• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.259-260
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• 2008

This paper presents fractional frequency reuse (FFR) with sub-channel borrowing to improve spectral efficiency of the wireless broadband (WiBro) system. FFR has constraints on usable sub-channels to balance the interference and cell capacity. Our FFR with sub-channel borrowing allows use of the dedicated sub-channels assigned to neighboring cells. Simulation results show that the proposed FFR with sub-channel borrowing improves the performance of the WiBro system.

• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.165-173
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• 2002

In the static channel assignment scheme for cellular mobile computing environment, each cell has a fixed number of channels and supports a service for a user′s request entering to the cell. This scheme has an advantage of simplicity. However, this scheme has a disadvantage that can′t control far hot cell problem. Therefore, to solve this problem, the "channel borrowing" concept is needed. In this paper, we propose a load balancing(channel borrowing, channel reassignment) approach using genetic algorithm. The purposes of using genetic algorithm in this paper are ${\circled1}$ to find early a cell including an available channel and ${\circled2}$ to decrease a number of probings and ${\circled3}$ to migrate to the cell after searching an available channel near upon optimality. To represent effectiveness of the proposed algorithm, we simulated various experiments.

• Journal of Broadcast Engineering
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• v.15 no.3
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• pp.407-413
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• 2010

In DCA (Dynamic Channel Allocation) scheme of uplink cellular system appling a frequency reuse factor of one, when a new call requests a channel, the new call will be blocked if its SINR (Carrier to Noise and Interference Ratio) is less than the required SINR or there is no available channel. The additional channel allocation for the blocked new call can be performed with channel borrowing in the adjacent cells. The channel borrowing causes the CCI (Co-Channel Interference), thus the SINR of the existing calls is deteriorated and the channel reallocation for the existing calls is required. As a result, the channel borrowing leads to a complex calculation so that it is a NP-hard problem. Therefore, to overcome the problem, we propose a novel Group Search-based DCA scheme which decreases the number of the blocked new calls and then reduces the number of the channel reallocation by the channel borrowing for the blocked new calls. The proposed scheme searches the all channels in a group of the adjacent cells and home cell at the same time in order to minimizes the number of the blocked new calls. The simulation results show that proposed Group Search-based DCA scheme provides better new call blocking probability and system throughput than the existing Single Search-based DCA scheme which searches only the channels in home cell.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2A
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• pp.61-65
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• 2005

We propose a soft QoS-based borrowing scheme for call admission control(CAC) in DVB-RCS(Digital Video Broadcast-Return Channel via Satellite). Some of the ongoing calls temporarily and fairly release bandwidths that can be used to accommodate a new call in an overloaded satellite network. The amount of bandwidth borrowed from each call is proportional to each user's critical bandwidth ratio, one of parameters for soft QoS mechanism. Simulation results show that the proposed scheme improves the system performance in terms of call blocking probability and bandwidth utilization.

• Journal of Communications and Networks
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• v.10 no.1
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• pp.38-43
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• 2008

In this paper, adaptive channel borrowing approach fuzzy neural networks for load balancing (ACB-FNN) is presented to maximized the number of served calls and the depending on asymmetries traffic load problem. In a wireless network, the call's arrival rate, the call duration and the communication overhead between the base station and the mobile switch center are vague and uncertain. A new load balancing algorithm with cell involved negotiation is also presented in this paper. The ACB-FNN exhibits better learning abilities, optimization abilities, robustness, and fault-tolerant capability thus yielding better performance compared with other algorithms. It aims to efficiently satisfy their diverse quality-of-service (QoS) requirements. The results show that our algorithm has lower blocking rate, lower dropping rate, less update overhead, and shorter channel acquisition delay than previous methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.156-160
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• 2002

In this paper, we have estimated by means of the theoretical analysis and the simulation of FCA(Fixed Channel Assignment) and CB(Channel Borrowing) in order to consider the CB as a technique to meet ducting interference from adjacent countries. Also, we assumed that the receiving power level of ducting interference with time rate can be characterized by the normal distribution due to the previous measured results, and the ducting interferences which are exceeding the reference power level can be regarded as calls. These calls can be processed by CR assignment and by which sharing channels between cells brings to us the method of meeting the ducting interference to use spectrum resources effectively. However, the spectrum frequency reusing and the interference effects between channels should be considered in CB simulation in the future.

• Journal of KIISE:Information Networking
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• v.37 no.6
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• pp.415-419
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• 2010

Bandwidth is an extremely valuable and scarce resource in a wireless network. Therefore, efficient bandwidth management is necessary in order to provide high quality service to users with different requirements. In this paper, we propose a bandwidth reservation algorithm based on Nash Bargaining Solution. The proposed algorithm has low complexity and are quite flexible in the different situations of network. Simulation results indicate that the proposed scheme has excellent performance than other existing schemes.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.21-24
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• 2001

For very large multimedia traffic to be supported successfully in wireless network environment, it is necessary to provide Quality-of-Service(QoS) guarantees between mobile hosts(clients). In order to guarantee the Qos, we have to keep the call blocking probability below target value during handoff session. However, the QoS negotiated between the client and the network may not be guaranteed due to lack of available channels for traffic in the new cell, since mobile clients should be able to continue their on-going sessions. In this paper we propose a efficient load-balancing algorithm based on the adaptive bandwidth reservation scheme for enlarging available channels in a cell. We design a new method to predict the mobility of clients using MPT(mobility profile table). This method is then used to reserve a part of bandwidths for handoff calls to its adjacent cells and this reserved bandwidth can be used for handoff call prior to new connection requests. If the number of free channels is also under a low threshold value, our scheme use a load-balancing algorithm with a adaptive bandwidth reservation. In order to evaluate the performance of our algorithm, we measure the metrics such as the blocking probability of new calls and dropping probability of handoff calls, and compare with other existing schemes.

• KDI Journal of Economic Policy
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• v.14 no.1
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• pp.89-119
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• 1992

This paper purports to analyze the economic rationale of compensating balance requirements and its impact on money supply. This practice has recently been severely criticized for artificially increasing the money supply and, therefore, limiting the nation's aggregate lending policy under the tight constraint of the given money supply target. A review of the existing literature implies that compensating balance requirements is a banking practice which leads to corrections in the distortion of financial resource allocation due to the imperfection of financial market stemming from asymmetric information and/or financial regulations on deposit and lending rates. Therefore, the economic rationale of this practice is deemed to improve the efficiency of financial resource allocation. On the other hand, the macroeconomic impact of compensating balance requirements on the money supply depends on the impact on the money multiplier, which in turn depends on the desired ratio of deposit that people wish to maintain on the money borrowed from the banking system, and on the desired reserve ratio that the banking system would like to hold for deposit withdrawal. If the compensating balance requirements could increase the desired ratio of deposit to borrowing (bank lending), it will increase the available amount of total reserve within the banking system and, in turn, the money multiplier. However, this channel has not been fully analyzed in the literature, and the direction of the effect is ambiguous. If the practice could reduce the turn-over rate of deposit and, thereby, reduce the desired reserve ratio of the banking system, then it will also increase the money multiplier. While this channel operates unambiguously toward increasing the money multiplier, this effect will be limited by the extent that the banking system holds the excess reserve over the required reserve because the excess reserve will set the maximum amount for the desired reserve to fall. This paper tries to determine the effect on the money supply by empirically estimating the multiplier and the desired ratio of deposit to lending equations as functions of the ratio of compensating balance to the related lending, which is not observable and is estimated for the regression purpose. The results suggest that the effect of compensating balance requirements on the money supply in Korea does not exist or is very tenuous even if it could operate. Therefore, this paper concludes that the well publicized policy of cross cancelling the compensating balance and the related lending will not be effective at controlling the money supply and increasing the amount of loans without expanding the money supply.