Mobility pattern learning and route prediction based location management in PCS network

The distribution of the interservice time, which is the interval between the end of a call served and the start of the succedent call served by a portable, is a crucial parameter for modeling and cost analysis for location management in personal communication service (PCS) networks. The interservice time differs from the interarrival time due to the busy-line effect. However, in the literature, most of the cost analyses for location management were carried out by ignoring the busy-line effect, i.e., by identifying the interservice time with the interarrival time, because, so far, there is no analytical result for the interservice time distribution considering the busy-line effect. In this paper, we develop an analytical model to investigate the busy-line effect on the interservice time distribution. Closed-form analytical formulas for the interservice time are derived. A numerical study shows that a big discrepancy exists between the interarrival time and the interservice time. Based on the analytical results for the interservice time, the impact of the busy-line effect on modeling of portable movements in PCS networks is further evaluated. An analytical result for the distribution of the number of cell-boundary crossings during the interservice time is obtained. Both analytical results and numerical examples indicate that the busy-line effect has influence on the distribution of the number of cell-boundary crossings during the interservice time. Therefore, cost analysis for location management without considering the busy-line effect may lead to unreliable results. The results presented in this paper pave the way for modeling location management and portable movements in PCS networks.

In Personal Communication Services (PCS) networks, mobile terminals (MT) are communicating frequently using variety of services. The increasing demands for diverse services dictate a high-quality framework for location management. To accomplish this objective, it is necessary to track MTs roving in the system within the time limit to deliver the services in timely manner. The expected reduction of the cell sizes due to transmission power concerns and for better frequency reuse in future PCS networks, and increasing speeds of MTs on the other hand, would cause a considerable signaling in the always updating (AU) strategy adopted in current PCS networks. Personalized location area (PLA) is an efficient way to reduce the location management cost by considering both the movement behavior of the individual users in the networks system and the system parameters. However, the PLA design problem is found to be NP-complete with high computation complexity. In this paper, we try to solve the problem by using the genetic algorithm (GA). Simulation results show that the location management cost of the designed PLAs by GA is significantly lower than that of the AU mechanism.

Over the last decade there has been a rapid growth of wireless communication technology. Among numerous wireless network architectures, the personal communication services (PCS) networks and wireless local area networks (WLAN) have attracted lots of attention. One of the core functionalities in wireless networks is the location service that provides location information for subscriber services, emergency services, and various mobile networks internal operations. In this paper, an integrated location management mechanism is proposed for heterogeneous wireless networks that combine PCS networks and WLAN. Three major functionalities in the integrated location management scheme are the determination of the WLAN connectivity for a mobile terminal, the development of a local area location scheme for WLAN, and the location prediction module for PCS networks. This mechanism not only determines the location of a mobile client more precisely, but also reduces the cost of locating. The performance evaluation is conducted to demonstrate the effectiveness of the proposed mechanism for heterogeneous wireless networks.

There has been rapid growth an demand for mobile communications over the past few years that has led to intensive research and development of complex PCS (personal communication service) networks. Capacity planning and performance modeling are necessary to maintain a high quality of service to the mobile subscriber while minimizing the cost. Simulation is widely used in such studies, however, because these models are extremely time consuming to execute, only small-scale PCS networks have previously been simulated. In this paper, we examine the use of the Time Warp distributed simulation mechanism in simulating large scale (1024 or more cells) PCS networks. An object-oriented, distributed, discrete event simulator using Time Warp has been developed, and initial performance measurements completed. Speedups in the range of 2.8 to 7.8 using 8 Unix workstations have been obtained, enabling simulation runs that require 20 hours on a single workstation to be completed in only 3.5 hours.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The arrival of calls (i.e., new and handoff calls) in a personal communications services (PCS) network are modeled by a Markov arrival process (MAP) in which we allow correlation of the interarrival times among new calls, among handoff calls, as well as between these two kinds of calls. Each cell of the network consists of a finite number of channels and a buffer with finite size for handoff calls. There exist some channels among each cell which can be used by splitting the original rate into two channels with different rates if necessary when a handoff call arrives and finds all the channels busy. We obtain the stationary joint probability of number of calls in the cell and the phase of the arrival process, the blocking probability of a new call, the forced termination probability of a handoff call, and the mean dwell time of a handoff call in the buffer. Finally, we obtain the distribution and the mean of the cell's busy period, the distribution and the mean of the first time to split the cth channel, and some other interesting performance measures for the network. Some explicit results for special cases obtained by Lin et al. (see IEEE Trans. Vech. Technol., vol.45, no.1, p.122-30, 1996 and vol.43, no.3, p.704-12, 1994), Tekinary et al. (1992) and by Yoon et al. (1993) can also be directly obtained from the general conclusion. The results presented can provide guidelines for field data processing in PCS network design and performance evaluation.

Future personal communication service (PCS) networks consider smaller cells to accommodate continuously growing population of subscribers. Frequently performed location updates caused by such an infrastructure incur extensive signaling and consequently higher cost. Thus, new strategies are demanded to locate mobile users more efficiently. Among several proposals, the direction-based location update (DBLU) scheme uses a dynamic strategy such that the mobile users update their locations only when a change of direction occurs. To locate users, the system pages cells along the direction of initial move. The scheme works well when the change of direction is infrequent and the ratio of location update cost to paging cost is low. Otherwise, the location update, and consequently the overall cost increase significantly. To attack this problem, we propose an enhanced direction-based location update (EDBLU) scheme, which takes into account both the moving distance and the moving direction. We analyze the performance of the EDBLU under different mobility patterns and call-to-mobility ratios based on a 2D Markov walk model. The numerical results demonstrate that the proposed scheme augments the performance reported by the distance-based and the direction-based methods.

Personal mobility and terminal mobility which are viable through wireless access to communication networks are the most fundamental goals of personal communication services (PCS). The technology needed for the wireless access in PCS networks is generally provided by the cellular networks and intelligent networks (IN). In cellular networks, the wireless mobile terminals (WMT) communicate with base stations (BS) which convey the messages among the WMTs and switching centers (SC). SCs and BSs are usually wired to the upper layers of the communication network. In this paper, we briefly review PCS and then propose an algorithm which determines the number of SCs and the BSs attached to the determined SCs in a network for which BS information together with the traffic requirements are given. While the algorithm produces these solutions, it also satisfies some constraints determined by the network designers such as the maximum capacities and the minimum utilization for the SCs.

This work deals with a design problem for a network of Personal Communication Services (PCS). The goal is to assign cells to switches in a PCS Network (PCSN) in an optimum manner so as to minimize the total cost which includes two types of cost, namely handoff cost between two adjacent cells, and cable cost between cells and switches. The design is to be optimized subject to the constraint that the call volume of each switch must not exceed its call handling capacity. In the literature, this problem has been conventionally formulated as an integer programming problem. However, because of the time complexity of the problem, the solution procedures are usually heuristic when the number of cells and switches are more. In this paper, we have proposed an assignment heuristic which is faster and much simpler than the existing algorithms. Despite its simplicity, experimental results show that it performs equally well in terms of solution quality, and, at the same time, it is faster than its predecessors. We present the algorithm as well as comparative results to justify our claim.

The authors examine the use of spread spectrum radios for personal communication services (PCS). Both theoretical and practical issues are presented to show the overall capacity advantage of spread spectrum CDMA (code division multiple access) over conventional narrowband FDMA (frequency division multiple access) and TDMA (time division multiple access). A PCS and wireless PBX system under development is described. The system uses synchronous-CDMA and TDD techniques to achieve full frequency reuse. A new error bound for an interference limited channel such as that encountered in the PCS network is derived. Computer simulation results indicate that a 6-10-fold increase in capacity over TDMA techniques can be achieved. >

미래의 PCS(Personal Communication Service) 네트워크 설계에서 하나의 중요한 문제는 위치 정보의 효율적인 관리이다. 이 논문에서, 우리는 n 위치 정보 데이터베이스들 중에 k개에 이동 단말의 위치를 저장하는 적응적 분산 동적 위치 관리 알고리즘을 제안한다. 제안하는 알고리즘은 무선 이동망 내의 위치 정보 데이터베이스들의 공간 지역성과 원격 이동 단말들로부터 로컬 이동 단말의 위치 질의 선호도에 따라 사본인자, k를 적응적으로 선택한다. 제안하는 알고리즘의 성능을 분석적 모델과 시뮬레이션을 통하여 평가한다. 성능 평가 결과, 호 이동율에 관계없이 제안한 알고리즘의 성능이 Krishnamurthi의 알고리즘에 비해 성능이 우수함을 알 수 있었다. An important issue in the design of future Personal Communication Service (PCS) networks is the efficient management of location information. In this paper, we propose an adaptive distributed dynamic location management algorithm that stores the position of the mobile terminal in k of the n location information databases (LIDs). The proposed algorithm chooses adaptively k. replication factor according to both the space locality of LIDs in wireless mobile networks and the location query popularity to local mobile terminal from remote mobile terminals. The performance of proposed algorithm is evaluated by both an analytical model and a simulation. Based on the results of performance evaluation, we know that the performance of the proposed algorithm is better than that of Krishnamurthi's algorithm regardless of call-mobility ratio.

With ever increased mobility in our dynamic society, the need for a low power portable handset and cost-effective access to a wide array of telecommunication network services has been recognized. A successfully deployed personal communication services (PCS) network will not only provide access to today's wire-line network services but also manage customer mobility seamlessly and transparently. In order to test this hypothesis and assess the capabilities of the state-of-the-art network technologies, a PCS technology trial network was established during the first half of 1993. The paper discusses the planning required and insights gained during the design, integration testing, establishing provisioning and fault isolation procedures phases of this multifaceted project. >

Personal communications services (PCS) key objective is to provide ubiquitous communication services. The success of PCS will depend on the network resources to ensure the quality-of-service required by service subscribers. Performance evaluation studies of different system configurations and implementation alternatives will play a major role in the planning and dimensioning of successful PCS networks. We undertake the analysis of some major implementation issues of a PCS architecture based on the IN system architecture. Different system configurations and traffic scenarios are considered in the study. The overall system performance is evaluated in terms of utilization rate of the key network elements and the end-to-end response time of the signaling network for various IN services.

Model-based movement patterns play a crucial role in evaluating the performance of mobility-dependent Personal Communication Service (PCS) strategies. This study proposes a new normal walk model to represent more closely the daily movement patterns of a mobile station (MS) in PCS networks than a conventional random walk model. The proposed walk model uses a drift angle θ to determine the direction in which an MS leaves a hexagonal cell in the next one step. The angle θ is assumed to approach the normal distribution with the parameters: μ = 0° and σ is on the interval [5°; 90°], based on the concept that most trips follow the shortest path, to make the movement patterns more realistic. A compact classification that types cells with side indices is further developed to partition an n-layer cluster of PCS networks into 12 mirror regions; consequently, the number of states can be reduced significantly, and the computational complexity is also reduced in the probability derivation. Two metrics are formulated in experiments to measure the expected and average numbers of steps taken by an MS to move out of an n-layer cluster. Experimental results confirm that for σ = 10°, 30°, 60°, and 90°, the discrepancies between the analytical computations and the simulated values are all within ±0.46%, and most are even within ±0.35%. Moreover, when σ is set to 71°, a normal walk can almost represent, and even replace, a conventional random walk, since the discrepancies between them are all within ±0.71%.

This paper deals with an approach for planning location areas (LAs) in a personal communication services network (PCSN) to be overlaid on an existing wired network. Given the average speed of mobile terminals, the number of mobile switching centers (MSCs), their locations, call handling capacity of each MSC, handoff cost between adjacent cells and call arrival rate, an important consideration in a PCSN is to identify the cells in every LA to be connected to the corresponding MSC in a cost effective manner. In this work, while planning a location area, we present a two-step approach, namely optimization of total system recurring cost (subproblem I) and optimization of hybrid cost (subproblem II). The planning first determines the optimum number of cells in an LA from subproblem I. Then, it finds out the exact LAs by assigning cells to the switches, while optimizing the hybrid cost which comprises the handoff cost and the cable cost, in subproblem II. This divide-and-conquer strategy provides a practical way for designing LAs. As our approach toward LA planning takes into accounts both cost and network planning factors, this unique combination will be of great interest to PCSN designers. It develops an optimum network planning method for a wide range of call-to-mobility ratios that minimizes the total system recurring cost while still ensuring a good system performance. Our study shows that acceptable results are achievable with a reasonable computational effort, which supports the engineered planning of a PCSN.

We address a problem of network design for personal communication services (PCS). The objective is to assign cells optimally to the switches in mobile as well as personal communications. Two types of costs are considered: the cost of handoffs between cells and the cost of cabling (or trunking) between a cell site and its associated switch. The problem is constrained by the call volume that each switch can handle. We adapt a powerful combinatorial search technique, called scatter search, to this optimization problem. We also develop a new optimization paradigm, called bounded scatter search, based on limited discrepancy search. Empirical results show promising performance with quality improvement.