Dropping Probability Of Handoff Calls Research Articles

Call Blocking Estimation Using Adaptive Channel Reservation for Hand‐Off Calls in Wireless Cellular Network

ABSTRACTThe wireless cellular network (WCN) provides services to many users with limited radio resources. In WCN, resource allocation is important to provide the desired quality of service (QoS). Among the two possible types of calls in WCN, hand‐off calls (HCs) have higher priority than new calls (NCs). In this paper, we developed a mathematical model to estimate call blocking using an optimal number of guard channel (GC) for HCs by considering target hand‐off call dropping probability (HCDP). We named this model the optimal guard channel reservation (OCR) policy. This analytical model assumes the long‐term average of the traffic parameters and so is far from making any correlation with the operation of the existing system. In real, the traffic parameters are dynamic. Further, we proposed an optimal adaptive guard channel reservation (OACR) policy to obtain optimal performance. It adjusts the GCs dynamically w.r.t the traffic conditions to keep HCDP below the target. We have implemented the OACR scheme by using a test bed. Finally, we have applied both mathematical model (i.e., OCR policy) and OACR policy to a wireless cellular network, that is, Global System for Mobile Communication (GSM) 900 system.

Optimal Guard Channel Reservation and its Comparison with Fractional Channel Policies in Mobile Cellular Network

In the current communication era, 2G voice services coexist with higher generation mobile network voice services like Voice over Long Term Evolution (VoLTE) in 4G and Voice over New Radio (VoNR) in 5G. Subscribers registered in the 5G network, but their voice option is in 4G so voice calls can be handled through the Evolved Packet System (EPS) Fallback or Radio access technology (RAT) Fallback. Similarly, subscribers register in a 4G network, but their voice option is in 3G or 2G so voice calls can be handled through Circuit Switched Fallback (CSFB). To provide uninterrupted voice service in such wireless networks usually handoff calls (HCs) receive higher priority than new calls (NCs). So, some guard radio resources (i.e., channels in 2G or RBs in 4G or 5G) may be reserved in each cell to handle this type of HCs. If more channels are reserved for HCs, then the handoff call-dropping probability (HCDP) will be decreased and at that time the new call-blocking probability (NCBP) will be increased. So, by considering the target HCDP if channels are reserved for HC, then HCDP will remain below the target and NCBP will be minimum. In this paper first, we proposed an optimal channel reservation (OCR) policy that reserves guard channels according to the given target HCDP. Second, we compared our OCR policy with fractional channel (FC), limited fractional channel (LFC), and uniform fractional channel (UFC) policies. Finally, we observed the performance of all these policies considering the Global System for the Mobile Communication (GSM) network.

A Joint CAC and Dynamic Bandwidth Allocation Technique for Capacity and QoS Analysis in Heterogeneous LTE based BWA Network: Few Case Studies

Broadband Wireless Access (BWA) network such as LTE brings heterogeneity in terms of different radio access technologies, multi-tier architectures and co-implementation of various protocols to support various types of services with desired Quality of Service (QoS) for the subscribers. However, due to limited bandwidth and high demand of LTE-BWA networks, effective network planning is required to utilize the available radio resources in an efficient way. To achieve this target, this paper aims to implement a unique Radio Resource Management scheme for a heterogeneous LTE based BWA network (BWA Het-Nets) which consists of Small cells along with Macro cells. The proposed analysis has two components: (1) Received Signal Strength (RSS) based CAC policy; and (2) Dynamic Bandwidth Allocation (DBA) scheme for QoS provisioning. The novelty of this work lies on the integration of the RSS based CAC policy with DBA scheme for improved performance in terms of different QoS parameters like New Call Blocking Probability (NCBP), Hand off Call Dropping Probability (HCDP) and Bandwidth Utilization (BU). A Continuous Time Markov Chain based mathematical model is also developed for the realistic analysis of those QoS parameters. The Joint CAC and DBA scheme (JCAC-DBA) in two-tier LTE BWA Het-Nets significantly improves NCBP, HCDP, BU and overall capacity of the network under different combinations of macro/small cells for heterogeneous multimedia services.

Mobility-Aware Call Admission Control Algorithm With Handoff Queue in Mobile Hotspots

In this paper, we propose a mobility-aware call admission control (MA-CAC) algorithm with a handoff queue (HQ) in mobile hotspots, where different admission control policies are employed, depending on the vehicle mobility. Specifically, when a vehicle is static, a handoff priority scheme with guard channels is studied to protect vehicular handoff users because handoff users may get on the vehicle. In addition, an HQ is examined during stopping to further accept handoff users. On the other hand, for a moving vehicle, no guard channels for handoff users are allocated to maximize channel utilization. By means of Markov chains, we evaluate MA-CAC with an HQ in terms of new-call blocking probability (NCBP), handoff-call dropping probability (HCDP), handoff-call waiting time in the HQ, and channel utilization. Analytical and simulation results demonstrate that MA-CAC with an HQ can lower both the HCDP and the NCBP while maintaining high channel utilization.

Performance Assessment for LTE-Advanced Networks with Uniform Fractional Guard Channel over Soft Frequency Reuse Scheme

Dropping probability of handoff calls and blocking probability of new calls are two important Quality of Service (QoS) measures for LTE-Advanced networks. Applying QoS for Cell edge users in soft frequency reuse scheme in LTE system is a challenge as they already suffer from limited resources. Assigning some resources for handover calls may enhance dropping probability but this is in price of degradation in the blocking probability for new calls in cell-edge. Uniform Fractional Guard Channel (UFGC) is a call admission policy that provides QoS without reserving resources for handover calls. In this paper, the performance of Soft Frequency Reuse (SFR) in presence of Uniform Fractional Guard Channel (UFGC) will be investigated using queuing analysis. The mathematical model and performance metrics will be deduced in this assessment. The impact of UFGC will be evaluated in edge and core part separately. Then the optimal value for the parameter of UFGC will be obtained to minimize the blocking probability of new calls with the constraint on the upper bound on the dropping probability of handoff calls.

A Satisfaction-Based Dynamic Bandwidth Allocation Algorithm for Heterogeneous Wireless Network

Due to the limited bandwidth resources, traditional networks can not completely guarantee the Quality of Service (QoS) among users with new class, thus how to allocate network resource effectively becomes a very important problem. In this paper, we propose an algorithm for an integrated cellular/WLAN network, namely Satisfaction-based Dynamic Bandwidth Allocation (SDBA) algorithm. The main objective is to guarantee users’ satisfaction through allocating network resource dynamically according to proportional fairness based degradation and one-by-one search based degradation. Numerical results show that our proposed algorithm not only reduces new call blocking probability (NCBP) and handoff call dropping probability (HCDP), but also maintain fairness among users.

Heuristic RAT selection policy to minimize call blocking probability in next generation wireless networks

AbstractIn next generation wireless network (NGWN) where multiple radio access technologies (RAT) co‐exist, a joint call admission control (JCAC) algorithm is needed to make a RAT selection decision for each arriving call. RAT selection policy has a significant effect on the overall new call blocking probability in the network. We propose a heuristic RAT selection policy to minimize new call blocking probability in NGWN. The proposed JCAC scheme measures the arrival rate of each class of calls in the heterogeneous wireless network. Based of the measured values of the arrival rates and using linear programming technique, the JCAC scheme determines the RAT selection policy that minimizes overall call blocking probability in the heterogeneous wireless network. Using Markov decision process, we develop an analytical model for the JCAC scheme, and derive new call blocking probability, handoff call dropping probability (HCDP), and call incompletion probability (CIP). Performance of the proposed scheme is compared with the performance of other JCAC scheme. Simulation results show that the proposed scheme reduces new call blocking probability, HCDP, and CIP in the heterogeneous wireless network. Copyright © 2009 John Wiley & Sons, Ltd.

A quality of service negotiation-based vertical handoff decision scheme in heterogeneous wireless systems

This paper introduces a novel vertical handoff decision scheme. The objective is to provide users with enhanced quality of service (QoS) and maximize the network revenue. This scheme balances both-side interests via a suitably defined network merit function and a user–operator negotiation model. The merit function evaluates network performance based on user preferences and decides the most appropriate network for users. The negotiation model is defined as a semi-Markov decision process (SMDP). An optimal policy that maximizes the network revenue without violating QoS constraints is found by resolving the SMDP problem using Q-learning. Furthermore, a time-adaptive QoS monitoring mechanism is combined with the merit function in order to decrease the power consumption on terminal interface activation. The simulation results demonstrate that the proposed vertical handoff decision scheme enhances the performance in terms of power consumption, handoff call-dropping probability (HCDP) and network revenue.

Multi-class Bandwidth Reservation Scheme Based on Mobility Prediction for Handoff in Multimedia Wireless/Mobile Cellular Networks

Next generation of wireless cellular networks aim at supporting a diverse range of multimedia services to Mobile Terminal (MT) with guaranteed Quality of Service (QoS). The challenge is to maintain the playing continuity of multimedia streams during handoff. In this paper, a bandwidth reservation scheme based on mobility prediction is proposed, to enable high accurate prediction of next crossing cell (target cell) which a MT is going to, in order to avoid too early or over reservation resulting in a waste of resources. The amount of bandwidth to be reserved is dynamically adjusted according to (a) the current position (location) and the extrapolated direction of MT and; (b) the sector and zones of the cell. A Call Admission Control scheme (CAC) is also considered to further guarantee the QoS of real time traffic. The performance of the system is evaluated through discrete event simulation of the wireless cellular environment. Simulation results show that the proposed scheme as compared to several existing schemes is able to reduce the Handoff Call Dropping Probability (HCDP) of real time traffic and the number of terminated ongoing calls of non-real time traffic. In addition, it is efficient to reduce the number of cancelled reservation and subsequently increase the system bandwidth utilization.

Enabling seamless multimedia wireless access through QoS‐based bandwidth adaptation

AbstractEffective support of real‐time multimedia applications in wireless access networks, viz. cellular networks and wireless LANs, requires a dynamic bandwidth adaptation framework where the bandwidth of an ongoing call is continuously monitored and adjusted. Since bandwidth is a scarce resource in wireless networking, it needs to be carefully allocated amidst competing connections with different Quality of Service (QoS) requirements. In this paper, we propose a new framework called QoS‐adaptive multimedia wireless access (QoS‐AMWA) for supporting heterogeneous traffic with different QoS requirements in wireless cellular networks. The QoS‐AMWA framework combines the following components: (i) a threshold‐based bandwidth allocation policy that gives priority to handoff calls over new calls and prioritizes between different classes of handoff calls by assigning a threshold to each class, (ii) an efficient threshold‐type connection admission control algorithm, and (iii) a bandwidth adaptation algorithm that dynamically adjusts the bandwidth of an ongoing multimedia call to minimize the number of calls receiving lower bandwidth than the requested. The framework can be modeled as a multi‐dimensional Markov chain, and therefore, a product‐form solution is provided. The QoS metrics—new call blocking probability (NCBP), handoff call dropping probability (HCDB), and degradation probability (DP)—are derived. The analytical results are supported by simulation and show that this work improves the service quality by minimizing the handoff call dropping probability and maintaining the bandwidth utilization efficiently. Copyright © 2006 John Wiley & Sons, Ltd.

Dynamic resource allocation for handoff using MC-CDMA in wireless ATM networks

Focusing on the characteristics of WATM networks based on multicarrier code-division multiple access technique, an improved optimised cell-scheduling algorithm and a dynamic resource allocation scheme with a resource compensation method to improve performance are proposed. Performance measurements are obtained by an analytical model and simulation experiments and compared for different schemes such as handoff call-dropping probability and new call-blocking probability. The results obtained by the proposed algorithms perform better than other algorithms.

MIMO ARIMA models for handoff resource reservation in multimedia wireless networks

AbstractThis paper presents a new approach to prediction of resource demand for future handoff calls in multimedia wireless IP networks. Our approach is based on application of multi‐input‐multi‐output (MIMO) multiplicative autoregressive‐integrated‐moving average (ARIMA) (p,d,q)x(P,D,Q)S models fitted to the traffic data measured in the considered cell itself and on the new call admission control (CAC) algorithm that simultaneously maximizes the system throughput while keeping the handoff call dropping probability (CDP) below the targeted value. The main advantages of the proposed approach are the following: first, the proposed multi‐variable prediction method gives on average better predictions (i.e. narrower prediction confidence interval) for realistic traffic situations, which results in lower new call blocking probability (CBP) at the targeted handoff CDP and second, the model is simple to implement since it does not require communication among the adjacent cells. Simulation results show the superiority of the proposed MIMO prediction approach combined with the proposed call admission control algorithm for some typical nonstationary situations in comparison with univariate models. Copyright © 2004 John Wiley & Sons, Ltd.

Priority-Determined Multiclass Handoff Scheme With Guaranteed Mobile QoS in Wireless Multimedia Networks

The provision of multiclass services is gaining wide acceptance and will be more ubiquitous in future wireless and mobile systems. The crucial issue is to provide the guaranteed mobile quality of service (QoS) for arriving multiclass calls. In multimedia cellular networks, we should not only minimize the dropping rate of handoff calls, but also control the blocking rate of new calls at an acceptable level. This paper proposes a novel multiclass call-admission-control mechanism that is based on a dynamic reservation pool for handoff requests. In this paper, we propose the concept of servicing multiclass connections based on priority determination through the combined analysis of mobile movement information and the desired QoS requirements of multimedia traffic. A practical framework is provided to determine the occurrence time of handoff-request reservations. In our simulation experiments, three kinds of timers are introduced for controlling the progress of discrete events. Our simulation results show that the individual QoS criteria of multiclass 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 multiclass calls over high-speed wireless multimedia networks.