• KIISE Transactions on Computing Practices
• /
• v.20 no.12
• /
• pp.688-693
• /
• 2014

With the advent of ubiquitous environments, the smart phone has come into wide use and the demand for various content increases. Thus, in order to efficiently utilize limited resources cognitive radio technology is regarded as a possible solution. Besides spectrum sensing or access schemes, the provision of VoIP traffic service for secondary users with limited spectrum resources is a very important issue. In this paper, a resource allocation and control system for VoIP QoS provision in cognitive radio networks is proposed. Firstly, as the system model, the time structure of the network is addressed and, according to the structure, a bandwidth broker is proposed. In addition, based on available bandwidth estimated by the bandwidth broker, a connection admission control for secondary users is developed. It is demonstrated that the provision of VoIP QoS is greatly affected by channel utilization, the number of channels, and the length of timeslot.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.4
• /
• pp.51-60
• /
• 2009

In radio frequency identification(RFID) systems, when an RFID reader uses the same or adjacent frequency with neighbor readers, the interference between the readers may occur, which causes the reader collision and errors in tag recognition. In the previous study on RFID reader anti-collision, the techniques based on Frequency Division Mutiplex(FDM) or Time Division Multiplex(TDM) are proposed. However in these paper, the problem on the condition of RFID reader-to-reader interference considering the distance between interfering readers, frequency and operating time is not define exactly. In this paper, the interference effect is analyzed through RFID reader interference model considering the TDM and FDM, and the optimization problem is defined. To solve this, genetic-resource allocation technique is proposed. Therefore the optimal resource allocation applied RFID environment faithfully is accomplished.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.3A
• /
• pp.254-266
• /
• 2006

Recently, researches about downlink resource allocation algorithms applying SDMA to enhance the system throughput and cell coverage have begun. Most OFDM/SDMA based resource allocation algorithms have some limitations such that those only concentrate on maximizing the system throughput or can be applied in single cell environment. In this paper, we propose an OFDM/SDMA based downlink resource allocation algorithm which considers high layer QoS parameters suitable for the required data traffic and it also minimizes the system throughput loss and considers inter-cell interference from adjacent cells. so it can be adopted in multi-cell environment. We manifest the performance of the proposed algorithm in Ped A and SCME MIMO Channel Model.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.205-206
• /
• 2008

We propose load balancing algorithm based on cross layer designing for MIMO OFDM system. When there are many users using data service, base station(BS) should distribute traffic. Moreover, cross layer design gives benefit managing radio resource and network bandwidth management. Proposed cross layer load balancing technique manages both BS's bandwidth allocation and MS’s power control. One BS request bandwidth to other BSes and other BSes reduce each bandwidth. And BSes reduce power of sub carriers for reserving available bandwidth of backhaul. MSes that didn't get service can be served by obtaining bandwidth from other BSes. The simulation result shows more users can be served and cell throughput was increased

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.12
• /
• pp.708-715
• /
• 2016

Quality of experience (QoE) for multimedia services in macro-femtocell networks is one of the key issues for 5G mobile and wireless communications. A service management structure needs to guarantee the QoE for mobile users based on end-to-end negotiation to support service continuity. Resource management is necessary to maintain the QoE requirements of different multimedia applications, because service continuity may be impeded by delays. This paper proposes four types of resource management scheme to support consistent QoE for different multimedia services. For this purpose, a QoE structure is suggested, and a resource allocation scheme is proposed by utilizing a fixed amount of radio resources reserved for dedicated use to support QoE. Various multimedia services with different requirements (such as voice, image, and data) can be serviced simultaneously, because QoE can be provided under our proposed scheme. Simulation results show that our scheme provides better performance than a conventional scheme with respect to outage probability and total data throughput.

• Journal of Information Processing Systems
• /
• v.16 no.4
• /
• pp.896-914
• /
• 2020

With the rapid growth of network traffic, a large number of connected devices, and higher application services, the traditional network is facing several challenges. In addition to improving the current network architecture and hardware specifications, effective resource management means the development trend of 5G. Although many existing potential technologies have been proposed to solve the some of 5G challenges, such as multiple-input multiple-output (MIMO), software-defined networking (SDN), network functions virtualization (NFV), edge computing, millimeter-wave, etc., research studies in 5G continue to enrich its function and move toward B5G mobile networks. In this paper, focusing on the resource allocation issues of 5G core networks and radio access networks, we address the latest technological developments and discuss the current challenges for resource management in 5G.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.2A
• /
• pp.179-187
• /
• 2007

As wireless networks evolve to orthogonal frequency division multiple access(OFDMA) systems, inter-cell interference control becomes a critical issue in radio resource management. The allocation of the same channels in neighbor cells cause inter-cell interference, so the channel allocation needs to be taken carefully to lower the inter-cell interference. In distributed channel allocation, each cell independently tries to allocate channels that suffer low interference level. In this paper, under the assumption of static users, we introduce the concept of interference range and use it in designing our two algorithms; basic and combined. The basic algorithm performs interference range detection and determines whether to use the considered channel, while the combined algorithm checks the channel quality in addition to detecting the interference range. The two algorithms dynamically perform channel allocation with low complexity and show good throughput and fairness performance.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.17 no.6
• /
• pp.211-223
• /
• 2018

Mobile relay systems have been adopted by $4^{th}$ generation mobile systems as an alternative method to extend cell coverage as well as to enhance the system throughput at cell-edges. In order to achieve such performance gains, the mobile relay systems require path selection and resource allocation schemes that are specifically designed for these systems which make use of additional radio resources not needed in single-hop systems. This paper proposes an integrated path selection and resource allocation scheme for LTE-Advanced relay systems using collaborative communication. We first define the problem of maximizing the downlink throughput of LTE-Advanced relay systems using collaborative communication and transform it into a multi-dimensional multi-choice backpacking problem. The proposed Lagrange multiplier-based heuristic algorithm is then applied to derive the approximate solution to the maximization problem. It is shown through simulations that the approximate solution obtained by the proposed scheme can achieve a near-optimal performance.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.31 no.3
• /
• pp.145-154
• /
• 2006

WiBro (Wireless Broadband Internet) system is going to be 9ot down to commercialization. The high portable internet system is able to be connected to the high-speed internet using 2.3 GHz frequency bandwidth, anytime and anywhere. An effective scheduling for UGS, rtPS, nrtPS and BE requiring different QoS, which are service types of the WiBro, is necessary to increase the efficiency of radio channels that are the limiting resource. This paper researches an uplink scheduling that plays a role in assignment for the radio channels from subscribers to base stations. The suggested scheduling provides priorities with each service type considering QoS of them but reserves some bandwidth for lower priory services. After deciding effective amount of bandwidth for reservation, we suggest analytical result on mean delayed time of packet transmission for each terminal, transmission rate for the data, and capacity for uplink. This research can be used as basic data for the standard in the high portable internet system and as data to predict the capacity of base stations.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2005.10a
• /
• pp.347-353
• /
• 2005

WiBro (Wireless Broadband Internet) system is going to be commercialized before long. The high portable internet system is abie to be connected to the high-speed internet using 2.3 CHz frequency bandwidth, anytime and anywhere. An effective scheduling for UCS, rtPS. nrtPS and BE requiring different QoS, which are service types of the WiBro, is necessary to increase the efficiency of radio channels that arc the limiting resource. This paper researches an uplink scheduling that plays a role in assignment for the radio channels from subscribers to base stations. The suggested scheduling provides priorities With each service type considering QoS of them but reserves some bandwidth for lower priory services. After deciding effective amount of bandwidth for reservation, we suggest analytical result on mean delayed time of packet transmission for each terminal, transmission rate for the data, and capacity for uplink. This research can be used as basic data for the standard in the high portable internet system and as data to predict the capacity of base stations.