A reservation-based call admission control scheme and system modeling in 4G vehicular networks

Abstract

In 4G cellular networks, call admission control (CAC) has a direct impact on quality of service (QoS) for individual connections and overall system efficiency. Reservation-based CAC schemes have been previously proposed for cellular networks where a certain amount of system bandwidth is reserved for high-priority calls, e.g., hand-off calls and real-time new calls. Traditional reservation-based schemes are not efficient for 4G vehicular networks, as the reserved bandwidth may not be utilized effectively in low hand-off rates. We propose a channel borrowing approach in which new best effort (BE) calls can borrow the reserved bandwidth for high-priority calls. Later, if a hand-off call arrives and all the channels are busy, it will pre-empt the service of a borrower BE call if there exists any. The pre-empted BE calls are kept in a queue and resume their service whenever a channel becomes available. The analytical model for this scheme is a mixed loss-queueing system for which it is difficult to calculate call blocking probability (CBP) and call dropping probability (CDP). Our focus in this paper is on the system modeling and performance evaluation of the proposed scheme. We present two system models that approximate the operation of the proposed scheme. For these models, we derive the CBP and CDP analytically. It is shown that our analytical results are very close to the ones obtained from simulations. Furthermore, it is observed that our channel borrowing approach decreases the CBP considerably while increases the CDP slightly over a large range of hand-off rates.

Um Algoritmo De Cac Com Reserva Dinâmica De Recursos E Preempção Para Redes Lte

“…O bloqueio de conexões diz respeito à rejeição de uma nova conexão por insuficiência de recursos de rádio ou requisitos de QoS. A perda de conexões diz respeito à interrupção de uma chamada em andamento devido a um processo de mobilidade do usuário (em handoff), seja veicular ou pedestre [39]. Do ponto de vista do usuário, é mais frustrante a queda de uma conexão em andamento do que o bloqueio de uma nova conexão, de forma que, via de regra, algoritmos de CAC que distinguem tipos de conexões acabam priorizando as conexões em andamento sobre as novas conexões, mantendo a taxa de perdas de conexões próxima do zero [36].…”

Call Blocking Probabilities under a Probabilistic Bandwidth Reservation Policy in Mobile Hotspots

“…Call admission control (CAC) is a significant quality of service (QoS) mechanism in contemporary networks, not only because it controls the access to the bandwidth units (b.u.) required by new mobile users but also because it provides fairness among different mobile applications and at the same time affects the QoS of in-service calls [1][2][3][4].…”

Analytical Modelling of a New Handover Algorithm to Improve Allocation of Resources in Highly Mobile Environments

“…The mean arrival and mean service rates are mainly application dependent. The assumptions in [3,5,7,8] and [9] are employed in this paper as well for consistency, unless stated otherwise.…”

“…The system parameters used are mainly taken from [3,5,7,8] and [9] based on the relevant literature [1,2,4,6,[10][11][12][13]16]. The system has a fixed number of identical channels: S =16.…”

“…Researchers have focused on the improved quality of service (QoS) and performance evaluation of 4G/5G networks in highly mobile environments [6,7,9]. One of the main challenges for seamless mobility in next-generation wireless networks is the availability of the resources in the networks which allow mobile users to roam among heterogeneous environments [4,9].…”