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Relay Selection with Network Coding in Two-Way Relay Channels  [PDF]
Yonghui Li,Raymond H. Y. Louie,Branka Vucetic
Mathematics , 2010,
Abstract: In this paper, we consider the design of joint network coding (NC)and relay selection (RS) in two-way relay channels. In the proposed schemes, two users first sequentially broadcast their respective information to all the relays. We propose two RS schemes, a single relay selection with NC and a dual relay selection with NC. For both schemes, the selected relay(s) perform NC on the received signals sent from the two users and forward them to both users. The proposed schemes are analyzed and the exact bit error rate (BER) expressions are derived and verified through Monte Carlo simulations. It is shown that the dual relay selection with NC outperforms other considered relay selection schemes in two-way relay channels. The results also reveal that the proposed NC relay selection schemes provide a selection gain compared to a NC scheme with no relay selection, and a network coding gain relative to a conventional relay selection scheme with no NC.
Joint Relay Selection and Analog Network Coding using Differential Modulation in Two-Way Relay Channels  [PDF]
Lingyang Song,Hong Guo,Bingli Jiao,Merouane Debbah
Mathematics , 2011,
Abstract: In this paper, we consider a general bi-directional relay network with two sources and N relays when neither the source nodes nor the relays know the channel state information (CSI). A joint relay selection and analog network coding using differential modulation (RS-ANC-DM) is proposed. In the proposed scheme, the two sources employ differential modulations and transmit the differential modulated symbols to all relays at the same time. The signals received at the relay is a superposition of two transmitted symbols, which we call the analog network coded symbols. Then a single relay which has minimum sum SER is selected out of N relays to forward the ANC signals to both sources. To facilitate the selection process, in this paper we also propose a simple sub-optimal Min-Max criterion for relay selection, where a single relay which minimizes the maximum SER of two source nodes is selected. Simulation results show that the proposed Min-Max selection has almost the same performance as the optimal selection, but is much simpler. The performance of the proposed RS-ANC-DM scheme is analyzed, and a simple asymptotic SER expression is derived. The analytical results are verified through simulations.
Relay Selection For Multiple Access Relay Channel With Decode-forward And Analog Network Coding
Ahmed Hassan M. Hassan,Bin Dai,Benxiong Huang,Edriss Eisa
International Journal of Distributed and Parallel Systems , 2012,
Abstract: This paper presents a relay selection for decode-and-forward based on network coding (DF-NC) and analog-NC protocols in general scheme of cellular network system. In the propose scheme the two source node simultaneously transmit their own information to all the relays as well as the destination node, and then, a single relay i.e. best with a minimum symbol error rate (SER) will be selected to forward the new version of the received signal. Simulation results show that, the DF-NC scheme with considerable performance has exactness over analog-NC scheme. To improve the system performance, optimal power allocation between the two sources and the best relay is determined based on the asymptotic SER. By increasing the number of relays node, the optimum power allocation achieve better performance than asymptotic SER.
Relay selection for multiple access relay channel with decode-forward and analog network coding  [PDF]
Ahmed Hassan M. Hassan,Bin Dai,Benxiong Huang,Edriss Eisa,Muhammad Azhar
Mathematics , 2012, DOI: 10.5121/ijdps.2012.3201
Abstract: This paper presents a relay selection for decode-and-forward based on network coding (DF-NC) and analog-NC protocols in general scheme of cellular network system. In the propose scheme the two source node simultaneously transmit their own information to all the relays as well as the destination node, and then, a single relay i.e. best with a minimum symbol error rate (SER) will be selected to forward the new version of the received signal. Simulation results show that, the DF-NC scheme with considerable performance has exactness over analog-NC scheme. To improve the system performance, optimal power allocation between the two sources and the best relay is determined based on the asymptotic SER. By increasing the number of relays node, the optimum power allocation achieve better performance than asymptotic SER.
Generalized Instantly Decodable Network Coding for Relay-Assisted Networks  [PDF]
Adel M. Elmahdy,Sameh Sorour,Karim G. Seddik
Computer Science , 2013,
Abstract: In this paper, we investigate the problem of minimizing the frame completion delay for Instantly Decodable Network Coding (IDNC) in relay-assisted wireless multicast networks. We first propose a packet recovery algorithm in the single relay topology which employs generalized IDNC instead of strict IDNC previously proposed in the literature for the same relay-assisted topology. This use of generalized IDNC is supported by showing that it is a super-set of the strict IDNC scheme, and thus can generate coding combinations that are at least as efficient as strict IDNC in reducing the average completion delay. We then extend our study to the multiple relay topology and propose a joint generalized IDNC and relay selection algorithm. This proposed algorithm benefits from the reception diversity of the multiple relays to further reduce the average completion delay in the network. Simulation results show that our proposed solutions achieve much better performance compared to previous solutions in the literature.
Bi-Directional Multi-Antenna Relay Communications with Wireless Network Coding  [PDF]
Chau Yuen,Woon Hau Chin,Yong Liang Guan,Wenhua Chen,Taoyi Tee
Mathematics , 2008,
Abstract: In this paper, we consider a two-way or bidirectional communications system with a relay equipped with multiple antennas. We show that when the downlink channel state information is not known at the relay, the benefit of having additional antennas at the relay can only be obtained by using decode and forward (DF) but not amplify and forward (AF). The gain becomes significant when we employ transmit diversity together with wireless network coding. We also demonstrate how the performance of such system can be improved by performing antenna selection at the relay. Our results show that if downlink channel state information is known at the relay, network coding may not provide additional gain than simple antenna selection scheme.
Power-Efficient Relay Selection in Cooperative Networks Using Decentralized Distributed Space-Time Block Coding  [cached]
Lu Zhang,Leonard J. Cimini
EURASIP Journal on Advances in Signal Processing , 2007, DOI: 10.1155/2008/362809
Abstract: Distributed space-time block coding (Dis-STBC) achieves diversity through cooperative transmission among geographically dispersed nodes. In this paper, we present a power-efficient relay-selection strategy for decentralized Dis-STBC in a selective decode-and-forward cooperative network. In particular, for a two-stage network, each decoded node broadcasts a small amount of information with limited power. This node then utilizes its own and its neighbors' information to decide whether or not to act as a relay for the source information. In this way, only part of the decoded set will act as relays. Further, by applying the idea of this relay-selection strategy to each relaying hop in a multihop network, a power-efficient hop-by-hop routing strategy is formulated. The outage analyses and simulations are presented to illustrate the advantage of these strategies.
Capacity Enhancement in Hybrid Wireless Relay Network with Network Coding  [cached]
Hsin-Yu Chao,Chun-Yen Huang,Fan-Min Tseng,Hung-Yu Wei
Journal of Communications , 2009, DOI: 10.4304/jcm.4.11.841-848
Abstract: Network coding technique increases wireless network communication efficiency. Wireless multihop relay network has been shown to achieve capacity gain over conventional single-hop wireless networks. Hybrid wireless relay networks integrate multihop ad hoc relay and infrastructure base stations to achieve better wireless network performance. Applying the promising network coding technique to hybrid wireless relay networks could increase wireless network capacity. Capacity of multihop cellular network with network coding is derived. To enhance network throughput, data forwarding strategy is proposed to determine if a packet should be transmitted through intra-cell ad hoc relay, inter-cell ad hoc relay, or infrastructure-assisted inter-cell transmission.
Using Network Coding to Achieve the Capacity of Deterministic Relay Networks with Relay Messages  [PDF]
Ahmed A. Zewail,Yahya Mohasseb,Mohammed Nafie,Hesham El Gamal
Mathematics , 2014,
Abstract: In this paper, we derive the capacity of the deterministic relay networks with relay messages. We consider a network which consists of five nodes, four of which can only communicate via the fifth one. However, the fifth node is not merely a relay as it may exchange private messages with the other network nodes. First, we develop an upper bound on the capacity region based on the notion of a single sided genie. In the course of the achievability proof, we also derive the deterministic capacity of a 4-user relay network (without private messages at the relay). The capacity achieving schemes use a combination of two network coding techniques: the Simple Ordering Scheme (SOS) and Detour Schemes (DS). In the SOS, we order the transmitted bits at each user such that the bi-directional messages will be received at the same channel level at the relay, while the basic idea behind the DS is that some parts of the message follow an indirect path to their respective destinations. This paper, therefore, serves to show that user cooperation and network coding can enhance throughput, even when the users are not directly connected to each other.
Capacity Bounds and Lattice Coding for the Star Relay Network  [PDF]
Hamidreza Ebrahimzadeh Saffar,Patrick Mitran
Mathematics , 2010,
Abstract: A half-duplex wireless network with 6 lateral nodes, 3 transmitters and 3 receivers, and a central relay is considered. The transmitters wish to send information to their corresponding receivers via a two phase communication protocol. The receivers decode their desired messages by using side information and the signals received from the relay. We derive an outer bound on the capacity region of any two phase protocol as well as 3 achievable regions by employing different relaying strategies. In particular, we combine physical and network layer coding to take advantage of the interference at the relay, using, for example, lattice-based codes. We then specialize our results to the exchange rate. It is shown that for any snr, we can achieve within 0.5 bit of the upper bound by lattice coding and within 0.34 bit, if we take the best of the 3 strategies. Also, for high snr, lattice coding is within log(3)/4 ~ 0.4 bit of the upper bound.
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