-balancing procedure to minimize the service disruptions that may occur because of radio resource shortage and to reduce power consumption during the HetNet operation. This JRRM scheme is analyzed by means of a multidimensional continuous-time Markov chain model. Third, we devise an algorithm to determine the threshold setting in the implementation-friendly JRRM scheme according to a desirable power saving level that is prespecified by the mobile network operator. Numerical results show that the proposed schemes achieve substantial energy savings while keeping satisfactory performance levels.

A semi-Markov decision process-based joint call admission control for inter-RAT cell re-selection in next generation wireless networks

In the next generation wireless networks (NGWNs), where different radio access technologies (RAT) will coexist and work in collaboration to provide ubiquitous access, a mechanism called Joint Call Admission Control (JCAC) will play an important role by deciding whether or not an incoming service request will be accepted according to an admission constraint as well as determining in which RAT (among the available) it will be connected. In this paper, we propose an optimal JCAC for inter-RAT cell re-selection problem also referred to as initial RAT selection in co-located wireless networks, which supports both real-time services and non-real-time services. To properly meet the JCAC goals, we propose a cost function that weigh two criteria: the blocking cost function, which takes into account the priority of each service class in each RAT, and the alternative acceptance cost, which reflects the multiplicity of RATs working in a collaborative fashion, mandatory in NGWN. We use the framework of Semi-Markov Decision Process (SMDP) to formulate the optimization problem and the value iteration algorithm to compute the optimal policy. Our model still takes into consideration the ratio between the radius of the co-located RATs and shows how it may impact on optimal initial RAT selection. Numerical results, supported by an analysis of the structure of the optimal policy, show that the proposed optimal JCAC selects for real-time service class the biggest RAT and for non-real-time service class the smallest one. This optimal JCAC policy is ratified by the current trend in the design of NGWN and also follows the 3rd Generation Partnership Project (3GPP) expectations.

Intercloud and HetNet for Mobile Cloud Computing in 5G Systems: Design Issues, Challenges, and Optimization

Emerging 5G systems will feature a closer collaboration between mobile network operators and cloud service providers to meet the communication and computational requirements of modern mobile applications and services in a mobile cloud computing (MCC) environment. In this article, we show how the marriage between heterogeneous wireless networks (HetNets) and multiple clouds (a collection of which is referred to here as Intercloud) stands out as an effective response for the mobile data deluge. First, we review the building blocks of a HetNet and an Intercloud as well as the resource management entities in both domains. Second, we outline how they might be orchestrated to better support the task offloading process. Third, we identify the key design criteria and challenges related to interoperation between an Intercloud and a HetNet. We then formulate a revenue sharing approach for a coalition between a mobile network operator and cloud service providers. The approach achieves the maximum revenue for the coalition by optimally associating the users to the clouds through the base stations. Next, the concept of Shapley value is applied to individualize the contribution of each player based on the maximum revenue for the optimal user association. Numerical results illustrate the benefits of the coalition for all players.

Optimal policy for Joint Call Admission Control in next generation wireless networks

In this paper, we propose an optimal Joint Call Admission Control (JCAC) in next generation wireless networks, where different radio access technologies (RAT) coexist in a co-located way. Moreover, we study the impact of the different RATs radius coverage area in the system performance and optimal policy structure. The Semi-Markov Decision Process (SMDP) framework is used for modeling of the JCAC proposed and the value iteration algorithm is used to compute the optimal policy. Numerical results show that variation in the proportionality of the radius of RAT coverage area impact on system performance.

A joint call admission control-based approach for initial RAT selection in HetNets

This paper proposes an optimal Joint-Call Admission Control (JCAC)-based approach for initial radio access technology (RAT) selection for Heterogeneous Wireless Networks (HetNets) composed of two co-located wireless networks supporting two different service classes. The framework of Semi-Markov Decision Process (SMDP) is used to formulate the problem as a JCAC optimization problem involving the design of a cost function that weights three criteria, namely, the blocking cost, the access price cost, and the energy consumption cost. Simulation results are provided, showing that the proposal network selection technique maximizes the systems capacity while selecting the RAT that consumes less energy.

The compromise with the covered area and the bit error rate in a suburban environment densely arboreous

In this paper a model is used for electromagnetic propagation waves in suburban environment densely arboreous to evaluate the covered efficiency of a cellular mobile communication system. The compromise with the covered area and the Bit Error Rate (BER) is identified as the key in the propagation characteristics that have the potential to influence the performance of the system. After that, the Bit Error Probability and the covered area is studies numerically for different heights of transmitter antenna. Experimental data had been gotten in one densely arboreous environment to adjust the considered model. Simulation for a GSM system had been carried through to evaluate the covered and the BER of the system and the results obtained indicate the performance of the system for the QoS requirement.

Energy Efficiency on Fully Cloudified Mobile Networks: Survey, Challenges, and Open Issues

Fully cloudified mobile network infrastructure, which is featured by the joint deployment of heterogeneous cloud radio access networks and edge computing, will successfully cope with the data deluge by densely deploying virtualized wireless base stations and servers while providing the system design with high flexibility, reliability, availability, and scalability. On the other hand, the massive replication of the wireless and computing infrastructure will significantly increase the energy footprint to prohibitive levels. In order to gain actionable insights on energy-efficiency for a fully cloudified mobile network infrastructure, this paper first presents a comprehensive survey of the recent research breakthroughs on each building block of the system, namely: remote radio heads, baseband unit pool, fronthaul, backhaul, HetNet, and edge and cloud computing. Next, we consolidate the discussion with the challenges and open issues of a joint operation.

An Energy-Efficient Routing Protocol for Infrastructure-Less Opportunistic Networks

In this paper, an energy-aware version of a recently proposed History-Based Prediction for Routing (HBPR) protocol for opportunistic networks (OppNets) called energy-efficient HBPR (AEHBPR) is proposed, which saves the energy consumption by avoiding unnecessary packets transmission in the network and by clearing the buffer of nodes carrying the copies of the already delivered packets. The proposed AEHBPR is simulated using the ONE simulator, using synthetic and real mobility traces, showing a superior performance compared to HBPR and AEProphet, in terms of average remaining energy, number of dead nodes, number of delivered messages, and overhead ratio, where AEProphet is the ProPHet routing protocol for OppNets, on which the same energy-aware mechanism has been implemented.

Analysis of Sub-Band Allocation in Multi-Service Cognitive Radio Access Networks

This letter addresses the sub-band allocation problem in dynamic spectrum access (DSA) scheme in a multi-service cognitive radio network (CRN) built over a multi-service primary network (PRN). Both access networks support connection-level and packet-level services, where the Poisson process and the Markov modulated Poisson process are used to describe the connection-level and packet-level services, respectively. By means of a multi-dimensional continuous-time Markov chain model, the DSA scheme is assessed under various traffic load profiles. Numerical results show that the connection-level secondary userss quality of service may be significantly deteriorated by the packet-level primary user service.