Multiservice Cellular Networks Research Articles

Resource Allocation for D2D Communication in Multiservice Cellular Network

Allowing different services with different requirements to coexist is a hot topic for future communication. In order to meet the different communication requirements of users, this paper proposes a cellular communication system based on filtered orthogonal frequency division multiplexing (filtered-OFDM) supporting device-to-device (D2D) communication. Further, in order to improve the system performance, we study the user resource allocation problem in the system and propose a dynamic iterative resource allocation algorithm based on Hungarian algorithm (DRABH). The algorithm allocates resource blocks for D2D user pairs and all cellular users in the cell under the constraint of the lowest threshold of signal to interference plus noise ratio (SINR), and cellular users have high priority. Under the condition of ensuring that all cellular users can communicate, resource blocks are allocated to as many D2D user pairs as possible to maximize the number of user links in the network. Simulation results show that considering the interference introduced by filtered-OFDM and D2D communication, the proposed resource allocation scheme can significantly improve the number of user links.

Resource Management for Rate Maximization with QoE Provisioning in Wireless Networks

In this work, we study the problem of allocating resources in a multi-service cellular network aiming at maximizing the total system rate while providing suitable Quality of Experience (QoE) to the network users. In our formulation, we try to satisfy at least a certain number of users per service plan, which is an important constraint from the mobile network operators' perspective. We manage to reformulate this nonlinear optimization problem as an Integer Linear Problem (ILP), that can be solved by standard methods. However, due to the exponentially high complexity to solve large instances of this problem, we propose and evaluate a suboptimal algorithm with a much lower complexity, called Rate Maximization under Experience Constraints (RMEC), whose main idea is to divide the problem into three smaller subproblems with reduced complexity. By means of computational simulations, we show that our proposed algorithm presents a near optimal performance and outperforms the state-of-art solution of the literature.

Modelling of Cellular Networks with Traffic Overflow

The paper proposes a new method for modelling multiservice cellular networks with traffic overflow. The proposed method employs a model of Erlang’s Ideal Grading (EIG) with multiservice traffic and differentiated availability. The fundamental advantage of the proposed method, as compared to other relevant methods, is a major simplification in modelling systems with traffic overflow that results from the elimination of the necessity of a determination of the parameters of overflow traffic, that is, the average value and the variance. According to the proposed method, calculations in the overflow system can be reduced to calculations in a system composed of one grading only. The paper presents the method for determining availability in such a grading that models a system with traffic overflow. The results of analytical calculations were compared with the results of simulation experiments. The results of the research study confirm high accuracy of the proposed method.

Analysis of a Cellular Network Model with Multiparameter Control for Call Admission to Channels and to Data Call Buffer1

A numerical method is proposed to calculate the quality of service (QoS) of multi-service cellular networks with multi-parameter call admission control. A finite or infinite queue for non-real time traffic only is allowed. A decision for the access of new and handover voice calls is chosen on the basis of the number of such calls in channels while appropriate decision for handover data calls depend on the total number of such calls in the buffer.

Traffic Engineering for Multicast Connections in Multiservice Cellular Networks

The dynamic development of multiservice cellular networks has resulted in significant changes in the system architecture, which, in turn, has led to a broad distribution of many mechanisms and functions responsible for traffic management. These mechanisms take advantage of appropriate algorithms and analytic dependencies to ensure optimal quality of service that can be tailored to the objectives of the network operator. This paper proposes a new analytical model of a cellular network that supports multicast connections in a distributed environment. It is assumed that, in the cells participating in multicast connections, it is possible to apply different and independent traffic management mechanisms such as, for example, threshold mechanisms and resource reservation mechanisms. The proposed method can be used in an evaluation and scientific methods of research in the traffic effectiveness of multicast connections in given load conditions of a cellular network. An application of the method can have a particular significance in designing high-bit-rate multicast services to users in 4G networks. The analytical model proposed in this paper is verified on the basis of simulation examinations of cellular networks with multicast connections. The investigations confirm high accuracy of the model and the correctness of all theoretical assumptions adopted in the study.

Approximate Analysis Method for Multiservice Cellular Networks with the Buffer for Data Calls

A numerical method for calculating the parameters of quality of service (QoS) metrics in multi-service cellular networks, which allow the formation of bounded or unbounded queues for data calls, is proposed. The access of voice calls is controlled via two-parameter strategy, and access of data calls is determined using one threshold parameter. The decision of access of different types of voice calls is made on the basis of information on the total number of busy channels of the cell, the corresponding decision to call the data is determined by the total length of the queue of the calls of the specified type.

Remark to the paper "Approximate Analysis Method for Multiservice Cellular Networks with the Buffer for Data Calls"

Remark to the paper "Approximate Analysis Method for Multiservice Cellular Networks with the Buffer for Data Calls"

Analytical model of the multi-service cellular network servicing multicast connections

In this paper, a new analytical method of blocking probability calculation in multi-service cellular systems with multicast connections is proposed. The new analytical method considers the influence of both WCDMA and Iub interfaces on multicast traffic streams characteristics. The basis for the discussed method is a model of the full-availability group with traffic compression and the fixed-point methodology. The results of the analytical calculations of the cellular system with multicast connections are compared with the results of the simulation experiments, which confirms the accuracy of the proposed method. The proposed scheme can be applicable for a cost-effective resource management in UMTS/HSPA/LTE mobile networks and can be easily applied in proper network dimensioning.

Multidimensional Erlang model with randomized call admission control strategy and its application in communication networks

An analytical method is proposed for the analysis of a multidimensional Erlang model with randomized call admission control strategy. The applications of this model in both wireless multiservice cellular networks and integrated voice/data networks are demonstrated.

Numerical investigation of a multithreshold access strategy in multiservice cellular wireless networks

An efficient numerical method is proposed for investigating the quality of service metrics in cellular wireless networks that support narrowband voice calls and wideband data calls. Call admission is controlled by a multithreshold strategy based on a guard channels scheme for priority calls. A method for the determination of a set of efficient values of threshold parameters is developed. Results of numerical experiments are presented.

Differentiated Backoff Strategies for Prioritized Random Access Delay in Multiservice Cellular Networks

In this paper, a novel prioritization mechanism for random access strategies in cellular networks is proposed. The proposed prioritized random access strategy sets different retransmission probabilities to users, depending on their priorities. First, a mathematical analysis method for simultaneously evaluating throughput and access delay, considering an infinite population model and different retransmission policies, is developed. Most of the previous related research has been done, considering both finite population and saturation conditions where all the nodes in the system always have a packet ready to be transmitted, and the transmission queue of each station is assumed to be always nonempty. This assumption is a good approximation for a local area network working at full capacity. However, in a cellular system, the assumptions of a finite population and every node in a cell always having a packet to transmit are not very realistic. Here, the analytical results consider a Poisson arrival process-which is more suitable for the traffic model in a cellular system-for the users in the cells. Then, considering slotted ALOHA as a random access strategy and the developed analysis method, the case where two different types of service exist (low-and high-priority users) is mathematically analyzed. With the proposed prioritized random access strategy, the average access delay achieved for the high priority users is always lower than that for the low-priority users. Additionally, a mathematical expression for the throughput is derived with and without service differentiation. Finally, two approaches for finding the optimum retransmission probabilities are developed; in the first approach, the number of backlogged packets is required, whereas a simpler and efficient alternative method requires only the knowledge of the mean new packet arrival rate. For the performance analysis, four of the most common backoff algorithms are considered: (1) Uniform (UB); (2) Binary Exponential (BEB); (3) Negative Exponential (XB); and (4) Geometric (GB).

Efficient Methods for Performance Evaluations of Call Admission Control Schemes in Multi-Service Cellular Networks

Many dynamic call admission control (CAC) schemes have been proposed in the literature for adaptive reservations in cellular networks. Efficient application of these schemes requires reliable and up-to-date feedback of system performance to the CAC mechanism. However, exact analyses of these schemes in real time using multi-dimensional Markov chain models are challenging due to the need to solve large sets of flow equations. One dimensional Markov chain models have been widely used to derive performance metrics such as call blocking probabilities of multiple traffic classes assuming that all classes of calls have equal capacity requirements and exponentially distributed channel holding times with equal mean values. These assumptions need to be relaxed for a more general evaluation of CAC performance in multi-service cellular networks. In this paper we classify CAC schemes according to their Markov chain models into two categories: symmetric and asymmetric, and develop computationally efficient analytical methods to compute call blocking probabilities of various traffic classes for several widely known CAC schemes under relaxed assumptions. We obtain a product form solution to evaluate symmetric schemes and propose a novel performance evaluation approximation method with low computational cost for asymmetric schemes. Numerical results demonstrate the accuracy and efficiency of the proposed method.

Analysis of multiservice cellular networks with asymmetrical traffic and handoff queue

The next generation mobile communication system should be able to accommodate various services, including voice and Internet dial-up. As is well known, voice service has symmetrical, i.e. equal uplink and downlink bandwidth requirements, whereas Internet dial-up traffic usually has asymmetrical, i.e. unequal uplink and downlink bandwidth requirements. Frequency division duplex (FDD) usually allocates the same bandwidth to both uplink and downlink, whereas time division duplex (TDD) can change the number of time slots allocated to uplink and downlink to allocate different bandwidth to uplink and downlink. Thus, for scenarios with asymmetrical traffic, TDD is a better solution. To provide better quality of service during handoff, make-before-break soft handoff is preferable to break-before-make hard handoff. Furthermore, as forced termination of an ongoing call is less tolerable than blocking of a new call, handoff calls are usually given priority over new calls. We consider cellular multiservice TDD networks supporting both symmetrical and asymmetrical traffic with soft handoff and handoff queueing. First, we derive the mathematical model of the considered system with multi-dimensional birth–death process. Second, since the asymmetrical traffic may lead to the waste of uplink or downlink bandwidth, the effects of the traffic mix and the number of uplink slots on the system performance are studied. Third, the comparison of TDD and FDD with the presence of asymmetrical traffic is performed. Fourth, as the handoff region area increases, more calls will enter into or originate at that region. Thus, we study the effect of handoff region area on performance. Fifth, as a handoff call that cannot obtain the required channel upon arrival will be rejected if the handoff queue is full, the effect of handoff queue size on the performance is studied.

A Robust M/M/1/k Scheme for Providing Handoff Dropping QoS in Multi-Service Mobile Networks

This paper presents a technique for ensuring that the probability of handoffs dropped in a multi-service mobile cellular network is kept below specified thresholds. The technique is robust in the sense that it does not require information exchanges amongst neighboring cells. The technique also accepts different Quality of Service (QoS) specifications for different grades of handoff calls and ensures that these QoS levels are preserved under changing load conditions.

Analysis and Design of Optimal Admission Control Policies in Multiservice Cellular Networks

Forthcoming cellular networks will provide multimedia services along with QoS guarantees. In this context admission control is a key aspect in the design and operation of such systems. In this paper we consider several admission control policies together with appropriate algorithms for their analysis and design. We conclude that the family of randomized stationary policies provide the required versatility to adapt to several goals for both network planning and operation. Appropriate algorithms stem from the fact that randomized stationary policies can be suitably analyzed and adjusted by means of Markov decision processes theory and linear programming techniques.

Analysis and Design of Optimal Admission Control Policies in Multiservice Cellular Networks

Analysis and Design of Optimal Admission Control Policies in Multiservice Cellular Networks

Multiple fractional channel reservation for optimum system capacity in multi-service cellular networks

The multiple fractional channel reservation (MFCR) strategy for service differentiation is proposed. It reserves, on average, real numbers of channels to prioritise new and/or handoff calls in multiple service environments. Also, an algorithm to determine the optimum numbers of reserved channels to achieve maximum system capacity when using the MFCR strategy is proposed.

Simulation of controlled queuing systems and its application to optimal resource management in multiservice cellular networks

We consider a controlled queuing model and derive the corresponding Markov decision process for simple G/M/1 call admission controller. As an application of the controlled queuing model, we look into an optimal resource management problem arising in the context of multiservice cellular network with reuse partitioning. In particular, we consider a channel borrowing scheme between zones in two-zone reuse partitioning in a two-class cellular network and investigated the performance of various channel borrowing policies via simulation. We also introduce the simulator developed for controlled queuing systems. Most importantly, we demonstrate that Markov decision processes are well suited to this kind of optimization problem.

A call admission control strategy for multiservice wireless cellular packet networks

A simple connection control system for multiservice cellular wireless networks is presented. Mobile stations are classified depending on the traffic they generate (e.g., voice, data). Within each class, two subclasses are also identified: stations which have originated inside the cell and stations which come from adjacent cells. The connection control mechanism is carried out by considering a number of priorities among the various classes and their subclasses. It works on two levels: static and dynamic. The static level looks at “packet-level” quality of service (QoS), such as cell loss and delay, while the dynamic level takes care of connection dynamics and allows the load of the system to be driven with respect to the various subclasses. Results that illustrate the performance of this control mechanism are presented.