• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.152-153
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• 2014

This paper proposes a new dynamic bandwidth allocation algorithm for an XG-PON (10-Gbps-capable passive optical network) system in which an ONU (optical network unit) does not explicitly send its request to an OLT (optical line termination). To estimate the request of the ONU, the OLT monitors the upstream bandwidth usage of the ONU and periodically allocates a probe slot to the ONU.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.9
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• pp.39-48
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• 2008

Recently, many multimedia services have emerged in Internet such as real-time and non- real time services. However, in this Internet environment, we have some limitations to satisfy each service feature. To guarantee the service features in Measurement-Based Admission Control(MBAC) based system on the flow-aware network, there is the method applying Dynamic Priority Scheduling(DPS) algorithm that gives a higher priority to an earlier incoming flow in all of the link bandwidth. This paper classifies all flows under several groups according to flow characteristics on per-flow MBAC algorithm based system. In each flow group, DPS algorithm is applied. This paper proposes two methods that are a DPS based bandwidth borrowing method and a bandwidth dynamic allocation method. The former is that if low priority class has available bandwidths, the flow of high priority class borrows the bandwidth of low priority class when high priority flow has insufficient bandwidth to connect a flow call. The later is that the each group has a minimum bandwidth and is allocated the bandwidth dynamically according to the excess rate for available bandwidth. We compare and analyze the characteristics of the two proposed methods through the simulation experiments. As the results of the experiment, the proposed methods are more effective than existing DPS based method on the packet loss and delay characteristics. Consequently the proposed two methods are very useful in various multimedia network environments.

• The KIPS Transactions:PartC
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• v.14C no.4
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• pp.349-358
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• 2007

Ethernet Passive Optical Network(EPON), which is one of PON technologies for realizing FTTx(Fiber-To-The-Curb/Home/Office), can cost-effectively construct optical access networks. In addition, EPON can provide high transmission rate up to 10Gbps and it is compatible with existing customer devices equipped with Ethernet card. To effectively control frame transmission from ONUs to OLT EPON can use Multi-Point Control Protocol(MPCP) with additional control functions in addition to Media Access Control(MAC) protocol function. For EPON, many researches on intra- and inter-ONU scheduling algorithms have been performed. Among the inter-ONU scheduling algorithms, IPS(Interleaved Polling with Stop) based on polling scheme is efficient because OLT assigns available time portion to each ONU given the request information from all ONUs. Since the IPS needs an idle time period on uplink between two consecutive frame transmission periods, it wastes time without frame transmissions. In this paper, we propose a dynamic bandwidth allocation algorithm to increase the channel utilization on uplink and evaluate its performance using simulations. The simulation results show that the proposed Two-phase Cycle Danamic Bandwidth Allocation(TCDBA) algorithm improves the throughput about 15%, compared with the IPS and Fast Gate Dynamic Bandwidth Allocation(FGDBA). Also, the average transmission time of the proposed algorithm is lower than those of other schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1490-1500
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• 1996

One of the important issues for multimedia communications over ATM netowrks is efficient use of net-work resources since transmitting video at low cost requires high utilization of channel bandwidth. In this paper, we propose an effective bandwidth estimation scheme for MPEG sources in ATM networks. It has been known difficult to allocate effective transmission bandwidth to MPEG sources due to its bursty charactersitics. The MPEG traffic stream can bemodeled using five traffic parameters:service rate, burst load ratio, interburst load ratio, burst period, and interburst period. Using these parameters, a transmission bandwidth for each source can be estimated, and the estimated bandwidth is applied synchronously to reduce the queue size in a buffer. For a simple network modelof a high speed link that multiplexes a number of virtual-circuit connections, simulations on adaptive bandwidth allocation were performed, and the results show that the queueing delay is significantly reduced, when compared to a fixed bandwidth allocation.

• Journal of the Korea Computer Industry Society
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• v.2 no.2
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• pp.165-180
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• 2001

This study is on the design and performance evaluation of a multi medium access control(MAC) protocol for multimedia access in the wireless ATM network. In general, MAC protocols for multimedia data transmission are classified into the fixed slot allocation algorithm that allocates base-station slots equally over terminals, and the dynamic slot allocation algorithm that with flexible penetration. The conventional slot allocation algorithms assign slots based on the average bandwidths required for various services types. Although the algorithms have a wide bandwidth for real-time-variant services, the slots are being wasted due the service types. To improve the slot waste problem, this thesis proposes a method that minimizes the waste by assigning variable slots based on the most appropriate bandwidth after a base-station analyzes the service type requested from terminals.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.3821-3841
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• 2019

Cloud radio access networks (C-RANs) have been regarded in recent times as a promising concept in future 5G technologies where all DSP processors are moved into a central base band unit (BBU) pool in the cloud, and distributed remote radio heads (RRHs) compress and forward received radio signals from mobile users to the BBUs through radio links. In such dynamic environment, automatic decision-making approaches, such as artificial intelligence based deep reinforcement learning (DRL), become imperative in designing new solutions. In this paper, we propose a generic framework of autonomous cell activation and customized physical resource allocation schemes for energy consumption and QoS optimization in wireless networks. We formulate the problem as fractional power control with bandwidth adaptation and full power control and bandwidth allocation models and set up a Q-learning model to satisfy the QoS requirements of users and to achieve low energy consumption with the minimum number of active RRHs under varying traffic demand and network densities. Extensive simulations are conducted to show the effectiveness of our proposed solution compared to existing schemes.

• The KIPS Transactions:PartC
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• v.11C no.4
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• pp.555-562
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• 2004

We consider differentiated bandwidth allocation for a piconet in short-range wireless personal network systems : Bluetooth. Since bandwidth requirements nay vary among applications/services, and/or it may change over time, it is important to decide how to allocate limited resources to various service classes to meet their service requirements. We propose a simple and efficient bandwidth allocation mechanism which meets bandwidth requirements of various service types while saving power consumption by a Power saying mode, i.e., sniff node. We compare our proposed mechanism with a conventional (weighted) round-robin polling scheme and show that it achieves significant improvement of hroughput, delay, and power consumption.

• Journal of the Korea Society of Computer and Information
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• v.7 no.4
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• pp.133-140
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• 2002

Distributed-queue Dual-Bus (DQDB) shows an unfair behavior in bandwidth allocation due to the nature of unidirectional bus architecture. The study on fairness control method for DQDB has been performed under specific load types such as equal Probability load. symmetric load and asymmetric load type. A client-server load type is more practical traffic pattern than specific load type in Web environments. In this paper, we propose an effective fairness control method to distribute DQDB network bandwidth fairly to all stations under Web environments. The proposed method directly calculates an access limit from the bandwidth demand pattern. Based on an access limit, it controls the allocation of bandwidth by yielding empty slots in clients to servers. And we were certain that it outperforms other mechanisms from simulation results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.5803-5819
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• 2017

In this paper, we proposed a contract theory based cooperative spectrum sharing scheme with joint power and bandwidth optimization under asymmetric information, where the primary user (PU) does not know the secondary users' (SUs) private information. To improve performance, PU needs to provide incentives to stimulate nearby SUs to help forward its signal. By using contract theory, PU and SUs' negotiations are modeled as a labor market. PU and SUs act as the employer and employees, respectively. Specifically, SUs provide labor (i.e. the relay power, which can be used for forwarding PU's signal) in exchange for the reward (i.e. the spectrum access bandwidth which can be used for transmitting their own signals). PU needs to overcome a challenge how to balance the relationship between contributions and incentives for the SUs. We study the optimal contract design which consists of relay power and spectrum access bandwidth allocation. We show that the most efficient SUs will be hired by the PU to attend the cooperative communication. PU can achieve the same maximum utility as in the symmetric information scenario. Simulation results confirm that the utility of PU is significantly enhanced with our proposed cooperative spectrum sharing scheme.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.679-686
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• 2002

The transmission of prerecorded and compressed video data without degradation of picture quality requires video servers to cope with large fluctuations in bandwidth requirement. Bandwidth smoothing techniques can reduce the burst of a variable-bit rate stream by prefetching data at a series of fixed rates and simplifying the allocation of resources in the video servers and the network. In this paper, the proposed smoothing algorithm results in the optimal transmission plans for (1) the smallest bandwidth requirements, (2) the minimum number of changes in transmission rate, and (3) the minimum amount of the server process overhead. The advantages of the proposed smoothing algorithm have been verified through the comparison with the existing smoothing algorithms in diverse environments.