This paper proposes a QoS approach for an adaptive call admission control (CAC) scheme for multiclass service wireless cellular networks. The QoS of the proposed CAC scheme is achieved through call bandwidth borrowing and call preemption techniques according to the priorities of the traffic classes, using complete sharing of the available bandwidth. The CAC scheme maintains QoS in each class to avoid performance deterioration through mechanisms for call bandwidth degradation, and call bandwidth upgrading based on min-max and max-min policies for fair resource deallocation and reallocation, respectively. The proposed adaptive CAC scheme utilizes a measurement-based online monitoring approach of the system performance, and a prediction model to determine the amount of bandwidth to be borrowed from calls, or the amount of bandwidth to be returned to calls. The simulation-based performance evaluation of the proposed adaptive CAC scheme shows the strength and effectiveness of our proposed scheme.Usually, a mobile terminal's (MT) request for a service may be denied access based on the nonavailability of resources adequate to the requirements of the service. In this work, the bandwidth allocated to a call is considered the main resource. The mobile terminal's denial of service is referred to as call blocking and its probability as the call blocking probability, P b . However, a mobile terminal may move from one cell to another, while being in active connection. To maintain continuity of the service, the mobile terminal must have a successful handoff from the previous cell to the current cell. A successful handoff of a call to the current cell's base station (BS) is made if the mobile terminal has been granted the required resources for the connection without deterioration of its QoS. The failure of a mobile terminal to have a successful handoff at any point in its path would terminate the call. The probability of a call termination or dropping is called the call dropping probability, P d . We will refer in this work to the duration of a call connection by the call holding time .t c /, and the duration of the time a mobile terminal exists in a cell by the cell residency time .t r / [2].Typically, service providers for wireless cellular networks would strive to achieve high profitability, while being able to maintain users' satisfaction. For the first goal, they would try to maximize the number of admitted calls into the network to ensure efficient bandwidth utilization. For the second, service providers work on minimizing the number of handoff call dropping and new call blocking, and reducing the latency and overheads of call admissions and handoff computations. Finding a compromise between the two conflicting goals is a challenging problem. In this work, we propose a bandwidth borrowing-based adaptive CAC scheme in multiclass service wireless cellular networks that tries to strike a balance between users' satisfaction and profitability. The proposed adaptive scheme achieves its objectives through techniques for rate deg...

This work describes an adaptive Call Admission Control (CAC) scheme for multi-class service wireless cellular networks. The proposed scheme uses complete sharing approach of the available bandwidth among all traffic classes. The proposed adaptive CAC is achieved through call bandwidth borrowing and call preemption techniques based on the priorities of the traffic classes. The CAC scheme achieves the QoS in each class through mechanisms for call bandwidth degradation, and call bandwidth upgrading based on Min-Max and Max-Min policies for fair resource deallocation and allocation. The simulation results of the proposed adaptive CAC scheme show the strength and effectiveness of our proposed scheme compared to other schemes.

Interconnection networks play a significant role in efficient on-chip communication for multicore systems. This paper introduces a new interconnection topology called the Hierarchical Cross Connected Recursive network (HCCR) and a shortest path routing algorithm for the HCCR. Proposed topology offers a high degree of regularity, scalability, and symmetry with a reduced number of links and node degree. A unique address encoding scheme is proposed for hierarchical graphical representation of HCCR networks, and based on this scheme a shortest path routing algorithm is devised. The algorithm requires ) time where and , in worst case to determine the next node along the shortest path.

Abstract-The scaling of semiconductor technologies is leading to processors with increasing numbers of cores. A key enabler in manycore systems is the use of Networks-on-Chip (NoC) as a global communication mechanism. The adoption of NoCs in manycore systems requires a shift in focus from computation to communication, as communication is fast becoming the dominant factor in processor performance. Many researchers have focused on direct communication between cores in the NoC; however in a manycore processor the communication is actually between the cores and the memory hierarchy. In this work, we investigate the memory communication traffic of shared threads in a hierarchical cache architecture.We argue that the performance scalability for shared-memory applications in a hierarchical cache architecture for systems with thousands of processor cores depends on the distance between threads sharing memory in terms of the cache hierarchy (the "memory distance"). We present latency and throughput results comparing fat quadtree, concentrated mesh and mesh topologies as a function of the "memory distance" between the threads. Our results using the ITRS physical data for 2023 show that the model of thread placement and the distance of placing them significantly affects the NoC performance, and that scale-invariant topologies perform better than flat topologies.

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