• Title, Summary, Keyword: Inter-channel Interference

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Channel Capacity for NOMA Weak Channel User and Capacity Region for NOMA with Gaussian Mixture Interference

  • Chung, Kyuhyuk
    • Journal of IKEEE
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    • v.23 no.1
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    • pp.302-305
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    • 2019
  • Non-orthogonal multiple access (NOMA) has been considered for the fifth generation (5G) mobile networks to provide high system capacity and low latency. We calculate the channel capacity for the weak channel user in NOMA and the channel capacity region for NOMA. In this paper, Gaussian mixture channel is compared to the additive white Gaussian noise (AWGN) channel. Gaussian mixture channel is modeled when we assume the practical signal modulation for the inter user interference, such as the binary phase shift keying (BPSK) modulation. It is shown that the channel capacity with BPSK inter user interference is better than that with Gaussian inter user interference. We also show that the channel capacity region with BPSK inter user interference is larger than that with Gaussian inter user interference. As a result, NOMA could perform better in the practical environments.

Inter-cell DCA Algorithm for Downlink Wireless Communication Systems (하향링크 무선 통신 시스템에서의 Inter-cell DCA 알고리즘)

  • Kim, Hyo-Su;Kim, Dong-Hoi;Park, Seung-Young
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.7A
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    • pp.693-701
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    • 2008
  • In OFDMA (Orthogonal Frequency Division Multiple Access) system that frequency reuse factor is 1, as the same channels in the neighborhood cells creates inter-cell co-channel interference which provides a resource underutilization problem, channel allocation schemes to minimize inter-cell interference have been studied. This paper proposes a new CNIR (Carrier to Noise and Interference Ratio)-based distributed Inter-cell DCA (Dynamic Channel Allocation) algorithm in the OFDMA environment with frequency reuse factor of 1. When a channel allocation is requested, if there is not a free channel in home cell or the available free channels in home cell do not satisfy a required threshold value, the proposed Inter-cell DCA algorithm finds CNIR values of available free channels in the neighborhood cells and then allocates a free channel with maximum CNIR value. Through the simulation results, we find that the proposed scheme decreases both new call block rate and forced termination rate due to new call generation at the same time because it increases channel allocation probability.

Dynamic Channel Allocation Considering the Interference Range in Multi-cell Downlink Systems (다중 셀 하향링크 시스템에서 간섭 영역을 고려한 동적 채널 할당)

  • Lee, Neung-Hyung;Bahk, Sae-Woong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.2A
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    • pp.179-187
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    • 2007
  • As wireless networks evolve to orthogonal frequency division multiple access(OFDMA) systems, inter-cell interference control becomes a critical issue in radio resource management. The allocation of the same channels in neighbor cells cause inter-cell interference, so the channel allocation needs to be taken carefully to lower the inter-cell interference. In distributed channel allocation, each cell independently tries to allocate channels that suffer low interference level. In this paper, under the assumption of static users, we introduce the concept of interference range and use it in designing our two algorithms; basic and combined. The basic algorithm performs interference range detection and determines whether to use the considered channel, while the combined algorithm checks the channel quality in addition to detecting the interference range. The two algorithms dynamically perform channel allocation with low complexity and show good throughput and fairness performance.

Interference Alignment Based Transceiver Design in OSG mode of HetNets

  • Niu, Qin;Zeng, Zhimin;Zhang, Tiankui;Hu, Zhirui
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.6
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    • pp.2014-2034
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    • 2015
  • This paper focuses on solving co-channel interference (CCI) issues arising in the open subscriber group (OSG) mode of heterogeneous networks (HetNets). Considering a general framework consisting of arbitrary number of picocells within a macro cell, where the inter-user interference (IUI) is the main CCI to macro user equipments (UEs), while the the inter-cell interference (ICI) is the major CCI to pico UEs. In this paper, three IA based transceiver design schemes are proposed. For macro cell, we uniformly use block diagonalization (BD) scheme to eliminate the IUI. And for picocells, three IA schemes are proposed to mitigate the ICI. The first scheme, named as zero forcing IA (ZF-IA) scheme, aligns the inter picocell interference onto an arbitrary sub-space of the cross-tier interference using ZF scheme. Considering the channel state information (CSI) of the desired channel of pico UEs, the second scheme, named as optimal desired sub-channel selected IA (ODC-IA) scheme, aligns the inter picocell interference onto a certain sub-space of the cross-tier interference, which guarantees the largest channel gain of the desired signal of pico UEs. The third IA scheme, named as maximum cross-tier interference selected IA (MI-IA) scheme, is designed for the system with less receive antennas. The inter picocell interference is aligned onto the space of the strongest cross-tier interference and only the interference on this space is nullified. The complexity analysis and simulations show that the proposed transceiver design schemes outperform the existing IA schemes in the OSG mode of HetNets, and the MI-IA scheme reduces the requirement of the receive antennas number with lower complexity.

A Minimum Interference Channel Assignment Algorithm for Performance Improvement of Large-Scale Wireless Mesh Networks (대규모 무선 메쉬 네트워크의 성능 향상을 위한 최소 간섭 채널 할당 알고리즘)

  • Ryu, Min-Woo;Cha, Si-Ho;Cho, Kuk-Hyun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.10B
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    • pp.964-972
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    • 2009
  • Wireless mesh network (WMN) is emerging a future core technology to resolve many problems derived from exist wireless networks by employing multi-interface and multi-channel. Ability to utilize multiple channels in WMNs substantially increases the effective bandwidth available to wireless network nodes. However, minimum interference channel assignment algorithms are required to use the effective bandwidth in multi-channel environments. This paper proposes a cluster-based minimum interference channel assignment (MI-CA) algorithm to improve the performance of WMN. The MI-CA algorithm is consists of Inter-Cluster and Intra-Cluster Intrchannel assignment between clusters and in the internal clusters, respectively. The Inter-Cluster channel assignment assigns a barebone channel to cluster heads and border nodes based on minimum spanning tree (MST) and the Intra-Cluster channel assignment minimizes channel interference by reassigning ortasgonal channels between cluster mespann. Our simheation results show that MI-CA can improve the performance of WMNs by minimizing channel interference.

The study for inter-cell interference reduction techniques in portable internet networks. (휴대인터넷의 셀간 간섭 제거에 관한 연구)

  • Park, Chi-Ho;Hwan, Oh-Young
    • Proceedings of the IEEK Conference
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    • pp.229-230
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    • 2006
  • In this thesis, we analyze performance related to reduction scheme of inter-cell interference causing serious problems in portable internet system. Frequency reusing factor(FUF) is 1 in portable internet system, and it means that a adjacent cell uses same frequency band. This channel environment raises inter-cell interference problem, which provokes serious problems related to system performance and channel capacity. Consequently, it affects deterioration in system performance as a whole. We analyze inter-cell interference when appling a various schemes such as (DCA)Dynamic Channel Allocation, CS(Channel Segregation), IDMA(Interleave Division Multiple Access), FH-OFDM, CRSA(Conceptual Random Subcarrier Allocation), and HDD

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A Channel Assignment Technique for OFDMA-based Wireless Mesh Network with Different Time Delays (서로 다른 지연 시간을 갖는 OFDMA 기반 Wireless Mesh Network에서의 채널 할당 기법)

  • Yoo, Hyun-Il;Park, Chang-Hwan;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.6A
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    • pp.568-576
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    • 2011
  • In this paper, a channel assignment technique to mitigate interferences due to ISI(Inter Symbol Interference) and ICI(Inter Carrier Interference) caused by TDoA(Time Difference of Arrival) among distributed MRs(Mesh Routers) in OFDMA(Orthogonal Frequency Division Multiple Access)-based WMN(Wireless Mesh Network) is proposed. The SINR(Signal to Interference and Noise Ratio) associated with the channel assignment for each MR is defined to minimize the effect of ISI and ICI due to TDoA in WMN, which is then used to propose an channel assignment technique considering fairness constraint. It is verified by computer simulation that the proposed channel assignment technique can improve the performance of BER(Bit Error Rate) in WMNs with compared to the conventional technique.

Channel Allocation Scheme considering Inter-Link Interference for Cognitive Radio Networks (인지무선통신에서 링크 간 간섭을 고려한 채널할당기법)

  • Kwon, Young-Min;Park, Hyung-Kun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.6
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    • pp.1080-1082
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    • 2016
  • In a multi-hop CR (Cognitive Radio) network, each node find a path to destination node through several links. If links have the same frequency channel, there can be a serious interference among the links and it can reduce the network capacity. In multi-channel CR networks, each channel has different capacity according to the inter-link interference, and each channel has different traffic properties of primary users. In this paper, we propose channel scheduling scheme to minimize channel interferences and collision with primary users. Simulation results show the improvement of channel capacity and collision rate with primary users.

A Rake receiver for CCK wireless LAN modem based on Channel Matched Filter (CCK 무선랜 모뎀을 위한 Channel Matched Filter 기반의 RAKE 수신기)

  • Lee Yusung;Park Hyuncheol
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.5C
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    • pp.329-337
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    • 2005
  • In this paper, we propose a new type of RAKE receiver for complementary code keying (CCK) codes, which is suitable for the multipath channel with large delay spread. Our proposed system is based on channel matched filter (CMF) with decision feedback equalizer (DFE) and contains codeword DFE structure. In our system, inter chip interference (ICI) and inter symbol interference (ISI) generated due to multipath environments are calculated by using detected CCK codeword. Also it uses the error correcting capability of CCK codes, and it can remove ISI and ICI at the same time.

Low Pilot Ratio Channel Estimation for OFDM Systems Based on GCE-BEM

  • Wang, Lidong;Lim, Dong-Min
    • Journal of electromagnetic engineering and science
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    • v.7 no.4
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    • pp.195-200
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    • 2007
  • Doubly-selective channel estimator for orthogonal frequency division multiplexing(OFDM) systems is proposed in this paper. Based on the generalized complex exponential basis expansion model(GCE-BEM), we describe the time-variant channel with time-invariant coefficients over multiple OFDM blocks. The time variation of the channel destroys the orthogonality between subcarriers, and the resulting channel matrix in the frequency domain is no longer diagonal, but the main interference comes from the near subcarriers. Based on this, we propose a channel estimator with low pilot ratio. We first develop a least-square(LS) estimator under the assumption that only the maximum Doppler frequency and the channel order are known at the receiver, and then verify that the correlation matrix of inter-channel interference(ICI) is a scaled identity matrix based on which we derive an optimal pilot insertion scheme for the LS estimator in the sense of minimum mean square error. The proposed estimator has the advantages of low pilot ratio and robustness against inter-carrier interference.