A comparative study of bandwidth reservation and admission control schemes in QoS-sensitive cellular networks

This paper compares five different schemes – called CHOI, NAG, AG, BHARG, and NCBF – for reserving bandwidths for handoffs and admission control for new connection requests in QoS-sensitive cellular networks. CHOI and NAG are to keep the handoff dropping probability below a target value, AG is to guarantee no handoff drops through per-connection bandwidth reservation, and BHARG and NCBF use another type of per-connection bandwidth reservation. CHOI predicts the bandwidth required to handle handoffs by estimating possible handoffs from adjacent cells, then performs admission control for each newly-requested connection. On the other hand, NAG predicts the total required bandwidth in the current cell by estimating both incoming and outgoing handoffs at each cell. AG requires the set of cells to be traversed by the mobile with a newly-requested connection, and reserves bandwidth for each connection in each of these cells. The last two schemes reserve bandwidth for each connection in the predicted next cell of a mobile where the two schemes use different admission control policies. We adopt the history-based mobility estimation for the first two schemes. Using extensive simulations, the five schemes are compared quantitatively in terms of (1) handoff dropping probability, connection-blocking probability, and bandwidth utilization; (2) dependence on the design parameters; (3) dependence on the accuracy of mobility estimation; and (4) complexity. The simulation results indicate that CHOI is the most desirable in that it achieves good performance while requiring much less memory and computation than the other four schemes.