• Title/Summary/Keyword: UWB Channel Model

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Capacity Analysis of M-ary PPM UWB System In Optical Fiber over AWGN (AWGN Optical Fiber에서 M-ary PPM UWB 시스템의 채널용량 분석)

  • Im, Joon-Soon;Shin, Myung-Gon;Kim, Tae-Woong;Park, Seung-Kwon
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.201-204
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    • 2005
  • In this paper, based on an extended model containing correlator and soft decision decoding, the capacity is evaluated in the single-user case when the inputs are equiprobable. With this method, we adjusted optical communication over AWGN. It is found that only when bit- signal-to-noise ratio (bit-SNR) is high enough, larger M leads to higher capacity; and for a specific M, the optimal values of PPM time offset parameter Td, which maximize the capacity, are independent of bit-SNR. In this paper, the capacity of UWB system in optical fiber over AWGN is proven to improve 1.73 times larger than AWGN channel Capacity.

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Distribution of Path Loss for Wireless Personal Networks Operating in a Square Region

  • Yang, Rumin;Shen, Bin;Kwak, Kyung-Sup
    • ETRI Journal
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    • v.33 no.2
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    • pp.283-286
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    • 2011
  • Path loss plays fundamental roles in system design, spectrum management, and performance evaluation. The traditional path loss model has a slight inconvenience; it depends on the unknown distance. In this letter, we explore the probability distribution function (PDF) of path loss in an indoor office environment by randomizing out the distance variable. It is shown that the resulting PDF is not Gaussian-like but is skewed to the right, and both the PDF and the moments are related to the size of the office instead of the unknown distance. To be specific, we incorporate the IEEE 802.15.4a channel parameters into our model and tabulate the cumulative distribution function with respect to different room sizes. Through a simple example, we show how our model helps a cognitive spectrum user to infer path loss information of primary users without necessarily knowing their transmitter-receiver distance.

Performance of Tactics Mobile Communication System Based on UWB with Double Binary Turbo Code in Multi-User Interference Environments (다중 사용자 간섭이 존재하는 환경에서 이중이진 터보부호를 이용한 UWB 기반의 전술이동통신시스템 성능)

  • Kim, Eun-Cheol;Seo, Sung-Il;Kim, Jin-Young
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.1
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    • pp.39-50
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    • 2010
  • In this paper, we analyze and simulate the performance of a tactics mobile communication system based on ultra wide band (UWB) in multi-user interference (MUI) environments. This system adopts a double binary turbo code for forward error correction (FEC). Wireless channel is modeled a modified Saleh and Valenzuela (SV) model. We employ a space time block coding (STBC) scheme for enhancing system performance. System performance is evaluated in terms of bit error probability. From the simulation results, it is confirmed that the tactics mobile communication system based on UWB, which is encoded with the double binary turbo code, can achieve a remarkable coding gain with reasonable encoding and decoding complexity in multi-user interference environments. It is also known that the bit error probability performance of the tactics mobile communication system based on UWB can be substantially improved by increasing the number of iterations in the decoding process for a fixed cod rate. Besides, we can demonstrate that the double binary turbo coding scheme is very effective for increasing the number of simultaneous users for a given bit error probability requirement.

Link Adaptation Method of the Block Coded Modulation for UWB-IR (무선광대역통신을 위한 블록부호화방식의 링크 적응 기법)

  • Min, Seungwook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.7
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    • pp.24-35
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    • 2018
  • In wireless communications environments, a link adaptation technique that selects the proper rate from among several transmission rates is adopted to cope with variations in channel status. In block coded modulation, the frame time and/or the block length can be adjusted to the channel status. A smaller frame time can cause inter-frame interference (IFI), however, a larger frame time can reduce the data rate. Therefore, frame time is the design factor decided by a tradeoff between performance and the data rate. This paper presents a method to determine the frame time based on the processing gain for the channel model, CM1~CM4, recommended by IEEE 802.15a. Also, a link adaptation technique for block coded modulation is proposed for efficient communications by varying the frame time and the block length. Through simulation, link adaptation can be carried out with a step size of 2~5 nsec in a frame time range of 14~ 50 nsec for channel models CM1~CM4.

Two Techniques of Angle-of-Arrival Estimation for Low-Data-Rate UWB Wireless Positioning (저속 초광대역 방식의 무선 측위에 알맞은 신호 도착 방향 추정 기법 두 가지)

  • Lee, Yong-Up;Lim, Kyeong-Sun;Park, Joo-Hyeon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.3A
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    • pp.163-171
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    • 2012
  • The signal model and weighted-average based estimation techniques are proposed to estimate the angle-of-arrival (AOA) parameters of multiple clusters for a low data rate ultrawide band (LR-UWB) based wireless positioning system. It is observed that the weighted-average based AOA estimation technique gives an optimal AOA estimate under few clusters condition, and the average based AOA estimation technique gives a correct AOA estimate under many clusters condition through computer simulation. Also, we can observe that the variance estimation error decreases as SNR increases, and the proposed techniques are superior to the conventional technique from the viewpoint of performance.

A Threshold Estimation Algorithm for a Noncoherent IR-UWB Receiver Using 1-bit Sampler (1-bit 샘플러를 사용한 비동기식 IR-UWB 수신기의 임계값 추정 알고리즘)

  • Lee, Soon-Woo;Park, Young-Jin;Kim, Kwan-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.8
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    • pp.17-22
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    • 2007
  • In this paper, we propose a threshold estimation algorithm for a noncoherent IR-UWB receiver using 1-bit sampler. The proposed method reduces the hardware complexity by using the information of binary data resulted from 1-bit sampler instead of measuring the energy level of a received signal. Besides, mathematical modeling shows that the performances are similar to those of theoretically optimal threshold in terms of bit error rate. Computer simulations based on the IEEE 802.15.4a channel model also demonstrate the superiority of the proposed algorithm.

A Study on the TH UWB-IR Medical Image Transmission System using the IEEE 802.15.4a (IEEE 802.15.4a를 활용한 TH UWB-IR 의료영상 전송 시스템에 관한 연구)

  • Lee, Yang-Sun;Kang, Heau-Jo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.11
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    • pp.1954-1959
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    • 2006
  • In this paper, we proposed TH UWB-IR medical image transmission system using the IEEE an. 802.15.4a specification in WPAN environment. Also, we analyzed reception performance of wireless medical image transmission system in indoor multi-path fading environment using ITU-R M.1225 channel model. As a results, the proposed scheme can solve the problem of interference from the medical equipment in same frequency band, and minimize the loss due to the indoor multi-path fading environment. Therefore, the transmission with low power usage is possible.

Performance Analysis of Noncoherent OOK UWB Transceiver for LR-WPAN (저속 WPAN용 비동기 OOK 방식 UWB 송수신기 성능 분석)

  • Ki Myoungoh;Choi Sungsoo;Oh Hui-Myoung;Kim Kwan-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.11A
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    • pp.1027-1034
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    • 2005
  • IEEE802.15.4a, which is started to realize the PHY layer including high precision ranging/positioning and low data rate communication functions, requires a simple and low power consumable transceiver architecture. To satisfy this requirements, the simple noncoherent on-off keying (OOK) UWB transceiver with the parallel energy window banks (PEWB) giving high precision signal processing interface is proposed. The flexibility of the proposed system in multipath fading channel environments is acquired with the pulse and bit repetition method. To analyze the bit error rate (BER) performance of this proposed system, a noise model in receiver is derived with commonly used random variable distribution, chi-square. BER of $10^{-5}$ under the line-of-sight (LOS) residential channel is achieved with the integration time of 32 ns and signal to noise ratio (SNR) of 15.3 dB. For the non-line-of-sight (NLOS) outdoor channel, the integration time of 72 ns and SNR of 16.2 dB are needed. The integrated energy to total received energy (IRR) for the best BER performance is about $86\%$.

Advanced Synchronization Scheme in the LR-UWB System (LR-UWB 시스템에서 개선된 동기 기법)

  • Kwon, Soon-Koo;Kim, Jae-Seok
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.7B
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    • pp.892-896
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    • 2011
  • This paper proposes a two-stage synchronization scheme using a serial search non-coherent correlator appropriate for the IEEE 802.15.4a system. The proposed method improved the synchronization performance by using multi-pulse signals unlike the conventional method using single-pulse signals. It also compensated for the degradation of performance at low SNR resulting from the use of fixed threshold by applying the adaptive threshold technique. The proposed method showed a detection probability that is higher by approximately 0.2-0.3 compared with the conventional method in the IEEE 802.15.4a channel model.

A Study on UWB Ranging and Positioning Technique using Common Clock (공통 클럭을 이용한 UWB 거리 인지 및 무선 측위 기술 연구)

  • Park, Jae-Wook;Choi, Yong-Sung;Lee, Soon-Woo;Lee, Won-Cheol
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.12A
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    • pp.1128-1135
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    • 2010
  • A wireless positioning system using ultra-wideband (UWB) for indoor wireless positioning uses ranging data in order to accurately estimate location. Commonly, ranging uses time of arrival (TOA), time difference of arrival (TDOA) based on arrival time. The most fundamental issue in the ranging for wireless positioning is to obtain clock synchronization among the sensor nodes and to correct an error caused by the relative clock offset from each node. In this paper, we propose ranging and positioning technique using common clock in order to solve both clock synchronization and clock offset problems. To verify the performance of proposed, we simulated ranging and positioning in channel model introduced by IEEE 802.15.4a Task Group and then results show that location estimation is unaffected by clock offset.