• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.17-28
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• 1994

A combined random/reservation multiple access protocol is proposed which can provide services for packet transmission in mobile satellite systems between mobile statons, or between mobile stations and fixed stations. Random multiple access protocol and reservation multiple access protocol which are currently employed in most satellite communication systems have some strengthes and some weeknesses in according to the kind of user and traffic. In this paper, a combined random/reservation multiple access protocol with better characteristics is proposed. The models of the modified random access protocol and the proposed access protocol is setted and analyzed. The performance of the PDAMA protocol, the random access protocol and the proposed access protocol is compared using simulation. For small packet arrival rate, the performance of the proposed access protocol is close at that of the modified random access protocol, and better than that of the PDAMA protocol. As the packet arrival rate is increased, the modified random access protocol is saturated and unstable at 0.23, and the performance of the proposed access protocol is better than that of the PDAMA protocol.

• Journal of information and communication convergence engineering
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• v.15 no.1
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• pp.28-36
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• 2017

The medium access control (MAC) protocol based on dynamic time division multiple access/time division duplex (TDMA/TDD) is responsible for random access control and radio resource allocation in dynamic traffic environments. These functions of random access and resource allocation are very important to prevent wastage of resources and improve MAC performance according to various network conditions. In this paper, we propose new random access and resource allocation schemes to guarantee quality of service (QoS) and provide priority services in a dynamic TDMA/TDD system. First, for the QoS guarantee, we propose an adaptive random access and resource allocation scheme by introducing an access probability. Second, for providing priority service, we propose a priority-based random access and resource allocation scheme by extending the first adaptive scheme in both a centralized and a distributed manner. The analysis and simulation results show that the proposed MAC protocol outperforms the legacy MAC protocol using a simple binary exponential backoff algorithm, and provides good differential performance according to priorities with respect to the throughput and delay.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.4
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• pp.893-910
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• 1996

Recently, there ary many researches on local area multichannel network as WDM technology developes. An ideal media access protocol in a multichannel network is one that shows short access delay under low load and high throughput under heavy load. This paper proposed a new media access protocol for WDM passive star coupler network. The proposed one is a random access rpotocol based on reservation. Access delay is short under low load by using random access method, and high throughput is achieved under heavy load by usin greservation access. Analytic model for the performance analysis of the proposed protocol is developed and performance of the proposed protocol is compared with the previous ones. The effect on the performance of the number of the nodes and channels, and the number of transceivers in each node are analyzed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.603-606
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• 2019

In this paper, we propose a slotted-ALOHA-based random access protocol and derive the optimal number of random slots that maximize channel throughput when multiple energy harvesting sensor devices perform random access in wireless-powered sensor networks (WPSN). Throughput numerical analysis, we prove that the throughput has a concavity with respect to the number of random slots and obtain the optimal number of slots. Simulation results show that the throughput of the proposed slotted ALOHA-based random access protocol is maximize when the derived optimal number of slots is employed in the considered WPSN.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.3
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• pp.156-161
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• 2012

Random access protocol takes advantage of constructing a decentralized wireless network due to its intrinsic spectrum sensing capability. Such technical feature goes well with cognitive radio networks consisting of heterogeneous wireless systems, in which a centralized control between heterogeneous wireless systems is hard to be implemented. Motivated by the decentralized feature of the random access, we adopt the random access protocol in cognitive radio networks, and evaluate the performance of a CSMA-based cognitive radio network.

• ETRI Journal
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• v.28 no.3
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• pp.311-319
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• 2006

This paper presents a terminal-assisted frame-based packet reservation multiple access (TAF-PRMA) protocol, which optimizes random access control between heterogeneous traffic aiming at more efficient voice/data integrated services in dynamic reservation TDMA-based broadband access networks. In order to achieve a differentiated quality-of-service (QoS) guarantee for individual service plus maximal system resource utilization, TAF-PRMA independently controls the random access parameters such as the lengths of the access regions dedicated to respective service traffic and the corresponding permission probabilities, on a frame-by-frame basis. In addition, we have adopted a terminal-assisted random access mechanism where the voice terminal readjusts a global permission probability from the central controller in order to handle the 'fair access' issue resulting from distributed queuing problems inherent in the access network. Our extensive simulation results indicate that TAF-PRMA achieves significant improvements in terms of voice capacity, delay, and fairness over most of the existing medium access control (MAC) schemes for integrated services.

• The Transactions of the Korea Information Processing Society
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• v.4 no.2
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• pp.515-522
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• 1997

A neat prefect stable random access protocol for a broadcast channel,the distributed queuing random access protocol(DQRAP)is presented and evaluated.The DQRAP prootcol utilizes minisolts to provide termaty chan-nel feedback and two distributed queues to:9a) resolve contention and (b) to schedute the transmission of messages.Three minislots are sufficient to resolve collisions faster than the tranmission times of all inboled mecages.Three minislots are suffcient to resolve collisions faster than the tranmission times of all inbolved arrivals when ternary minislot feedback is used.Modelingand simulation indicate that the DQRAP protocol, using as few as three minislits,achives a performance level which approaches that of hypothetical perfect cheduling protocol,ie,the M/D/I system,with respect to propagation delay,thus offers the potential of improved performance over current protocols in satellite,metropolitan and packet radio networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.175-182
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• 2018

As Internet of things with a large number of nodes emerges, wireless-power communication networks (WPCN) based on a random access protocol needs to be investigated. In the random access-based WPCN, a terminal accessing later in given random access (RA) slots can harvest more energy before transmission and thus can transmit data with higher power and achieve higher throughput if the access is successful. On the basis of this property, the proposed random access control protocol gives the terminals priority and distinguishes the RA slots according to the priority level, so that a near terminal with access point allows to access preferentially other than a remote terminal. This operation decreases the throughput of near terminal and increases the throughput of remote terminal, and then, the doubly near-far problem in WPCN is resolved and the user fairness is improved. Results show that the proposed random access control improves both channel throughput and user fairness according to the priority level.

• Journal of information and communication convergence engineering
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• v.5 no.2
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• pp.88-92
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• 2007

In this paper, an SS-RRA protocol that is based on Code Division Multiple Access is proposed and analyzed under the integrated voice and data traffic load. The backward logical channels consist of slotted time division frames with multiple spreading codes per slot. The protocol uses a reservation mechanism for the voice traffic, and a random access scheme for the data traffic. A discrete-time, discrete-state Markov chain is used to evaluate the performance. The numerical results show that the performance can be significantly improved by a few distinct spreading codes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.687-708
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• 2017

The machine-to-machine (M2M) communication is featured by tremendous number of devices, small data transmission, and large uplink to downlink traffic ratio. The massive access requests generated by M2M devices would result in the current medium access control (MAC) protocol in LTE/LTE-A networks suffering from physical random access channel (PRACH) overload, high signaling overhead, and resource underutilization. As such, fairness should be carefully considered when M2M traffic coexists with human-to-human (H2H) traffic. To tackle these problems, we propose an adaptive Slotted ALOHA (S-ALOHA) and time division multiple access (TDMA) hybrid protocol. In particular, the proposed hybrid protocol divides the reserved uplink resource blocks (RBs) in a transmission cycle into the S-ALOHA part for M2M traffic with small-size packets and the TDMA part for H2H traffic with large-size packets. Adaptive resource allocation and access class barring (ACB) are exploited and optimized to maximize the channel utility with fairness constraint. Moreover, an upper performance bound for the proposed hybrid protocol is provided by performing the system equilibrium analysis. Simulation results demonstrate that, compared with pure S-ALOHA and pure TDMA protocol under a target fairness constraint of 0.9, our proposed hybrid protocol can improve the capacity by at least 9.44% when ${\lambda}_1:{\lambda}_2=1:1$and by at least 20.53% when ${\lambda}_1:{\lambda}_2=10:1$, where ${\lambda}_1,{\lambda}_2$ are traffic arrival rates of M2M and H2H traffic, respectively.