• Title/Summary/Keyword: Side information transmission scheme

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Side Information Transmission Using Pilot Tones for PAPR Reduction of OFDM Signal

  • Wang, Lei;Yoon, Dong-Weon;Park, Sang-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.4A
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    • pp.467-472
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    • 2008
  • One of the maindisadvantages of Orthogonal Frequency Division Multiplexing (OFDM) is the Peak to Average Power Ratio (PAPR) problem. To reduce PAPR and improve the error performance of the OFDM signal over a fading channel, an OFDM system combining an Adaptive Symbol Selection Scheme (ASSS) and channel estimation can be used. Because of the side information of ASSS, however, the data rate decreases in the conventional ASSS OFDM system. In this letter, to overcome this impairment, we propose a technique to transmit side information by using pilot tones, and demonstrate that the proposed technique can give reasonable bit error rate (BER) performance.

A study of error correction scheme using RTP for real-time transmission (Realtime 전송을 위해 RTP를 사용한 Error Correction Scheme 연구)

  • 박덕근;박원배
    • Proceedings of the IEEK Conference
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    • 2000.06a
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    • pp.9-12
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    • 2000
  • A forward error correction (FEC) is usually used to correct the errors of the real-time data occurred at the reciever side which require a real-time transmission. The data transmission is peformed after being encapsulating by RTP and UDP. In the ITU-T study group 16, four FEC schemes using the XORing are presented. In the paper, a new supplementary scheme is proposed. In the delay problem the new scheme performs better than the scheme 3 but in the recovery ability for successive packet loss is worse than scheme 3. The proposed scheme which supplements the present schemes can be adapted easily to the current network environment.

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Side Information Transmission using Reference Symbol in PTS Scheme (PTS 방식에서 기준 심볼을 이용한 부가정보 전송)

  • 유흥균;박종현;박진수
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.4
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    • pp.414-420
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    • 2004
  • Partial transmit sequence(PTS) scheme has been widely studied to reduce the peak-to-average power ratio(PAPR) of Orthogonal frequency-division multiplexing(OFDM) signal since it is flexible ad any spectral regrowth is not made. A necessity of the PTS scheme is to transmit the side information about the phase rotation factors for correct OFDM symbol recovery. In this paper, a new side information embedded PTS scheme using the reference symbols is proposed fur the PAPR reduction and the BER(bit error rate) performance is analyzed when the erroneous side information is received. In this proposed method, the information about the rotation factors is expressed by the phase of reference symbols. The proposed method maintains the same PAPR reduction performance as the conventional PTS scheme and OFDM symbols are correctly recovered by the side information to meet the required BER level, which is verified via the computer simulation. Also, it is shown that the proposed method can be easily realized and can be used for all kinds of digital modulation formats in the OFDM communication system.

A low-complexity PAPR reduction SLM scheme for STBC MIMO-OFDM systems based on constellation extension

  • Li, Guang;Li, Tianyun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.6
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    • pp.2908-2924
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    • 2019
  • Multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) is widely applied in wireless communication by virtue of its excellent properties in data transmission rate and transmission accuracy. However, as a major drawback of MIMO-OFDM systems, the high peak-to-average power ratio (PAPR) complicates the design of the power amplifier at the receiver end. Some available PAPR reduction methods such as selective mapping (SLM) suffer from high computational complexity. In this paper, a low-complexity SLM method based on active constellation extension (ACE) and joint space-time selective mapping (AST-SLM) for reducing PAPR in Alamouti STBC MIMO-OFDM systems is proposed. In SLM scheme, two IFFT operations are required for obtaining each transmission sequence pair, and the selected phase vector is transmitted as side information(SI). However, in the proposed AST-SLM method, only a few IFFT operations are required for generating all the transmission sequence pairs. The complexity of AST-SLM is at least 86% less than SLM. In addition, the SI needed in AST-SLM is at least 92.1% less than SLM by using the presented blind detection scheme to estimate SI. We show, analytically and with simulations, that AST-SLM can achieve significant performance of PAPR reduction and close performance of bit error rate (BER) compared to SLM scheme.

An Experimental Implementation of a Cross-Layer Approach for Improving TCP Performance over Cognitive Radio Networks

  • Byun, Sang-Seon
    • Journal of Information Processing Systems
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    • v.12 no.1
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    • pp.73-82
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    • 2016
  • In cognitive radio networks (CRNs), the performance of the transmission control protocol (TCP) at the secondary user (SU) severely drops due to the mistrigger of congestion control. A long disruption is caused by the transmission of primary user, leading to the mistrigger. In this paper, we propose a cross-layer approach, called a CR-aware scheme that enhances TCP performance at the SU. The scheme is a sender side addition to the standard TCP (i.e., TCP-NewReno), and utilizes an explicit cross-layer signal delivered from a physical (or link) layer and the signal gives an indication of detecting the primary transmission (i.e., transmission of the primary user). We evaluated our scheme by implementing it onto a software radio platform, the Universal Software Radio Peripheral (USRP), where many parts of lower layer operations (i.e., operations in a link or physical layer) run as user processes. In our implementation, we ran our CR-aware scheme over IEEE 802.15.4. Furthermore, for the purpose of comparison, we implemented a selective ACK-based local recovery scheme that helps TCP isolate congestive loss from a random loss in a wireless section.

Additional Data Transmission Technique Based on SSB-OFDM Visible Light Communication System (SSB-OFDM 가시광 통신 기반 부가정보 전송기법)

  • Lee, Jung-Hoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38C no.8
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    • pp.713-718
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    • 2013
  • In this paper, additional data transmission scheme was proposed based on SSB-OFDM Communication system which was know as efficient technique for bandwidth, because it used only single side band instead of double side band. When sending additional data which should be well spreaded for low power characteristics and error robustness. Gold code was selected for spreading code because it has excellent low-cross correlation characteristics. Through computer simulation, the validity was proved that proposed system is well worked with SSB-OFDM system.

Control Signal Transmission Scheme Using OFDM PTS Embedded Side Information in Cognitive Radio System (무선 인지 시스템에서 OFDM PTS 임베디드 부가정보를 이용한 제어신호 전송 기법)

  • Jeong, Bong-Min;Sohn, Sung-Hwan;Jang, Sung-Jeen;Kim, Jae-Moung
    • Journal of Internet Computing and Services
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    • v.12 no.2
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    • pp.75-83
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    • 2011
  • Wireless services and devices that use frequency increase more and more because of advancement of the industry. Therefore, the available spectrum band becomes increasingly insufficient. Cognitive Radio, which adaptively utilizes the vacant licensed spectrum band, is considered as an effective way to utilize the spectrum resource shortage. CR user should move from current allocated channel to vacant channel to avoid the interference to the primary user when the primary user appears in the current channel. In this case, CR system undergoes the break off time until handshake is completed. So, in order to guarantee the Quality of Service(QoS) of CR system, fast handshake method is required. In this paper, we propose the embedded control signal transmission technique to reduce the break off time. This method can transmit the control signals in data transmission period as well as the broadcasting period. Proposed method can improve the data throughput and decrease the break off time. Computer based simulation proves that our proposed scheme outperforms conventional one.

A Sender-oriented Automatic Rate Adaptation Scheme in IEEE 802.11 WLANs (IEEE 802.11 WLAN에서 송신단 기반 전송률 적응기법)

  • Lee, Sun-Hun;Chung, Kwang-Sue
    • Journal of KIISE:Information Networking
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    • v.36 no.2
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    • pp.143-152
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    • 2009
  • IEEE 802.11 WLANs provide multiple transmission rates to improve the system throughput by adapting the transmission rate to the current wireless channel conditions. Many rate adaptation schemes have been proposed because IEEE 802.11 standard does not contain any specifications for the rate adaptation scheme. In this paper, in order to overcome limitations of the previous research, we propose a new rate adaptation scheme called SARA(Sender-oriented Automatic Rate Adaptation). The SARA scheme, a proposed rate adaptation scheme, appropriately adjusts the data transmission rate based on the estimated wireless channel conditions, specifically the measured RSSI at the sender-side. Moreover it continuously updates the thresholds for selecting the transmission rate and selectively enforces the RTS/CTS exchanges to adapt the changes in the wireless channel conditions. Through the performance evaluations, we prove that the SARA scheme overcomes the limitations of the previous research and improves the wireless link utilization.

Certificate Revocation Scheme using MOT Protocol over T-DMB Infrastructure

  • Kim, Hyun-Gon;Kim, Min-Soo;Jung, Seok-Won;Seo, Jae-Hyun
    • Journal of Korea Multimedia Society
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    • v.14 no.12
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    • pp.1583-1590
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    • 2011
  • A Certificate Revocation List(CRL) should be distributed quickly to all the vehicles for vehicular communications to protect them from malicious users and malfunctioning equipment as well as to increase the overall security and safety of vehicular networks. Thus, a major challenge in vehicular networks is how to efficiently distribute CRLs. This paper proposes a Multimedia Object Transfer(MOT) protocol based on CRL distribution scheme over T-DMB infrastructure. To complete the proposed scheme, a handoff method, CRL encoding rules based on the MOT protocol, and relative comparison are presented. The scheme can broaden breadth of network coverage and can get real-time delivery with enhanced transmission reliability. Even if road side units are sparsely deployed or, even not deployed, vehicles can obtain recent CRLs from T-DMB infrastructure effectively.