• Title, Summary, Keyword: co-channel interference

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Analysis on Co-channel Interference of Human Body Communication Supporting IEEE 802.15.6 BAN Standard

  • Hwang, Jung-Hwan;Kang, Tae-Wook;Kim, Youn-Tae;Park, Seong-Ook
    • ETRI Journal
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    • v.37 no.3
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    • pp.439-449
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    • 2015
  • Human body communication (HBC) is being recognized as a new communication technology for mobile and wearable devices in a body area network (BAN). This paper presents co-channel interference experienced by HBC supporting the physical layer in the IEEE 802.15.6 BAN standard. To analyze the co-channel interference, a co-channel interference model is introduced, and space-domain and time-domain parameters representing an interference environment are generated using the co-channel interference model. A new signal-to-interference ratio (SIR) parameter depending on the peak amplitudes of the data signals causing co-channel interference is defined; co-channel interference can be easily analyzed and modelled using the newly defined SIR. The BER degradation model derived using the co-channel interference model and SIR in this paper can be effectively used to estimate the performance.

ML Frame Synchronization for Gaussian Channel with Co-channel Interference (가우스 잡음과 CO-CHANNEL 간섭이 존재하는 채널에서의 최대추정 프레임 동기)

  • 문병현;우홍체;김신환;이채욱
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.5
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    • pp.643-649
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    • 1993
  • The problem of locating a periodically inserted frame synchronization pattern in random data for a binary pulse amplitude modulated (PAM) digital communication system over a additive white Gaussian noise(AWGN) channel with co-channel interference is considered. The performance degradation of frame synchronization for the correlation rule due to the presence of co-channel interference is shown. The maximum likelihood(ML) decision rule for the frame synchronization over an AWGN channel with co-channel interference is derived. For the entire range of SNR considered, the ML frame synchronization rule obtains about 1dB signal energy gain over the correlation rule. Specially, the ML rule obtains as much as 2dB gain over the correlation rule when the SNR is greater than 0dB.

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Interference Avoidance through Pilot-Based Spectrum Sensing Algorithm in Overlaid Femtocell Networks

  • Sambanthan, Padmapriya;Muthu, Tamilarasi
    • ETRI Journal
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    • v.38 no.1
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    • pp.30-40
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    • 2016
  • Co-channel interference between macro-femtocell networks is an unresolved problem, due to the frequency reuse phenomenon. To mitigate such interference, a secondary femtocell must acquire channel-state knowledge about a co-channel macrocell user and accordingly condition the maximum transmit power of femtocell user. This paper proposes a pilot-based spectrum sensing (PSS) algorithm for overlaid femtocell networks to sense the presence of a macrocell user over a channel of interest. The PSS algorithm senses the pilot tones in the received signal through the power level and the correlation metric comparisons between the received signal and the local reference pilots. On ensuring the existence of a co-channel macrocell user, the maximum transmit power of the corresponding femtocell user is optimized so as to avoid interference. Time and frequency offsets are carefully handled in our proposal. Simulation results show that the PSS algorithm outperforms existing sensing techniques, even at poor received signal quality. It requires less sensing time and provides better detection probability over existing techniques.

Performance Improvement of Alamouti coded OFDM System under Co-Channel Interference (Co-Channel Interference 환경에서 Alamouti coded OFDM System의 성능개선)

  • Lee, Sung-Geun;Oh, Tae-Won
    • Proceedings of the KIEE Conference
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    • pp.390-391
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    • 2008
  • 대용량의 이동 고속통신 환경 하 에서 다중경로 페이딩에 의한 성능열화 영향을 효과적으로 줄이고, 용량을 극대화하기 위해 MIMO(Multi-Input Multi-Output) 와 OFDM (Orthogonal Frequency Division Multiplexing) 기술들이 차세대 이동통신시스템으로 최근에 각광을 받고 있다. 그러나 cellular 시스템에서는 Co-Channel Interference의 영향을 피할 수도 없으며, 그 영향 또한 그 무엇보다도 크다. 그러므로 본 논문에서는 이러한 MIMO OFDM 시스템의 Co-Channel Interference 의 영향을 줄이고 성능 향상을 위해 Interference Cancelling 기법을 응용한 STBC-OFDM 시스템의 성능을 MATLAB simulation을 통해 기술하였다.

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Degrees of Freedom of Multi-Cell MIMO Interference Broadcast Channels With Distributed Base Stations

  • Huang, Hongbing;Liu, Junyi;Zhang, Yi;Cai, Qing;Zhang, Bowei;Jiang, Fengwen
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.2
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    • pp.635-656
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    • 2019
  • In this paper, we investigate the degrees of freedom (DoF) of a multi-cell multi-user multiple-input multiple-output (MIMO) interference broadcast channel (IBC) with non-cooperation distributed base stations (BS), where each BS serves users of its corresponding cell. When all BSs simultaneously transmit their own signals over the same frequency band in the MIMO IBC, the edge users in each cell will suffer the inter-cell interference (ICI) and inter-user interference (IUI) signals. In order to eliminate the ICI and IUI signals, a distributed space time interference alignment (DSTIA) approach is proposed where each BS has only limited access to distributed moderately-delay channel state information at the transmitter (CSIT). It is shown that the DSTIA scheme can obtain the appreciate DoF gains. In addition, the DoF upper bound is asymptotically achievable as the number of antenna at each BS increases. It is shown that the DSTIA method can get DoF gains over other interference alignment schemes with delayed CSIT in literature. Moreover, the DSTIA method can attain higher DoFs than the IA schemes with global CSIT for certain antenna configurations.

Lattice Code of Interference Alignment for Interference Channel with 3 Users in CoMP (세 명의 사용자의 간섭 채널을 위한 협력 다중점 송수신(CoMP)에서의 격자(Lattice) 부호 간섭 정렬)

  • Lee, Moon-Ho;Peng, Bu Shi
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.6
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    • pp.27-38
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    • 2012
  • In this paper, we introduce CoMP in 3GPP LTE-Advanced Release 11 to take care of shadowing effects appearing in cell-edge areas to meet rapidly increasing demand for high speed transmission and multi-media data. In order to mitigate interference, orthogonalizing is ideal but it is slightly difficult to be applied to real systems. Therefore, interference alignment and avoidance are used in practical applications. Interference alignment is a scheme enabling us to consider interference our friend not enemy. We show lattice codes in Gaussian channel achieve Shannon capacity where strong interference exists. In addition, we show the relationship between channel parameter a and DoF(Degree of Freedom) applying lattice codes to interference alignment for interference channel with three users.

Cooperative Interference Mitigation Using Fractional Frequency Reuse and Intercell Spatial Demultiplexing

  • Chang, Jae-Won;Heo, Jun;Sung, Won-Jin
    • Journal of Communications and Networks
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    • v.10 no.2
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    • pp.127-136
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    • 2008
  • For mobile wireless systems with full frequency reuse, co-channel interference near the cell coverage boundaries has a significant impact on the signal reception performance. This paper addresses an approach to efficiently mitigate the effect of downlink co-channel interference when multi-antenna terminals are used in cellular environments, by proposing a signal detection strategy combined with a system-level coordination for dynamic frequency reuse. We demonstrate the utilization of multi-antennas to perform spatial demultiplexing of both the desired signal and interfering signals from adjacent cells results in significant improvement of spectral efficiency compared to the maximal ratio combining (MRC) performance, especially when an appropriate frequency reuse based on the traffic loading condition is coordinated among cells. Both analytic expressions for the capacity and experimental results using the adaptive modulation and coding (AMC) are used to confirm the performance gain. The robustness of the proposed scheme against varying operational conditions such as the channel estimation error and shadowing effects are also verified by simulation results.

On the Bit Error Probabilities of GMSK in the Rayleigh Fading Channels (Rayleigh 페이팅 채널에서 GMSK의 비트 에러 발생 확률)

  • 정영모;이상욱;김재명
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.5
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    • pp.473-481
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    • 1988
  • In this paper, we investigated bit error probabilities of GMSK, which is known to be one of promising modulation techniques for a digital mobile radio, under various mobile radio environments.: AWGN, slow Rayleigh fading channel, co-channel interference and adjacent channel interference. We employed an MSK-type receiver for a coherent detection and assumed degrading to both signals than adjacent channel interference. Especially, it is found that GMSK suffers more degradations than MSK from the co-channel interference. But with a high power adjacent channel interference, GMSK shows less bit error rate than MSK. The results confirm a higher spectrum efficiency of GMSK.

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Co-Channel Interference Cancellation in Cellular OFDM Networks - PART I : Maximum-Likelihood Co-Channel Interference Cancellation with Power Control for Cellular OFDM Networks

  • Mohaisen, Manar;Chang, Kyung-Hi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.5A
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    • pp.409-416
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    • 2007
  • In cellular orthogonal frequency division multiplexing (OFDM) networks, co-channel interference (CCI) leads to severe degradation in the BER performance. To solve this problem, maximum-likelihood estimation (MLE) CCI cancellation scheme has been proposed in the literature. MLE CCI cancellation scheme generates weighted replicas of the transmitted signals where weights represent the estimated channel transfer functions. The replica with the smallest Euclidean distance from the received signal is selected and data are detected. When the received power of the desired and interference signals are nearly the same, the BER performance is degraded. In this paper, we propose a closed-loop power control (PC) scheme capable of detecting the equal received power situation at the mobile station (MS) receiver by using the newly introduced parameter power ratio (PR). When this situation is detected, the MS sends a feedback to the desired base station (BS) which boosts the transmission power in the next frame. At cell edge where signal to interferer ratio (SIR) is considered to have average value between -5 dB and 10 dB, computer simulations show that the proposed CCI cancellation scheme has a gain of 7 dB at 28 Km/h.

Co-Channel Interference Mitigation and System Throughput Maximization Using Hybrid Joint Reuse Partitioning in Multimedia Mobile Communications (멀티미디어 이동 통신에서 Hybrid Joint 주파수 재사용 구간을 이용한 동일 채널 간섭 억제 및 시스템 전송량 최대화 방법)

  • Kim, Jeong-Su
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.5
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    • pp.465-470
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    • 2007
  • The co-channel interference is a primary factor of loss in multimedia mobile communications. In this paper, we present a performance of the frequency reuse partitioning to refrain the co-channel interference and maximize system performance. First, we analyze the co-channel interference using the frequency reuse partitioning through the statistical modeling. From this results, we decide on the frequency reuse partitioning for the system throughput which is maximized. Finally, analysis and simulation results show that the frequency reuse partitioning based cellular system can mitigate the co-channel interference and maximize the system throughput. The experimental results show that system throughput is maximized from 0.7 to 0.8 according to traffic road. We can maximize the system throughput using the results with cellular system design parameter.