• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.4
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• pp.741-762
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• 2011

Recently, multicast routing protocols become increasingly important aspect in Mobile Ad hoc Networks (MANETs), as they effectively manage group communications. Meanwhile, multimedia and real-time applications are becoming essential need for users of MANET. Thus it is necessary to design efficient and effective Quality of Service (QoS) multicast routing strategies. In this paper, we address the scalability problem of multicast routing protocols to support QoS over MANETs. In particular, we introduce a Position-Based QoS Multicast Routing Protocol (PBQMRP). Basically, the protocol based on dividing the network area into virtual hexagonal cells. Then, the location information is exploited to perform efficient and scalable route discovery. In comparison with other existing QoS multicast routing protocols, PBQMRP incurs less control packets by eliminating network flooding behavior. Through simulation, the efficiency and scalability of PBQMRP are evaluated and compared with the well-known On-Demand Multicast Routing Protocol (ODMRP). Simulation results justify that our protocol has better performance, less control overhead and higher scalability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2199-2214
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• 1994

In order to sufficiently utilize the potential effectiveness of ATM networks, systematic and effective network management and control systems must be employed. In addition to network design, planning, and call routing techniques used in traditional circuit-switched networks. ATM networks can provide logical VP(Virtual Path) reconfiguration capabilities which can adapt to changes in the network environment. With a proper application of the VP reconfiguration technique, ATM networks can reduce the overhead of frequent network redesign and the overhead of call routing processing. However, ATM VP reconfiguration is a very complex and difficult problem which consists of many facets of optimization subproblems such as VP routing. VP sizing, VP terminating point location and VC routing. Most previous research on the ATM logical network reconfiguration problem dealt with the subset of the problem. This paper mathematically formulates the ATM network reconfiguration problem completely considering all subproblems. Since it is very difficult to derive the optimal solution of the formulated problem, we develop a heuristic method based on a Max min bandwidth allocation principle. We show the feasibility of the proposed heuristic method with a simple example.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.2
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• pp.189-197
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• 2016

Mobile ad-hoc networks (MANETs) experience frequent link disconnections due to non-uniform node distribution and mobility. Thus, end-to-end path establishment-based routing protocols cause frequent transmission failures in MANETs, resulting in heavy control messages for path reestablishment. While location-based MANET routing protocols, such as Greedy Perimeter Stateless Routing (GPSR), use location information to forward messages in a hop-by-hop routing fashion without an end-to-end path establishment procedure, such protocols encounter communication void problems when message forwarding to the next hop fails due to the absence of a relay node. Therefore, to solve this problem, this paper proposes a Delay Tolerant-GPSR (DT-GPSR) protocol, which combines Delay Tolerant Networking (DTN) technology with the GPSR protocol. The performance of DT-GPSR is compared with the performances of the original GPSR and PRoPHET routing protocols through simulation using NS-2. The simulation results confirm that DT-GPSR outperforms GPSR and PRoPHET in terms of the message delivery ratio and message delivery delay.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.339-345
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• 2014

This study has a purpose that improves efficiency of energy management and adaptation followed by movement of node better than the various early studied routing techniques. The purpose of this paper is the technique that uses RSSI value and location of sensor that is received by each sensor node to routing. This sduty does not save node information of 1-hop distance. And it solves energy-inefficient traffic problem that happens during data exchange process for middle node selection in close range multi hop transmission technique. The routing protocol technique that is proposed in this study selects a node relevant to the range of transmission which is set for RSSI value that is received by each node and selects the closest node as a middle node followed by location data. Therefore, it is for not exhaustion of node's energy by managing energy efficiently and cutting data transmission consuming until the destination node.

• Korean Management Science Review
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• v.26 no.3
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• pp.23-35
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• 2009

This study deals with the location management in WCDMA (Wideband Code Division Multiple Access) networks. The new location management method is the one of the many techniques used to provide the packet switched (PS) services effectively in WCDMA networks. WCDMA introduces RA (routing area) for the PS services in addition to LA (location area) for the circuit switched (CS) services. WCDMA system also adopts the cooperative paging and the combined area update which are to decrease signaling traffic using the PS network resources for the CS services. Considering the characteristics of the WCDMA networks, this study formulate into the mathematical programming problem for the location management. Rather than the existing researches which consider the single MSC/SGSN networks, we deal with the multi MSC/SGSN networks, where both MSC area and SGSN area should be determined as well. Fairness between traffic loads of MSC/SGSN and the system cost incurred to MSC/SGSN are also incorporated into our model, which make the model more realistic. We propose greedy algorithms for the problems, which consists of the merger of two neighboring areas and the movement of an area. Extensive experiment has been done based on the realistic problem examples. Followed by the analysis of parameter effect on the final solutions and the quality of final solutions obtained by our greedy algorithms. Our proposed model and analysis result can be used to determine WCDMA system areas and to predict the system performance measures by the determination.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.209-215
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• 2002

In this paper, we propose a freight and fleet optimization model under CVO environment. The model is a kind of multi commodity network flow model based on Vehicle Routing Problem(VRP) and Vehicle Scheduling Problem(VSP), and considering operations and purposes of CVO. The main purpose of CVO is the freight and fleet management to reduce logistics cost and to Improve in vehicle safety. Thus, the objective of this model is to minimize routing cost of all the vehicle and to find the location of commodities which have origin and destination. We also present some computing test results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4B
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• pp.219-226
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• 2012

In wireless sensor networks (WSNs), location-based multicast routing (LMR) technique can increase the network life time and the channel capacity by reducing the number of duplicated data transmissions and control messages. However, previous LMR techniques can suffer from significant performance degradation due to concrete walls or other interfering objects deployed in the real environment, since they transmit the packets by using only the locations of the sensor nodes. To solve this problem, we propose an interference-aware location based multicast algorithm for WSNs. In the proposed algorithm, each node adjusts the energy cost for each link adaptively considering the interference effect and uses it for multicast decision in order to minimize the interference impact. Experimental results show that the proposed algorithm improves the delivery and energy performance when the network is affected by interference.

• Journal of KIISE:Information Networking
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• v.33 no.6
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• pp.428-437
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• 2006

Wireless ad-hoc routing has been extensively studied and many clever schemes have been proposed over the last several years. One class of ad-hoc routing is geographic routing where each intermediate node independently selects the next hop using the given location information of destination. Geographic routing, which eliminates the overhead of route request packet flooding, is scalable and suitable for large scale ad hoc networks. However, geographic routing may select the long detour paths when there are voids between a source and a destination. In this paper, we propose a novel geographic routing approach called Geographic Landmark Routing(GLR). GLR recursively discovers the intermediate nodes called landmarks and constructs sub-paths that connect the subsequent landmarks. Simulation results on various network topologies show that GLR significantly improves the performance of geographic routing.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.108-116
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• 2013

The input buffer in Network on Chip (NoC) router plays a key role in on-chip-network performance, which is utilized in flow control and virtual channel. However, increase in area and power due to input buffers as the network size gets larger is becoming severe. To solve this problem, a bufferless deflection routing without input buffer was suggested. Since the bufferless deflection routing shows poor performance at high network load, other approaches which combine the deflection routing with small size side buffers were also proposed. Nonetheless these new methods still show deficiencies caused by frequent path collisions. In this paper, we propose a modified deflection routing technique using a location based priority. In comparison with existing deflection routers, experimental results show improvement by 12% in throughput with only 3% increase in area.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.7
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• pp.62-66
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• 2008

In this paper we have proposed a power aware location based routing protocol for wireless ad hoc network. The existing greedy perimeter stateless routing (GPSR) has some problems which are certain node overloaded and void situation. The proposed power aware greedy perimeter stateless routing (PAGPSR) protocol gives a solution for these problems in GPSR. PAGPSR uses power aware and geographically informed neighbor selection to route a packet towards the destination. It also gives a solution for the fundamental problem in geographical routing called communication void. It considers residual energy of battery and distance to the destination for the next hope node selection. When it encounters a void it starts limited-flooding to select next hop node. To evaluate the performance of our protocol we simulated PAGPSR in ns-2. Our simulation results show that our protocol achieves longer network lifetime compared with greedy perimeter stateless routing (GPSR).