A finite buffer shared by multiple packet queues is considered. Partitioning the buffer to maximize total throughput is formulated as a resource allocation problem, the solution is shown to be achieved by a greedy incremental algorithm in polynomial time. The optimal buffer allocation strategy is applied to different models for a wireless downlink. First, a set of parallel M/M/1/mi queues, corresponding to a downlink with orthogonal channels is considered. It is verified that at high load, optimal buffer partitioning can boost the throughput significantly with respect to complete sharing of the buffer. Next, the problem of optimal combined buffer allocation and channel assignment problems are shown to be separable in an outage scenario. Motivated by this observation, buffer allocation is considered in a system where users need to be multiplexed and scheduled based on channel state. It is observed that under finite buffers in the high load regime, scheduling simply with respect to channel state with a simply partitioned buffer achieves comparable throughput to combined channel and queue-aware scheduling.

This letter reports on an approximation of the mean waiting time in a finite buffer queue with delay priority and loss priority. Both priorities are controlled by head-of-the-line (HOL) priority scheduling and buffer reservation. The proposed approximation is based on the known results on a HOL-priority queue with infinite buffer and a finite buffer queue with FIFO scheduling and buffer reservation. The accuracy of the approximation is validated by comparing exact and approximate results. The approximation provides good estimates when the blocking probabilities at the buffer controlled by the buffer reservation are low.

This paper studies the local Poisson property of aggregated IP traffic. First, it describes the scenario where IP traffic presents a Poisson-like characteristic within some limited range of time scales when packets from independent traffic streams are aggregated. Each of the independent traffic streams corresponds to a series of correlated IP packets such as those of a transport connection. Since the Poisson-like characteristic is observed only within some limited range of time scales, we call this characteristic the local Poisson property. The limited range of time scales of the local Poisson property can be estimated from a network configuration and characteristics of transport connections. Second, based on these observations, we seek the possibility to apply an ordinary Poisson process to evaluation of the packet loss probability in IP networks. The analytical investigation, where IP traffic is modeled by a superposition of independent branching Poisson processes that presents the local Poisson property, suggests that the packet loss probability can be estimated by a finite-buffer queue with a Poisson process when the buffer size is within a certain range. The investigation is verified by simulations. These findings expand the applicability of conventional Poisson-based approaches to IP network design issues.

A partial buffer sharing scheme is proposed as loss-priority control for a finite buffer with batch Poisson inputs under a whole batch acceptance rule. Customer and batch loss probabilities for high- and low-priority customers are derived under this batch acceptance rule using a supplementary variable method. A comparison of the partial buffer sharing scheme and a system without loss-priority control is made in terms of admissible offered load. Whole batch acceptance and partial batch acceptance rules are also compared in terms of admissible offered load.

A partial buffer sharing scheme is proposed as loss-priority control for a finite buffer with batch inputs. A partial batch acceptance strategy is used for a batch arriving at a finite buffer. Customer loss probabilities for high- and low-priority customers are derived under this batch acceptance strategy, using a supplementary variable method that is a standard tool for queueing analysis. A comparison of the partial buffer sharing scheme and a system without loss-priority control is made in terms of admissible offered load.

CDMA unslotted ALOHA system with finite size of queueing buffers is discussed in this paper. We introduce an analytical model in which the system is divided into two Markov chains; one is in the user part, and the other is in the channel part. In the user part, we can model the queueing behavior of the user station as an M/G/1/B queue. In the channel part, we can consider the number of simultaneously transmitted packets as an M1 + M2/D///K queue. We analyze the queueing system by using this analytical model, and evaluate the effect of buffer capacity in terms of the throughput, the rejection probability and the average delay. As a result, increase in the buffer size brings about an improvement in the grade of service in terms of higher throughput and lower rejection probability.

In this paper, CDMA slotted ALOHA system with finite size of buffers is proposed. To analyze the system performance, we use the linear approximate solution based on restricted occupancy urn models. We evaluate the system performance in terms of throughput, average delay, and rejection probability and clarify the effect of buffer capacity.

For mobile/personal satellite systems, an ARQ protocol with low transmitter/receiver complexity as well as high throughput performance in a long Round-Trip-Delay (RTD) and even in a bad channel condition is required. In this paper, a new Selective-Repeat (SR) ARQ with multicopy retransmission is proposed and a performance on an AWGN channel is analyzed. The proposed scheme can be viewed as a modified version for SR + Stutter (ST) Scheme 2 [6]. The basic idea of the strategy is to repeat only erroneous blocks stored in the vN block transmitter buffer multiple times, when v consecutive retransmissions in SR mode are received in error, where N denotes RTD in blocks. Numerical analysis and simuration results in the case of N block transmitter/receiver buffer show that the proposed scheme presents better performance than SR + ST scheme 2 of 2N block buffer, especially that the robustness in the high BER region is remarkable.

This paper is a study on the behavioral aspects of the input buffer limiting scheme whose basic feature is to award priority to the transit messages over the input messages so that congestion does not develop in the network. The numerical method employed in the analysis is that proposed in Ref.(7). The performance aspects are studied for different buffer capacities, different message handling capacities and different levels of reservation for transit traffic. The numerical method indicates that thrashing occurs at low levels of reservation for the transit messages, irrespective of the buffer size or the processor capacities of the node. This observation is supported by simulation results. With reference to the state-space of the model of our study, the congestion aspects are related to two Liapunov functions. Under the domain of one of the Liapunov functions, the evolution of the perturbed system is towards a congested state whereas, under the domain of the other Liapunov function, the evolution is towards a congestion-free state. Regardless of the configuration, it is found that the fundamental characteristic of the congestion under the input buffer limiting scheme is the characteristic of a fold catastrophe. In the systems with insufficient level of reservation for the transit traffic, the performance degradation appears to be inevitable, irrespective of the capacities of the nodal processor and output channel processor, and the size of the buffer pool. Given such an inevitability, the active life of a node under a typical node configuration is studied by simulation. A suitable performance index is suggested to assess the performance of deadlock-prone nodes.