Improving Voice and Data Services in Cellular/WLAN Integrated Networks by Admission Control

Abstract

Abstract-In this paper, we study voice and data service provisioning in an integrated system of cellular and wireless local area networks (WLANs). With the ubiquitous coverage of the cellular network and the disjoint deployment of WLANs in hot-spot areas, the integrated system has a two-tier overlaying structure. As an essential resource allocation aspect, admission control can be used to properly admit voice and data calls to the overlaying cells and WLANs. A simple admission scheme is proposed in this study to analyze the dependence of resource utilization and the impact of user mobility and traffic characteristics on admission parameters. Both admission control and rate control are considered to limit the input traffic to the WLAN, so that the WLAN operates in its most efficient states and effectively complements the cellular network. The call blocking/dropping probabilities and data call throughput are evaluated for effective and accurate derivation of the admission parameters. It is observed that the utilization varies with the configuration of admission parameters, which properly distributes the voice and data traffic load to the cells and WLANs. Mobility and traffic variability have a significant impact on the selection of the admission parameters.Index Terms-Cellular/WLAN interworking, quality of service, call admission control, rate control, WLAN capacity.

Joint source-channel coding and optimization for mobile video streaming in heterogeneous wireless networks

“…The IEEE 802.11b is adopted as the WLAN protocol. The configurations of heterogeneous wireless networks are summarized in Table 3 [4,5,45].…”

Call admission control with heterogeneous mobile stations in cellular/WLAN interworking systems

“…In the WLAN coverage, MSs with both WLAN and cellular interfaces can access both systems and therefore the WLAN coverage area is referred to as a "double coverage" area. On the other hand, the region outside the WLAN is denoted as a "cellular only" area [7][8][9], i.e., a cell area consists of a double coverage area and a cellular only area. Hereinafter, 'dca', 'coa', and 'ca' stand for double coverage areas, cellular only areas, and cell areas, respectively.…”

“…We assume that the call duration T v follows an exponential distribution with mean 1/μ v [7][8][9]. Since the call duration time and cell residence time are independent, the WLAN channel holding time of a WLAN-only call …”

“…Extensive work has been done in the integration of heterogeneous networks [2][3][4][5][6][7][8][9] and to allow seamless mobility across these heterogeneous networks (i.e., vertical handoff), two integration architectures, having both tightly coupled and loosely coupled architectures, have been introduced in [2,3]. In [4,5], vertical handover decisions where an mobile station (MS) selects the most appropriate network to avoid unnecessary handovers and wastages of resource have been proposed.…”

“…In [4,5], vertical handover decisions where an mobile station (MS) selects the most appropriate network to avoid unnecessary handovers and wastages of resource have been proposed. The resource allocation in heterogeneous wireless networks has been investigated in [6][7][8][9]; the study in [6] investigates the admission control strategies for the data traffic in a hierarchical system consisting of macrocell and microcell layers; the authors of [7] introduce the first WLAN scheme and analyze its performance; Song et al [8] determine an admission control scheme in which MSs try to access networks with specific probabilities for the maximum number of users; and Stevens-Navarro et al [9] introduce an admission control scheme for multi-services. In these previous studies, it is assumed that all MSs have dual interfaces to cellular/WLAN systems and they can access both systems even though it is obvious that some MSs have only one interface, either cellular or WLAN.…”