• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.768-776
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• 2009

This paper analyses the message complexity of TDMA ad hoc MAC protocols. Since the network resource of ad hoc networks is limited due to the multiple interferences and the contention-based wireless channel, the scalability issue is one of the main research topics in developing ad hoc algorithms. Simulation demonstrates that SMACS protocol has the lowest message complexity, whereas TMMAC has the highest. In addition, it is found that since the effect of unicast dominates in the message complexity compared to other factors with an increasing number of nodes, Z-MAC tends to have the property of linearity, whereas BMA and TMMAC show exponential increases in their complexities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1088-1094
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• 2021

This paper proposes a partial BMA (Broadcasting Multiple Access) network structure and D-ARP (Distributed Address Resolution Protocol) method in order to support full mesh routing function in the DAMA (Demand Assigned Multiple Access)-based MF-TDMA (Multi Frequency-Time Division Multiple Access) satellite system. The partial BMA network enables legacy router devices and routing protocols to be adopted in the satellite communication system, and decreases the amount of routing protocol overhead. In addition, we introduce the D-ARP method that help a spoke satellite node acquiring the MAC (Media Access Control) address from remote satellite nodes in none BMA satellite network. The D-ARP method provides the MAC address of remote nodes to each other nodes through the broadcasting-enabled satellite channel. And we lastly evaluate and analysis the network performance of the proposed approach.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.5
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• pp.107-116
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• 2011

In this paper, a traffic adaptive sleep based medium access control (TAS-MAC) protocol for wireless sensor networks (WSNs) is proposed. The protocol aims for WSNs which consist of clustered sensor nodes and is based on TDMA-like schema. It is a typical schedule based mechanism which is adopted in previous protocols such as LEACH and Bit-Map Assisted MAC. The proposed MAC, however, considers unexpected long silent period in which sensor nodes have no data input and events do not happen in monitoring environment. With the simple traffic measurement, the TAS-MAC eliminates scheduling phases consuming energy in previous centralized approaches. A frame structure of the protocol includes three periods, investigation (I), transmission (T), and sleep-period (S). Through the I-period, TAS-MAC aggregates current traffic information from each end node and dynamically decide the length of sleep period to avoid energy waste in long silent period. In spite of the energy efficiency of this approach, the delay of data might increase. Thus, we propose an advanced version of TAS-MAC as well, each node in cluster sends one or more data packets to cluster head during the T-period of a frame. Through simulation, the performance in terms of energy consumption and transmission delay is evaluated. By comparing to BMA-MAC, the results indicate the proposed protocol is more energy efficient with tolerable expense in latency, especially in variable traffic situation.

• Journal of the Korea Society of Computer and Information
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• v.15 no.5
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• pp.103-111
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• 2010

This paper proposes an efficient data transmission strategy using adaptive-tier low transmission power schedule in a TDMA-based ad hoc MAC protocol. Since the network resource of ad hoc networks has the characteristic of reassignment due to the multiple interferences and the contention-based limited wireless channel, the efficient time slot assignment and low power transmission scheme are the main research topics in developing ad hoc algorithms. Based on the proposed scheme of interference avoidance when neighbor clusters transmit packets, this paper can minimize the total energy dissipation and maximize the utilization of time slot in each ad hoc node. Simulation demonstrates that the proposed algorithm yields 15.8 % lower energy dissipation and 4.66% higher time slot utilization compared to the ones of two-tier conventional energy dissipation model.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.8 s.338
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• pp.11-16
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• 2005

This paper proposes a bit manipulation accelerator (BMA) having application specific instructions, which efficiently supports scrambling, convolutional encoding, puncturing, and interleaving. Conventional DSPs cannot effectively perform bit manipulation functions since かey have multiply accumulate (MAC) oriented data paths and word-based functions. However, the proposed accelerator can efficiently process bit manipulation functions using parallel shift and Exclusive-OR (XOR) operations and bit jnsertion/extraction operations on multiple data. The proposed BMA has been modeled by VHDL and synthesized using the SEC $0.18\mu m$ standard cell library and the gate count of the BMA is only about 1,700 gates. Performance comparisons show that the number of clock cycles can be reduced about $40\%\sim80\%$ for scrambling, convolutional encoding and interleaving compared with existing DSPs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.535-538
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• 2010

In this paper, this study goal is development for WSN-based fire prevention systems of using temperature/humidity Sensor. So, distributed sensor nodes structural and packet transfer characteristics study for fire monitoring. Battery-operated wireless sensor networks is data transfer manner of multi-hop. WSN fire prevention system need to sensor nodes management and energy consumption of efficient adjust for sustained action. Thus, study with efficient energy consumption the normal WSN environment is not, characteristics for WSN fire prevention environment.