A NEW QoS GUARANTEE SLA BASED-SCHEME FOR HANDOFF CALLS IN WIRELESS NETWORKS

The most important thing is guarantee QoS over wireless infrastructures. The efficient of service level agreement (SLA) is becoming increasingly important to both service providers and customers. This paper presents some traffic control schemes for improving QoS, trafficmodel and performance evaluation are described. We are defining a new scheme for improving handoff call performances in wireless networks, a finite queuing scheme for the handoff calls. SLA measurement calculates the packet delay parameter (PD) of handoff calls. The handoff calls will be accepted into queue if their PD will be smaller than the average waiting time of the queue. Important performance measures of the suggested scheme such as the blocking probability of new call and dropping probability of handoff call are described and evaluated.

A Novel Call Admission Control Algorithm for Next Generation Wireless Mobile Communication

Wireless communication technology is progressing very vastly. With this change in technology customer services for multimedia and non-multimedia are increasing day by day. But due to limited resources of the wireless network, we need to design an efficient CAC algorithm to enhance QoS levels for end users. The Quality of service (QoS) enhancement in the wireless network is related to making an efficient use of current network resources and the optimization of the users. Call acceptance in CAC is one of the challenge in mobile cellular networks to ensure that the acceptance of a new call into a resource limited wireless network should not deviate the service level Agreement (SLAs) at the time of conversations. In the next generation wireless network, CAC has the direct impact on QoS for user calls & overall system performance. To handle handoff calls and new calls in cellular network channel reservation scheme have been already proposed to reserve system bandwidth for higher priority call for CAC. This earlier proposed scheme is not as per the required level of satisfaction because the available reversed bandwidth is not allocated properly in case of least handoff rate. In this, the authors like to present a new channel borrowing scheme where new non real time (NRT) calls can make use of reserved channels. It can borrow this reserved channel on a temporary basis and after this immediately if any handoff call enters the current cell and no any other channels are available, then it will pre-empt the channel from an earlier borrowed NRT user if exists. This pre-empted NRT call is kept in the priority queue to consider its service when any channel becomes free. The number of NRT calls in the queue should not be large to avoid delayed service. The fundamental objective of the proposed scheme to design of the system for evaluating the results and comparing with the results of the existing system. From the results of current research work, it is observed that proposed scheme decreases call dropping probability which increase slightly in call blocking rate over high-density handoff call rate.

Call Admission Scheme for Multidimensional Traffic Assuming Finite Handoff User

Usually, the number of users within a cell in a mobile cellular network is considered infinite; hence,M/M/n/kmodel is appropriate for new originated traffic, but the number of ongoing calls around a cell is always finite. Hence, the traffic model of handoff call will beM/M/n/k/N. In this paper, aK-dimensional traffic model of a mobile cellular network is proposed using the combination of limited and unlimited users case. A new call admission scheme (CAS) is proposed based on both thinning scheme and fading condition. The fading condition of the wireless channel access to a handoff call is prioritized compared to newly originated calls.

Enhanced Handoff Scheme for Downlink-Uplink Asymmetric Channels in Cellular Systems

In the latest cellular networks, data services like SNS and UCC can create asymmetric packet generation rates over the downlink and uplink channels. This asymmetry can lead to a downlink-uplink asymmetric channel condition being experienced by cell edge users. This paper proposes a handoff scheme to cope effectively with downlink-uplink asymmetric channels. The proposed handoff scheme exploits the uplink channel quality as well as the downlink channel quality to determine the appropriate timing and direction of handoff. We first introduce downlink and uplink channel models that consider the intercell interference, to verify the downlink-uplink channel asymmetry. Based on these results, we propose an enhanced handoff scheme that exploits both the uplink and downlink channel qualities to reduce the handoff-call dropping probability and the service interruption time. The simulation results show that the proposed handoff scheme reduces the handoff-call dropping probability about 30% and increases the satisfaction of the service interruption time requirement about 7% under high-offered load, compared to conventional mobile-assisted handoff. Especially, the proposed handoff scheme is more efficient when the uplink QoS requirement is much stricter than the downlink QoS requirement or uplink channel quality is worse than downlink channel quality.