• Title/Summary/Keyword: IEEE 802.16e/m

검색결과 32건 처리시간 0.16초

Handover Ranging Power Adjustment Using Uplink Channel Information in IEEE 802.16e/m

  • Kim, Ji-Su;Kim, Jae-Hyun
    • ETRI Journal
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    • 제32권5호
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    • pp.823-826
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    • 2010
  • This letter proposes a handover ranging power adjustment scheme to improve handover performance. Incorrect ranging power can degrade handover performance due to the increased handover latency; therefore, the proposed scheme exploits the uplink channel information to adjust the uplink handover ranging power. Simulation results demonstrate that the proposed scheme reduces call outage probability by 33% compared to that of the conventional scheme. It also improves the number of users who satisfy the system requirements for handover interruption time.

A Study on Lawful Interception Architecture for IEEE 802.16e Wireless/Mobile Networks (IEEE 802.16e/WiBro 휴대 인터넷망을 위한 합법적 감청 아키텍처에 관한 연구)

  • Myoung-rak Lee;Dong-hyun Lee;Seung-bin Kim;Hoh Peter In
    • Proceedings of the Korea Information Processing Society Conference
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    • 한국정보처리학회 2008년도 추계학술발표대회
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    • pp.1485-1488
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    • 2008
  • Lawful Interception (LI) 이란 합법적인 형태의 도청을 말하며, 전통적인 Wired tapping 뿐만 아니라, 최근의 복잡해진 인터넷 및 통신환경의 여러 형태의 데이터들에 대한 감청이 포함 될 수 있다. 미국과 유럽 중심으로 개발 된 감청 표준들은 3 세대 통신망 위주의 감청을 위한 표준들이 대부분이며, 802.16e 기술중의 하나인 모바일 WiMax 를 위한 합법적 감청 표준 개발은 진행 중에 있는 실정이다. 특히, Wibro 와 같이 모바일 유닛(MU)이 Radio Access Contro (RAS)와 Access Control Router (ACR)를 자유롭게 이동하는 상황에서 패킷들에 대한 지속적인 추적은 합법적 감청 분야의 중요한 이슈 중의 하나이다. 따라서, 본 논문에서는 국내의 802.16e/WiBro 네트워크 사용자의 증가 및 그에 따른 보안위협 발생의 가능성 증가에 따라 합법적인 감청을 위한 효과적인 아키텍처를 제안하고자 한다. 본 논문에서 제안하는 아키텍처는 802.16e/WiBro 망내의 합법적 감청을 위하여 네트워크상에서의 효과적인 감청 관련 정보 교환을 위한 기본적인 메커니즘을 포함하고 있다.

Performance Evaluation of the VoIP Services of the Cognitive Radio System, Based on DTMC

  • Habiba, Ummy;Islam, Md. Imdadul;Amin, M.R.
    • Journal of Information Processing Systems
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    • 제10권1호
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    • pp.119-131
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    • 2014
  • In recent literature on traffic scheduling, the combination of the two-dimensional discrete-time Markov chain (DTMC) and the Markov modulated Poisson process (MMPP) is used to analyze the capacity of VoIP traffic in the cognitive radio system. The performance of the cognitive radio system solely depends on the accuracy of spectrum sensing techniques, the minimization of false alarms, and the scheduling of traffic channels. In this paper, we only emphasize the scheduling of traffic channels (i.e., traffic handling techniques for the primary user [PU] and the secondary user [SU]). We consider the following three different traffic models: the cross-layer analytical model, M/G/1(m) traffic, and the IEEE 802.16e/m scheduling approach to evaluate the performance of the VoIP services of the cognitive radio system from the context of blocking probability and throughput.

Code Rate 1/2, 2304-b LDPC Decoder for IEEE 802.16e WiMAX (IEEE 802.16e WiMAX용 부호율 1/2, 2304-비트 LDPC 복호기)

  • Kim, Hae-Ju;Shin, Kyung-Wook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제36권4A호
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    • pp.414-422
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    • 2011
  • This paper describes a design of low-density parity-check(LDPC) decoder supporting block length 2,304-bit and code rate 1/2 of IEEE 802.16e mobile WiMAX standard. The designed LDPC decoder employs the min-sum algorithm and partially parallel layered-decoding architecture which processes a sub-matrix of $96{\times}96$ in parallel. By exploiting the properties of the min-sum algorithm, a new memory reduction technique is proposed, which reduces check node memory by 46% compared to conventional method. Functional verification results show that it has average bit-error-rate(BER) of $4.34{\times}10^{-5}$ for AWGN channel with Fb/No=2.1dB. Our LDPC decoder synthesized with a $0.18{\mu}m$ CMOS cell library has 174,181 gates and 52,992 bits memory, and the estimated throughput is about 417 Mbps at 100-MHz@l.8-V.

Fixed-point Implementation for Downlink Traffic Channel of IEEE 802.16e OFDMA TDD System (IEEE 802.16e OFDMA TDD 시스템 하향링크 트래픽 채널의 Fixed-point 구현 방법론)

  • Kim Kyoo-Hyun;Sun Tae-Hyung;Wang Yu-Peng;Chang Kyung-Hi;Park Hyung-Il;Eo Ik-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제31권6A호
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    • pp.593-602
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    • 2006
  • This paper propose to methodology for deciding suitable bit size that minimizes hardware complexity and performance degradation from floating-point design the fixed-point implementation of downlink traffic channel of IEEE 802.16e OFDMA TDD system. One of the major considering issues for implementing fixed-point design is to select Saturation or Quantization properly with the knowledge of signal distribution by pdf or histogram. Also, through trial and error, we should execute exhaustive computer simulation for various bit sizes, hence obtain appropriate bit size while minimizing performance degradation. We carry out computer simulation to decide the optimized bit size of downlink traffic channel under AWGN and ITU-R M.1225 Veh-A channel model.

Improved ErtPS Scheduling Algorithm for AMR Speech Codec with CNG Mode in IEEE 802.16e Systems (IEEE 802.16e 시스템에서의 CNG 모드 AMR 음성 코덱을 위한 개선된 ErtPS 스케줄링 알고리즘)

  • Woo, Hyun-Je;Kim, Joo-Young;Lee, Mee-Jeong
    • The KIPS Transactions:PartC
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    • 제16C권5호
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    • pp.661-668
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    • 2009
  • The Extended real-time Polling Service (ErtPS) is proposed tosupport QoS of VoIP service with silence suppression which generates variable size data packets in IEEE 802.16e systems. If the silence is suppressed, VoIP should support Comfort Noise Generation (CNG) which generates comfort noise for receiver's auditory sense to notify the status of connection to the user. CNG mode in silent-period generates a data with lower bit rate at long packet transmission intervals in comparison with talk-spurt. Therefore, if the ErtPS, which is designed to support service flows that generate data packets on a periodic basis, is applied to silent-period, resources of the uplink are used inefficiently. In this paper, we proposed the Improved ErtPS algorithm for efficient resource utilization of the silent-period in VoIP traffic supporting CNG. In the proposed algorithm, the base station allocates bandwidth depending on the status of voice at the appropriate interval by havingthe user inform the changes of voice status. The Improved ErtPS utilizes the Cannel Quality Information Channel (CQICH) which is an uplink subchannel for delivering quality information of channel to the base station on a periodic basis in 802.16e systems. We evaluated the performance of proposed algorithm using OPNET simulator. We validated that proposed algorithm improves the bandwidth utilization of the uplink and packet transmission latency

Design and Analysis of Transmission Parameters for DH(Dog-Horse) Systems Based on IEEE802.16e (WiBro) (견마로봇 시스템의 상향링크 고속신호 전송을 위한 시스템 WiBro(IEEE802.16e) 통신변수 설계 및 분석)

  • Lee, Il-Shin;Yoo, Jae-Ho;Lee, Yoon-Ju;Kwon, Dong-Seung;Chung, Jae-Hak
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • 제45권6호
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    • pp.1-9
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    • 2008
  • This paper presents transmission parameters of DH(Dog-Horse) systems based on IEEE802.16e(WiBro) systems. DH requires higher uplink multimedia data rate, which is different from commercial WiBro systems. This paper designes some transmission parameters satisfying the DH system requirements and demonstrates link performance evaluation based on the parameters. For the transmission parameters, the number dwon/up link OFDM symbols are determined by 6/30, respectively. For reliable transmission of control signals, downlink modulation and coding rate are selected by QPSK, 1/2 coding rate and that of uplink is chosen by 16QAM 1/2 and 3/4 coding rate. Based on these parameters, computer simulations demonstrate the system performance of DH system.

A 2.3-2.7 GHz Dual-Mode RF Receiver for WLAN and Mobile WiMAX Applications in $0.13{\mu}m$ CMOS (WLAN 및 Mobile WiMAX를 위한 2.3-2.7 GHz 대역 이중모드 CMOS RF 수신기)

  • Lee, Seong-Ku;Kim, Jong-Sik;Kim, Young-Cho;Shin, Hyun-Chol
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • 제47권3호
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    • pp.51-57
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    • 2010
  • A dual-mode direct conversion receiver is developed in $0.13\;{\mu}m$ RF CMOS process for IEEE 802.11n based wireless LAN and IEEE 802.16e based mobile WiMAX application. The RF receiver covers the frequency band between 2.3 and 2.7 GHz. Three-step gain control is realized in LNA by using current steering technique. Current bleeding technique is applied to the down-conversion mixer in order to lower the flicker noise. A frequency divide-by-2 circuit is included in the receiver for LO I/Q differential signal generation. The receiver consumes 56 mA at 1.4 V supply voltage including all LO buffers. Measured results show a power gain of 32 dB, a noise figure of 4.8 dB, a output $P_{1dB}$ of +6 dBm over the entire band.

M/G/1 복수 휴가 모델을 이용한 IEEE 802.16e 무선 MAN 수면모드 작동에 대한 성능분석

  • Jeong, Seong-Hwan;Hong, Jeong-Wan;Jang, U-Jin;Lee, Chang-Hun
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 한국경영과학회 2007년도 추계학술대회 및 정기총회
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    • pp.195-203
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    • 2007
  • In this paper, an analytic model of sleep model operation in the IEEE 802.16e is investigated. A mobile subscribe. station (MSS) goes to sleep mode after negotiations with the base station (BS) and wakes up periodically for a short interval to check whether there is downlink traffic to it. If the arrival of traffic is notified, an MSS returns to wake mode. Otherwise, it again enters increased sleep interval which is double as the previous one. In order to consider the situation more practically, we propose the sleep mode starting threshold, during which MSS should await packets before it enters the sleep mode. By modifying the M/G/1 with multiple vacations model, energy consumption ratio(ECR) and average packet response time are calculated. Our analytic model provides potential guidance in determining the optimal parameters values such as sleep mode starting threshold, minimal sleep and maximal sleep window.

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A Design of Multi-Standard LDPC Decoder for WiMAX/WLAN (WiMAX/WLAN용 다중표준 LDPC 복호기 설계)

  • Seo, Jin-Ho;Park, Hae-Won;Shin, Kyung-Wook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • 제17권2호
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    • pp.363-371
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    • 2013
  • This paper describes a multi-standard LDPC decoder which supports 19 block lengths(576~2304) and 6 code rates(1/2, 2/3A, 2/3B, 3/4A, 3/4B, 5/6) of IEEE 802.16e mobile WiMAX standard and 3 block lengths(648, 1296, 1944) and 4 code rates(1/2, 2/3, 3/4, 5/6) of IEEE 802.11n WLAN standard. To minimize hardware complexity, it adopts a block-serial (partially parallel) architecture based on the layered decoding scheme. A DFU(decoding function unit) based on sign-magnitude arithmetic is used for hardware reduction. The designed LDPC decoder is verified by FPGA implementation, and synthesized with a 0.13-${\mu}m$ CMOS cell library. It has 312,000 gates and 70,000 bits RAM. The estimated throughput is about 79~210 Mbps at 100 MHz@1.8v.