사용자 이동성을 고려한 Decode-and-Forward기반 셀룰러 릴레이 네트워크의 트래픽 전송용량 분석

이기동 에스케이텔레콤 (주) 2008 Telecommunications Review Vol.18 No.2

본 논문은 decode-and-forward기법을 사용하는 셀룰러 릴레이 네트워크의 outage비율을 기준으로 둔 경우의 트래픽 전송용량분석을 다룬다. 기존의 단일 홉 셀룰러 네트워크의 트래픽 용량분석은 Erlang손실공식에 따른 접근방법을 통해 이루어지는 성향을 보였다. 그러나, OFDMA를 사용하는 경우와 릴레이를 사용하는 경우의 트래픽 용량분석은 기존의 방식으로 분석이 어려운 점을 지니고 있다. 두 개의 통신 노드들간의 거리 등에 따른 채널게인의 변화가 트래픽 용량에 주는 영향, 노드 다이버시티 (node cooperation diversity)가 트래픽 용량에 주는 영향 등을 들 수 있다. 본 논문에서는, 통신 노드들이 이동하는 경우, 그 거리의 변화가 랜덤하므로 노드 다이버시티를 활용하는 OFDMA 셀룰러 릴레이 네트워크가 갖는 트래픽 전송용량분석에 대한 새로운 접근 방법이 이용되었다. 소스 노드와 릴레이 노드의 전송전력의 변화, 목표 비트오류율의 변화, 요구 데이터 전송률의 변화가 트래픽 용량에 미치는 영향이 분석되었다.

Diversity Analysis of MIMO Decode-and-Forward Relay Network by Using Near-ML Decoder

JIN, Xianglan,JIN, Dong-Sup,NO, Jong-Seon,SHIN, Dong-Joon The Institute of Electronics, Information and Comm 2011 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.eb94 No.10

<P>The probability of making mistakes on the decoded signals at the relay has been used for the maximum-likelihood (ML) decision at the receiver in the decode-and-forward (DF) relay network. It is well known that deriving the probability is relatively easy for the uncoded single-antenna transmission with <I>M</I>-pulse amplitude modulation (PAM). However, in the multiplexing multiple-input multiple-output (MIMO) transmission, the multi-dimensional decision region is getting too complicated to derive the probability. In this paper, a high-performance near-ML decoder is devised by applying a well-known pairwise error probability (PEP) of two paired-signals at the relay in the MIMO DF relay network. It also proves that the near-ML decoder can achieve the maximum diversity of <I>M<SUB>S</SUB>M<SUB>D</SUB></I>+<I>M<SUB>R</SUB></I> min(<I>M<SUB>S</SUB></I>,<I>M<SUB>D</SUB></I>), where <I>M<SUB>S</SUB></I>, <I>M<SUB>R</SUB></I>, and<I>M<SUB>D</SUB></I> are the number of antennas at the source, relay, and destination, respectively. The simulation results show that 1) the near-ML decoder achieves the diversity we derived and 2) the bit error probability of the near-ML decoder is almost the same as that of the ML decoder.</P>

Decode-and-Forward 협력 릴레이 통신에서의 Balanced 전송 기법

조수범 ( Soobum Cho ),박상규 ( Sang Kyu Park ) 한국인터넷정보학회 2011 인터넷정보학회논문지 Vol.12 No.6

무선 네트워크를 위한 협력 릴레이 통신은 공간 다이버시티를 통해 페이딩현상을 효율적으로 감소 시킬 수 있기 때문에 최근 활발히 연구되어 오고 있다. 본 논문에서 협력 릴레이 통신환경에서 decode-and-forward 기법을 적용한 balanced 전송기법을 제안한다. 제안된 기법은 최고의 협력 다이버시티 이득을 얻기 위해 피드백 비트들을 선택한다. 제안된 기법은 기존의 기법과 비교하여 비트 오류 확률 성능을 증가시킬 수 있는 것을 모의 실험을 통해 증명하였다. Cooperative relay communication for wireless networks has been extensively studied due to its ability to mitigate fading effectively via spatial diversity. In this paper, we propose a balanced transmit scheme in cooperative relay communication with decode-and-forward (DF) scheme. The proposed scheme selects the feedback bits to obtain the maximum cooperative diversity gain. The simulation results show that the proposed scheme improves the bit error rate (BER) performance as compare with a conventional scheme.

Maximum Diversity Achieving Decoders in MIMO Decode-and-Forward Relay Systems with Partial CSI

Jin, Xianglan,Kum, Eun-Ji,Lim, Dae-Woon The Korea Institute of Information and Commucation 2014 Journal of communications and networks Vol.16 No.1

We consider multiple-input multiple-output decode-and-forward relay systems in Rayleigh fading channels under the partial channel state information (CSI) that the channel statistics of the source-relay (SR) link and the instantaneous CSI of the source-destination and relay-destination links are known at the destination. In this paper, we propose a new near maximum likelihood (near-ML) decoder with two-level pairwise error probability (near-ML-2PEP) which uses the average PEP instead of the exact PEP. Then, we theoretically prove that the near-ML and near-ML-2PEP decoders achieve the maximum diversity, which is confirmed by Monte Carlo simulations. Moreover, we show that the near-ML-2PEP decoder can also achieve the maximum diversity by substituting the average PEP with the values that represent the error performance of the SR link.

Naïve Decode-and-Forward Relay Achieves Optimal DMT for Cooperative Underwater Communication

Shin, Won-Yong,Yi, Hyoseok The Korea Institute of Information and Commucation 2013 Journal of information and communication convergen Vol.11 No.4

Diversity-multiplexing tradeoff (DMT) characterizes the fundamental relationship between the diversity gain in terms of outage probability and the multiplexing gain as the normalized rate parameter r, where the limiting transmission rate is give by rlog SNR (here, SNR denote the received signal-to-noise ratio). In this paper, we analyze the DMT and performance of an underwater network with a cooperative relay. Since over an acoustic channel, the propagation delay is commonly considerably higher than the processing delay, the existing transmission protocols need to be explained accordingly. For this underwater network, we briefly describe two well-known relay transmissions: decode-and-forward (DF) and amplify-and-forward (AF). As our main result, we then show that an instantaneous DF relay scheme achieves the same DMT curve as that of multiple-input single-output channels and thus guarantees the DMT optimality, while using an instantaneous AF relay leads at most only to the DMT for the direct transmission with no cooperation. To validate our analysis, computer simulations are performed in terms of outage probability.

Opportunistic Decode-and-Forward Cooperation in Mixed Rayleigh and Rician Fading Channels

Changqing Yang,Wenbo Wang,Shuang Zhao,Mugen Peng 한국전자통신연구원 2011 ETRI Journal Vol.33 No.2

We consider a two-hop multiple-relay network implemented with opportunistic decode-and-forward cooperative strategy, where the first hop and second hop links experience different fading (Rayleigh and Rician). We derive the exact expressions of end-to-end outage probability and analyze the approximate results in high signal-to-noise ratio region. The analysis shows that the same diversity order can be achieved even in different mixed fading environments. Simulation results are provided to verify our analysis.

The Performance of Multistage Cooperation in Relay Networks

Kanchan Vardhe,Daryl Reynolds 한국통신학회 2015 Journal of communications and networks Vol.17 No.5

We analyze the performance of multistage cooperation in decode-and-forward relay networks where the transmission between source and destination takes place in T ≥ 2 equal duration and orthogonal time phases with the help of relays. The source transmits only in the first time phase. All relays that can decode the source’s transmission forward the source’s message to the destination in the second time phase, using a space-time code. During subsequent time phases, the relays that have successfully decoded the source message using information from all previous transmitting relays, transmit the space-time coded symbols for the source’s message. The non-decoding relays keep accumulating information and transmit in the later stages when they are able to decode. This process continues for T cooperation phases. We develop and analyze the outage probability of multistage cooperation protocol under orthogonal relaying. Through analytical results, we obtain the near-optimal placement strategy for relays that gives the best performance when compared with most other candidate relay location strategies of interest. For different relay network topologies, we also investigate an interesting tradeoff between an increased SNR and decreased spectral efficiency as the number of cooperation stages is increased. It is also shown that the largest multistage cooperation gain is obtained in the low and moderate SNR regime.

Performance Analysis of Hybrid Decode-Amplify-Forward Incremental Relaying Cooperative Diversity Protocol Using SNR-Based Relay Selection

Tran, Trung Duy,Kong, Hyung-Yun The Korea Institute of Information and Commucation 2012 Journal of communications and networks Vol.14 No.6

In this paper, we propose a hybrid decode-amplify-forward incremental cooperative diversity protocol using SNR-based relay selection. In the proposed protocol, whenever destination unsuccessfully receives the source's signal, one of relays that exploit hybrid decode-amplify-forward technique is chosen to retransmit the signal. We derive approximate closed-form expressions of outage probability and average channel capacity. Monte-Carlo simulations are presented to verify the theoretical results and compare the performance of the proposed protocol with the direct transmission protocol and conventional incremental relaying protocols.

단일 노드에서 다중 안테나를 사용하는 HD DDF Relay 프로토콜에 대한 DMT 분석

임창호(Changho Yim),김태영(Taeyoung Kim),윤은철(Eunchul Yoon) 한국통신학회 2013 韓國通信學會論文誌 Vol.38 No.5C

소스 노드, 목적지 노드, 릴레이 노드 중 하나의 노드에서 다중 안테나를 사용하는 특별한 세 가지 경우의 half-duplex (HD) dynamic decode and forward (DDF) 릴레이 프로토콜들에 대한 diversity multiplexing tradeoff (DMT) 함수를 유도하였다. 이 세 가지 릴레이 프로토콜들의 DMT 함수들을 상호 비교하였으며 nonorthogonal amplify-and-forward (NAF) 프로토콜들의 DMT 함수와 비교하였다. The diversity-multiplexing tradeoff (DMT) functions of three special half-duplex (HD) dynamic decode-and-forward (DDF) protocols with multiple antennas only at the source node, only at the destination node, and only at the relay node are analytically derived. The DMT functions of these three relay protocols are compared with one another and with those of the nonorthogonal amplify and forward (NAF) protocols.

BER Analysis of Multi-Hop Decode-and-Forward Relaying with Generalized Selection Combining

BAO, Vo-Nguyen Quoc,KONG, Hyung-Yun The Institute of Electronics, Information and Comm 2010 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.93 No.7

<P>Generalized selection combining (GSC) was recently proposed as a low-complexity diversity combining technique for diversity-rich environments. This letter proposes a multi-hop Decode-and-Forward Relaying (MDFR) scheme in conjunction with GSC and describes its performance in terms of average bit error probability. We have shown that the proposed protocol offers a remarkable diversity advantage over direct transmission as well as the conventional decode-and-forward relaying (CDFR) scheme. Simulation results are also given to verify the analytical results.</P>