• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.168-171
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• 2003

IEEE 802.16 Wireless MAN standard specifies the air interface of fixed point-to-multipoint broadband wireless access systems providing multiple services. Among the service classes supported by the wireless MAN, the best effort service class is ranked on the lowest position in priority and is assisted by a MAC scheme based on reservation ALOHL Such MAC scheme must include a number of components, while many of them are not specified in the standard. In this paper, we thus reveal main components of a MAC scheme supporting the best effort service and present candidate schemes implementing such components. Combining schemes for implementing components, we then construct distinctive MAC schemes supporting best effort service. In designing a MAC scheme, the delay performance induced by the scheme should be considered since scarce resource may be available for the best effort service after the preemptive resource occupation by other service classes. In this paper, we focus on the delay fairness among the subscriber stations using the best effort service. For evaluating a MAC scheme in delay fairness, we present two definitions of delay fairness and provide a criterion for optimal MAC scheme according to each definition of delay fairness. Using a simulation method we investigate the mean delay performance exhibited by each MAC scheme arid find an optimal scheme in delay fairness. From numerical examples, we observe that SR/ED/PG＋P scheme has strong delay fairness compared with MR/ED/PG＋P and SR/ED/PG＋D schemes according to a definition of delay fairness. However, other schemes are rather shown to have better delay fairness when the other definition is adopted.

• Journal of Broadcast Engineering
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• v.20 no.1
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• pp.40-47
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• 2015

This paper discusses QoS enhancement in the Best-effort services of the service plan provided by MPEG Media Transport (MMT) systems for video streaming applications. Among MMT services, i.e. per-flow, per-class, and best-effort services, the server does not provide guaranteed bandwidth for the best-effort service only. Therefore, in the best-effort services, a bandwidth access priority is defined for various services, where the lowest priority is assigned to the low-level video services. To alleviate the issue of bandwidth limitation in the best-effort services, this paper investigates transmission of low-resolution video with low bitrate and up-sampling. Our experimental results prove the superiority of the proposed method in terms of delivered video quality.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.1
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• pp.9-19
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• 1999

An increase of the number of the real time applications and the Internet hosts make the Internet architecture changed. Current Internet architecture has some problems to process the real time traffics. To solve these problem, a new Internet architecture is proposed as the Integrated Service model. In the current Internet, as multicast protocols, the QoS multicast and the best-effort multicast have been studied in their separate network environments. But, the Integrated Service Packet Network is a heterogeneous network composed of the QoS delivery domain and the best-effort delivery domain. Thus, those separated multicast protocols have limitations in an ISPN. In this paper, we propose a multicast protocol for the ISPN with the QoS and the best-effort multicasting, and analyze the performance of this protocol. As a result, we find that the packet losses are same for hybrid multicast and best-effort multicast when the bandwidth is sufficient. But, if there exist some background traffics, the hybrid multicast has less packet loss than of the best-effort multicast.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.150-153
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• 2001

Today Internet is only Best-Effort service. During the past few years, new types of internet applications which require performance beyond the best-effort service that is provided by the current internet have emerged. These applications required QoS(Quality of Services) guarantee and Security between end-to-end. In this paper simulations Differentiated Services that IETF(Internet Engineering Task Forte) has proposed one of QoS(Quality of Services) guarantee VPN(Virtual private Network) using QoS(Quality of Services) guarantee and IP Security between end-to-end.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.5
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• pp.103-111
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• 2002

Historically, IP-based internets have been able to provide a simple best-effort delivery service to all applications they carry. Best effort treats all packets equally, with no service level, packet loss, and delay. The best-effort style has generally worked fine. But the needs of users have changed. The want to use the new real-time, multimedia, and multicasting applications. Thus, there is a strong need to be able to support a variety of traffic with a variety of quality-of-service requirements, within the TCP/IP architecture. This paper propose a framework that offers QoS in a DS domain using dynamic node setting method.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.20-21
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• 2008

In the IEEE 802.16 Wireless MAN standard, the best effort service class is ranked on the lowest position in priority so that only scarce resource may be available for it. Also, the best effort service is usually assisted by a MAC scheme based on reservation ALOHA without explicit acknowledgement. However, the standard only specifies the skeleton of the MAC scheme. In this paper, we propose some rules to specify the indefinite part of the MAC scheme as well as to improve the throughput and delay performance of the MAC scheme. As generic rules for demanding and granting resource, we first propose non-gated exhaustive, gated exhaustive, non-gated limited, and gated limited demand rules, and deficient and full grant rules. Secondly, we propose grant regulation rules, identified as replacement and lifetime rules, to avoid excessive grant incurred by not giving acknowledgement. Noting the residual resource is inflated by adopting a grant regulation rule, we finally propose a rule for investing the residual resource to a subscriber station. Simulation results confirm that a combination of proposed rules improves the performance of the MAC scheme.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2002.11a
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• pp.400-406
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• 2002

Historically, IP-based internets have been able to provide a simple best-effort delivery service to all applications they carry. Best effort treats all packets equally, with no service level, packet loss, and delay. The best-effort style has generally worked fine. But the needs of users have changed. The want to use the new real-time, multimedia, and multicasting applications. Thus, there is a strong need to be able to support a variety of traffic with a variety of quality-of-service requirements, within the TCP/IP architecture. This paper propose a framework that offers QoS in a DS domain using dynamic node setting method.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.11a
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• pp.400-406
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• 2002

Historically, IP-based internets have been able to provide a simple best-effort delivery service to all applications they carry. Best effort treats all packets equally, with no service level, packet loss, and delay. The best-effort style has generally worked One. But the needs of users have changed. The want to use the new real-time multimedia, and multicasting applications. Thus, there is a strong need to be able to support a variety of traffic with a variety of quality-or-service requirements, within the TCP/IP architecture. This paper propose a framework that offers QoS in a DS domain using dynamic node setting method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.128-140
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• 2006

In the IEEE 802.16 Wireless MAN standard specifies the air interface of fixed point-to-multipoint broadband wireless access systems providing multiple services. Among the service classes supported between the base station and subscriber stations in the wireless MAN, the best effort service class is ranked on the lowest position in priority and is assisted by a MAC scheme based on reservation ALOHA. The wireless MAN standard, however, does not reveal every detail of the MAC scheme but only describes the skeleton of the MAC scheme. Focusing on the amount of resource that a subscriber demands by a request and the amount of resource that the base grants to a request we thus present a number of resource demand rules and resource grant rules. Also, we construct a candidate MAC scheme by implanting a pair of resource demand and grant rules into the skeleton of the MAC scheme. Meanwhile a difficult situation for the best effort service is expected wherein only scarce resource is available after most of the resource is already preempted by other services. Perceiving such a situation, we evaluate the throughput and delay performance of each candidate MAC scheme. Especially we develop an analytical method to approximately calculate the throughput in the saturated environment. From the numerical results, we observe that the candidate MAC scheme which adopts the non-gated exhaustive demand rule paired with the full grant rule attains superior performance at the expense of the fairness.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.78-87
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• 2009

In the IEEE 802.16 Wireless MAN standard, the best effort service class is ranked on the lowest position in priority and is assisted by a MAC scheme based on reservation ALOHA. In such a MAC scheme, a collision among the requests is unavoidable so that the standard adopted a binary exponential back-off rule to arbitrate a collision. Aiming at improving throughput performance, we present two generic collision arbitration rules based on p-persistence rule, (identified as pristine and metamorphosed rules), as alternatives in a wireless MAN. For each of these rules, we then develop an analytical method to calculate an approximate value of saturated throughput. In comparison with simulation results, we confirm the high accuracy of the analytical method. Also, the pristine and metamorphosed rules are observed to exhibit higher saturated throughput compared with the binary exponential back-off rule.