The scarcity of the radio resources and variable channel quality cause many challenges to the resource management for future all-IP wireless communications. One technique to guarantee a certain level of quality of service (QoS) is call admission control (CAC). Briefly, CAC is a mechanism which decides whether a new call could be admitted or rejected depending on its impacts on the current calls’ QoS. Conventional CACs such as guard channel, channel borrowing and queuing priority techniques only consider the instantaneous radio resource availabilities to make a decision on admission problem, thus they are neither able to prevent the network congestion problem nor meet the QoS requirements of different users with multi-service requirements.

In this work, we propose a new CAC technique with a future look into the needed extra resources through a reservation technique to offset the changes of the channel condition due to mobility. We show that during a call session, the needed radio resources may be increased compared with the negotiated resources during call setup. Although such fluctuations are fairly low for a single call, it is not negligible when the network is congested. As a result, some ongoing calls may experience QoS degradation. We show that such a consideration is critical in orthogonal frequency division multiplexing (OFDM) wireless networks such as 3GPP LTE where the radio resources are assigned to the users depending on the channel quality. The study assumes two types of applications denoted by wide-band and narrow-band and the performance of the proposed algorithm is modeled through queuing theory and event-driven simulation approaches. The results show that such a reservation technique improves the call admission performance significantly in terms of call blocking, call drop and call QoS degradation probabilities, and it outperforms the conventional CACs with insignificant loss in network capacity.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error