• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37A no.12
• /
• pp.1013-1022
• /
• 2012

Tag collection is one of the major concerns in radio frequency identification(RFID) system. All tags in RFID reader's transmission range send response message back to the reader in response to collection request message on the given rf channel. When multiple tags respond simultaneously, tag-collision may occur. Tag-collision problem is one of the most important issues in active RFID performance. To mitigate this problem, frame slotted ALOHA(FSA) anti-collision protocol is widely used in active RFID system. Several studies show that the maximum system efficiency of FSA anti-collision protocol is 36.8%. In this paper, we propose an efficient slotted CSMA/CA protocol to improve tag collection performance. We compare our protocol to the FSA anti-collision protocol. For the experiment, an 433MHz active RFID system is implemented, which is composed of an RFID reader and multiple tags. We evaluated the tag collection performance using one RFID reader and 40 tags in the real test bed. The experimental result shows that proposed protocol improves the tag collection time, round and collision probability by 18%, 37.4% and 77.8%, respectively.

• Proceedings of the KIEE Conference
• /
• 2007.04a
• /
• pp.445-447
• /
• 2007

This paper is seeing as one big cause that reduce Life Time of sensor node become soft if BackOff Time is prolonged in CDMA/CA of competition way that consist at data transmission of each sensor nodes base sensor network environment. So solution method uses GTS, wish to reduce competition Node's, and minimise data transmission delay.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.42 no.3
• /
• pp.604-611
• /
• 2017

In wireless sensor networks, an energy efficient operation is important since the energy of the sensors is limited. This paper proposes an energy efficient method that reduces a packet generation with Matrix Completion method where sensor value matrix has low-rank and decreases a collision rate and an overhead by transmitting only sensor ID to a time slot corresponding to the sensor value. Computer simulations demonstrates that the proposed method shows 17% of transmission failure and 73% of the packet generation compared to a conventional CSMA/CS. Delay time of transmitting information of the proposed method exhibits 22% of the CSMA/CA and the MSE error after reconstructing sensor values by Singular Value Thresholding(SVT) in Fusion Center is 87% of the CSMA/CA.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.11
• /
• pp.2385-2390
• /
• 2010

The PRC-999K radio widely used in Korean Army is half-duplex and also has the broadcasting radio wave character that all subscribers listen when one subscriber speaks in time. The radio data communication system configures a 1:1 unicast network between a command post and network members in a military fire control system. The system also applies CSMA/CA technique to avoid data collision and additionally applies SDLC protocol for efficiency and fast communication. This paper shows that allocating address to network members in serial order can reduce data transmitting/receiving time, and thereby a command post needs to broadcast data only one time and the assigned members can reply in order without data collision. It is validated through an experimental test.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.531-534
• /
• 2010

Currently the functionality of the PRC-999K radio that is widely used in Korean Army is half-duplex and the broadcasting system that all subscribers have to listen when one subscriber speaks in time. Radio data communication system configures peer-to-peer network between command post and network members in military fire control system. And the system applies CSMA/CA(Carrier Sense Multiple Access/Collision Avoidance) technique to avoid data collision. Such a data transmitting/receiving time could be reduced by allocating address in serial order to each network members. By doing that, command post need to broadcast data only one time and assigned members will reply in order without data collision. This paper provides such a protocol and algorithm.

• IEIE Transactions on Smart Processing and Computing
• /
• v.3 no.4
• /
• pp.173-180
• /
• 2014

Random access protocols feature inherent sensing functionality and distributed coordination, making them suitable for cognitive radio communication environments, where secondary users must detect the white space of the primary spectrum and utilize the idle primary spectrum efficiently without centralized control. These characteristics have led to the adoption of carrier-sensing-multiple-access/collision-avoidance (CSMA/CA) in cognitive radio. This paper proposes a new analytical framework for evaluating the performance of a CSMA/CA protocol that considers the characteristics of idle periods based on the primary traffic behavior in cognitive radio systems. In particular, the CSMA/CA-based secondary network was analyzed in the terms of idle period utilization, which is the average effective data transmission time portion in an idle period. The use of the idle period was maximized by taking its statistical features into consideration.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.1
• /
• pp.87-93
• /
• 2012

Due to the development of information and communication, there is a rising interest on WBAN(Wireless Body Area Network) that maintain and check the human being health. According to the application of different quality of service and a special mechanism for transferring medical data are required in WBAN environment. In this paper, we proposed the new formed superframe that has CSMA/CA based TDMA scheduling and CSMA/CA used IEEE 802.15.4 in order to process emergency data and on-demand data in WBAN environment. We estimated performance of the proposed MAC protocol by compared performance of other MAC protocols that are IEEE 802.15.4 MAC protocl and Z-MAC protocol has contention access period based TDMA scheduling.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.7
• /
• pp.1394-1399
• /
• 2007

In this paper we propose a Hybrid MAC(HMAC) to enhance the transmission throughput in Wireless Sensor Networks(WSNs). In the proposed HMAC, sender nodes send transmission request packets to the receiver nodes using CSMA/CA MAC protocol. And the receiver node assigns slots according to the network topology and the amount of traffics using TDMA. Using HMAC we get the enhanced throughput by lowering the duplicated slot assignment.

• Journal of information and communication convergence engineering
• /
• v.19 no.1
• /
• pp.1-7
• /
• 2021

Reinforcement learning is an area of machine learning that studies how an intelligent agent takes actions in a given environment to maximize the cumulative reward. In this paper, we propose a new MAC protocol based on the Q-learning technique of reinforcement learning to improve the performance of the IEEE 802.11 wireless LAN CSMA/CA MAC protocol. Furthermore, the operation of each access point (AP) and station is proposed. The AP adjusts the value of the contention window (CW), which is the range for determining the backoff number of the station, according to the wireless traffic load. The station improves the performance by selecting an optimal backoff number with the lowest packet collision rate and the highest transmission success rate through Q-learning within the CW value transmitted from the AP. The result of the performance evaluation through computer simulations showed that the proposed scheme has a higher throughput than that of the existing CSMA/CA scheme.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.5A
• /
• pp.460-466
• /
• 2007

There are two coordination functions in IEEE 802.11 standard. One is PCF, polling based function, and the other is DCF, contention based function. DCF is simpler than PCF but the performance is similar with the latter. That's the reason why DCF is more popular than PCF. However, DCF has a risk of collision with other nodes in the network because the function is a distributed contention based one. CSMA/CA of DCF has collision avoidance algorithm in it, but the performance of avoidance algorithm has limitations. In this paper we proposed a new scheme called TAR(Tone-based Access scheme with Repetitive conention). In TAR, there is narrow contention-only channel other than original data transmitting channel, so that both a data transmission and the contention can be performed simultaneously. The TAR uses the same contention concept with the CSMA/CA, but it has the originality for the narrow contention channel and the repetitive contention scheme which greatly reduce the collision probability. We proved the performance of TAR by some simulations, and it showed good results.